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* [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements.
@ 2014-12-08 14:09 Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 1/7] ARM: probes: move all probe code to dedicate directory Wang Nan
                   ` (6 more replies)
  0 siblings, 7 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

This is v15 patch series of kprobeopt related code. V14 uses
stop_machine() incorrectly, this version fixes it.

Previous discussion can be found from:

https://lkml.org/lkml/2014/12/8/21
https://lkml.org/lkml/2014/12/4/942
https://lkml.org/lkml/2014/12/4/4
https://lkml.org/lkml/2014/12/1/64
https://lkml.org/lkml/2014/11/22/18
https://lkml.org/lkml/2014/11/21/55
https://lkml.org/lkml/2014/11/18/26
https://lkml.org/lkml/2014/11/19/31
https://lkml.org/lkml/2014/11/18/41
https://lkml.org/lkml/2014/10/25/48
https://lkml.org/lkml/2014/10/22/254
https://lkml.org/lkml/2014/8/27/255
https://lkml.org/lkml/2014/8/12/12
https://lkml.org/lkml/2014/8/8/992
https://lkml.org/lkml/2014/8/8/5
https://lkml.org/lkml/2014/8/5/63

Jon Medhurst (1):
  ARM: kprobes: Add test cases for stack consuming instructions

Masami Hiramatsu (1):
  kprobes: Pass the original kprobe for preparing optimized kprobe

Wang Nan (5):
  ARM: probes: move all probe code to dedicate directory
  ARM: kprobes: introduces checker
  ARM: kprobes: collects stack consumption for store instructions
  ARM: kprobes: disallow probing stack consuming instructions
  ARM: kprobes: enable OPTPROBES for ARM 32

 arch/arm/Kconfig                                   |   1 +
 arch/arm/Makefile                                  |   1 +
 arch/arm/{kernel => include/asm}/insn.h            |   0
 arch/arm/include/asm/kprobes.h                     |  30 +-
 arch/arm/{kernel => include/asm}/patch.h           |   0
 arch/arm/include/asm/probes.h                      |  13 +
 arch/arm/kernel/Makefile                           |  16 +-
 arch/arm/kernel/entry-armv.S                       |   3 +-
 arch/arm/kernel/ftrace.c                           |   3 +-
 arch/arm/kernel/jump_label.c                       |   5 +-
 arch/arm/kernel/patch.c                            |   3 +-
 arch/arm/probes/Makefile                           |   7 +
 .../{kernel/probes-arm.c => probes/decode-arm.c}   |  12 +-
 .../{kernel/probes-arm.h => probes/decode-arm.h}   |   7 +-
 .../probes-thumb.c => probes/decode-thumb.c}       |  16 +-
 .../probes-thumb.h => probes/decode-thumb.h}       |  10 +-
 arch/arm/{kernel/probes.c => probes/decode.c}      |  74 ++++-
 arch/arm/{kernel/probes.h => probes/decode.h}      |  13 +-
 arch/arm/probes/kprobes/Makefile                   |  12 +
 .../kprobes-arm.c => probes/kprobes/actions-arm.c} |   9 +-
 .../kprobes/actions-common.c}                      |   4 +-
 .../kprobes/actions-thumb.c}                       |  10 +-
 arch/arm/probes/kprobes/checkers-arm.c             |  99 +++++++
 arch/arm/probes/kprobes/checkers-common.c          | 101 +++++++
 arch/arm/probes/kprobes/checkers-thumb.c           | 110 +++++++
 arch/arm/probes/kprobes/checkers.h                 |  54 ++++
 .../{kernel/kprobes.c => probes/kprobes/core.c}    |  49 +++-
 .../{kernel/kprobes.h => probes/kprobes/core.h}    |  12 +-
 arch/arm/probes/kprobes/opt-arm.c                  | 317 +++++++++++++++++++++
 .../kprobes/test-arm.c}                            |  31 +-
 .../kprobes-test.c => probes/kprobes/test-core.c}  |   8 +-
 .../kprobes-test.h => probes/kprobes/test-core.h}  |   2 +-
 .../kprobes/test-thumb.c}                          |  16 +-
 arch/arm/probes/uprobes/Makefile                   |   2 +
 .../uprobes-arm.c => probes/uprobes/actions-arm.c} |   6 +-
 .../{kernel/uprobes.c => probes/uprobes/core.c}    |   8 +-
 .../{kernel/uprobes.h => probes/uprobes/core.h}    |   0
 arch/x86/kernel/kprobes/opt.c                      |   3 +-
 include/linux/kprobes.h                            |   3 +-
 kernel/kprobes.c                                   |   4 +-
 40 files changed, 976 insertions(+), 98 deletions(-)
 rename arch/arm/{kernel => include/asm}/insn.h (100%)
 rename arch/arm/{kernel => include/asm}/patch.h (100%)
 create mode 100644 arch/arm/probes/Makefile
 rename arch/arm/{kernel/probes-arm.c => probes/decode-arm.c} (99%)
 rename arch/arm/{kernel/probes-arm.h => probes/decode-arm.h} (93%)
 rename arch/arm/{kernel/probes-thumb.c => probes/decode-thumb.c} (98%)
 rename arch/arm/{kernel/probes-thumb.h => probes/decode-thumb.h} (90%)
 rename arch/arm/{kernel/probes.c => probes/decode.c} (85%)
 rename arch/arm/{kernel/probes.h => probes/decode.h} (97%)
 create mode 100644 arch/arm/probes/kprobes/Makefile
 rename arch/arm/{kernel/kprobes-arm.c => probes/kprobes/actions-arm.c} (98%)
 rename arch/arm/{kernel/kprobes-common.c => probes/kprobes/actions-common.c} (98%)
 rename arch/arm/{kernel/kprobes-thumb.c => probes/kprobes/actions-thumb.c} (98%)
 create mode 100644 arch/arm/probes/kprobes/checkers-arm.c
 create mode 100644 arch/arm/probes/kprobes/checkers-common.c
 create mode 100644 arch/arm/probes/kprobes/checkers-thumb.c
 create mode 100644 arch/arm/probes/kprobes/checkers.h
 rename arch/arm/{kernel/kprobes.c => probes/kprobes/core.c} (94%)
 rename arch/arm/{kernel/kprobes.h => probes/kprobes/core.h} (79%)
 create mode 100644 arch/arm/probes/kprobes/opt-arm.c
 rename arch/arm/{kernel/kprobes-test-arm.c => probes/kprobes/test-arm.c} (97%)
 rename arch/arm/{kernel/kprobes-test.c => probes/kprobes/test-core.c} (99%)
 rename arch/arm/{kernel/kprobes-test.h => probes/kprobes/test-core.h} (99%)
 rename arch/arm/{kernel/kprobes-test-thumb.c => probes/kprobes/test-thumb.c} (98%)
 create mode 100644 arch/arm/probes/uprobes/Makefile
 rename arch/arm/{kernel/uprobes-arm.c => probes/uprobes/actions-arm.c} (98%)
 rename arch/arm/{kernel/uprobes.c => probes/uprobes/core.c} (97%)
 rename arch/arm/{kernel/uprobes.h => probes/uprobes/core.h} (100%)

-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 1/7] ARM: probes: move all probe code to dedicate directory
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 2/7] ARM: kprobes: introduces checker Wang Nan
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

In discussion on LKML (https://lkml.org/lkml/2014/11/28/158), Russell
King suggests to move all probe related code to arch/arm/probes. This
patch does the work. Due to dependency on 'arch/arm/kernel/patch.h', this
patch also moves patch.h to 'arch/arm/include/asm/patch.h', and related
'#include' directives are also midified to '#include <asm/patch.h>'.

Following is an overview of this patch:

 ./arch/arm/kernel/               ./arch/arm/probes/
 |-- Makefile                     |-- Makefile
 |-- probes-arm.c          ==>    |-- decode-arm.c
 |-- probes-arm.h          ==>    |-- decode-arm.h
 |-- probes-thumb.c        ==>    |-- decode-thumb.c
 |-- probes-thumb.h        ==>    |-- decode-thumb.h
 |-- probes.c              ==>    |-- decode.c
 |-- probes.h              ==>    |-- decode.h
 |                                |-- kprobes
 |                                |   |-- Makefile
 |-- kprobes-arm.c         ==>    |   |-- actions-arm.c
 |-- kprobes-common.c      ==>    |   |-- actions-common.c
 |-- kprobes-thumb.c       ==>    |   |-- actions-thumb.c
 |-- kprobes.c             ==>    |   |-- core.c
 |-- kprobes.h             ==>    |   |-- core.h
 |-- kprobes-test-arm.c    ==>    |   |-- test-arm.c
 |-- kprobes-test.c        ==>    |   |-- test-core.c
 |-- kprobes-test.h        ==>    |   |-- test-core.h
 |-- kprobes-test-thumb.c  ==>    |   `-- test-thumb.c
 |                                `-- uprobes
 |                                    |-- Makefile
 |-- uprobes-arm.c         ==>        |-- actions-arm.c
 |-- uprobes.c             ==>        |-- core.c
 |-- uprobes.h             ==>        `-- core.h
 |
 `-- patch.h               ==>    arch/arm/include/asm/patch.h

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
v1 -> v2:
 - Rename source files to describe their functions.
 - Add Makefiles in kprobes and uprobes directories.
---
 arch/arm/Makefile                                        |  1 +
 arch/arm/{kernel => include/asm}/patch.h                 |  0
 arch/arm/kernel/Makefile                                 | 16 ++--------------
 arch/arm/kernel/jump_label.c                             |  2 +-
 arch/arm/kernel/patch.c                                  |  3 +--
 arch/arm/probes/Makefile                                 |  7 +++++++
 arch/arm/{kernel/probes-arm.c => probes/decode-arm.c}    |  7 ++++---
 arch/arm/{kernel/probes-arm.h => probes/decode-arm.h}    |  4 +++-
 .../arm/{kernel/probes-thumb.c => probes/decode-thumb.c} |  6 +++---
 .../arm/{kernel/probes-thumb.h => probes/decode-thumb.h} |  4 +++-
 arch/arm/{kernel/probes.c => probes/decode.c}            |  4 ++--
 arch/arm/{kernel/probes.h => probes/decode.h}            |  2 +-
 arch/arm/probes/kprobes/Makefile                         | 11 +++++++++++
 .../kprobes-arm.c => probes/kprobes/actions-arm.c}       |  6 +++---
 .../kprobes-common.c => probes/kprobes/actions-common.c} |  4 ++--
 .../kprobes-thumb.c => probes/kprobes/actions-thumb.c}   |  6 +++---
 arch/arm/{kernel/kprobes.c => probes/kprobes/core.c}     |  8 ++++----
 arch/arm/{kernel/kprobes.h => probes/kprobes/core.h}     |  3 ++-
 .../kprobes-test-arm.c => probes/kprobes/test-arm.c}     |  2 +-
 .../kprobes-test.c => probes/kprobes/test-core.c}        |  8 ++++----
 .../kprobes-test.h => probes/kprobes/test-core.h}        |  2 +-
 .../kprobes-test-thumb.c => probes/kprobes/test-thumb.c} |  4 ++--
 arch/arm/probes/uprobes/Makefile                         |  2 ++
 .../uprobes-arm.c => probes/uprobes/actions-arm.c}       |  6 +++---
 arch/arm/{kernel/uprobes.c => probes/uprobes/core.c}     |  6 +++---
 arch/arm/{kernel/uprobes.h => probes/uprobes/core.h}     |  0
 26 files changed, 69 insertions(+), 55 deletions(-)
 rename arch/arm/{kernel => include/asm}/patch.h (100%)
 create mode 100644 arch/arm/probes/Makefile
 rename arch/arm/{kernel/probes-arm.c => probes/decode-arm.c} (99%)
 rename arch/arm/{kernel/probes-arm.h => probes/decode-arm.h} (97%)
 rename arch/arm/{kernel/probes-thumb.c => probes/decode-thumb.c} (99%)
 rename arch/arm/{kernel/probes-thumb.h => probes/decode-thumb.h} (97%)
 rename arch/arm/{kernel/probes.c => probes/decode.c} (99%)
 rename arch/arm/{kernel/probes.h => probes/decode.h} (99%)
 create mode 100644 arch/arm/probes/kprobes/Makefile
 rename arch/arm/{kernel/kprobes-arm.c => probes/kprobes/actions-arm.c} (99%)
 rename arch/arm/{kernel/kprobes-common.c => probes/kprobes/actions-common.c} (98%)
 rename arch/arm/{kernel/kprobes-thumb.c => probes/kprobes/actions-thumb.c} (99%)
 rename arch/arm/{kernel/kprobes.c => probes/kprobes/core.c} (99%)
 rename arch/arm/{kernel/kprobes.h => probes/kprobes/core.h} (96%)
 rename arch/arm/{kernel/kprobes-test-arm.c => probes/kprobes/test-arm.c} (99%)
 rename arch/arm/{kernel/kprobes-test.c => probes/kprobes/test-core.c} (99%)
 rename arch/arm/{kernel/kprobes-test.h => probes/kprobes/test-core.h} (99%)
 rename arch/arm/{kernel/kprobes-test-thumb.c => probes/kprobes/test-thumb.c} (99%)
 create mode 100644 arch/arm/probes/uprobes/Makefile
 rename arch/arm/{kernel/uprobes-arm.c => probes/uprobes/actions-arm.c} (98%)
 rename arch/arm/{kernel/uprobes.c => probes/uprobes/core.c} (98%)
 rename arch/arm/{kernel/uprobes.h => probes/uprobes/core.h} (100%)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 034a949..a57d9bb 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -266,6 +266,7 @@ core-$(CONFIG_KVM_ARM_HOST) 	+= arch/arm/kvm/
 
 # If we have a machine-specific directory, then include it in the build.
 core-y				+= arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
+core-y				+= arch/arm/probes/
 core-y				+= arch/arm/net/
 core-y				+= arch/arm/crypto/
 core-y				+= arch/arm/firmware/
diff --git a/arch/arm/kernel/patch.h b/arch/arm/include/asm/patch.h
similarity index 100%
rename from arch/arm/kernel/patch.h
rename to arch/arm/include/asm/patch.h
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 38ddd9f..40d3e00 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -51,20 +51,8 @@ obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o insn.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
-obj-$(CONFIG_UPROBES)		+= probes.o probes-arm.o uprobes.o uprobes-arm.o
-obj-$(CONFIG_KPROBES)		+= probes.o kprobes.o kprobes-common.o patch.o
-ifdef CONFIG_THUMB2_KERNEL
-obj-$(CONFIG_KPROBES)		+= kprobes-thumb.o probes-thumb.o
-else
-obj-$(CONFIG_KPROBES)		+= kprobes-arm.o probes-arm.o
-endif
-obj-$(CONFIG_ARM_KPROBES_TEST)	+= test-kprobes.o
-test-kprobes-objs		:= kprobes-test.o
-ifdef CONFIG_THUMB2_KERNEL
-test-kprobes-objs		+= kprobes-test-thumb.o
-else
-test-kprobes-objs		+= kprobes-test-arm.o
-endif
+# Main staffs in KPROBES are in arch/arm/probes/ .
+obj-$(CONFIG_KPROBES)		+= patch.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index 4ce4f78..c6c73ed 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c
@@ -1,8 +1,8 @@
 #include <linux/kernel.h>
 #include <linux/jump_label.h>
+#include <asm/patch.h>
 
 #include "insn.h"
-#include "patch.h"
 
 #ifdef HAVE_JUMP_LABEL
 
diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
index 07314af..08bcfa1 100644
--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -5,8 +5,7 @@
 #include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include <asm/opcodes.h>
-
-#include "patch.h"
+#include <asm/patch.h>
 
 struct patch {
 	void *addr;
diff --git a/arch/arm/probes/Makefile b/arch/arm/probes/Makefile
new file mode 100644
index 0000000..aa1f859
--- /dev/null
+++ b/arch/arm/probes/Makefile
@@ -0,0 +1,7 @@
+obj-$(CONFIG_UPROBES)		+= decode.o decode-arm.o uprobes/
+obj-$(CONFIG_KPROBES)		+= decode.o kprobes/
+ifdef CONFIG_THUMB2_KERNEL
+obj-$(CONFIG_KPROBES)		+= decode-thumb.o
+else
+obj-$(CONFIG_KPROBES)		+= decode-arm.o
+endif
diff --git a/arch/arm/kernel/probes-arm.c b/arch/arm/probes/decode-arm.c
similarity index 99%
rename from arch/arm/kernel/probes-arm.c
rename to arch/arm/probes/decode-arm.c
index 8eaef81..e39cc75 100644
--- a/arch/arm/kernel/probes-arm.c
+++ b/arch/arm/probes/decode-arm.c
@@ -1,5 +1,6 @@
 /*
- * arch/arm/kernel/probes-arm.c
+ *
+ * arch/arm/probes/decode-arm.c
  *
  * Some code moved here from arch/arm/kernel/kprobes-arm.c
  *
@@ -20,8 +21,8 @@
 #include <linux/stddef.h>
 #include <linux/ptrace.h>
 
-#include "probes.h"
-#include "probes-arm.h"
+#include "decode.h"
+#include "decode-arm.h"
 
 #define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
 
diff --git a/arch/arm/kernel/probes-arm.h b/arch/arm/probes/decode-arm.h
similarity index 97%
rename from arch/arm/kernel/probes-arm.h
rename to arch/arm/probes/decode-arm.h
index ace6572..9c56b40 100644
--- a/arch/arm/kernel/probes-arm.h
+++ b/arch/arm/probes/decode-arm.h
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/probes-arm.h
+ * arch/arm/probes/decode-arm.h
  *
  * Copyright 2013 Linaro Ltd.
  * Written by: David A. Long
@@ -15,6 +15,8 @@
 #ifndef _ARM_KERNEL_PROBES_ARM_H
 #define  _ARM_KERNEL_PROBES_ARM_H
 
+#include "decode.h"
+
 enum probes_arm_action {
 	PROBES_EMULATE_NONE,
 	PROBES_SIMULATE_NOP,
diff --git a/arch/arm/kernel/probes-thumb.c b/arch/arm/probes/decode-thumb.c
similarity index 99%
rename from arch/arm/kernel/probes-thumb.c
rename to arch/arm/probes/decode-thumb.c
index 4131351..2f0453a 100644
--- a/arch/arm/kernel/probes-thumb.c
+++ b/arch/arm/probes/decode-thumb.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/probes-thumb.c
+ * arch/arm/probes/decode-thumb.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
@@ -12,8 +12,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 
-#include "probes.h"
-#include "probes-thumb.h"
+#include "decode.h"
+#include "decode-thumb.h"
 
 
 static const union decode_item t32_table_1110_100x_x0xx[] = {
diff --git a/arch/arm/kernel/probes-thumb.h b/arch/arm/probes/decode-thumb.h
similarity index 97%
rename from arch/arm/kernel/probes-thumb.h
rename to arch/arm/probes/decode-thumb.h
index 7c6f6eb..039013c 100644
--- a/arch/arm/kernel/probes-thumb.h
+++ b/arch/arm/probes/decode-thumb.h
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/probes-thumb.h
+ * arch/arm/probes/decode-thumb.h
  *
  * Copyright 2013 Linaro Ltd.
  * Written by: David A. Long
@@ -15,6 +15,8 @@
 #ifndef _ARM_KERNEL_PROBES_THUMB_H
 #define  _ARM_KERNEL_PROBES_THUMB_H
 
+#include "decode.h"
+
 /*
  * True if current instruction is in an IT block.
  */
diff --git a/arch/arm/kernel/probes.c b/arch/arm/probes/decode.c
similarity index 99%
rename from arch/arm/kernel/probes.c
rename to arch/arm/probes/decode.c
index a8ab540..3b05d57 100644
--- a/arch/arm/kernel/probes.c
+++ b/arch/arm/probes/decode.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/probes.c
+ * arch/arm/probes/decode.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
@@ -17,7 +17,7 @@
 #include <asm/ptrace.h>
 #include <linux/bug.h>
 
-#include "probes.h"
+#include "decode.h"
 
 
 #ifndef find_str_pc_offset
diff --git a/arch/arm/kernel/probes.h b/arch/arm/probes/decode.h
similarity index 99%
rename from arch/arm/kernel/probes.h
rename to arch/arm/probes/decode.h
index dba9f24..1d0b531 100644
--- a/arch/arm/kernel/probes.h
+++ b/arch/arm/probes/decode.h
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/probes.h
+ * arch/arm/probes/decode.h
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
new file mode 100644
index 0000000..eb38a42
--- /dev/null
+++ b/arch/arm/probes/kprobes/Makefile
@@ -0,0 +1,11 @@
+obj-$(CONFIG_KPROBES)		+= core.o actions-common.o
+obj-$(CONFIG_ARM_KPROBES_TEST)	+= test-kprobes.o
+test-kprobes-objs		:= test-core.o
+
+ifdef CONFIG_THUMB2_KERNEL
+obj-$(CONFIG_KPROBES)		+= actions-thumb.o
+test-kprobes-objs		+= test-thumb.o
+else
+obj-$(CONFIG_KPROBES)		+= actions-arm.o
+test-kprobes-objs		+= test-arm.o
+endif
diff --git a/arch/arm/kernel/kprobes-arm.c b/arch/arm/probes/kprobes/actions-arm.c
similarity index 99%
rename from arch/arm/kernel/kprobes-arm.c
rename to arch/arm/probes/kprobes/actions-arm.c
index ac300c6..8797879 100644
--- a/arch/arm/kernel/kprobes-arm.c
+++ b/arch/arm/probes/kprobes/actions-arm.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/kprobes-decode.c
+ * arch/arm/probes/kprobes/actions-arm.c
  *
  * Copyright (C) 2006, 2007 Motorola Inc.
  *
@@ -62,8 +62,8 @@
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
 
-#include "kprobes.h"
-#include "probes-arm.h"
+#include "../decode-arm.h"
+#include "core.h"
 
 #if  __LINUX_ARM_ARCH__ >= 6
 #define BLX(reg)	"blx	"reg"		\n\t"
diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/probes/kprobes/actions-common.c
similarity index 98%
rename from arch/arm/kernel/kprobes-common.c
rename to arch/arm/probes/kprobes/actions-common.c
index 0bf5d64..bd20a71 100644
--- a/arch/arm/kernel/kprobes-common.c
+++ b/arch/arm/probes/kprobes/actions-common.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/kprobes-common.c
+ * arch/arm/probes/kprobes/actions-common.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
@@ -15,7 +15,7 @@
 #include <linux/kprobes.h>
 #include <asm/opcodes.h>
 
-#include "kprobes.h"
+#include "core.h"
 
 
 static void __kprobes simulate_ldm1stm1(probes_opcode_t insn,
diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/probes/kprobes/actions-thumb.c
similarity index 99%
rename from arch/arm/kernel/kprobes-thumb.c
rename to arch/arm/probes/kprobes/actions-thumb.c
index 9495d7f..6c4e60b 100644
--- a/arch/arm/kernel/kprobes-thumb.c
+++ b/arch/arm/probes/kprobes/actions-thumb.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/kprobes-thumb.c
+ * arch/arm/probes/kprobes/actions-thumb.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
@@ -13,8 +13,8 @@
 #include <linux/ptrace.h>
 #include <linux/kprobes.h>
 
-#include "kprobes.h"
-#include "probes-thumb.h"
+#include "../decode-thumb.h"
+#include "core.h"
 
 /* These emulation encodings are functionally equivalent... */
 #define t32_emulate_rd8rn16rm0ra12_noflags \
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/probes/kprobes/core.c
similarity index 99%
rename from arch/arm/kernel/kprobes.c
rename to arch/arm/probes/kprobes/core.c
index 6d64420..701f49d 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -30,11 +30,11 @@
 #include <asm/cacheflush.h>
 #include <linux/percpu.h>
 #include <linux/bug.h>
+#include <asm/patch.h>
 
-#include "kprobes.h"
-#include "probes-arm.h"
-#include "probes-thumb.h"
-#include "patch.h"
+#include "../decode-arm.h"
+#include "../decode-thumb.h"
+#include "core.h"
 
 #define MIN_STACK_SIZE(addr) 				\
 	min((unsigned long)MAX_STACK_SIZE,		\
diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/probes/kprobes/core.h
similarity index 96%
rename from arch/arm/kernel/kprobes.h
rename to arch/arm/probes/kprobes/core.h
index 9a2712e..2e1e5a3 100644
--- a/arch/arm/kernel/kprobes.h
+++ b/arch/arm/probes/kprobes/core.h
@@ -19,7 +19,8 @@
 #ifndef _ARM_KERNEL_KPROBES_H
 #define _ARM_KERNEL_KPROBES_H
 
-#include "probes.h"
+#include <asm/kprobes.h>
+#include "../decode.h"
 
 /*
  * These undefined instructions must be unique and
diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/probes/kprobes/test-arm.c
similarity index 99%
rename from arch/arm/kernel/kprobes-test-arm.c
rename to arch/arm/probes/kprobes/test-arm.c
index cb14242..d9a1255 100644
--- a/arch/arm/kernel/kprobes-test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -13,7 +13,7 @@
 #include <asm/system_info.h>
 #include <asm/opcodes.h>
 
-#include "kprobes-test.h"
+#include "test-core.h"
 
 
 #define TEST_ISA "32"
diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/probes/kprobes/test-core.c
similarity index 99%
rename from arch/arm/kernel/kprobes-test.c
rename to arch/arm/probes/kprobes/test-core.c
index b206d77..7ab633d 100644
--- a/arch/arm/kernel/kprobes-test.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -209,10 +209,10 @@
 #include <linux/bug.h>
 #include <asm/opcodes.h>
 
-#include "kprobes.h"
-#include "probes-arm.h"
-#include "probes-thumb.h"
-#include "kprobes-test.h"
+#include "core.h"
+#include "test-core.h"
+#include "../decode-arm.h"
+#include "../decode-thumb.h"
 
 
 #define BENCHMARKING	1
diff --git a/arch/arm/kernel/kprobes-test.h b/arch/arm/probes/kprobes/test-core.h
similarity index 99%
rename from arch/arm/kernel/kprobes-test.h
rename to arch/arm/probes/kprobes/test-core.h
index 4430990..9991754 100644
--- a/arch/arm/kernel/kprobes-test.h
+++ b/arch/arm/probes/kprobes/test-core.h
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/kprobes-test.h
+ * arch/arm/probes/kprobes/test-core.h
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
diff --git a/arch/arm/kernel/kprobes-test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
similarity index 99%
rename from arch/arm/kernel/kprobes-test-thumb.c
rename to arch/arm/probes/kprobes/test-thumb.c
index 844dd10..6c6e9a9 100644
--- a/arch/arm/kernel/kprobes-test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -1,5 +1,5 @@
 /*
- * arch/arm/kernel/kprobes-test-thumb.c
+ * arch/arm/probes/kprobes/test-thumb.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
@@ -12,7 +12,7 @@
 #include <linux/module.h>
 #include <asm/opcodes.h>
 
-#include "kprobes-test.h"
+#include "test-core.h"
 
 
 #define TEST_ISA "16"
diff --git a/arch/arm/probes/uprobes/Makefile b/arch/arm/probes/uprobes/Makefile
new file mode 100644
index 0000000..6c4c735
--- /dev/null
+++ b/arch/arm/probes/uprobes/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_UPROBES)		+= core.o actions-arm.o
+
diff --git a/arch/arm/kernel/uprobes-arm.c b/arch/arm/probes/uprobes/actions-arm.c
similarity index 98%
rename from arch/arm/kernel/uprobes-arm.c
rename to arch/arm/probes/uprobes/actions-arm.c
index d3b655f..1dd4916 100644
--- a/arch/arm/kernel/uprobes-arm.c
+++ b/arch/arm/probes/uprobes/actions-arm.c
@@ -13,9 +13,9 @@
 #include <linux/uprobes.h>
 #include <linux/module.h>
 
-#include "probes.h"
-#include "probes-arm.h"
-#include "uprobes.h"
+#include "../decode.h"
+#include "../decode-arm.h"
+#include "core.h"
 
 static int uprobes_substitute_pc(unsigned long *pinsn, u32 oregs)
 {
diff --git a/arch/arm/kernel/uprobes.c b/arch/arm/probes/uprobes/core.c
similarity index 98%
rename from arch/arm/kernel/uprobes.c
rename to arch/arm/probes/uprobes/core.c
index 56adf9c..b2954f6 100644
--- a/arch/arm/kernel/uprobes.c
+++ b/arch/arm/probes/uprobes/core.c
@@ -17,9 +17,9 @@
 #include <asm/opcodes.h>
 #include <asm/traps.h>
 
-#include "probes.h"
-#include "probes-arm.h"
-#include "uprobes.h"
+#include "../decode.h"
+#include "../decode-arm.h"
+#include "core.h"
 
 #define UPROBE_TRAP_NR	UINT_MAX
 
diff --git a/arch/arm/kernel/uprobes.h b/arch/arm/probes/uprobes/core.h
similarity index 100%
rename from arch/arm/kernel/uprobes.h
rename to arch/arm/probes/uprobes/core.h
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 2/7] ARM: kprobes: introduces checker
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 1/7] ARM: probes: move all probe code to dedicate directory Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 3/7] ARM: kprobes: collects stack consumption for store instructions Wang Nan
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

This patch introdces 'checker' to decoding phase, and calls checkers
when instruction decoding. This allows further decoding for specific
instructions.  This patch introduces a stub call of checkers in kprobe
arch_prepare_kprobe() as an example and for further expansion.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
v1 -> v2:
 - kprobe checker stubs are introduced in this patch.

v2 -> v3:
 - Code cleanups following Masami Hiramatsu and Tixy's advises.
 - Commit message improvements.

v3 -> v4:
 - Move to arch/arm/probes.
---
 arch/arm/probes/decode-arm.c            |  5 +--
 arch/arm/probes/decode-arm.h            |  3 +-
 arch/arm/probes/decode-thumb.c          | 10 +++---
 arch/arm/probes/decode-thumb.h          |  6 ++--
 arch/arm/probes/decode.c                | 60 +++++++++++++++++++++++++++++----
 arch/arm/probes/decode.h                | 11 +++++-
 arch/arm/probes/kprobes/actions-arm.c   |  2 ++
 arch/arm/probes/kprobes/actions-thumb.c |  3 ++
 arch/arm/probes/kprobes/core.c          |  6 +++-
 arch/arm/probes/kprobes/core.h          |  7 ++--
 arch/arm/probes/uprobes/core.c          |  2 +-
 11 files changed, 95 insertions(+), 20 deletions(-)

diff --git a/arch/arm/probes/decode-arm.c b/arch/arm/probes/decode-arm.c
index e39cc75..f46d8fc 100644
--- a/arch/arm/probes/decode-arm.c
+++ b/arch/arm/probes/decode-arm.c
@@ -726,10 +726,11 @@ static void __kprobes arm_singlestep(probes_opcode_t insn,
  */
 enum probes_insn __kprobes
 arm_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
-		       bool emulate, const union decode_action *actions)
+		       bool emulate, const union decode_action *actions,
+		       const struct decode_checker *checkers[])
 {
 	asi->insn_singlestep = arm_singlestep;
 	asi->insn_check_cc = probes_condition_checks[insn>>28];
 	return probes_decode_insn(insn, asi, probes_decode_arm_table, false,
-				  emulate, actions);
+				  emulate, actions, checkers);
 }
diff --git a/arch/arm/probes/decode-arm.h b/arch/arm/probes/decode-arm.h
index 9c56b40..a7b0398 100644
--- a/arch/arm/probes/decode-arm.h
+++ b/arch/arm/probes/decode-arm.h
@@ -70,6 +70,7 @@ extern const union decode_item probes_decode_arm_table[];
 
 enum probes_insn arm_probes_decode_insn(probes_opcode_t,
 		struct arch_probes_insn *, bool emulate,
-		const union decode_action *actions);
+		const union decode_action *actions,
+		const struct decode_checker *checkers[]);
 
 #endif
diff --git a/arch/arm/probes/decode-thumb.c b/arch/arm/probes/decode-thumb.c
index 2f0453a..985e7dd 100644
--- a/arch/arm/probes/decode-thumb.c
+++ b/arch/arm/probes/decode-thumb.c
@@ -863,20 +863,22 @@ static void __kprobes thumb32_singlestep(probes_opcode_t opcode,
 
 enum probes_insn __kprobes
 thumb16_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
-			   bool emulate, const union decode_action *actions)
+			   bool emulate, const union decode_action *actions,
+			   const struct decode_checker *checkers[])
 {
 	asi->insn_singlestep = thumb16_singlestep;
 	asi->insn_check_cc = thumb_check_cc;
 	return probes_decode_insn(insn, asi, probes_decode_thumb16_table, true,
-				  emulate, actions);
+				  emulate, actions, checkers);
 }
 
 enum probes_insn __kprobes
 thumb32_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
-			   bool emulate, const union decode_action *actions)
+			   bool emulate, const union decode_action *actions,
+			   const struct decode_checker *checkers[])
 {
 	asi->insn_singlestep = thumb32_singlestep;
 	asi->insn_check_cc = thumb_check_cc;
 	return probes_decode_insn(insn, asi, probes_decode_thumb32_table, true,
-				  emulate, actions);
+				  emulate, actions, checkers);
 }
diff --git a/arch/arm/probes/decode-thumb.h b/arch/arm/probes/decode-thumb.h
index 039013c..8457add 100644
--- a/arch/arm/probes/decode-thumb.h
+++ b/arch/arm/probes/decode-thumb.h
@@ -91,9 +91,11 @@ extern const union decode_item probes_decode_thumb16_table[];
 
 enum probes_insn __kprobes
 thumb16_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
-		bool emulate, const union decode_action *actions);
+		bool emulate, const union decode_action *actions,
+		const struct decode_checker *checkers[]);
 enum probes_insn __kprobes
 thumb32_probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
-		bool emulate, const union decode_action *actions);
+		bool emulate, const union decode_action *actions,
+		const struct decode_checker *checkers[]);
 
 #endif
diff --git a/arch/arm/probes/decode.c b/arch/arm/probes/decode.c
index 3b05d57..c7d4420 100644
--- a/arch/arm/probes/decode.c
+++ b/arch/arm/probes/decode.c
@@ -342,6 +342,31 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 	[DECODE_TYPE_REJECT]	= sizeof(struct decode_reject)
 };
 
+static int run_checkers(const struct decode_checker *checkers[],
+		int action, probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	const struct decode_checker **p;
+
+	if (!checkers)
+		return INSN_GOOD;
+
+	p = checkers;
+	while (*p != NULL) {
+		int retval;
+		probes_check_t *checker_func = (*p)[action].checker;
+
+		retval = INSN_GOOD;
+		if (checker_func)
+			retval = checker_func(insn, asi, h);
+		if (retval == INSN_REJECTED)
+			return retval;
+		p++;
+	}
+	return INSN_GOOD;
+}
+
 /*
  * probes_decode_insn operates on data tables in order to decode an ARM
  * architecture instruction onto which a kprobe has been placed.
@@ -388,11 +413,17 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 int __kprobes
 probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 		   const union decode_item *table, bool thumb,
-		   bool emulate, const union decode_action *actions)
+		   bool emulate, const union decode_action *actions,
+		   const struct decode_checker *checkers[])
 {
 	const struct decode_header *h = (struct decode_header *)table;
 	const struct decode_header *next;
 	bool matched = false;
+	/*
+	 * @insn can be modified by decode_regs. Save its original
+	 * value for checkers.
+	 */
+	probes_opcode_t origin_insn = insn;
 
 	if (emulate)
 		insn = prepare_emulated_insn(insn, asi, thumb);
@@ -422,24 +453,41 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 		}
 
 		case DECODE_TYPE_CUSTOM: {
+			int err;
 			struct decode_custom *d = (struct decode_custom *)h;
-			return actions[d->decoder.action].decoder(insn, asi, h);
+			int action = d->decoder.action;
+
+			err = run_checkers(checkers, action, origin_insn, asi, h);
+			if (err == INSN_REJECTED)
+				return INSN_REJECTED;
+			return actions[action].decoder(insn, asi, h);
 		}
 
 		case DECODE_TYPE_SIMULATE: {
+			int err;
 			struct decode_simulate *d = (struct decode_simulate *)h;
-			asi->insn_handler = actions[d->handler.action].handler;
+			int action = d->handler.action;
+
+			err = run_checkers(checkers, action, origin_insn, asi, h);
+			if (err == INSN_REJECTED)
+				return INSN_REJECTED;
+			asi->insn_handler = actions[action].handler;
 			return INSN_GOOD_NO_SLOT;
 		}
 
 		case DECODE_TYPE_EMULATE: {
+			int err;
 			struct decode_emulate *d = (struct decode_emulate *)h;
+			int action = d->handler.action;
+
+			err = run_checkers(checkers, action, origin_insn, asi, h);
+			if (err == INSN_REJECTED)
+				return INSN_REJECTED;
 
 			if (!emulate)
-				return actions[d->handler.action].decoder(insn,
-					asi, h);
+				return actions[action].decoder(insn, asi, h);
 
-			asi->insn_handler = actions[d->handler.action].handler;
+			asi->insn_handler = actions[action].handler;
 			set_emulated_insn(insn, asi, thumb);
 			return INSN_GOOD;
 		}
diff --git a/arch/arm/probes/decode.h b/arch/arm/probes/decode.h
index 1d0b531..f9b08ba 100644
--- a/arch/arm/probes/decode.h
+++ b/arch/arm/probes/decode.h
@@ -314,6 +314,14 @@ union decode_action {
 	probes_custom_decode_t	*decoder;
 };
 
+typedef enum probes_insn (probes_check_t)(probes_opcode_t,
+					   struct arch_probes_insn *,
+					   const struct decode_header *);
+
+struct decode_checker {
+	probes_check_t	*checker;
+};
+
 #define DECODE_END			\
 	{.bits = DECODE_TYPE_END}
 
@@ -402,6 +410,7 @@ probes_insn_handler_t probes_emulate_none;
 int __kprobes
 probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const union decode_item *table, bool thumb, bool emulate,
-		const union decode_action *actions);
+		const union decode_action *actions,
+		const struct decode_checker **checkers);
 
 #endif
diff --git a/arch/arm/probes/kprobes/actions-arm.c b/arch/arm/probes/kprobes/actions-arm.c
index 8797879..3c3afa4 100644
--- a/arch/arm/probes/kprobes/actions-arm.c
+++ b/arch/arm/probes/kprobes/actions-arm.c
@@ -341,3 +341,5 @@ const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = {
 	[PROBES_BRANCH] = {.handler = simulate_bbl},
 	[PROBES_LDMSTM] = {.decoder = kprobe_decode_ldmstm}
 };
+
+const struct decode_checker *kprobes_arm_checkers[] = {NULL};
diff --git a/arch/arm/probes/kprobes/actions-thumb.c b/arch/arm/probes/kprobes/actions-thumb.c
index 6c4e60b..2796121 100644
--- a/arch/arm/probes/kprobes/actions-thumb.c
+++ b/arch/arm/probes/kprobes/actions-thumb.c
@@ -664,3 +664,6 @@ const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
 	[PROBES_T32_MUL_ADD_LONG] = {
 		.handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
 };
+
+const struct decode_checker *kprobes_t32_checkers[] = {NULL};
+const struct decode_checker *kprobes_t16_checkers[] = {NULL};
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 701f49d..74f3dc3 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -61,6 +61,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	kprobe_decode_insn_t *decode_insn;
 	const union decode_action *actions;
 	int is;
+	const struct decode_checker **checkers;
 
 	if (in_exception_text(addr))
 		return -EINVAL;
@@ -74,9 +75,11 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 		insn = __opcode_thumb32_compose(insn, inst2);
 		decode_insn = thumb32_probes_decode_insn;
 		actions = kprobes_t32_actions;
+		checkers = kprobes_t32_checkers;
 	} else {
 		decode_insn = thumb16_probes_decode_insn;
 		actions = kprobes_t16_actions;
+		checkers = kprobes_t16_checkers;
 	}
 #else /* !CONFIG_THUMB2_KERNEL */
 	thumb = false;
@@ -85,12 +88,13 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	insn = __mem_to_opcode_arm(*p->addr);
 	decode_insn = arm_probes_decode_insn;
 	actions = kprobes_arm_actions;
+	checkers = kprobes_arm_checkers;
 #endif
 
 	p->opcode = insn;
 	p->ainsn.insn = tmp_insn;
 
-	switch ((*decode_insn)(insn, &p->ainsn, true, actions)) {
+	switch ((*decode_insn)(insn, &p->ainsn, true, actions, checkers)) {
 	case INSN_REJECTED:	/* not supported */
 		return -EINVAL;
 
diff --git a/arch/arm/probes/kprobes/core.h b/arch/arm/probes/kprobes/core.h
index 2e1e5a3..f88c79f 100644
--- a/arch/arm/probes/kprobes/core.h
+++ b/arch/arm/probes/kprobes/core.h
@@ -37,16 +37,19 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_probes_insn *asi,
 typedef enum probes_insn (kprobe_decode_insn_t)(probes_opcode_t,
 						struct arch_probes_insn *,
 						bool,
-						const union decode_action *);
+						const union decode_action *,
+						const struct decode_checker *[*]);
 
 #ifdef CONFIG_THUMB2_KERNEL
 
 extern const union decode_action kprobes_t32_actions[];
 extern const union decode_action kprobes_t16_actions[];
-
+extern const struct decode_checker *kprobes_t32_checkers[];
+extern const struct decode_checker *kprobes_t16_checkers[];
 #else /* !CONFIG_THUMB2_KERNEL */
 
 extern const union decode_action kprobes_arm_actions[];
+extern const struct decode_checker *kprobes_arm_checkers[];
 
 #endif
 
diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c
index b2954f6..d1329f1 100644
--- a/arch/arm/probes/uprobes/core.c
+++ b/arch/arm/probes/uprobes/core.c
@@ -88,7 +88,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN);
 
 	ret = arm_probes_decode_insn(insn, &auprobe->asi, false,
-				     uprobes_probes_actions);
+				     uprobes_probes_actions, NULL);
 	switch (ret) {
 	case INSN_REJECTED:
 		return -EINVAL;
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 3/7] ARM: kprobes: collects stack consumption for store instructions
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 1/7] ARM: probes: move all probe code to dedicate directory Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 2/7] ARM: kprobes: introduces checker Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 4/7] ARM: kprobes: disallow probing stack consuming instructions Wang Nan
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

This patch uses the previously introduced checker functionality on
store instructions to record their stack consumption information to
arch_probes_insn.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
---
v1 -> v2:
 - Bugfix and code improvements following Tixy's suggestion. See:
    http://www.spinics.net/lists/arm-kernel/msg372912.html

v2 -> v3:
 - Totaly reconstructed following Tixy' instruction. See:
   https://lkml.org/lkml/2014/10/27/662 .
   Add his SOB.

v3 -> v4:
 - Commit message improvements.
 - Comments improvements and code cleanup.
 - A bug is found and fixed in decode table in arm_check_stack().

v4 -> v5:
 - Bugs in thumb2 decoding table is found by Tixy and fixed.

v5 -> v6:
 - Move to arch/arm/probes/ .
---
 arch/arm/include/asm/probes.h             |   1 +
 arch/arm/probes/decode.c                  |  10 +++
 arch/arm/probes/kprobes/Makefile          |   6 +-
 arch/arm/probes/kprobes/actions-arm.c     |   3 +-
 arch/arm/probes/kprobes/actions-thumb.c   |   5 +-
 arch/arm/probes/kprobes/checkers-arm.c    |  99 +++++++++++++++++++++++++++
 arch/arm/probes/kprobes/checkers-common.c | 101 +++++++++++++++++++++++++++
 arch/arm/probes/kprobes/checkers-thumb.c  | 110 ++++++++++++++++++++++++++++++
 arch/arm/probes/kprobes/checkers.h        |  54 +++++++++++++++
 9 files changed, 383 insertions(+), 6 deletions(-)
 create mode 100644 arch/arm/probes/kprobes/checkers-arm.c
 create mode 100644 arch/arm/probes/kprobes/checkers-common.c
 create mode 100644 arch/arm/probes/kprobes/checkers-thumb.c
 create mode 100644 arch/arm/probes/kprobes/checkers.h

diff --git a/arch/arm/include/asm/probes.h b/arch/arm/include/asm/probes.h
index 806cfe6..ccf9af3 100644
--- a/arch/arm/include/asm/probes.h
+++ b/arch/arm/include/asm/probes.h
@@ -38,6 +38,7 @@ struct arch_probes_insn {
 	probes_check_cc			*insn_check_cc;
 	probes_insn_singlestep_t	*insn_singlestep;
 	probes_insn_fn_t		*insn_fn;
+	int stack_space;
 };
 
 #endif
diff --git a/arch/arm/probes/decode.c b/arch/arm/probes/decode.c
index c7d4420..f9d7c42 100644
--- a/arch/arm/probes/decode.c
+++ b/arch/arm/probes/decode.c
@@ -425,6 +425,16 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
 	 */
 	probes_opcode_t origin_insn = insn;
 
+	/*
+	 * stack_space is initialized to 0 here. Checker functions
+	 * should update is value if they find this is a stack store
+	 * instruction: positive value means bytes of stack usage,
+	 * negitive value means unable to determine stack usage
+	 * statically. For instruction doesn't store to stack, checker
+	 * do nothing with it.
+	 */
+	asi->stack_space = 0;
+
 	if (emulate)
 		insn = prepare_emulated_insn(insn, asi, thumb);
 
diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
index eb38a42..bc8d504 100644
--- a/arch/arm/probes/kprobes/Makefile
+++ b/arch/arm/probes/kprobes/Makefile
@@ -1,11 +1,11 @@
-obj-$(CONFIG_KPROBES)		+= core.o actions-common.o
+obj-$(CONFIG_KPROBES)		+= core.o actions-common.o checkers-common.o
 obj-$(CONFIG_ARM_KPROBES_TEST)	+= test-kprobes.o
 test-kprobes-objs		:= test-core.o
 
 ifdef CONFIG_THUMB2_KERNEL
-obj-$(CONFIG_KPROBES)		+= actions-thumb.o
+obj-$(CONFIG_KPROBES)		+= actions-thumb.o checkers-thumb.o
 test-kprobes-objs		+= test-thumb.o
 else
-obj-$(CONFIG_KPROBES)		+= actions-arm.o
+obj-$(CONFIG_KPROBES)		+= actions-arm.o checkers-arm.o
 test-kprobes-objs		+= test-arm.o
 endif
diff --git a/arch/arm/probes/kprobes/actions-arm.c b/arch/arm/probes/kprobes/actions-arm.c
index 3c3afa4..1e67839 100644
--- a/arch/arm/probes/kprobes/actions-arm.c
+++ b/arch/arm/probes/kprobes/actions-arm.c
@@ -64,6 +64,7 @@
 
 #include "../decode-arm.h"
 #include "core.h"
+#include "checkers.h"
 
 #if  __LINUX_ARM_ARCH__ >= 6
 #define BLX(reg)	"blx	"reg"		\n\t"
@@ -342,4 +343,4 @@ const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = {
 	[PROBES_LDMSTM] = {.decoder = kprobe_decode_ldmstm}
 };
 
-const struct decode_checker *kprobes_arm_checkers[] = {NULL};
+const struct decode_checker *kprobes_arm_checkers[] = {arm_stack_checker, NULL};
diff --git a/arch/arm/probes/kprobes/actions-thumb.c b/arch/arm/probes/kprobes/actions-thumb.c
index 2796121..07cfd9b 100644
--- a/arch/arm/probes/kprobes/actions-thumb.c
+++ b/arch/arm/probes/kprobes/actions-thumb.c
@@ -15,6 +15,7 @@
 
 #include "../decode-thumb.h"
 #include "core.h"
+#include "checkers.h"
 
 /* These emulation encodings are functionally equivalent... */
 #define t32_emulate_rd8rn16rm0ra12_noflags \
@@ -665,5 +666,5 @@ const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
 		.handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
 };
 
-const struct decode_checker *kprobes_t32_checkers[] = {NULL};
-const struct decode_checker *kprobes_t16_checkers[] = {NULL};
+const struct decode_checker *kprobes_t32_checkers[] = {t32_stack_checker, NULL};
+const struct decode_checker *kprobes_t16_checkers[] = {t16_stack_checker, NULL};
diff --git a/arch/arm/probes/kprobes/checkers-arm.c b/arch/arm/probes/kprobes/checkers-arm.c
new file mode 100644
index 0000000..f817663
--- /dev/null
+++ b/arch/arm/probes/kprobes/checkers-arm.c
@@ -0,0 +1,99 @@
+/*
+ * arch/arm/probes/kprobes/checkers-arm.c
+ *
+ * Copyright (C) 2014 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include "../decode.h"
+#include "../decode-arm.h"
+#include "checkers.h"
+
+static enum probes_insn __kprobes arm_check_stack(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	/*
+	 * PROBES_LDRSTRD, PROBES_LDMSTM, PROBES_STORE,
+	 * PROBES_STORE_EXTRA may get here. Simply mark all normal
+	 * insns as STACK_USE_NONE.
+	 */
+	static const union decode_item table[] = {
+		/*
+		 * 'STR{,D,B,H}, Rt, [Rn, Rm]' should be marked as UNKNOWN
+		 * if Rn or Rm is SP.
+		 *                                 x
+		 * STR (register)	cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx
+		 * STRB (register)	cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx
+		 */
+		DECODE_OR	(0x0e10000f, 0x0600000d),
+		DECODE_OR	(0x0e1f0000, 0x060d0000),
+
+		/*
+		 *                                                     x
+		 * STRD (register)	cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx
+		 * STRH (register)	cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx
+		 */
+		DECODE_OR	(0x0e5000bf, 0x000000bd),
+		DECODE_CUSTOM	(0x0e5f00b0, 0x000d00b0, STACK_USE_UNKNOWN),
+
+		/*
+		 * For PROBES_LDMSTM, only stmdx sp, [...] need to examine
+		 *
+		 * Bit B/A (bit 24) encodes arithmetic operation order. 1 means
+		 * before, 0 means after.
+		 * Bit I/D (bit 23) encodes arithmetic operation. 1 means
+		 * increment, 0 means decrement.
+		 *
+		 * So:
+		 *                              B I
+		 *                              / /
+		 *                              A D   | Rn |
+		 * STMDX SP, [...]	cccc 100x 00x0 xxxx xxxx xxxx xxxx xxxx
+		 */
+		DECODE_CUSTOM	(0x0edf0000, 0x080d0000, STACK_USE_STMDX),
+
+		/*                              P U W | Rn | Rt |     imm12    |*/
+		/* STR (immediate)	cccc 010x x0x0 1101 xxxx xxxx xxxx xxxx */
+		/* STRB (immediate)	cccc 010x x1x0 1101 xxxx xxxx xxxx xxxx */
+		/*                              P U W | Rn | Rt |imm4|    |imm4|*/
+		/* STRD (immediate)	cccc 000x x1x0 1101 xxxx xxxx 1111 xxxx */
+		/* STRH (immediate)	cccc 000x x1x0 1101 xxxx xxxx 1011 xxxx */
+		/*
+		 * index = (P == '1'); add = (U == '1').
+		 * Above insns with:
+		 *    index == 0 (str{,d,h} rx, [sp], #+/-imm) or
+		 *    add == 1 (str{,d,h} rx, [sp, #+<imm>])
+		 * should be STACK_USE_NONE.
+		 * Only str{,b,d,h} rx,[sp,#-n] (P == 1 and U == 0) are
+		 * required to be examined.
+		 */
+		/* STR{,B} Rt,[SP,#-n]	cccc 0101 0xx0 1101 xxxx xxxx xxxx xxxx */
+		DECODE_CUSTOM	(0x0f9f0000, 0x050d0000, STACK_USE_FIXED_XXX),
+
+		/* STR{D,H} Rt,[SP,#-n]	cccc 0001 01x0 1101 xxxx xxxx 1x11 xxxx */
+		DECODE_CUSTOM	(0x0fdf00b0, 0x014d00b0, STACK_USE_FIXED_X0X),
+
+		/* fall through */
+		DECODE_CUSTOM	(0, 0, STACK_USE_NONE),
+		DECODE_END
+	};
+
+	return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL);
+}
+
+const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = {
+	[PROBES_LDRSTRD] = {.checker = arm_check_stack},
+	[PROBES_STORE_EXTRA] = {.checker = arm_check_stack},
+	[PROBES_STORE] = {.checker = arm_check_stack},
+	[PROBES_LDMSTM] = {.checker = arm_check_stack},
+};
diff --git a/arch/arm/probes/kprobes/checkers-common.c b/arch/arm/probes/kprobes/checkers-common.c
new file mode 100644
index 0000000..971119c
--- /dev/null
+++ b/arch/arm/probes/kprobes/checkers-common.c
@@ -0,0 +1,101 @@
+/*
+ * arch/arm/probes/kprobes/checkers-common.c
+ *
+ * Copyright (C) 2014 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include "../decode.h"
+#include "../decode-arm.h"
+#include "checkers.h"
+
+enum probes_insn checker_stack_use_none(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	asi->stack_space = 0;
+	return INSN_GOOD_NO_SLOT;
+}
+
+enum probes_insn checker_stack_use_unknown(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	asi->stack_space = -1;
+	return INSN_GOOD_NO_SLOT;
+}
+
+#ifdef CONFIG_THUMB2_KERNEL
+enum probes_insn checker_stack_use_imm_0xx(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	int imm = insn & 0xff;
+	asi->stack_space = imm;
+	return INSN_GOOD_NO_SLOT;
+}
+
+/*
+ * Different from other insn uses imm8, the real addressing offset of
+ * STRD in T32 encoding should be imm8 * 4. See ARMARM description.
+ */
+enum probes_insn checker_stack_use_t32strd(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	int imm = insn & 0xff;
+	asi->stack_space = imm << 2;
+	return INSN_GOOD_NO_SLOT;
+}
+#else
+enum probes_insn checker_stack_use_imm_x0x(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	int imm = ((insn & 0xf00) >> 4) + (insn & 0xf);
+	asi->stack_space = imm;
+	return INSN_GOOD_NO_SLOT;
+}
+#endif
+
+enum probes_insn checker_stack_use_imm_xxx(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	int imm = insn & 0xfff;
+	asi->stack_space = imm;
+	return INSN_GOOD_NO_SLOT;
+}
+
+enum probes_insn checker_stack_use_stmdx(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	unsigned int reglist = insn & 0xffff;
+	int pbit = insn & (1 << 24);
+	asi->stack_space = (hweight32(reglist) - (!pbit ? 1 : 0)) * 4;
+
+	return INSN_GOOD_NO_SLOT;
+}
+
+const union decode_action stack_check_actions[] = {
+	[STACK_USE_NONE] = {.decoder = checker_stack_use_none},
+	[STACK_USE_UNKNOWN] = {.decoder = checker_stack_use_unknown},
+#ifdef CONFIG_THUMB2_KERNEL
+	[STACK_USE_FIXED_0XX] = {.decoder = checker_stack_use_imm_0xx},
+	[STACK_USE_T32STRD] = {.decoder = checker_stack_use_t32strd},
+#else
+	[STACK_USE_FIXED_X0X] = {.decoder = checker_stack_use_imm_x0x},
+#endif
+	[STACK_USE_FIXED_XXX] = {.decoder = checker_stack_use_imm_xxx},
+	[STACK_USE_STMDX] = {.decoder = checker_stack_use_stmdx},
+};
diff --git a/arch/arm/probes/kprobes/checkers-thumb.c b/arch/arm/probes/kprobes/checkers-thumb.c
new file mode 100644
index 0000000..d608e3b
--- /dev/null
+++ b/arch/arm/probes/kprobes/checkers-thumb.c
@@ -0,0 +1,110 @@
+/*
+ * arch/arm/probes/kprobes/checkers-thumb.c
+ *
+ * Copyright (C) 2014 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include "../decode.h"
+#include "../decode-thumb.h"
+#include "checkers.h"
+
+static enum probes_insn __kprobes t32_check_stack(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	/*
+	 * PROBES_T32_LDMSTM, PROBES_T32_LDRDSTRD and PROBES_T32_LDRSTR
+	 * may get here. Simply mark all normal insns as STACK_USE_NONE.
+	 */
+	static const union decode_item table[] = {
+
+		/*
+		 * First, filter out all ldr insns to make our life easier.
+		 * Following load insns may come here:
+		 * LDM, LDRD, LDR.
+		 * In T32 encoding, bit 20 is enough for distinguishing
+		 * load and store. All load insns have this bit set, when
+		 * all store insns have this bit clear.
+		 */
+		DECODE_CUSTOM	(0x00100000, 0x00100000, STACK_USE_NONE),
+
+		/*
+		 * Mark all 'STR{,B,H}, Rt, [Rn, Rm]' as STACK_USE_UNKNOWN
+		 * if Rn or Rm is SP. T32 doesn't encode STRD.
+		 */
+		/*                                 xx | Rn | Rt |         | Rm |*/
+		/* STR (register)	1111 1000 0100 xxxx xxxx 0000 00xx xxxx */
+		/* STRB (register)	1111 1000 0000 xxxx xxxx 0000 00xx xxxx */
+		/* STRH (register)	1111 1000 0010 xxxx xxxx 0000 00xx xxxx */
+		/* INVALID INSN		1111 1000 0110 xxxx xxxx 0000 00xx xxxx */
+		/* By Introducing INVALID INSN, bit 21 and 22 can be ignored. */
+		DECODE_OR	(0xff9f0fc0, 0xf80d0000),
+		DECODE_CUSTOM	(0xff900fcf, 0xf800000d, STACK_USE_UNKNOWN),
+
+
+		/*                                 xx | Rn | Rt | PUW|   imm8  |*/
+		/* STR (imm 8)		1111 1000 0100 1101 xxxx 110x xxxx xxxx */
+		/* STRB (imm 8)		1111 1000 0000 1101 xxxx 110x xxxx xxxx */
+		/* STRH (imm 8)		1111 1000 0010 1101 xxxx 110x xxxx xxxx */
+		/* INVALID INSN		1111 1000 0110 1101 xxxx 110x xxxx xxxx */
+		/* Only consider U == 0 and P == 1: strx rx, [sp, #-<imm>] */
+		DECODE_CUSTOM	(0xff9f0e00, 0xf80d0c00, STACK_USE_FIXED_0XX),
+
+		/* For STR{,B,H} (imm 12), offset is always positive, so ignore them. */
+
+		/*                              P U W | Rn | Rt | Rt2|   imm8  |*/
+		/* STRD (immediate)	1110 1001 01x0 1101 xxxx xxxx xxxx xxxx */
+		/*
+		 * Only consider U == 0 and P == 1.
+		 * Also note that STRD in T32 encoding is special:
+		 * imm = ZeroExtend(imm8:'00', 32)
+		 */
+		DECODE_CUSTOM	(0xffdf0000, 0xe94d0000, STACK_USE_T32STRD),
+
+		/*                                    | Rn | */
+		/* STMDB		1110 1001 00x0 1101 xxxx xxxx xxxx xxxx */
+		DECODE_CUSTOM	(0xffdf0000, 0xe90d0000, STACK_USE_STMDX),
+
+		/* fall through */
+		DECODE_CUSTOM	(0, 0, STACK_USE_NONE),
+		DECODE_END
+	};
+
+	return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL);
+}
+
+const struct decode_checker t32_stack_checker[NUM_PROBES_T32_ACTIONS] = {
+	[PROBES_T32_LDMSTM] = {.checker = t32_check_stack},
+	[PROBES_T32_LDRDSTRD] = {.checker = t32_check_stack},
+	[PROBES_T32_LDRSTR] = {.checker = t32_check_stack},
+};
+
+/*
+ * See following comments. This insn must be 'push'.
+ */
+static enum probes_insn __kprobes t16_check_stack(probes_opcode_t insn,
+		struct arch_probes_insn *asi,
+		const struct decode_header *h)
+{
+	unsigned int reglist = insn & 0x1ff;
+	asi->stack_space = hweight32(reglist) * 4;
+	return INSN_GOOD;
+}
+
+/*
+ * T16 encoding is simple: only the 'push' insn can need extra stack space.
+ * Other insns, like str, can only use r0-r7 as Rn.
+ */
+const struct decode_checker t16_stack_checker[NUM_PROBES_T16_ACTIONS] = {
+	[PROBES_T16_PUSH] = {.checker = t16_check_stack},
+};
diff --git a/arch/arm/probes/kprobes/checkers.h b/arch/arm/probes/kprobes/checkers.h
new file mode 100644
index 0000000..bddfa0e
--- /dev/null
+++ b/arch/arm/probes/kprobes/checkers.h
@@ -0,0 +1,54 @@
+/*
+ * arch/arm/probes/kprobes/checkers.h
+ *
+ * Copyright (C) 2014 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#ifndef _ARM_KERNEL_PROBES_CHECKERS_H
+#define _ARM_KERNEL_PROBES_CHECKERS_H
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include "../decode.h"
+
+extern probes_check_t checker_stack_use_none;
+extern probes_check_t checker_stack_use_unknown;
+#ifdef CONFIG_THUMB2_KERNEL
+extern probes_check_t checker_stack_use_imm_0xx;
+#else
+extern probes_check_t checker_stack_use_imm_x0x;
+#endif
+extern probes_check_t checker_stack_use_imm_xxx;
+extern probes_check_t checker_stack_use_stmdx;
+
+enum {
+	STACK_USE_NONE,
+	STACK_USE_UNKNOWN,
+#ifdef CONFIG_THUMB2_KERNEL
+	STACK_USE_FIXED_0XX,
+	STACK_USE_T32STRD,
+#else
+	STACK_USE_FIXED_X0X,
+#endif
+	STACK_USE_FIXED_XXX,
+	STACK_USE_STMDX,
+	NUM_STACK_USE_TYPES
+};
+
+extern const union decode_action stack_check_actions[];
+
+#ifndef CONFIG_THUMB2_KERNEL
+extern const struct decode_checker arm_stack_checker[];
+#else
+#endif
+extern const struct decode_checker t32_stack_checker[];
+extern const struct decode_checker t16_stack_checker[];
+#endif
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 4/7] ARM: kprobes: disallow probing stack consuming instructions
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
                   ` (2 preceding siblings ...)
  2014-12-08 14:09 ` [RESEND][PATCH v15 3/7] ARM: kprobes: collects stack consumption for store instructions Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 5/7] ARM: kprobes: Add test cases for " Wang Nan
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

This patch prohibits probing instructions for which the stack
requirements are unable to be determined statically. Some test cases
are found not work again after the modification, this patch also
removes them.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
---
v1 -> v2:
 - Use MAX_STACK_SIZE macro instead of hard coded stack size.

v2 -> v3:
 - Commit message improvements.

v3 -> v4:
 - Commit message improvements.

v4 -> v5:
 - Move to arch/arm/probes.
---
 arch/arm/include/asm/kprobes.h     |  1 -
 arch/arm/include/asm/probes.h      | 12 ++++++++++++
 arch/arm/kernel/entry-armv.S       |  3 ++-
 arch/arm/probes/kprobes/core.c     |  9 +++++++++
 arch/arm/probes/kprobes/test-arm.c | 16 ++++++++++------
 5 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index 49fa0df..56f9ac6 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -22,7 +22,6 @@
 
 #define __ARCH_WANT_KPROBES_INSN_SLOT
 #define MAX_INSN_SIZE			2
-#define MAX_STACK_SIZE			64	/* 32 would probably be OK */
 
 #define flush_insn_slot(p)		do { } while (0)
 #define kretprobe_blacklist_size	0
diff --git a/arch/arm/include/asm/probes.h b/arch/arm/include/asm/probes.h
index ccf9af3..f0a1ee8 100644
--- a/arch/arm/include/asm/probes.h
+++ b/arch/arm/include/asm/probes.h
@@ -19,6 +19,8 @@
 #ifndef _ASM_PROBES_H
 #define _ASM_PROBES_H
 
+#ifndef __ASSEMBLY__
+
 typedef u32 probes_opcode_t;
 
 struct arch_probes_insn;
@@ -41,4 +43,14 @@ struct arch_probes_insn {
 	int stack_space;
 };
 
+#endif /* __ASSEMBLY__ */
+
+/*
+ * We assume one instruction can consume at most 64 bytes stack, which is
+ * 'push {r0-r15}'. Instructions consume more or unknown stack space like
+ * 'str r0, [sp, #-80]' and 'str r0, [sp, r1]' should be prohibit to probe.
+ * Both kprobe and jprobe use this macro.
+ */
+#define MAX_STACK_SIZE			64
+
 #endif
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 2f5555d..672b219 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -31,6 +31,7 @@
 
 #include "entry-header.S"
 #include <asm/entry-macro-multi.S>
+#include <asm/probes.h>
 
 /*
  * Interrupt handling.
@@ -249,7 +250,7 @@ __und_svc:
 	@ If a kprobe is about to simulate a "stmdb sp..." instruction,
 	@ it obviously needs free stack space which then will belong to
 	@ the saved context.
-	svc_entry 64
+	svc_entry MAX_STACK_SIZE
 #else
 	svc_entry
 #endif
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 74f3dc3..3a58db4 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -115,6 +115,15 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 		break;
 	}
 
+	/*
+	 * Never instrument insn like 'str r0, [sp, +/-r1]'. Also, insn likes
+	 * 'str r0, [sp, #-68]' should also be prohibited.
+	 * See __und_svc.
+	 */
+	if ((p->ainsn.stack_space < 0) ||
+			(p->ainsn.stack_space > MAX_STACK_SIZE))
+		return -EINVAL;
+
 	return 0;
 }
 
diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
index d9a1255..fdeb300 100644
--- a/arch/arm/probes/kprobes/test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -476,7 +476,8 @@ void kprobe_arm_test_cases(void)
 	TEST_GROUP("Extra load/store instructions")
 
 	TEST_RPR(  "strh	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")
-	TEST_RPR(  "streqh	r",14,VAL2,", [r",13,0, ", r",12, 48,"]")
+	TEST_RPR(  "streqh	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")
+	TEST_UNSUPPORTED(  "streqh	r14, [r13, r12]")
 	TEST_RPR(  "strh	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")
 	TEST_RPR(  "strneh	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strh	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")
@@ -565,7 +566,8 @@ void kprobe_arm_test_cases(void)
 
 #if __LINUX_ARM_ARCH__ >= 5
 	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
-	TEST_RPR(  "strccd	r",8, VAL2,", [r",13,0, ", r",12,48,"]")
+	TEST_RPR(  "strccd	r",8, VAL2,", [r",11,0, ", r",12,48,"]")
+	TEST_UNSUPPORTED(  "strccd r8, [r13, r12]")
 	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
 	TEST_RPR(  "strcsd	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strd	r",2, VAL1,", [r",5, 24,"], r",4,48,"")
@@ -638,13 +640,15 @@ void kprobe_arm_test_cases(void)
 	TEST_RP( "str"byte"	r",2, VAL1,", [r",3, 24,"], #48")		\
 	TEST_RP( "str"byte"	r",10,VAL2,", [r",9, 64,"], #-48")		\
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")	\
-	TEST_RPR("str"byte"	r",14,VAL2,", [r",13,0, ", r",12, 48,"]")	\
+	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")	\
+	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")	\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")	\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")	\
 	TEST_RPR("str"byte"	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")	\
 	TEST_RPR("str"byte"	r",10,VAL2,", [r",9, 48,"], -r",11,24,"")	\
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 24,", r",2,  32,", asl #1]")\
-	TEST_RPR("str"byte"	r",14,VAL2,", [r",13,0, ", r",12, 32,", lsr #2]")\
+	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\
+	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  32,", asr #3]!")\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\
 	TEST_P(  "ldr"byte"	r0, [r",0,  24,", #-2]")			\
@@ -668,12 +672,12 @@ void kprobe_arm_test_cases(void)
 
 	LOAD_STORE("")
 	TEST_P(   "str	pc, [r",0,0,", #15*4]")
-	TEST_R(   "str	pc, [sp, r",2,15*4,"]")
+	TEST_UNSUPPORTED(   "str	pc, [sp, r2]")
 	TEST_BF(  "ldr	pc, [sp, #15*4]")
 	TEST_BF_R("ldr	pc, [sp, r",2,15*4,"]")
 
 	TEST_P(   "str	sp, [r",0,0,", #13*4]")
-	TEST_R(   "str	sp, [sp, r",2,13*4,"]")
+	TEST_UNSUPPORTED(   "str	sp, [sp, r2]")
 	TEST_BF(  "ldr	sp, [sp, #13*4]")
 	TEST_BF_R("ldr	sp, [sp, r",2,13*4,"]")
 
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 5/7] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
                   ` (3 preceding siblings ...)
  2014-12-08 14:09 ` [RESEND][PATCH v15 4/7] ARM: kprobes: disallow probing stack consuming instructions Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-09 16:43   ` [PATCH v2] " Jon Medhurst (Tixy)
  2014-12-08 14:09 ` [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe Wang Nan
  2014-12-08 14:09 ` [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32 Wang Nan
  6 siblings, 1 reply; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

From: Jon Medhurst <tixy@linaro.org>

These have extra 'checker' functions associated with them so
lets make sure those get covered by testing.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
v1 -> v2:
 - Move to arch/arm/probes/ .
---
 arch/arm/probes/kprobes/test-arm.c   | 17 +++++++++++++++--
 arch/arm/probes/kprobes/test-thumb.c | 12 ++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
index fdeb300..9b3b1b4 100644
--- a/arch/arm/probes/kprobes/test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <asm/system_info.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -478,6 +479,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strh	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")
 	TEST_RPR(  "streqh	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")
 	TEST_UNSUPPORTED(  "streqh	r14, [r13, r12]")
+	TEST_UNSUPPORTED(  "streqh	r14, [r12, r13]")
 	TEST_RPR(  "strh	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")
 	TEST_RPR(  "strneh	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strh	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")
@@ -502,6 +504,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strplh	r",12,VAL2,", [r",11,24,", #-4]!")
 	TEST_RP(   "strh	r",2, VAL1,", [r",3, 24,"], #48")
 	TEST_RP(   "strh	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strh	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strh r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strh	r",4, VAL1,", [r",14,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3b0) "	@ strh r12, [pc, #48]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe0c9f3b0) "	@ strh pc, [r9], #48")
 
@@ -568,6 +573,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
 	TEST_RPR(  "strccd	r",8, VAL2,", [r",11,0, ", r",12,48,"]")
 	TEST_UNSUPPORTED(  "strccd r8, [r13, r12]")
+	TEST_UNSUPPORTED(  "strccd r8, [r12, r13]")
 	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
 	TEST_RPR(  "strcsd	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strd	r",2, VAL1,", [r",5, 24,"], r",4,48,"")
@@ -591,6 +597,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strvcd	r",12,VAL2,", [r",11,24,", #-16]!")
 	TEST_RP(   "strd	r",2, VAL1,", [r",4, 24,"], #48")
 	TEST_RP(   "strd	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strd	r",6, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strd	r",4, VAL1,", [r",12,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3f0) "	@ strd r12, [pc, #48]!")
 
 	TEST_P(	   "ldrd	r0, [r",0, 24,", #-8]")
@@ -639,16 +648,20 @@ void kprobe_arm_test_cases(void)
 	TEST_RP( "str"byte"	r",12,VAL2,", [r",11,24,", #-4]!")		\
 	TEST_RP( "str"byte"	r",2, VAL1,", [r",3, 24,"], #48")		\
 	TEST_RP( "str"byte"	r",10,VAL2,", [r",9, 64,"], #-48")		\
+	TEST_RP( "str"byte"	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"byte" r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")				\
+	TEST_RP( "str"byte"	r",4, VAL1,", [r",10,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")	\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")	\
-	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")	\
+	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")				\
+	TEST_UNSUPPORTED("str"byte" r14, [r12, r13]")				\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")	\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")	\
 	TEST_RPR("str"byte"	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")	\
 	TEST_RPR("str"byte"	r",10,VAL2,", [r",9, 48,"], -r",11,24,"")	\
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 24,", r",2,  32,", asl #1]")\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\
-	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")\
+	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")		\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  32,", asr #3]!")\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\
 	TEST_P(  "ldr"byte"	r0, [r",0,  24,", #-2]")			\
diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
index 6c6e9a9..e8cf193 100644
--- a/arch/arm/probes/kprobes/test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -416,6 +417,9 @@ void kprobe_thumb32_test_cases(void)
 	TEST_RR( "strd	r",14,VAL2,", r",12,VAL1,", [sp, #16]!")
 	TEST_RRP("strd	r",1, VAL1,", r",0, VAL2,", [r",7, 24,"], #16")
 	TEST_RR( "strd	r",7, VAL2,", r",8, VAL1,", [sp], #-16")
+	TEST_RRP("strd	r",6, VAL1,", r",7, VAL2,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, r7, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RRP("strd	r",4, VAL1,", r",5, VAL2,", [r",14, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe9efec04) "	@ strd	r14, r12, [pc, #16]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe8efec04) "	@ strd	r14, r12, [pc], #16")
 
@@ -821,14 +825,22 @@ CONDITION_INSTRUCTIONS(22,
 	TEST_RP( "str"size"	r",14,VAL2,", [r",1, 256,  ", #-128]!")		\
 	TEST_RPR("str"size".w	r",0, VAL1,", [r",1, 0,", r",2, 4,"]")		\
 	TEST_RPR("str"size"	r",14,VAL2,", [r",10,0,", r",11,4,", lsl #1]")	\
+	TEST_UNSUPPORTED("str"size"	r0, [r13, r1]")				\
 	TEST_R(  "str"size".w	r",7, VAL1,", [sp, #24]")			\
 	TEST_RP( "str"size".w	r",0, VAL2,", [r",0,0, "]")			\
+	TEST_RP( "str"size"	r",6, VAL1,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"size"	r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")			\
+	TEST_RP( "str"size"	r",4, VAL2,", [r",12, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_UNSUPPORTED("str"size"t	r0, [r1, #4]")
 
 	SINGLE_STORE("b")
 	SINGLE_STORE("h")
 	SINGLE_STORE("")
 
+	TEST_UNSUPPORTED(__inst_thumb32(0xf801000d) "	@ strb	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf821000d) "	@ strh	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf841000d) "	@ str	r0, [r1, r13]")
+
 	TEST("str	sp, [sp]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cfe000) "	@ str	r14, [pc]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cef000) "	@ str	pc, [r14]")
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
                   ` (4 preceding siblings ...)
  2014-12-08 14:09 ` [RESEND][PATCH v15 5/7] ARM: kprobes: Add test cases for " Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-10 13:23   ` Jon Medhurst (Tixy)
  2014-12-08 14:09 ` [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32 Wang Nan
  6 siblings, 1 reply; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Pass the original kprobe for preparing an optimized kprobe arch-dep
part, since for some architecture (e.g. ARM32) requires the information
in original kprobe.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 arch/x86/kernel/kprobes/opt.c | 3 ++-
 include/linux/kprobes.h       | 3 ++-
 kernel/kprobes.c              | 4 ++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index f1314d0..7028296 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -320,7 +320,8 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
  * Target instructions MUST be relocatable (checked inside)
  * This is called when new aggr(opt)probe is allocated or reused.
  */
-int arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
+int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
+				  struct kprobe *__unused)
 {
 	u8 *buf;
 	int ret;
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index f7296e5..7ab2c93 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -308,7 +308,8 @@ struct optimized_kprobe {
 /* Architecture dependent functions for direct jump optimization */
 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
-extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
+extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
+					 struct kprobe *orig);
 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 extern void arch_optimize_kprobes(struct list_head *oplist);
 extern void arch_unoptimize_kprobes(struct list_head *oplist,
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3995f54..9f28aa7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -717,7 +717,7 @@ static void prepare_optimized_kprobe(struct kprobe *p)
 	struct optimized_kprobe *op;
 
 	op = container_of(p, struct optimized_kprobe, kp);
-	arch_prepare_optimized_kprobe(op);
+	arch_prepare_optimized_kprobe(op, p);
 }
 
 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
@@ -731,7 +731,7 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 
 	INIT_LIST_HEAD(&op->list);
 	op->kp.addr = p->addr;
-	arch_prepare_optimized_kprobe(op);
+	arch_prepare_optimized_kprobe(op, p);
 
 	return &op->kp;
 }
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
                   ` (5 preceding siblings ...)
  2014-12-08 14:09 ` [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe Wang Nan
@ 2014-12-08 14:09 ` Wang Nan
  2014-12-09  6:47   ` Masami Hiramatsu
  6 siblings, 1 reply; 22+ messages in thread
From: Wang Nan @ 2014-12-08 14:09 UTC (permalink / raw)
  To: masami.hiramatsu.pt, tixy, linux; +Cc: lizefan, linux-kernel, linux-arm-kernel

This patch introduce kprobeopt for ARM 32.

Limitations:
 - Currently only kernel compiled with ARM ISA is supported.

 - Offset between probe point and optinsn slot must not larger than
   32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
   things complex. Futher patch can make such optimization.

Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
replace probed instruction by a 'b', branch to trampoline code and then
calls optimized_callback(). optimized_callback() calls opt_pre_handler()
to execute kprobe handler. It also emulate/simulate replaced instruction.

When unregistering kprobe, the deferred manner of unoptimizer may leave
branch instruction before optimizer is called. Different from x86_64,
which only copy the probed insn after optprobe_template_end and
reexecute them, this patch call singlestep to emulate/simulate the insn
directly. Futher patch can optimize this behavior.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
---
v1 -> v2:
 - Improvement: if replaced instruction is conditional, generate a
   conditional branch instruction for it;
 - Introduces RELATIVEJUMP_OPCODES due to ARM kprobe_opcode_t is 4
   bytes;
 - Removes size field in struct arch_optimized_insn;
 - Use arm_gen_branch() to generate branch instruction;
 - Remove all recover logic: ARM doesn't use tail buffer, no need
   recover replaced instructions like x86;
 - Remove incorrect CONFIG_THUMB checking;
 - can_optimize() always returns true if address is well aligned;
 - Improve optimized_callback: using opt_pre_handler();
 - Bugfix: correct range checking code and improve comments;
 - Fix commit message.

v2 -> v3:
 - Rename RELATIVEJUMP_OPCODES to MAX_COPIED_INSNS;
 - Remove unneeded checking:
      arch_check_optimized_kprobe(), can_optimize();
 - Add missing flush_icache_range() in arch_prepare_optimized_kprobe();
 - Remove unneeded 'return;'.

v3 -> v4:
 - Use __mem_to_opcode_arm() to translate copied_insn to ensure it
   works in big endian kernel;
 - Replace 'nop' placeholder in trampoline code template with
   '.long 0' to avoid confusion: reader may regard 'nop' as an
   instruction, but it is value in fact.

v4 -> v5:
 - Don't optimize stack store operations.
 - Introduce prepared field to arch_optimized_insn to indicate whether
   it is prepared. Similar to size field with x86. See v1 -> v2.

v5 -> v6:
 - Dynamically reserve stack according to instruction.
 - Rename: kprobes-opt.c -> kprobes-opt-arm.c.
 - Set op->optinsn.insn after all works are done.

v6 -> v7:
  - Using checker to check stack consumption.

v7 -> v8:
  - Small code adjustments.

v8 -> v9:
  - Utilize original kprobe passed to arch_prepare_optimized_kprobe()
    to avoid copy ainsn twice.
  - A bug in arch_prepare_optimized_kprobe() is found and fixed.

v9 -> v10:
  - Commit message improvements.

v10 -> v11:
  - Move to arch/arm/probes/, insn.h is moved to arch/arm/include/asm.
  - Code cleanup.
  - Bugfix based on Tixy's test result:
    - Trampoline deal with ARM -> Thumb transision instructions and
      AEABI stack alignment requirement correctly.
    - Trampoline code buffer should start at 4 byte aligned address.
      We enforces it in this series by using macro to wrap 'code' var.

v11 -> v12:
  - Remove trampoline code stack trick and use r4 to save original
    stack.
  - Remove trampoline code buffer alignment trick.
  - Names of files are changed.

v12 -> v13:
  - Assume stack always aligned by 4-bytes in any case.
  - Comments update.

v13 -> v14:
  - Use stop_machine to wrap arch_optimize_kprobes to avoid a racing.

v14 -> v15:
  - In v14, stop_machine() wraps a coarse-grained piece of code which
    makes things complex than it should be. In this version,
    kprobes_remove_breakpoint() is extracted, core.c and opt-arm.c use it
    to replace breakpoint to valid instruction. stop_machine() used inside
    in kprobes_remove_breakpoint().
---
 arch/arm/Kconfig                        |   1 +
 arch/arm/{kernel => include/asm}/insn.h |   0
 arch/arm/include/asm/kprobes.h          |  29 +++
 arch/arm/kernel/Makefile                |   2 +-
 arch/arm/kernel/ftrace.c                |   3 +-
 arch/arm/kernel/jump_label.c            |   3 +-
 arch/arm/probes/kprobes/Makefile        |   1 +
 arch/arm/probes/kprobes/core.c          |  26 ++-
 arch/arm/probes/kprobes/core.h          |   2 +
 arch/arm/probes/kprobes/opt-arm.c       | 317 ++++++++++++++++++++++++++++++++
 10 files changed, 372 insertions(+), 12 deletions(-)
 rename arch/arm/{kernel => include/asm}/insn.h (100%)
 create mode 100644 arch/arm/probes/kprobes/opt-arm.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 89c4b5c..2471240 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -59,6 +59,7 @@ config ARM
 	select HAVE_MEMBLOCK
 	select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
+	select HAVE_OPTPROBES if !THUMB2_KERNEL
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
diff --git a/arch/arm/kernel/insn.h b/arch/arm/include/asm/insn.h
similarity index 100%
rename from arch/arm/kernel/insn.h
rename to arch/arm/include/asm/insn.h
diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index 56f9ac6..50ff3bc 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -50,5 +50,34 @@ int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
 int kprobe_exceptions_notify(struct notifier_block *self,
 			     unsigned long val, void *data);
 
+/* optinsn template addresses */
+extern __visible kprobe_opcode_t optprobe_template_entry;
+extern __visible kprobe_opcode_t optprobe_template_val;
+extern __visible kprobe_opcode_t optprobe_template_call;
+extern __visible kprobe_opcode_t optprobe_template_end;
+extern __visible kprobe_opcode_t optprobe_template_sub_sp;
+extern __visible kprobe_opcode_t optprobe_template_add_sp;
+
+#define MAX_OPTIMIZED_LENGTH	4
+#define MAX_OPTINSN_SIZE				\
+	((unsigned long)&optprobe_template_end -	\
+	 (unsigned long)&optprobe_template_entry)
+#define RELATIVEJUMP_SIZE	4
+
+struct arch_optimized_insn {
+	/*
+	 * copy of the original instructions.
+	 * Different from x86, ARM kprobe_opcode_t is u32.
+	 */
+#define MAX_COPIED_INSN	DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
+	kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
+	/* detour code buffer */
+	kprobe_opcode_t *insn;
+	/*
+	 * We always copy one instruction on ARM,
+	 * so size will always be 4, and unlike x86, there is no
+	 * need for a size field.
+	 */
+};
 
 #endif /* _ARM_KPROBES_H */
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 40d3e00..1d0f4e7 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -52,7 +52,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
 # Main staffs in KPROBES are in arch/arm/probes/ .
-obj-$(CONFIG_KPROBES)		+= patch.o
+obj-$(CONFIG_KPROBES)		+= patch.o insn.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index af9a8a9..ec7e332 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -19,8 +19,7 @@
 #include <asm/cacheflush.h>
 #include <asm/opcodes.h>
 #include <asm/ftrace.h>
-
-#include "insn.h"
+#include <asm/insn.h>
 
 #ifdef CONFIG_THUMB2_KERNEL
 #define	NOP		0xf85deb04	/* pop.w {lr} */
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index c6c73ed..35a8fbb 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c
@@ -1,8 +1,7 @@
 #include <linux/kernel.h>
 #include <linux/jump_label.h>
 #include <asm/patch.h>
-
-#include "insn.h"
+#include <asm/insn.h>
 
 #ifdef HAVE_JUMP_LABEL
 
diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
index bc8d504..76a36bf 100644
--- a/arch/arm/probes/kprobes/Makefile
+++ b/arch/arm/probes/kprobes/Makefile
@@ -7,5 +7,6 @@ obj-$(CONFIG_KPROBES)		+= actions-thumb.o checkers-thumb.o
 test-kprobes-objs		+= test-thumb.o
 else
 obj-$(CONFIG_KPROBES)		+= actions-arm.o checkers-arm.o
+obj-$(CONFIG_OPTPROBES)		+= opt-arm.o
 test-kprobes-objs		+= test-arm.o
 endif
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 3a58db4..a4ec240 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -163,19 +163,31 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
  * memory. It is also needed to atomically set the two half-words of a 32-bit
  * Thumb breakpoint.
  */
-int __kprobes __arch_disarm_kprobe(void *p)
-{
-	struct kprobe *kp = p;
-	void *addr = (void *)((uintptr_t)kp->addr & ~1);
-
-	__patch_text(addr, kp->opcode);
+struct patch {
+	void *addr;
+	unsigned int insn;
+};
 
+static int __kprobes_remove_breakpoint(void *data)
+{
+	struct patch *p = data;
+	__patch_text(p->addr, p->insn);
 	return 0;
 }
 
+void __kprobes kprobes_remove_breakpoint(void *addr, unsigned int insn)
+{
+	struct patch p = {
+		.addr = addr,
+		.insn = insn,
+	};
+	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
+}
+
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
-	stop_machine(__arch_disarm_kprobe, p, cpu_online_mask);
+	kprobes_remove_breakpoint((void *)((uintptr_t)p->addr & ~1),
+			p->opcode);
 }
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)
diff --git a/arch/arm/probes/kprobes/core.h b/arch/arm/probes/kprobes/core.h
index f88c79f..b3036c5 100644
--- a/arch/arm/probes/kprobes/core.h
+++ b/arch/arm/probes/kprobes/core.h
@@ -30,6 +30,8 @@
 #define KPROBE_THUMB16_BREAKPOINT_INSTRUCTION	0xde18
 #define KPROBE_THUMB32_BREAKPOINT_INSTRUCTION	0xf7f0a018
 
+extern void kprobes_remove_breakpoint(void *addr, unsigned int insn);
+
 enum probes_insn __kprobes
 kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *h);
diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c
new file mode 100644
index 0000000..6a60df3
--- /dev/null
+++ b/arch/arm/probes/kprobes/opt-arm.c
@@ -0,0 +1,317 @@
+/*
+ *  Kernel Probes Jump Optimization (Optprobes)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ * Copyright (C) Hitachi Ltd., 2012
+ * Copyright (C) Huawei Inc., 2014
+ */
+
+#include <linux/kprobes.h>
+#include <linux/jump_label.h>
+#include <asm/kprobes.h>
+#include <asm/cacheflush.h>
+/* for arm_gen_branch */
+#include <asm/insn.h>
+/* for patch_text */
+#include <asm/patch.h>
+
+#include "core.h"
+
+/*
+ * NOTE: the first sub and add instruction will be modified according
+ * to the stack cost of the instruction.
+ */
+asm (
+			".global optprobe_template_entry\n"
+			"optprobe_template_entry:\n"
+			".global optprobe_template_sub_sp\n"
+			"optprobe_template_sub_sp:"
+			"	sub	sp, sp, #0xff\n"
+			"	stmia	sp, {r0 - r14} \n"
+			".global optprobe_template_add_sp\n"
+			"optprobe_template_add_sp:"
+			"	add	r3, sp, #0xff\n"
+			"	str	r3, [sp, #52]\n"
+			"	mrs	r4, cpsr\n"
+			"	str	r4, [sp, #64]\n"
+			"	mov	r1, sp\n"
+			"	ldr	r0, 1f\n"
+			"	ldr	r2, 2f\n"
+			/*
+			 * AEABI requires an 8-bytes alignment stack. If
+			 * SP % 8 != 0 (SP % 4 == 0 should be ensured),
+			 * alloc more bytes here.
+			 */
+			"	and	r4, sp, #4\n"
+			"	sub	sp, sp, r4\n"
+			"	blx	r2\n"
+			"	add	sp, sp, r4\n"
+			"	ldr	r1, [sp, #64]\n"
+			"	tst	r1, #"__stringify(PSR_T_BIT)"\n"
+			"	ldrne	r2, [sp, #60]\n"
+			"	orrne	r2, #1\n"
+			"	strne	r2, [sp, #60] @ set bit0 of PC for thumb\n"
+			"	msr	cpsr_cxsf, r1\n"
+			"	ldmia	sp, {r0 - r15}\n"
+			".global optprobe_template_val\n"
+			"optprobe_template_val:\n"
+			"1:	.long 0\n"
+			".global optprobe_template_call\n"
+			"optprobe_template_call:\n"
+			"2:	.long 0\n"
+			".global optprobe_template_end\n"
+			"optprobe_template_end:\n");
+
+#define TMPL_VAL_IDX \
+	((unsigned long *)&optprobe_template_val - (unsigned long *)&optprobe_template_entry)
+#define TMPL_CALL_IDX \
+	((unsigned long *)&optprobe_template_call - (unsigned long *)&optprobe_template_entry)
+#define TMPL_END_IDX \
+	((unsigned long *)&optprobe_template_end - (unsigned long *)&optprobe_template_entry)
+#define TMPL_ADD_SP \
+	((unsigned long *)&optprobe_template_add_sp - (unsigned long *)&optprobe_template_entry)
+#define TMPL_SUB_SP \
+	((unsigned long *)&optprobe_template_sub_sp - (unsigned long *)&optprobe_template_entry)
+
+/*
+ * ARM can always optimize an instruction when using ARM ISA, except
+ * instructions like 'str r0, [sp, r1]' which store to stack and unable
+ * to determine stack space consumption statically.
+ */
+int arch_prepared_optinsn(struct arch_optimized_insn *optinsn)
+{
+	return optinsn->insn != NULL;
+}
+
+/*
+ * In ARM ISA, kprobe opt always replace one instruction (4 bytes
+ * aligned and 4 bytes long). It is impossible to encounter another
+ * kprobe in the address range. So always return 0.
+ */
+int arch_check_optimized_kprobe(struct optimized_kprobe *op)
+{
+	return 0;
+}
+
+/* Caller must ensure addr & 3 == 0 */
+static int can_optimize(struct kprobe *kp)
+{
+	if (kp->ainsn.stack_space < 0)
+		return 0;
+	/*
+	 * 255 is the biggest imm can be used in 'sub r0, r0, #<imm>'.
+	 * Number larger than 255 needs special encoding.
+	 */
+	if (kp->ainsn.stack_space > 255 - sizeof(struct pt_regs))
+		return 0;
+	return 1;
+}
+
+/* Free optimized instruction slot */
+static void
+__arch_remove_optimized_kprobe(struct optimized_kprobe *op, int dirty)
+{
+	if (op->optinsn.insn) {
+		free_optinsn_slot(op->optinsn.insn, dirty);
+		op->optinsn.insn = NULL;
+	}
+}
+
+extern void kprobe_handler(struct pt_regs *regs);
+
+static void
+optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
+{
+	unsigned long flags;
+	struct kprobe *p = &op->kp;
+	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+	/* Save skipped registers */
+	regs->ARM_pc = (unsigned long)op->kp.addr;
+	regs->ARM_ORIG_r0 = ~0UL;
+
+	local_irq_save(flags);
+
+	if (kprobe_running()) {
+		kprobes_inc_nmissed_count(&op->kp);
+	} else {
+		__this_cpu_write(current_kprobe, &op->kp);
+		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+		opt_pre_handler(&op->kp, regs);
+		__this_cpu_write(current_kprobe, NULL);
+	}
+
+	/* In each case, we must singlestep the replaced instruction. */
+	op->kp.ainsn.insn_singlestep(p->opcode, &p->ainsn, regs);
+
+	local_irq_restore(flags);
+}
+
+int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *orig)
+{
+	kprobe_opcode_t *code;
+	unsigned long rel_chk;
+	unsigned long val;
+	unsigned long stack_protect = sizeof(struct pt_regs);
+
+	if (!can_optimize(orig))
+		return -EILSEQ;
+
+	code = get_optinsn_slot();
+	if (!code)
+		return -ENOMEM;
+
+	/*
+	 * Verify if the address gap is in 32MiB range, because this uses
+	 * a relative jump.
+	 *
+	 * kprobe opt use a 'b' instruction to branch to optinsn.insn.
+	 * According to ARM manual, branch instruction is:
+	 *
+	 *   31  28 27           24 23             0
+	 *  +------+---+---+---+---+----------------+
+	 *  | cond | 1 | 0 | 1 | 0 |      imm24     |
+	 *  +------+---+---+---+---+----------------+
+	 *
+	 * imm24 is a signed 24 bits integer. The real branch offset is computed
+	 * by: imm32 = SignExtend(imm24:'00', 32);
+	 *
+	 * So the maximum forward branch should be:
+	 *   (0x007fffff << 2) = 0x01fffffc =  0x1fffffc
+	 * The maximum backword branch should be:
+	 *   (0xff800000 << 2) = 0xfe000000 = -0x2000000
+	 *
+	 * We can simply check (rel & 0xfe000003):
+	 *  if rel is positive, (rel & 0xfe000000) shoule be 0
+	 *  if rel is negitive, (rel & 0xfe000000) should be 0xfe000000
+	 *  the last '3' is used for alignment checking.
+	 */
+	rel_chk = (unsigned long)((long)code -
+			(long)orig->addr + 8) & 0xfe000003;
+
+	if ((rel_chk != 0) && (rel_chk != 0xfe000000)) {
+		/*
+		 * Different from x86, we free code buf directly instead of
+		 * calling __arch_remove_optimized_kprobe() because
+		 * we have not fill any field in op.
+		 */
+		free_optinsn_slot(code, 0);
+		return -ERANGE;
+	}
+
+	/* Copy arch-dep-instance from template. */
+	memcpy(code, &optprobe_template_entry,
+			TMPL_END_IDX * sizeof(kprobe_opcode_t));
+
+	/* Adjust buffer according to instruction. */
+	BUG_ON(orig->ainsn.stack_space < 0);
+
+	stack_protect += orig->ainsn.stack_space;
+
+	/* Should have been filtered by can_optimize(). */
+	BUG_ON(stack_protect > 255);
+
+	/* Create a 'sub sp, sp, #<stack_protect>' */
+	code[TMPL_SUB_SP] = __opcode_to_mem_arm(0xe24dd000 | stack_protect);
+	/* Create a 'add r3, sp, #<stack_protect>' */
+	code[TMPL_ADD_SP] = __opcode_to_mem_arm(0xe28d3000 | stack_protect);
+
+	/* Set probe information */
+	val = (unsigned long)op;
+	code[TMPL_VAL_IDX] = val;
+
+	/* Set probe function call */
+	val = (unsigned long)optimized_callback;
+	code[TMPL_CALL_IDX] = val;
+
+	flush_icache_range((unsigned long)code,
+			   (unsigned long)(&code[TMPL_END_IDX]));
+
+	/* Set op->optinsn.insn means prepared. */
+	op->optinsn.insn = code;
+	return 0;
+}
+
+void __kprobes arch_optimize_kprobes(struct list_head *oplist)
+{
+	struct optimized_kprobe *op, *tmp;
+
+	list_for_each_entry_safe(op, tmp, oplist, list) {
+		unsigned long insn;
+		WARN_ON(kprobe_disabled(&op->kp));
+
+		/*
+		 * Backup instructions which will be replaced
+		 * by jump address
+		 */
+		memcpy(op->optinsn.copied_insn, op->kp.addr,
+				RELATIVEJUMP_SIZE);
+
+		insn = arm_gen_branch((unsigned long)op->kp.addr,
+				(unsigned long)op->optinsn.insn);
+		BUG_ON(insn == 0);
+
+		/*
+		 * Make it a conditional branch if replaced insn
+		 * is consitional
+		 */
+		insn = (__mem_to_opcode_arm(
+			  op->optinsn.copied_insn[0]) & 0xf0000000) |
+			(insn & 0x0fffffff);
+
+		/*
+		 * Similar to __arch_disarm_kprobe, operations which
+		 * removing breakpoints must be wrapped by stop_machine
+		 * to avoid racing.
+		 */
+		kprobes_remove_breakpoint(op->kp.addr, insn);
+
+		list_del_init(&op->list);
+	}
+}
+
+void arch_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+	arch_arm_kprobe(&op->kp);
+}
+
+/*
+ * Recover original instructions and breakpoints from relative jumps.
+ * Caller must call with locking kprobe_mutex.
+ */
+void arch_unoptimize_kprobes(struct list_head *oplist,
+			    struct list_head *done_list)
+{
+	struct optimized_kprobe *op, *tmp;
+
+	list_for_each_entry_safe(op, tmp, oplist, list) {
+		arch_unoptimize_kprobe(op);
+		list_move(&op->list, done_list);
+	}
+}
+
+int arch_within_optimized_kprobe(struct optimized_kprobe *op,
+				unsigned long addr)
+{
+	return ((unsigned long)op->kp.addr <= addr &&
+		(unsigned long)op->kp.addr + RELATIVEJUMP_SIZE > addr);
+}
+
+void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
+{
+	__arch_remove_optimized_kprobe(op, 1);
+}
-- 
1.8.4


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-08 14:09 ` [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32 Wang Nan
@ 2014-12-09  6:47   ` Masami Hiramatsu
  2014-12-09  9:14     ` Jon Medhurst (Tixy)
  2014-12-09 10:12     ` Wang Nan
  0 siblings, 2 replies; 22+ messages in thread
From: Masami Hiramatsu @ 2014-12-09  6:47 UTC (permalink / raw)
  To: Wang Nan; +Cc: tixy, linux, lizefan, linux-kernel, linux-arm-kernel

(2014/12/08 23:09), Wang Nan wrote:
> This patch introduce kprobeopt for ARM 32.
> 
> Limitations:
>  - Currently only kernel compiled with ARM ISA is supported.
> 
>  - Offset between probe point and optinsn slot must not larger than
>    32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
>    things complex. Futher patch can make such optimization.
> 
> Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
> ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
> replace probed instruction by a 'b', branch to trampoline code and then
> calls optimized_callback(). optimized_callback() calls opt_pre_handler()
> to execute kprobe handler. It also emulate/simulate replaced instruction.
> 
> When unregistering kprobe, the deferred manner of unoptimizer may leave
> branch instruction before optimizer is called. Different from x86_64,
> which only copy the probed insn after optprobe_template_end and
> reexecute them, this patch call singlestep to emulate/simulate the insn
> directly. Futher patch can optimize this behavior.
> 
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
> Cc: Will Deacon <will.deacon@arm.com>
> ---
> v1 -> v2:
>  - Improvement: if replaced instruction is conditional, generate a
>    conditional branch instruction for it;
>  - Introduces RELATIVEJUMP_OPCODES due to ARM kprobe_opcode_t is 4
>    bytes;
>  - Removes size field in struct arch_optimized_insn;
>  - Use arm_gen_branch() to generate branch instruction;
>  - Remove all recover logic: ARM doesn't use tail buffer, no need
>    recover replaced instructions like x86;
>  - Remove incorrect CONFIG_THUMB checking;
>  - can_optimize() always returns true if address is well aligned;
>  - Improve optimized_callback: using opt_pre_handler();
>  - Bugfix: correct range checking code and improve comments;
>  - Fix commit message.
> 
> v2 -> v3:
>  - Rename RELATIVEJUMP_OPCODES to MAX_COPIED_INSNS;
>  - Remove unneeded checking:
>       arch_check_optimized_kprobe(), can_optimize();
>  - Add missing flush_icache_range() in arch_prepare_optimized_kprobe();
>  - Remove unneeded 'return;'.
> 
> v3 -> v4:
>  - Use __mem_to_opcode_arm() to translate copied_insn to ensure it
>    works in big endian kernel;
>  - Replace 'nop' placeholder in trampoline code template with
>    '.long 0' to avoid confusion: reader may regard 'nop' as an
>    instruction, but it is value in fact.
> 
> v4 -> v5:
>  - Don't optimize stack store operations.
>  - Introduce prepared field to arch_optimized_insn to indicate whether
>    it is prepared. Similar to size field with x86. See v1 -> v2.
> 
> v5 -> v6:
>  - Dynamically reserve stack according to instruction.
>  - Rename: kprobes-opt.c -> kprobes-opt-arm.c.
>  - Set op->optinsn.insn after all works are done.
> 
> v6 -> v7:
>   - Using checker to check stack consumption.
> 
> v7 -> v8:
>   - Small code adjustments.
> 
> v8 -> v9:
>   - Utilize original kprobe passed to arch_prepare_optimized_kprobe()
>     to avoid copy ainsn twice.
>   - A bug in arch_prepare_optimized_kprobe() is found and fixed.
> 
> v9 -> v10:
>   - Commit message improvements.
> 
> v10 -> v11:
>   - Move to arch/arm/probes/, insn.h is moved to arch/arm/include/asm.
>   - Code cleanup.
>   - Bugfix based on Tixy's test result:
>     - Trampoline deal with ARM -> Thumb transision instructions and
>       AEABI stack alignment requirement correctly.
>     - Trampoline code buffer should start at 4 byte aligned address.
>       We enforces it in this series by using macro to wrap 'code' var.
> 
> v11 -> v12:
>   - Remove trampoline code stack trick and use r4 to save original
>     stack.
>   - Remove trampoline code buffer alignment trick.
>   - Names of files are changed.
> 
> v12 -> v13:
>   - Assume stack always aligned by 4-bytes in any case.
>   - Comments update.
> 
> v13 -> v14:
>   - Use stop_machine to wrap arch_optimize_kprobes to avoid a racing.
> 
> v14 -> v15:
>   - In v14, stop_machine() wraps a coarse-grained piece of code which
>     makes things complex than it should be. In this version,
>     kprobes_remove_breakpoint() is extracted, core.c and opt-arm.c use it
>     to replace breakpoint to valid instruction. stop_machine() used inside
>     in kprobes_remove_breakpoint().
> ---
>  arch/arm/Kconfig                        |   1 +
>  arch/arm/{kernel => include/asm}/insn.h |   0
>  arch/arm/include/asm/kprobes.h          |  29 +++
>  arch/arm/kernel/Makefile                |   2 +-
>  arch/arm/kernel/ftrace.c                |   3 +-
>  arch/arm/kernel/jump_label.c            |   3 +-
>  arch/arm/probes/kprobes/Makefile        |   1 +
>  arch/arm/probes/kprobes/core.c          |  26 ++-
>  arch/arm/probes/kprobes/core.h          |   2 +
>  arch/arm/probes/kprobes/opt-arm.c       | 317 ++++++++++++++++++++++++++++++++
>  10 files changed, 372 insertions(+), 12 deletions(-)
>  rename arch/arm/{kernel => include/asm}/insn.h (100%)
>  create mode 100644 arch/arm/probes/kprobes/opt-arm.c
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 89c4b5c..2471240 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -59,6 +59,7 @@ config ARM
>  	select HAVE_MEMBLOCK
>  	select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND
>  	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
> +	select HAVE_OPTPROBES if !THUMB2_KERNEL
>  	select HAVE_PERF_EVENTS
>  	select HAVE_PERF_REGS
>  	select HAVE_PERF_USER_STACK_DUMP
> diff --git a/arch/arm/kernel/insn.h b/arch/arm/include/asm/insn.h
> similarity index 100%
> rename from arch/arm/kernel/insn.h
> rename to arch/arm/include/asm/insn.h
> diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
> index 56f9ac6..50ff3bc 100644
> --- a/arch/arm/include/asm/kprobes.h
> +++ b/arch/arm/include/asm/kprobes.h
> @@ -50,5 +50,34 @@ int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
>  int kprobe_exceptions_notify(struct notifier_block *self,
>  			     unsigned long val, void *data);
>  
> +/* optinsn template addresses */
> +extern __visible kprobe_opcode_t optprobe_template_entry;
> +extern __visible kprobe_opcode_t optprobe_template_val;
> +extern __visible kprobe_opcode_t optprobe_template_call;
> +extern __visible kprobe_opcode_t optprobe_template_end;
> +extern __visible kprobe_opcode_t optprobe_template_sub_sp;
> +extern __visible kprobe_opcode_t optprobe_template_add_sp;
> +
> +#define MAX_OPTIMIZED_LENGTH	4
> +#define MAX_OPTINSN_SIZE				\
> +	((unsigned long)&optprobe_template_end -	\
> +	 (unsigned long)&optprobe_template_entry)
> +#define RELATIVEJUMP_SIZE	4
> +
> +struct arch_optimized_insn {
> +	/*
> +	 * copy of the original instructions.
> +	 * Different from x86, ARM kprobe_opcode_t is u32.
> +	 */
> +#define MAX_COPIED_INSN	DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
> +	kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
> +	/* detour code buffer */
> +	kprobe_opcode_t *insn;
> +	/*
> +	 * We always copy one instruction on ARM,
> +	 * so size will always be 4, and unlike x86, there is no
> +	 * need for a size field.
> +	 */
> +};
>  
>  #endif /* _ARM_KPROBES_H */
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index 40d3e00..1d0f4e7 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -52,7 +52,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
>  obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
>  obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
>  # Main staffs in KPROBES are in arch/arm/probes/ .
> -obj-$(CONFIG_KPROBES)		+= patch.o
> +obj-$(CONFIG_KPROBES)		+= patch.o insn.o
>  obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
>  obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
>  obj-$(CONFIG_KGDB)		+= kgdb.o
> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> index af9a8a9..ec7e332 100644
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -19,8 +19,7 @@
>  #include <asm/cacheflush.h>
>  #include <asm/opcodes.h>
>  #include <asm/ftrace.h>
> -
> -#include "insn.h"
> +#include <asm/insn.h>
>  
>  #ifdef CONFIG_THUMB2_KERNEL
>  #define	NOP		0xf85deb04	/* pop.w {lr} */
> diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
> index c6c73ed..35a8fbb 100644
> --- a/arch/arm/kernel/jump_label.c
> +++ b/arch/arm/kernel/jump_label.c
> @@ -1,8 +1,7 @@
>  #include <linux/kernel.h>
>  #include <linux/jump_label.h>
>  #include <asm/patch.h>
> -
> -#include "insn.h"
> +#include <asm/insn.h>
>  
>  #ifdef HAVE_JUMP_LABEL
>  
> diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
> index bc8d504..76a36bf 100644
> --- a/arch/arm/probes/kprobes/Makefile
> +++ b/arch/arm/probes/kprobes/Makefile
> @@ -7,5 +7,6 @@ obj-$(CONFIG_KPROBES)		+= actions-thumb.o checkers-thumb.o
>  test-kprobes-objs		+= test-thumb.o
>  else
>  obj-$(CONFIG_KPROBES)		+= actions-arm.o checkers-arm.o
> +obj-$(CONFIG_OPTPROBES)		+= opt-arm.o
>  test-kprobes-objs		+= test-arm.o
>  endif
> diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
> index 3a58db4..a4ec240 100644
> --- a/arch/arm/probes/kprobes/core.c
> +++ b/arch/arm/probes/kprobes/core.c
> @@ -163,19 +163,31 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
>   * memory. It is also needed to atomically set the two half-words of a 32-bit
>   * Thumb breakpoint.
>   */
> -int __kprobes __arch_disarm_kprobe(void *p)
> -{
> -	struct kprobe *kp = p;
> -	void *addr = (void *)((uintptr_t)kp->addr & ~1);
> -
> -	__patch_text(addr, kp->opcode);
> +struct patch {
> +	void *addr;
> +	unsigned int insn;
> +};
>  
> +static int __kprobes_remove_breakpoint(void *data)
> +{
> +	struct patch *p = data;
> +	__patch_text(p->addr, p->insn);
>  	return 0;
>  }
>  
> +void __kprobes kprobes_remove_breakpoint(void *addr, unsigned int insn)
> +{
> +	struct patch p = {
> +		.addr = addr,
> +		.insn = insn,
> +	};
> +	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
> +}

Hmm, I think finally we should fix patch_text() in patch.c to forcibly use stop_machine
by adding "bool stop" parameter, instead of introducing new another patch_text()
implementation, because we'd better avoid two private "patch" data structures.
Maybe someday we can find another better solution for self modifying.
(I actually doesn't like stop_machine() which disturbs real-time processing)

The other parts look good to me :)

Thank you!


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-09  6:47   ` Masami Hiramatsu
@ 2014-12-09  9:14     ` Jon Medhurst (Tixy)
  2014-12-09 10:25       ` Masami Hiramatsu
  2014-12-09 10:12     ` Wang Nan
  1 sibling, 1 reply; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-09  9:14 UTC (permalink / raw)
  To: Masami Hiramatsu; +Cc: Wang Nan, linux, lizefan, linux-kernel, linux-arm-kernel

On Tue, 2014-12-09 at 15:47 +0900, Masami Hiramatsu wrote:
> (2014/12/08 23:09), Wang Nan wrote:
> > This patch introduce kprobeopt for ARM 32.
> > 
> > Limitations:
> >  - Currently only kernel compiled with ARM ISA is supported.
> > 
> >  - Offset between probe point and optinsn slot must not larger than
> >    32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
> >    things complex. Futher patch can make such optimization.
> > 
> > Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
> > ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
> > replace probed instruction by a 'b', branch to trampoline code and then
> > calls optimized_callback(). optimized_callback() calls opt_pre_handler()
> > to execute kprobe handler. It also emulate/simulate replaced instruction.
> > 
> > When unregistering kprobe, the deferred manner of unoptimizer may leave
> > branch instruction before optimizer is called. Different from x86_64,
> > which only copy the probed insn after optprobe_template_end and
> > reexecute them, this patch call singlestep to emulate/simulate the insn
> > directly. Futher patch can optimize this behavior.
> > 
> > Signed-off-by: Wang Nan <wangnan0@huawei.com>
> > Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> > Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
> > Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
> > Cc: Will Deacon <will.deacon@arm.com>
> > ---
> > v1 -> v2:
> >  - Improvement: if replaced instruction is conditional, generate a
> >    conditional branch instruction for it;
> >  - Introduces RELATIVEJUMP_OPCODES due to ARM kprobe_opcode_t is 4
> >    bytes;
> >  - Removes size field in struct arch_optimized_insn;
> >  - Use arm_gen_branch() to generate branch instruction;
> >  - Remove all recover logic: ARM doesn't use tail buffer, no need
> >    recover replaced instructions like x86;
> >  - Remove incorrect CONFIG_THUMB checking;
> >  - can_optimize() always returns true if address is well aligned;
> >  - Improve optimized_callback: using opt_pre_handler();
> >  - Bugfix: correct range checking code and improve comments;
> >  - Fix commit message.
> > 
> > v2 -> v3:
> >  - Rename RELATIVEJUMP_OPCODES to MAX_COPIED_INSNS;
> >  - Remove unneeded checking:
> >       arch_check_optimized_kprobe(), can_optimize();
> >  - Add missing flush_icache_range() in arch_prepare_optimized_kprobe();
> >  - Remove unneeded 'return;'.
> > 
> > v3 -> v4:
> >  - Use __mem_to_opcode_arm() to translate copied_insn to ensure it
> >    works in big endian kernel;
> >  - Replace 'nop' placeholder in trampoline code template with
> >    '.long 0' to avoid confusion: reader may regard 'nop' as an
> >    instruction, but it is value in fact.
> > 
> > v4 -> v5:
> >  - Don't optimize stack store operations.
> >  - Introduce prepared field to arch_optimized_insn to indicate whether
> >    it is prepared. Similar to size field with x86. See v1 -> v2.
> > 
> > v5 -> v6:
> >  - Dynamically reserve stack according to instruction.
> >  - Rename: kprobes-opt.c -> kprobes-opt-arm.c.
> >  - Set op->optinsn.insn after all works are done.
> > 
> > v6 -> v7:
> >   - Using checker to check stack consumption.
> > 
> > v7 -> v8:
> >   - Small code adjustments.
> > 
> > v8 -> v9:
> >   - Utilize original kprobe passed to arch_prepare_optimized_kprobe()
> >     to avoid copy ainsn twice.
> >   - A bug in arch_prepare_optimized_kprobe() is found and fixed.
> > 
> > v9 -> v10:
> >   - Commit message improvements.
> > 
> > v10 -> v11:
> >   - Move to arch/arm/probes/, insn.h is moved to arch/arm/include/asm.
> >   - Code cleanup.
> >   - Bugfix based on Tixy's test result:
> >     - Trampoline deal with ARM -> Thumb transision instructions and
> >       AEABI stack alignment requirement correctly.
> >     - Trampoline code buffer should start at 4 byte aligned address.
> >       We enforces it in this series by using macro to wrap 'code' var.
> > 
> > v11 -> v12:
> >   - Remove trampoline code stack trick and use r4 to save original
> >     stack.
> >   - Remove trampoline code buffer alignment trick.
> >   - Names of files are changed.
> > 
> > v12 -> v13:
> >   - Assume stack always aligned by 4-bytes in any case.
> >   - Comments update.
> > 
> > v13 -> v14:
> >   - Use stop_machine to wrap arch_optimize_kprobes to avoid a racing.
> > 
> > v14 -> v15:
> >   - In v14, stop_machine() wraps a coarse-grained piece of code which
> >     makes things complex than it should be. In this version,
> >     kprobes_remove_breakpoint() is extracted, core.c and opt-arm.c use it
> >     to replace breakpoint to valid instruction. stop_machine() used inside
> >     in kprobes_remove_breakpoint().
> > ---
> >  arch/arm/Kconfig                        |   1 +
> >  arch/arm/{kernel => include/asm}/insn.h |   0
> >  arch/arm/include/asm/kprobes.h          |  29 +++
> >  arch/arm/kernel/Makefile                |   2 +-
> >  arch/arm/kernel/ftrace.c                |   3 +-
> >  arch/arm/kernel/jump_label.c            |   3 +-
> >  arch/arm/probes/kprobes/Makefile        |   1 +
> >  arch/arm/probes/kprobes/core.c          |  26 ++-
> >  arch/arm/probes/kprobes/core.h          |   2 +
> >  arch/arm/probes/kprobes/opt-arm.c       | 317 ++++++++++++++++++++++++++++++++
> >  10 files changed, 372 insertions(+), 12 deletions(-)
> >  rename arch/arm/{kernel => include/asm}/insn.h (100%)
> >  create mode 100644 arch/arm/probes/kprobes/opt-arm.c
> > 
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 89c4b5c..2471240 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -59,6 +59,7 @@ config ARM
> >  	select HAVE_MEMBLOCK
> >  	select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND
> >  	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
> > +	select HAVE_OPTPROBES if !THUMB2_KERNEL
> >  	select HAVE_PERF_EVENTS
> >  	select HAVE_PERF_REGS
> >  	select HAVE_PERF_USER_STACK_DUMP
> > diff --git a/arch/arm/kernel/insn.h b/arch/arm/include/asm/insn.h
> > similarity index 100%
> > rename from arch/arm/kernel/insn.h
> > rename to arch/arm/include/asm/insn.h
> > diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
> > index 56f9ac6..50ff3bc 100644
> > --- a/arch/arm/include/asm/kprobes.h
> > +++ b/arch/arm/include/asm/kprobes.h
> > @@ -50,5 +50,34 @@ int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
> >  int kprobe_exceptions_notify(struct notifier_block *self,
> >  			     unsigned long val, void *data);
> >  
> > +/* optinsn template addresses */
> > +extern __visible kprobe_opcode_t optprobe_template_entry;
> > +extern __visible kprobe_opcode_t optprobe_template_val;
> > +extern __visible kprobe_opcode_t optprobe_template_call;
> > +extern __visible kprobe_opcode_t optprobe_template_end;
> > +extern __visible kprobe_opcode_t optprobe_template_sub_sp;
> > +extern __visible kprobe_opcode_t optprobe_template_add_sp;
> > +
> > +#define MAX_OPTIMIZED_LENGTH	4
> > +#define MAX_OPTINSN_SIZE				\
> > +	((unsigned long)&optprobe_template_end -	\
> > +	 (unsigned long)&optprobe_template_entry)
> > +#define RELATIVEJUMP_SIZE	4
> > +
> > +struct arch_optimized_insn {
> > +	/*
> > +	 * copy of the original instructions.
> > +	 * Different from x86, ARM kprobe_opcode_t is u32.
> > +	 */
> > +#define MAX_COPIED_INSN	DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
> > +	kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
> > +	/* detour code buffer */
> > +	kprobe_opcode_t *insn;
> > +	/*
> > +	 * We always copy one instruction on ARM,
> > +	 * so size will always be 4, and unlike x86, there is no
> > +	 * need for a size field.
> > +	 */
> > +};
> >  
> >  #endif /* _ARM_KPROBES_H */
> > diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> > index 40d3e00..1d0f4e7 100644
> > --- a/arch/arm/kernel/Makefile
> > +++ b/arch/arm/kernel/Makefile
> > @@ -52,7 +52,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
> >  obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
> >  obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
> >  # Main staffs in KPROBES are in arch/arm/probes/ .
> > -obj-$(CONFIG_KPROBES)		+= patch.o
> > +obj-$(CONFIG_KPROBES)		+= patch.o insn.o
> >  obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
> >  obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
> >  obj-$(CONFIG_KGDB)		+= kgdb.o
> > diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> > index af9a8a9..ec7e332 100644
> > --- a/arch/arm/kernel/ftrace.c
> > +++ b/arch/arm/kernel/ftrace.c
> > @@ -19,8 +19,7 @@
> >  #include <asm/cacheflush.h>
> >  #include <asm/opcodes.h>
> >  #include <asm/ftrace.h>
> > -
> > -#include "insn.h"
> > +#include <asm/insn.h>
> >  
> >  #ifdef CONFIG_THUMB2_KERNEL
> >  #define	NOP		0xf85deb04	/* pop.w {lr} */
> > diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
> > index c6c73ed..35a8fbb 100644
> > --- a/arch/arm/kernel/jump_label.c
> > +++ b/arch/arm/kernel/jump_label.c
> > @@ -1,8 +1,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/jump_label.h>
> >  #include <asm/patch.h>
> > -
> > -#include "insn.h"
> > +#include <asm/insn.h>
> >  
> >  #ifdef HAVE_JUMP_LABEL
> >  
> > diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
> > index bc8d504..76a36bf 100644
> > --- a/arch/arm/probes/kprobes/Makefile
> > +++ b/arch/arm/probes/kprobes/Makefile
> > @@ -7,5 +7,6 @@ obj-$(CONFIG_KPROBES)		+= actions-thumb.o checkers-thumb.o
> >  test-kprobes-objs		+= test-thumb.o
> >  else
> >  obj-$(CONFIG_KPROBES)		+= actions-arm.o checkers-arm.o
> > +obj-$(CONFIG_OPTPROBES)		+= opt-arm.o
> >  test-kprobes-objs		+= test-arm.o
> >  endif
> > diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
> > index 3a58db4..a4ec240 100644
> > --- a/arch/arm/probes/kprobes/core.c
> > +++ b/arch/arm/probes/kprobes/core.c
> > @@ -163,19 +163,31 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
> >   * memory. It is also needed to atomically set the two half-words of a 32-bit
> >   * Thumb breakpoint.
> >   */
> > -int __kprobes __arch_disarm_kprobe(void *p)
> > -{
> > -	struct kprobe *kp = p;
> > -	void *addr = (void *)((uintptr_t)kp->addr & ~1);
> > -
> > -	__patch_text(addr, kp->opcode);
> > +struct patch {
> > +	void *addr;
> > +	unsigned int insn;
> > +};
> >  
> > +static int __kprobes_remove_breakpoint(void *data)
> > +{
> > +	struct patch *p = data;
> > +	__patch_text(p->addr, p->insn);
> >  	return 0;
> >  }
> >  
> > +void __kprobes kprobes_remove_breakpoint(void *addr, unsigned int insn)
> > +{
> > +	struct patch p = {
> > +		.addr = addr,
> > +		.insn = insn,
> > +	};
> > +	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
> > +}
> 
> Hmm, I think finally we should fix patch_text() in patch.c to forcibly use stop_machine
> by adding "bool stop" parameter, instead of introducing new another patch_text()
> implementation, because we'd better avoid two private "patch" data structures.

That was my first thought too, then I realised that breaks encapsulation
of the patch_text implementation, because its use of stop_machine is an
implementation detail and it could be rewritten to not use stop machine.
(That is sort of on my long term todo list
https://lkml.org/lkml/2014/9/4/188)

Whereas stop machine is used by kprobes to avoid race conditions with
the undefined instruction exception handler and something like that
would be needed even if patch_text didn't use stop_machine.

-- 
Tixy


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-09  6:47   ` Masami Hiramatsu
  2014-12-09  9:14     ` Jon Medhurst (Tixy)
@ 2014-12-09 10:12     ` Wang Nan
  1 sibling, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-09 10:12 UTC (permalink / raw)
  To: Masami Hiramatsu; +Cc: tixy, linux, lizefan, linux-kernel, linux-arm-kernel

On 2014/12/9 14:47, Masami Hiramatsu wrote:
> (2014/12/08 23:09), Wang Nan wrote:
>> This patch introduce kprobeopt for ARM 32.
>>
>> Limitations:
>>  - Currently only kernel compiled with ARM ISA is supported.
>>
>>  - Offset between probe point and optinsn slot must not larger than
>>    32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
>>    things complex. Futher patch can make such optimization.
>>
>> Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
>> ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
>> replace probed instruction by a 'b', branch to trampoline code and then
>> calls optimized_callback(). optimized_callback() calls opt_pre_handler()
>> to execute kprobe handler. It also emulate/simulate replaced instruction.
>>
>> When unregistering kprobe, the deferred manner of unoptimizer may leave
>> branch instruction before optimizer is called. Different from x86_64,
>> which only copy the probed insn after optprobe_template_end and
>> reexecute them, this patch call singlestep to emulate/simulate the insn
>> directly. Futher patch can optimize this behavior.
>>
>> Signed-off-by: Wang Nan <wangnan0@huawei.com>
>> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>> Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
>> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
>> Cc: Will Deacon <will.deacon@arm.com>
>> ---
>> v1 -> v2:
>>  - Improvement: if replaced instruction is conditional, generate a
>>    conditional branch instruction for it;
>>  - Introduces RELATIVEJUMP_OPCODES due to ARM kprobe_opcode_t is 4
>>    bytes;
>>  - Removes size field in struct arch_optimized_insn;
>>  - Use arm_gen_branch() to generate branch instruction;
>>  - Remove all recover logic: ARM doesn't use tail buffer, no need
>>    recover replaced instructions like x86;
>>  - Remove incorrect CONFIG_THUMB checking;
>>  - can_optimize() always returns true if address is well aligned;
>>  - Improve optimized_callback: using opt_pre_handler();
>>  - Bugfix: correct range checking code and improve comments;
>>  - Fix commit message.
>>
>> v2 -> v3:
>>  - Rename RELATIVEJUMP_OPCODES to MAX_COPIED_INSNS;
>>  - Remove unneeded checking:
>>       arch_check_optimized_kprobe(), can_optimize();
>>  - Add missing flush_icache_range() in arch_prepare_optimized_kprobe();
>>  - Remove unneeded 'return;'.
>>
>> v3 -> v4:
>>  - Use __mem_to_opcode_arm() to translate copied_insn to ensure it
>>    works in big endian kernel;
>>  - Replace 'nop' placeholder in trampoline code template with
>>    '.long 0' to avoid confusion: reader may regard 'nop' as an
>>    instruction, but it is value in fact.
>>
>> v4 -> v5:
>>  - Don't optimize stack store operations.
>>  - Introduce prepared field to arch_optimized_insn to indicate whether
>>    it is prepared. Similar to size field with x86. See v1 -> v2.
>>
>> v5 -> v6:
>>  - Dynamically reserve stack according to instruction.
>>  - Rename: kprobes-opt.c -> kprobes-opt-arm.c.
>>  - Set op->optinsn.insn after all works are done.
>>
>> v6 -> v7:
>>   - Using checker to check stack consumption.
>>
>> v7 -> v8:
>>   - Small code adjustments.
>>
>> v8 -> v9:
>>   - Utilize original kprobe passed to arch_prepare_optimized_kprobe()
>>     to avoid copy ainsn twice.
>>   - A bug in arch_prepare_optimized_kprobe() is found and fixed.
>>
>> v9 -> v10:
>>   - Commit message improvements.
>>
>> v10 -> v11:
>>   - Move to arch/arm/probes/, insn.h is moved to arch/arm/include/asm.
>>   - Code cleanup.
>>   - Bugfix based on Tixy's test result:
>>     - Trampoline deal with ARM -> Thumb transision instructions and
>>       AEABI stack alignment requirement correctly.
>>     - Trampoline code buffer should start at 4 byte aligned address.
>>       We enforces it in this series by using macro to wrap 'code' var.
>>
>> v11 -> v12:
>>   - Remove trampoline code stack trick and use r4 to save original
>>     stack.
>>   - Remove trampoline code buffer alignment trick.
>>   - Names of files are changed.
>>
>> v12 -> v13:
>>   - Assume stack always aligned by 4-bytes in any case.
>>   - Comments update.
>>
>> v13 -> v14:
>>   - Use stop_machine to wrap arch_optimize_kprobes to avoid a racing.
>>
>> v14 -> v15:
>>   - In v14, stop_machine() wraps a coarse-grained piece of code which
>>     makes things complex than it should be. In this version,
>>     kprobes_remove_breakpoint() is extracted, core.c and opt-arm.c use it
>>     to replace breakpoint to valid instruction. stop_machine() used inside
>>     in kprobes_remove_breakpoint().
>> ---
>>  arch/arm/Kconfig                        |   1 +
>>  arch/arm/{kernel => include/asm}/insn.h |   0
>>  arch/arm/include/asm/kprobes.h          |  29 +++
>>  arch/arm/kernel/Makefile                |   2 +-
>>  arch/arm/kernel/ftrace.c                |   3 +-
>>  arch/arm/kernel/jump_label.c            |   3 +-
>>  arch/arm/probes/kprobes/Makefile        |   1 +
>>  arch/arm/probes/kprobes/core.c          |  26 ++-
>>  arch/arm/probes/kprobes/core.h          |   2 +
>>  arch/arm/probes/kprobes/opt-arm.c       | 317 ++++++++++++++++++++++++++++++++
>>  10 files changed, 372 insertions(+), 12 deletions(-)
>>  rename arch/arm/{kernel => include/asm}/insn.h (100%)
>>  create mode 100644 arch/arm/probes/kprobes/opt-arm.c
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index 89c4b5c..2471240 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -59,6 +59,7 @@ config ARM
>>  	select HAVE_MEMBLOCK
>>  	select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND
>>  	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
>> +	select HAVE_OPTPROBES if !THUMB2_KERNEL
>>  	select HAVE_PERF_EVENTS
>>  	select HAVE_PERF_REGS
>>  	select HAVE_PERF_USER_STACK_DUMP
>> diff --git a/arch/arm/kernel/insn.h b/arch/arm/include/asm/insn.h
>> similarity index 100%
>> rename from arch/arm/kernel/insn.h
>> rename to arch/arm/include/asm/insn.h
>> diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
>> index 56f9ac6..50ff3bc 100644
>> --- a/arch/arm/include/asm/kprobes.h
>> +++ b/arch/arm/include/asm/kprobes.h
>> @@ -50,5 +50,34 @@ int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
>>  int kprobe_exceptions_notify(struct notifier_block *self,
>>  			     unsigned long val, void *data);
>>  
>> +/* optinsn template addresses */
>> +extern __visible kprobe_opcode_t optprobe_template_entry;
>> +extern __visible kprobe_opcode_t optprobe_template_val;
>> +extern __visible kprobe_opcode_t optprobe_template_call;
>> +extern __visible kprobe_opcode_t optprobe_template_end;
>> +extern __visible kprobe_opcode_t optprobe_template_sub_sp;
>> +extern __visible kprobe_opcode_t optprobe_template_add_sp;
>> +
>> +#define MAX_OPTIMIZED_LENGTH	4
>> +#define MAX_OPTINSN_SIZE				\
>> +	((unsigned long)&optprobe_template_end -	\
>> +	 (unsigned long)&optprobe_template_entry)
>> +#define RELATIVEJUMP_SIZE	4
>> +
>> +struct arch_optimized_insn {
>> +	/*
>> +	 * copy of the original instructions.
>> +	 * Different from x86, ARM kprobe_opcode_t is u32.
>> +	 */
>> +#define MAX_COPIED_INSN	DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
>> +	kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
>> +	/* detour code buffer */
>> +	kprobe_opcode_t *insn;
>> +	/*
>> +	 * We always copy one instruction on ARM,
>> +	 * so size will always be 4, and unlike x86, there is no
>> +	 * need for a size field.
>> +	 */
>> +};
>>  
>>  #endif /* _ARM_KPROBES_H */
>> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
>> index 40d3e00..1d0f4e7 100644
>> --- a/arch/arm/kernel/Makefile
>> +++ b/arch/arm/kernel/Makefile
>> @@ -52,7 +52,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
>>  obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
>>  obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
>>  # Main staffs in KPROBES are in arch/arm/probes/ .
>> -obj-$(CONFIG_KPROBES)		+= patch.o
>> +obj-$(CONFIG_KPROBES)		+= patch.o insn.o
>>  obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
>>  obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
>>  obj-$(CONFIG_KGDB)		+= kgdb.o
>> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
>> index af9a8a9..ec7e332 100644
>> --- a/arch/arm/kernel/ftrace.c
>> +++ b/arch/arm/kernel/ftrace.c
>> @@ -19,8 +19,7 @@
>>  #include <asm/cacheflush.h>
>>  #include <asm/opcodes.h>
>>  #include <asm/ftrace.h>
>> -
>> -#include "insn.h"
>> +#include <asm/insn.h>
>>  
>>  #ifdef CONFIG_THUMB2_KERNEL
>>  #define	NOP		0xf85deb04	/* pop.w {lr} */
>> diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
>> index c6c73ed..35a8fbb 100644
>> --- a/arch/arm/kernel/jump_label.c
>> +++ b/arch/arm/kernel/jump_label.c
>> @@ -1,8 +1,7 @@
>>  #include <linux/kernel.h>
>>  #include <linux/jump_label.h>
>>  #include <asm/patch.h>
>> -
>> -#include "insn.h"
>> +#include <asm/insn.h>
>>  
>>  #ifdef HAVE_JUMP_LABEL
>>  
>> diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
>> index bc8d504..76a36bf 100644
>> --- a/arch/arm/probes/kprobes/Makefile
>> +++ b/arch/arm/probes/kprobes/Makefile
>> @@ -7,5 +7,6 @@ obj-$(CONFIG_KPROBES)		+= actions-thumb.o checkers-thumb.o
>>  test-kprobes-objs		+= test-thumb.o
>>  else
>>  obj-$(CONFIG_KPROBES)		+= actions-arm.o checkers-arm.o
>> +obj-$(CONFIG_OPTPROBES)		+= opt-arm.o
>>  test-kprobes-objs		+= test-arm.o
>>  endif
>> diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
>> index 3a58db4..a4ec240 100644
>> --- a/arch/arm/probes/kprobes/core.c
>> +++ b/arch/arm/probes/kprobes/core.c
>> @@ -163,19 +163,31 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
>>   * memory. It is also needed to atomically set the two half-words of a 32-bit
>>   * Thumb breakpoint.
>>   */
>> -int __kprobes __arch_disarm_kprobe(void *p)
>> -{
>> -	struct kprobe *kp = p;
>> -	void *addr = (void *)((uintptr_t)kp->addr & ~1);
>> -
>> -	__patch_text(addr, kp->opcode);
>> +struct patch {
>> +	void *addr;
>> +	unsigned int insn;
>> +};
>>  
>> +static int __kprobes_remove_breakpoint(void *data)
>> +{
>> +	struct patch *p = data;
>> +	__patch_text(p->addr, p->insn);
>>  	return 0;
>>  }
>>  
>> +void __kprobes kprobes_remove_breakpoint(void *addr, unsigned int insn)
>> +{
>> +	struct patch p = {
>> +		.addr = addr,
>> +		.insn = insn,
>> +	};
>> +	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
>> +}
> 
> Hmm, I think finally we should fix patch_text() in patch.c to forcibly use stop_machine
> by adding "bool stop" parameter, instead of introducing new another patch_text()
> implementation, because we'd better avoid two private "patch" data structures.
> Maybe someday we can find another better solution for self modifying.
> (I actually doesn't like stop_machine() which disturbs real-time processing)
> 
> The other parts look good to me :)
> 

So what's your opinion about this series of patches? Do you think they can be merged
into upstream code already? Or do you think we should eliminate stop_machine() first?

> Thank you!
> 
> 



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-09  9:14     ` Jon Medhurst (Tixy)
@ 2014-12-09 10:25       ` Masami Hiramatsu
  0 siblings, 0 replies; 22+ messages in thread
From: Masami Hiramatsu @ 2014-12-09 10:25 UTC (permalink / raw)
  To: Jon Medhurst (Tixy)
  Cc: Wang Nan, linux, lizefan, linux-kernel, linux-arm-kernel

(2014/12/09 18:14), Jon Medhurst (Tixy) wrote:
[...]
>>> diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
>>> index 3a58db4..a4ec240 100644
>>> --- a/arch/arm/probes/kprobes/core.c
>>> +++ b/arch/arm/probes/kprobes/core.c
>>> @@ -163,19 +163,31 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
>>>   * memory. It is also needed to atomically set the two half-words of a 32-bit
>>>   * Thumb breakpoint.
>>>   */
>>> -int __kprobes __arch_disarm_kprobe(void *p)
>>> -{
>>> -	struct kprobe *kp = p;
>>> -	void *addr = (void *)((uintptr_t)kp->addr & ~1);
>>> -
>>> -	__patch_text(addr, kp->opcode);
>>> +struct patch {
>>> +	void *addr;
>>> +	unsigned int insn;
>>> +};
>>>  
>>> +static int __kprobes_remove_breakpoint(void *data)
>>> +{
>>> +	struct patch *p = data;
>>> +	__patch_text(p->addr, p->insn);
>>>  	return 0;
>>>  }
>>>  
>>> +void __kprobes kprobes_remove_breakpoint(void *addr, unsigned int insn)
>>> +{
>>> +	struct patch p = {
>>> +		.addr = addr,
>>> +		.insn = insn,
>>> +	};
>>> +	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
>>> +}
>>
>> Hmm, I think finally we should fix patch_text() in patch.c to forcibly use stop_machine
>> by adding "bool stop" parameter, instead of introducing new another patch_text()
>> implementation, because we'd better avoid two private "patch" data structures.
> 
> That was my first thought too, then I realised that breaks encapsulation
> of the patch_text implementation, because its use of stop_machine is an
> implementation detail and it could be rewritten to not use stop machine.
> (That is sort of on my long term todo list
> https://lkml.org/lkml/2014/9/4/188)

Indeed. OK, now let it goes. :)

> Whereas stop machine is used by kprobes to avoid race conditions with
> the undefined instruction exception handler and something like that
> would be needed even if patch_text didn't use stop_machine.

At this point, it's OK.

However, I'm not convinced completely. Perhaps, it depends on cache-coherent bus
implementation, but there may be some implementations which can allow us to
change one instruction atomically without stop_machine.

I'm actually interested in PREEMPT_RT on arm32, and this stop_machine() is a barrier
to apply kprobes on real-time systems.

Thank you,


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v2] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-08 14:09 ` [RESEND][PATCH v15 5/7] ARM: kprobes: Add test cases for " Wang Nan
@ 2014-12-09 16:43   ` Jon Medhurst (Tixy)
  2014-12-09 17:11     ` [PATCH v3] " Jon Medhurst (Tixy)
  0 siblings, 1 reply; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-09 16:43 UTC (permalink / raw)
  To: Wang Nan
  Cc: masami.hiramatsu.pt, linux, lizefan, linux-kernel, linux-arm-kernel

These have extra 'checker' functions associated with them so lets make
sure those get covered by testing. As they may create uninitialised
space on the stack we also update the test code to ensure such space is
consistent between test runs. This is done by disabling interrupts in
setup_test_context().

Signed-off-by: Jon Medhurst <tixy@linaro.org>
---

OK, so I lied in [1] when I said I won't be looking at the test failure
for a few days, I had a sudden inspiration on how to fix things and the
changes to test-core.c in this patch are the result. Rest of the patch
is the same as the version posted in Wang Nan's v15 patch set [2]

With this change the kprobe test code passes on my TC2 with both ARM and
Thumb kernels and both with and without optprobes forced using
wait_for_kprobe_optimizer() hacks.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/309574.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/309399.html


 arch/arm/probes/kprobes/test-arm.c   | 17 +++++++++++++++--
 arch/arm/probes/kprobes/test-core.c  | 10 ++++++++++
 arch/arm/probes/kprobes/test-thumb.c | 12 ++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
index fdeb300..9b3b1b4 100644
--- a/arch/arm/probes/kprobes/test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <asm/system_info.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -478,6 +479,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strh	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")
 	TEST_RPR(  "streqh	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")
 	TEST_UNSUPPORTED(  "streqh	r14, [r13, r12]")
+	TEST_UNSUPPORTED(  "streqh	r14, [r12, r13]")
 	TEST_RPR(  "strh	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")
 	TEST_RPR(  "strneh	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strh	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")
@@ -502,6 +504,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strplh	r",12,VAL2,", [r",11,24,", #-4]!")
 	TEST_RP(   "strh	r",2, VAL1,", [r",3, 24,"], #48")
 	TEST_RP(   "strh	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strh	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strh r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strh	r",4, VAL1,", [r",14,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3b0) "	@ strh r12, [pc, #48]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe0c9f3b0) "	@ strh pc, [r9], #48")
 
@@ -568,6 +573,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
 	TEST_RPR(  "strccd	r",8, VAL2,", [r",11,0, ", r",12,48,"]")
 	TEST_UNSUPPORTED(  "strccd r8, [r13, r12]")
+	TEST_UNSUPPORTED(  "strccd r8, [r12, r13]")
 	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
 	TEST_RPR(  "strcsd	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strd	r",2, VAL1,", [r",5, 24,"], r",4,48,"")
@@ -591,6 +597,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strvcd	r",12,VAL2,", [r",11,24,", #-16]!")
 	TEST_RP(   "strd	r",2, VAL1,", [r",4, 24,"], #48")
 	TEST_RP(   "strd	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strd	r",6, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strd	r",4, VAL1,", [r",12,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3f0) "	@ strd r12, [pc, #48]!")
 
 	TEST_P(	   "ldrd	r0, [r",0, 24,", #-8]")
@@ -639,16 +648,20 @@ void kprobe_arm_test_cases(void)
 	TEST_RP( "str"byte"	r",12,VAL2,", [r",11,24,", #-4]!")		\
 	TEST_RP( "str"byte"	r",2, VAL1,", [r",3, 24,"], #48")		\
 	TEST_RP( "str"byte"	r",10,VAL2,", [r",9, 64,"], #-48")		\
+	TEST_RP( "str"byte"	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"byte" r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")				\
+	TEST_RP( "str"byte"	r",4, VAL1,", [r",10,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")	\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")	\
-	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")	\
+	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")				\
+	TEST_UNSUPPORTED("str"byte" r14, [r12, r13]")				\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")	\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")	\
 	TEST_RPR("str"byte"	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")	\
 	TEST_RPR("str"byte"	r",10,VAL2,", [r",9, 48,"], -r",11,24,"")	\
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 24,", r",2,  32,", asl #1]")\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\
-	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")\
+	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")		\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  32,", asr #3]!")\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\
 	TEST_P(  "ldr"byte"	r0, [r",0,  24,", #-2]")			\
diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
index 7ab633d..2b854ed 100644
--- a/arch/arm/probes/kprobes/test-core.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -1196,6 +1196,13 @@ static void setup_test_context(struct pt_regs *regs)
 			regs->uregs[arg->reg] =
 				(unsigned long)current_stack + arg->val;
 			memory_needs_checking = true;
+			/*
+			 * Test memory at an address below SP is in danger of
+			 * being altered by an interrupt occurring and pushing
+			 * data onto the stack. Disable interrupts to stop this.
+			 */
+			if (arg->reg == 13)
+				regs->ARM_cpsr |= PSR_I_BIT;
 			break;
 		}
 		case ARG_TYPE_MEM: {
@@ -1206,6 +1213,7 @@ static void setup_test_context(struct pt_regs *regs)
 		default:
 			break;
 		}
+
 }
 
 struct test_probe {
@@ -1272,6 +1280,8 @@ test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 	/* Undo any changes done to SP by the test case */
 	regs->ARM_sp = (unsigned long)current_stack;
+	/* Enable interrupts in case setup_test_context diabled them */
+	regs->ARM_cpsr &= ~PSR_I_BIT;
 
 	container_of(p, struct test_probe, kprobe)->hit = test_instance;
 	return 0;
diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
index 6c6e9a9..e8cf193 100644
--- a/arch/arm/probes/kprobes/test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -416,6 +417,9 @@ void kprobe_thumb32_test_cases(void)
 	TEST_RR( "strd	r",14,VAL2,", r",12,VAL1,", [sp, #16]!")
 	TEST_RRP("strd	r",1, VAL1,", r",0, VAL2,", [r",7, 24,"], #16")
 	TEST_RR( "strd	r",7, VAL2,", r",8, VAL1,", [sp], #-16")
+	TEST_RRP("strd	r",6, VAL1,", r",7, VAL2,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, r7, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RRP("strd	r",4, VAL1,", r",5, VAL2,", [r",14, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe9efec04) "	@ strd	r14, r12, [pc, #16]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe8efec04) "	@ strd	r14, r12, [pc], #16")
 
@@ -821,14 +825,22 @@ CONDITION_INSTRUCTIONS(22,
 	TEST_RP( "str"size"	r",14,VAL2,", [r",1, 256,  ", #-128]!")		\
 	TEST_RPR("str"size".w	r",0, VAL1,", [r",1, 0,", r",2, 4,"]")		\
 	TEST_RPR("str"size"	r",14,VAL2,", [r",10,0,", r",11,4,", lsl #1]")	\
+	TEST_UNSUPPORTED("str"size"	r0, [r13, r1]")				\
 	TEST_R(  "str"size".w	r",7, VAL1,", [sp, #24]")			\
 	TEST_RP( "str"size".w	r",0, VAL2,", [r",0,0, "]")			\
+	TEST_RP( "str"size"	r",6, VAL1,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"size"	r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")			\
+	TEST_RP( "str"size"	r",4, VAL2,", [r",12, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_UNSUPPORTED("str"size"t	r0, [r1, #4]")
 
 	SINGLE_STORE("b")
 	SINGLE_STORE("h")
 	SINGLE_STORE("")
 
+	TEST_UNSUPPORTED(__inst_thumb32(0xf801000d) "	@ strb	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf821000d) "	@ strh	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf841000d) "	@ str	r0, [r1, r13]")
+
 	TEST("str	sp, [sp]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cfe000) "	@ str	r14, [pc]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cef000) "	@ str	pc, [r14]")
-- 
2.1.3




^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-09 16:43   ` [PATCH v2] " Jon Medhurst (Tixy)
@ 2014-12-09 17:11     ` Jon Medhurst (Tixy)
  2014-12-10  8:23       ` Wang Nan
  0 siblings, 1 reply; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-09 17:11 UTC (permalink / raw)
  To: Wang Nan
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

These have extra 'checker' functions associated with them so lets make
sure those get covered by testing. As they may create uninitialised
space on the stack we also update the test code to ensure such space is
consistent between test runs. This is done by disabling interrupts in
setup_test_context().

Signed-off-by: Jon Medhurst <tixy@linaro.org>
---

Sorry for the extra noise, sent this new version to correct whitespace
and spelling errors in previous one.

 arch/arm/probes/kprobes/test-arm.c   | 17 +++++++++++++++--
 arch/arm/probes/kprobes/test-core.c  |  9 +++++++++
 arch/arm/probes/kprobes/test-thumb.c | 12 ++++++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
index fdeb300..9b3b1b4 100644
--- a/arch/arm/probes/kprobes/test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <asm/system_info.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -478,6 +479,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strh	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")
 	TEST_RPR(  "streqh	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")
 	TEST_UNSUPPORTED(  "streqh	r14, [r13, r12]")
+	TEST_UNSUPPORTED(  "streqh	r14, [r12, r13]")
 	TEST_RPR(  "strh	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")
 	TEST_RPR(  "strneh	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strh	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")
@@ -502,6 +504,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strplh	r",12,VAL2,", [r",11,24,", #-4]!")
 	TEST_RP(   "strh	r",2, VAL1,", [r",3, 24,"], #48")
 	TEST_RP(   "strh	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strh	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strh r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strh	r",4, VAL1,", [r",14,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3b0) "	@ strh r12, [pc, #48]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe0c9f3b0) "	@ strh pc, [r9], #48")
 
@@ -568,6 +573,7 @@ void kprobe_arm_test_cases(void)
 	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
 	TEST_RPR(  "strccd	r",8, VAL2,", [r",11,0, ", r",12,48,"]")
 	TEST_UNSUPPORTED(  "strccd r8, [r13, r12]")
+	TEST_UNSUPPORTED(  "strccd r8, [r12, r13]")
 	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
 	TEST_RPR(  "strcsd	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
 	TEST_RPR(  "strd	r",2, VAL1,", [r",5, 24,"], r",4,48,"")
@@ -591,6 +597,9 @@ void kprobe_arm_test_cases(void)
 	TEST_RP(   "strvcd	r",12,VAL2,", [r",11,24,", #-16]!")
 	TEST_RP(   "strd	r",2, VAL1,", [r",4, 24,"], #48")
 	TEST_RP(   "strd	r",10,VAL2,", [r",9, 64,"], #-48")
+	TEST_RP(   "strd	r",6, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RP(   "strd	r",4, VAL1,", [r",12,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3f0) "	@ strd r12, [pc, #48]!")
 
 	TEST_P(	   "ldrd	r0, [r",0, 24,", #-8]")
@@ -639,16 +648,20 @@ void kprobe_arm_test_cases(void)
 	TEST_RP( "str"byte"	r",12,VAL2,", [r",11,24,", #-4]!")		\
 	TEST_RP( "str"byte"	r",2, VAL1,", [r",3, 24,"], #48")		\
 	TEST_RP( "str"byte"	r",10,VAL2,", [r",9, 64,"], #-48")		\
+	TEST_RP( "str"byte"	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"byte" r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")				\
+	TEST_RP( "str"byte"	r",4, VAL1,", [r",10,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")	\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")	\
-	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")	\
+	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")				\
+	TEST_UNSUPPORTED("str"byte" r14, [r12, r13]")				\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")	\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")	\
 	TEST_RPR("str"byte"	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")	\
 	TEST_RPR("str"byte"	r",10,VAL2,", [r",9, 48,"], -r",11,24,"")	\
 	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 24,", r",2,  32,", asl #1]")\
 	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\
-	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")\
+	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")		\
 	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  32,", asr #3]!")\
 	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\
 	TEST_P(  "ldr"byte"	r0, [r",0,  24,", #-2]")			\
diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
index 7ab633d..7c5ddd5 100644
--- a/arch/arm/probes/kprobes/test-core.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -1196,6 +1196,13 @@ static void setup_test_context(struct pt_regs *regs)
 			regs->uregs[arg->reg] =
 				(unsigned long)current_stack + arg->val;
 			memory_needs_checking = true;
+			/*
+			 * Test memory at an address below SP is in danger of
+			 * being altered by an interrupt occurring and pushing
+			 * data onto the stack. Disable interrupts to stop this.
+			 */
+			if (arg->reg == 13)
+				regs->ARM_cpsr |= PSR_I_BIT;
 			break;
 		}
 		case ARG_TYPE_MEM: {
@@ -1272,6 +1279,8 @@ test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 	/* Undo any changes done to SP by the test case */
 	regs->ARM_sp = (unsigned long)current_stack;
+	/* Enable interrupts in case setup_test_context disabled them */
+	regs->ARM_cpsr &= ~PSR_I_BIT;
 
 	container_of(p, struct test_probe, kprobe)->hit = test_instance;
 	return 0;
diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
index 6c6e9a9..e8cf193 100644
--- a/arch/arm/probes/kprobes/test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <asm/opcodes.h>
+#include <asm/probes.h>
 
 #include "test-core.h"
 
@@ -416,6 +417,9 @@ void kprobe_thumb32_test_cases(void)
 	TEST_RR( "strd	r",14,VAL2,", r",12,VAL1,", [sp, #16]!")
 	TEST_RRP("strd	r",1, VAL1,", r",0, VAL2,", [r",7, 24,"], #16")
 	TEST_RR( "strd	r",7, VAL2,", r",8, VAL1,", [sp], #-16")
+	TEST_RRP("strd	r",6, VAL1,", r",7, VAL2,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
+	TEST_UNSUPPORTED("strd r6, r7, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
+	TEST_RRP("strd	r",4, VAL1,", r",5, VAL2,", [r",14, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe9efec04) "	@ strd	r14, r12, [pc, #16]!")
 	TEST_UNSUPPORTED(__inst_thumb32(0xe8efec04) "	@ strd	r14, r12, [pc], #16")
 
@@ -821,14 +825,22 @@ CONDITION_INSTRUCTIONS(22,
 	TEST_RP( "str"size"	r",14,VAL2,", [r",1, 256,  ", #-128]!")		\
 	TEST_RPR("str"size".w	r",0, VAL1,", [r",1, 0,", r",2, 4,"]")		\
 	TEST_RPR("str"size"	r",14,VAL2,", [r",10,0,", r",11,4,", lsl #1]")	\
+	TEST_UNSUPPORTED("str"size"	r0, [r13, r1]")				\
 	TEST_R(  "str"size".w	r",7, VAL1,", [sp, #24]")			\
 	TEST_RP( "str"size".w	r",0, VAL2,", [r",0,0, "]")			\
+	TEST_RP( "str"size"	r",6, VAL1,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
+	TEST_UNSUPPORTED("str"size"	r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")			\
+	TEST_RP( "str"size"	r",4, VAL2,", [r",12, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
 	TEST_UNSUPPORTED("str"size"t	r0, [r1, #4]")
 
 	SINGLE_STORE("b")
 	SINGLE_STORE("h")
 	SINGLE_STORE("")
 
+	TEST_UNSUPPORTED(__inst_thumb32(0xf801000d) "	@ strb	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf821000d) "	@ strh	r0, [r1, r13]")
+	TEST_UNSUPPORTED(__inst_thumb32(0xf841000d) "	@ str	r0, [r1, r13]")
+
 	TEST("str	sp, [sp]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cfe000) "	@ str	r14, [pc]")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf8cef000) "	@ str	pc, [r14]")
-- 
2.1.3




^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-09 17:11     ` [PATCH v3] " Jon Medhurst (Tixy)
@ 2014-12-10  8:23       ` Wang Nan
  2014-12-10 12:34         ` Jon Medhurst (Tixy)
  0 siblings, 1 reply; 22+ messages in thread
From: Wang Nan @ 2014-12-10  8:23 UTC (permalink / raw)
  To: Jon Medhurst (Tixy)
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

Hi Tixy,

I experienced another FAIL during test:

[11567.220477] Miscellaneous instructions
[11567.265397] ---------------------------------------------------------
[11567.342626] mrs	r0, cpsr	@ e10f0000
[11568.612656] FAIL: registers differ
[11568.653414] FAIL: Test mrs	r0, cpsr
[11568.695210] FAIL: Scenario 5
[11568.729709] initial_regs:
[11568.761083] r0  21522152 | r1  21522052 | r2  21522352 | r3  21522252
[11568.838301] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
[11568.915526] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
[11568.992748] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f590
[11569.069969] cpsr 58050013
[11569.101336] expected_regs:
[11569.133750] r0  58050013 | r1  21522052 | r2  21522352 | r3  21522252
[11569.210975] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
[11569.288197] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
[11569.365417] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
[11569.442634] cpsr 58050013
[11569.474010] result_regs:
[11569.504337] r0  58050113 | r1  21522052 | r2  21522352 | r3  21522252     <--- see R0 in this line
[11569.581556] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
[11569.658776] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
[11569.736000] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
[11569.813222] cpsr 58050013
[11569.844593] mrspl	r7, cpsr	@ 510f7000
[11571.842652] mrs	r14, cpsr	@ e10fe000

The failure is raise when testing in "mrs r0, cpsr". The added bit is PSR_A_BIT, which
should be ignored.

So looks like this is also a problem in your test framework. If you don't have
enough time, you can give me some hints to deal with it.

On 2014/12/10 1:11, Jon Medhurst (Tixy) wrote:
> These have extra 'checker' functions associated with them so lets make
> sure those get covered by testing. As they may create uninitialised
> space on the stack we also update the test code to ensure such space is
> consistent between test runs. This is done by disabling interrupts in
> setup_test_context().
> 
> Signed-off-by: Jon Medhurst <tixy@linaro.org>
> ---
> 
> Sorry for the extra noise, sent this new version to correct whitespace
> and spelling errors in previous one.
> 
>  arch/arm/probes/kprobes/test-arm.c   | 17 +++++++++++++++--
>  arch/arm/probes/kprobes/test-core.c  |  9 +++++++++
>  arch/arm/probes/kprobes/test-thumb.c | 12 ++++++++++++
>  3 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
> index fdeb300..9b3b1b4 100644
> --- a/arch/arm/probes/kprobes/test-arm.c
> +++ b/arch/arm/probes/kprobes/test-arm.c
> @@ -12,6 +12,7 @@
>  #include <linux/module.h>
>  #include <asm/system_info.h>
>  #include <asm/opcodes.h>
> +#include <asm/probes.h>
>  
>  #include "test-core.h"
>  
> @@ -478,6 +479,7 @@ void kprobe_arm_test_cases(void)
>  	TEST_RPR(  "strh	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")
>  	TEST_RPR(  "streqh	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")
>  	TEST_UNSUPPORTED(  "streqh	r14, [r13, r12]")
> +	TEST_UNSUPPORTED(  "streqh	r14, [r12, r13]")
>  	TEST_RPR(  "strh	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")
>  	TEST_RPR(  "strneh	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
>  	TEST_RPR(  "strh	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")
> @@ -502,6 +504,9 @@ void kprobe_arm_test_cases(void)
>  	TEST_RP(   "strplh	r",12,VAL2,", [r",11,24,", #-4]!")
>  	TEST_RP(   "strh	r",2, VAL1,", [r",3, 24,"], #48")
>  	TEST_RP(   "strh	r",10,VAL2,", [r",9, 64,"], #-48")
> +	TEST_RP(   "strh	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
> +	TEST_UNSUPPORTED("strh r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
> +	TEST_RP(   "strh	r",4, VAL1,", [r",14,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
>  	TEST_UNSUPPORTED(__inst_arm(0xe1efc3b0) "	@ strh r12, [pc, #48]!")
>  	TEST_UNSUPPORTED(__inst_arm(0xe0c9f3b0) "	@ strh pc, [r9], #48")
>  
> @@ -568,6 +573,7 @@ void kprobe_arm_test_cases(void)
>  	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
>  	TEST_RPR(  "strccd	r",8, VAL2,", [r",11,0, ", r",12,48,"]")
>  	TEST_UNSUPPORTED(  "strccd r8, [r13, r12]")
> +	TEST_UNSUPPORTED(  "strccd r8, [r12, r13]")
>  	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
>  	TEST_RPR(  "strcsd	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")
>  	TEST_RPR(  "strd	r",2, VAL1,", [r",5, 24,"], r",4,48,"")
> @@ -591,6 +597,9 @@ void kprobe_arm_test_cases(void)
>  	TEST_RP(   "strvcd	r",12,VAL2,", [r",11,24,", #-16]!")
>  	TEST_RP(   "strd	r",2, VAL1,", [r",4, 24,"], #48")
>  	TEST_RP(   "strd	r",10,VAL2,", [r",9, 64,"], #-48")
> +	TEST_RP(   "strd	r",6, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
> +	TEST_UNSUPPORTED("strd r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
> +	TEST_RP(   "strd	r",4, VAL1,", [r",12,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
>  	TEST_UNSUPPORTED(__inst_arm(0xe1efc3f0) "	@ strd r12, [pc, #48]!")
>  
>  	TEST_P(	   "ldrd	r0, [r",0, 24,", #-8]")
> @@ -639,16 +648,20 @@ void kprobe_arm_test_cases(void)
>  	TEST_RP( "str"byte"	r",12,VAL2,", [r",11,24,", #-4]!")		\
>  	TEST_RP( "str"byte"	r",2, VAL1,", [r",3, 24,"], #48")		\
>  	TEST_RP( "str"byte"	r",10,VAL2,", [r",9, 64,"], #-48")		\
> +	TEST_RP( "str"byte"	r",3, VAL1,", [r",13,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
> +	TEST_UNSUPPORTED("str"byte" r3, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")				\
> +	TEST_RP( "str"byte"	r",4, VAL1,", [r",10,TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
>  	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 48,", -r",2, 24,"]")	\
>  	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 48,"]")	\
> -	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")	\
> +	TEST_UNSUPPORTED("str"byte" r14, [r13, r12]")				\
> +	TEST_UNSUPPORTED("str"byte" r14, [r12, r13]")				\
>  	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  48,"]!")	\
>  	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,48,", -r",10,24,"]!")	\
>  	TEST_RPR("str"byte"	r",2, VAL1,", [r",3, 24,"], r",4, 48,"")	\
>  	TEST_RPR("str"byte"	r",10,VAL2,", [r",9, 48,"], -r",11,24,"")	\
>  	TEST_RPR("str"byte"	r",0, VAL1,", [r",1, 24,", r",2,  32,", asl #1]")\
>  	TEST_RPR("str"byte"	r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\
> -	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")\
> +	TEST_UNSUPPORTED("str"byte"	r14, [r13, r12, lsr #2]")		\
>  	TEST_RPR("str"byte"	r",1, VAL1,", [r",2, 24,", r",3,  32,", asr #3]!")\
>  	TEST_RPR("str"byte"	r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\
>  	TEST_P(  "ldr"byte"	r0, [r",0,  24,", #-2]")			\
> diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
> index 7ab633d..7c5ddd5 100644
> --- a/arch/arm/probes/kprobes/test-core.c
> +++ b/arch/arm/probes/kprobes/test-core.c
> @@ -1196,6 +1196,13 @@ static void setup_test_context(struct pt_regs *regs)
>  			regs->uregs[arg->reg] =
>  				(unsigned long)current_stack + arg->val;
>  			memory_needs_checking = true;
> +			/*
> +			 * Test memory at an address below SP is in danger of
> +			 * being altered by an interrupt occurring and pushing
> +			 * data onto the stack. Disable interrupts to stop this.
> +			 */
> +			if (arg->reg == 13)
> +				regs->ARM_cpsr |= PSR_I_BIT;
>  			break;
>  		}
>  		case ARG_TYPE_MEM: {
> @@ -1272,6 +1279,8 @@ test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
>  
>  	/* Undo any changes done to SP by the test case */
>  	regs->ARM_sp = (unsigned long)current_stack;
> +	/* Enable interrupts in case setup_test_context disabled them */
> +	regs->ARM_cpsr &= ~PSR_I_BIT;
>  
>  	container_of(p, struct test_probe, kprobe)->hit = test_instance;
>  	return 0;
> diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
> index 6c6e9a9..e8cf193 100644
> --- a/arch/arm/probes/kprobes/test-thumb.c
> +++ b/arch/arm/probes/kprobes/test-thumb.c
> @@ -11,6 +11,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <asm/opcodes.h>
> +#include <asm/probes.h>
>  
>  #include "test-core.h"
>  
> @@ -416,6 +417,9 @@ void kprobe_thumb32_test_cases(void)
>  	TEST_RR( "strd	r",14,VAL2,", r",12,VAL1,", [sp, #16]!")
>  	TEST_RRP("strd	r",1, VAL1,", r",0, VAL2,", [r",7, 24,"], #16")
>  	TEST_RR( "strd	r",7, VAL2,", r",8, VAL1,", [sp], #-16")
> +	TEST_RRP("strd	r",6, VAL1,", r",7, VAL2,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!")
> +	TEST_UNSUPPORTED("strd r6, r7, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")
> +	TEST_RRP("strd	r",4, VAL1,", r",5, VAL2,", [r",14, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xe9efec04) "	@ strd	r14, r12, [pc, #16]!")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xe8efec04) "	@ strd	r14, r12, [pc], #16")
>  
> @@ -821,14 +825,22 @@ CONDITION_INSTRUCTIONS(22,
>  	TEST_RP( "str"size"	r",14,VAL2,", [r",1, 256,  ", #-128]!")		\
>  	TEST_RPR("str"size".w	r",0, VAL1,", [r",1, 0,", r",2, 4,"]")		\
>  	TEST_RPR("str"size"	r",14,VAL2,", [r",10,0,", r",11,4,", lsl #1]")	\
> +	TEST_UNSUPPORTED("str"size"	r0, [r13, r1]")				\
>  	TEST_R(  "str"size".w	r",7, VAL1,", [sp, #24]")			\
>  	TEST_RP( "str"size".w	r",0, VAL2,", [r",0,0, "]")			\
> +	TEST_RP( "str"size"	r",6, VAL1,", [r",13, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"]!") \
> +	TEST_UNSUPPORTED("str"size"	r6, [r13, #-"__stringify(MAX_STACK_SIZE)"-8]!")			\
> +	TEST_RP( "str"size"	r",4, VAL2,", [r",12, TEST_MEMORY_SIZE,", #-"__stringify(MAX_STACK_SIZE)"-8]!") \
>  	TEST_UNSUPPORTED("str"size"t	r0, [r1, #4]")
>  
>  	SINGLE_STORE("b")
>  	SINGLE_STORE("h")
>  	SINGLE_STORE("")
>  
> +	TEST_UNSUPPORTED(__inst_thumb32(0xf801000d) "	@ strb	r0, [r1, r13]")
> +	TEST_UNSUPPORTED(__inst_thumb32(0xf821000d) "	@ strh	r0, [r1, r13]")
> +	TEST_UNSUPPORTED(__inst_thumb32(0xf841000d) "	@ str	r0, [r1, r13]")
> +
>  	TEST("str	sp, [sp]")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xf8cfe000) "	@ str	r14, [pc]")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xf8cef000) "	@ str	pc, [r14]")
> 



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-10  8:23       ` Wang Nan
@ 2014-12-10 12:34         ` Jon Medhurst (Tixy)
  2014-12-10 13:18           ` Wang Nan
  0 siblings, 1 reply; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-10 12:34 UTC (permalink / raw)
  To: Wang Nan
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

On Wed, 2014-12-10 at 16:23 +0800, Wang Nan wrote:
> Hi Tixy,
> 
> I experienced another FAIL during test:
> 
> [11567.220477] Miscellaneous instructions
> [11567.265397] ---------------------------------------------------------
> [11567.342626] mrs	r0, cpsr	@ e10f0000
> [11568.612656] FAIL: registers differ
> [11568.653414] FAIL: Test mrs	r0, cpsr
> [11568.695210] FAIL: Scenario 5
> [11568.729709] initial_regs:
> [11568.761083] r0  21522152 | r1  21522052 | r2  21522352 | r3  21522252
> [11568.838301] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
> [11568.915526] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
> [11568.992748] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f590
> [11569.069969] cpsr 58050013
> [11569.101336] expected_regs:
> [11569.133750] r0  58050013 | r1  21522052 | r2  21522352 | r3  21522252
> [11569.210975] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
> [11569.288197] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
> [11569.365417] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
> [11569.442634] cpsr 58050013
> [11569.474010] result_regs:
> [11569.504337] r0  58050113 | r1  21522052 | r2  21522352 | r3  21522252     <--- see R0 in this line
> [11569.581556] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
> [11569.658776] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
> [11569.736000] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
> [11569.813222] cpsr 58050013
> [11569.844593] mrspl	r7, cpsr	@ 510f7000
> [11571.842652] mrs	r14, cpsr	@ e10fe000
> 
> The failure is raise when testing in "mrs r0, cpsr". The added bit is PSR_A_BIT, which
> should be ignored.
> 
> So looks like this is also a problem in your test framework. If you don't have
> enough time, you can give me some hints to deal with it.

The problem is that the A bit can change randomly when interrupts or
reschedules happen (I'm not sure it should, and it may be a bug). For
the purposes of this test code, we can't disable interrupts and
scheduling around all the iterations of a test case, because inserting
and removing probes requires them to be enabled. So we need a method of
ignoring bits in cpsr, how about the following patch...

----------------------------------------------------------------------------

From: Jon Medhurst <tixy@linaro.org>
Subject: [PATCH] ARM: kprobes: Fix unreliable MRS instruction tests

For the instruction 'mrs Rn, cpsr' the resulting value of Rn can vary due to
external factors we can't control. So get the test code to mask out these
indeterminate bits.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
---
 arch/arm/probes/kprobes/test-arm.c   |  6 +++---
 arch/arm/probes/kprobes/test-core.c  | 19 ++++++++++---------
 arch/arm/probes/kprobes/test-core.h  | 33 ++++++++++++++++++++++++++++-----
 arch/arm/probes/kprobes/test-thumb.c |  4 ++--
 4 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
index 9b3b1b4..e72b07e 100644
--- a/arch/arm/probes/kprobes/test-arm.c
+++ b/arch/arm/probes/kprobes/test-arm.c
@@ -204,9 +204,9 @@ void kprobe_arm_test_cases(void)
 #endif
 	TEST_GROUP("Miscellaneous instructions")
 
-	TEST("mrs	r0, cpsr")
-	TEST("mrspl	r7, cpsr")
-	TEST("mrs	r14, cpsr")
+	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
+	TEST_RMASKED("mrspl	r",7,~PSR_IGNORE_BITS,", cpsr")
+	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
 	TEST_UNSUPPORTED(__inst_arm(0xe10ff000) "	@ mrs r15, cpsr")
 	TEST_UNSUPPORTED("mrs	r0, spsr")
 	TEST_UNSUPPORTED("mrs	lr, spsr")
diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
index 7c5ddd5..e495127 100644
--- a/arch/arm/probes/kprobes/test-core.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -1056,15 +1056,6 @@ static int test_case_run_count;
 static bool test_case_is_thumb;
 static int test_instance;
 
-/*
- * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
- * can change randomly as the kernel doesn't take care to preserve or initialise
- * this across context switches. Also, with Security Extentions, the flag may
- * not be under control of the kernel; for this reason we ignore the state of
- * the FIQ disable flag CPSR.F as well.
- */
-#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
-
 static unsigned long test_check_cc(int cc, unsigned long cpsr)
 {
 	int ret = arm_check_condition(cc << 28, cpsr);
@@ -1271,11 +1262,21 @@ test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
 static int __kprobes
 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
 {
+	struct test_arg *args;
+
 	if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
 		return 0; /* Already run for this test instance */
 
 	result_regs = *regs;
+
+	/* Mask out results which are indeterminate */
 	result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
+	for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
+		if (args[0].type == ARG_TYPE_REG_MASKED) {
+			struct test_arg_regptr *arg =
+				(struct test_arg_regptr *)args;
+			result_regs.uregs[arg->reg] &= arg->val;
+		}
 
 	/* Undo any changes done to SP by the test case */
 	regs->ARM_sp = (unsigned long)current_stack;
diff --git a/arch/arm/probes/kprobes/test-core.h b/arch/arm/probes/kprobes/test-core.h
index 9991754..32f7aa7 100644
--- a/arch/arm/probes/kprobes/test-core.h
+++ b/arch/arm/probes/kprobes/test-core.h
@@ -45,10 +45,11 @@ extern int kprobe_test_cc_position;
  *
  */
 
-#define	ARG_TYPE_END	0
-#define	ARG_TYPE_REG	1
-#define	ARG_TYPE_PTR	2
-#define	ARG_TYPE_MEM	3
+#define	ARG_TYPE_END		0
+#define	ARG_TYPE_REG		1
+#define	ARG_TYPE_PTR		2
+#define	ARG_TYPE_MEM		3
+#define	ARG_TYPE_REG_MASKED	4
 
 #define ARG_FLAG_UNSUPPORTED	0x01
 #define ARG_FLAG_SUPPORTED	0x02
@@ -61,7 +62,7 @@ struct test_arg {
 };
 
 struct test_arg_regptr {
-	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR */
+	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR or ARG_TYPE_REG_MASKED */
 	u8	reg;
 	u8	_padding[2];
 	u32	val;
@@ -138,6 +139,12 @@ struct test_arg_end {
 	".short	0					\n\t"	\
 	".word	"#val"					\n\t"
 
+#define	TEST_ARG_REG_MASKED(reg, val)				\
+	".byte	"__stringify(ARG_TYPE_REG_MASKED)"	\n\t"	\
+	".byte	"#reg"					\n\t"	\
+	".short	0					\n\t"	\
+	".word	"#val"					\n\t"
+
 #define	TEST_ARG_END(flags)					\
 	".byte	"__stringify(ARG_TYPE_END)"		\n\t"	\
 	".byte	"TEST_ISA flags"			\n\t"	\
@@ -395,6 +402,22 @@ struct test_arg_end {
 	"	"codex"			\n\t"					\
 	TESTCASE_END
 
+#define TEST_RMASKED(code1, reg, mask, code2)		\
+	TESTCASE_START(code1 #reg code2)		\
+	TEST_ARG_REG_MASKED(reg, mask)			\
+	TEST_ARG_END("")				\
+	TEST_INSTRUCTION(code1 #reg code2)		\
+	TESTCASE_END
+
+/*
+ * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
+ * can change randomly as the kernel doesn't take care to preserve or initialise
+ * this across context switches. Also, with Security Extensions, the flag may
+ * not be under control of the kernel; for this reason we ignore the state of
+ * the FIQ disable flag CPSR.F as well.
+ */
+#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
+
 
 /*
  * Macros for defining space directives spread over multiple lines.
diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
index e8cf193..b683b45 100644
--- a/arch/arm/probes/kprobes/test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -778,8 +778,8 @@ CONDITION_INSTRUCTIONS(22,
 
 	TEST_UNSUPPORTED("subs	pc, lr, #4")
 
-	TEST("mrs	r0, cpsr")
-	TEST("mrs	r14, cpsr")
+	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
+	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8d00) "	@ mrs	sp, spsr")
 	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8f00) "	@ mrs	pc, spsr")
 	TEST_UNSUPPORTED("mrs	r0, spsr")
-- 
2.1.3





^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-10 12:34         ` Jon Medhurst (Tixy)
@ 2014-12-10 13:18           ` Wang Nan
  2014-12-10 13:49             ` Jon Medhurst (Tixy)
  2014-12-11  9:56             ` Wang Nan
  0 siblings, 2 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-10 13:18 UTC (permalink / raw)
  To: Jon Medhurst (Tixy)
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

On 2014/12/10 20:34, Jon Medhurst (Tixy) wrote:
> On Wed, 2014-12-10 at 16:23 +0800, Wang Nan wrote:
>> Hi Tixy,
>>
>> I experienced another FAIL during test:
>>
>> [11567.220477] Miscellaneous instructions
>> [11567.265397] ---------------------------------------------------------
>> [11567.342626] mrs	r0, cpsr	@ e10f0000
>> [11568.612656] FAIL: registers differ
>> [11568.653414] FAIL: Test mrs	r0, cpsr
>> [11568.695210] FAIL: Scenario 5
>> [11568.729709] initial_regs:
>> [11568.761083] r0  21522152 | r1  21522052 | r2  21522352 | r3  21522252
>> [11568.838301] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>> [11568.915526] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>> [11568.992748] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f590
>> [11569.069969] cpsr 58050013
>> [11569.101336] expected_regs:
>> [11569.133750] r0  58050013 | r1  21522052 | r2  21522352 | r3  21522252
>> [11569.210975] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>> [11569.288197] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>> [11569.365417] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
>> [11569.442634] cpsr 58050013
>> [11569.474010] result_regs:
>> [11569.504337] r0  58050113 | r1  21522052 | r2  21522352 | r3  21522252     <--- see R0 in this line
>> [11569.581556] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>> [11569.658776] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>> [11569.736000] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
>> [11569.813222] cpsr 58050013
>> [11569.844593] mrspl	r7, cpsr	@ 510f7000
>> [11571.842652] mrs	r14, cpsr	@ e10fe000
>>
>> The failure is raise when testing in "mrs r0, cpsr". The added bit is PSR_A_BIT, which
>> should be ignored.
>>
>> So looks like this is also a problem in your test framework. If you don't have
>> enough time, you can give me some hints to deal with it.
> 
> The problem is that the A bit can change randomly when interrupts or
> reschedules happen (I'm not sure it should, and it may be a bug). For
> the purposes of this test code, we can't disable interrupts and
> scheduling around all the iterations of a test case, because inserting
> and removing probes requires them to be enabled. So we need a method of
> ignoring bits in cpsr, how about the following patch...
> 
> ----------------------------------------------------------------------------
> 
> From: Jon Medhurst <tixy@linaro.org>
> Subject: [PATCH] ARM: kprobes: Fix unreliable MRS instruction tests
> 
> For the instruction 'mrs Rn, cpsr' the resulting value of Rn can vary due to
> external factors we can't control. So get the test code to mask out these
> indeterminate bits.
> 
> Signed-off-by: Jon Medhurst <tixy@linaro.org>
> ---
>  arch/arm/probes/kprobes/test-arm.c   |  6 +++---
>  arch/arm/probes/kprobes/test-core.c  | 19 ++++++++++---------
>  arch/arm/probes/kprobes/test-core.h  | 33 ++++++++++++++++++++++++++++-----
>  arch/arm/probes/kprobes/test-thumb.c |  4 ++--
>  4 files changed, 43 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
> index 9b3b1b4..e72b07e 100644
> --- a/arch/arm/probes/kprobes/test-arm.c
> +++ b/arch/arm/probes/kprobes/test-arm.c
> @@ -204,9 +204,9 @@ void kprobe_arm_test_cases(void)
>  #endif
>  	TEST_GROUP("Miscellaneous instructions")
>  
> -	TEST("mrs	r0, cpsr")
> -	TEST("mrspl	r7, cpsr")
> -	TEST("mrs	r14, cpsr")
> +	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
> +	TEST_RMASKED("mrspl	r",7,~PSR_IGNORE_BITS,", cpsr")
> +	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
>  	TEST_UNSUPPORTED(__inst_arm(0xe10ff000) "	@ mrs r15, cpsr")
>  	TEST_UNSUPPORTED("mrs	r0, spsr")
>  	TEST_UNSUPPORTED("mrs	lr, spsr")
> diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
> index 7c5ddd5..e495127 100644
> --- a/arch/arm/probes/kprobes/test-core.c
> +++ b/arch/arm/probes/kprobes/test-core.c
> @@ -1056,15 +1056,6 @@ static int test_case_run_count;
>  static bool test_case_is_thumb;
>  static int test_instance;
>  
> -/*
> - * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
> - * can change randomly as the kernel doesn't take care to preserve or initialise
> - * this across context switches. Also, with Security Extentions, the flag may
> - * not be under control of the kernel; for this reason we ignore the state of
> - * the FIQ disable flag CPSR.F as well.
> - */
> -#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
> -
>  static unsigned long test_check_cc(int cc, unsigned long cpsr)
>  {
>  	int ret = arm_check_condition(cc << 28, cpsr);
> @@ -1271,11 +1262,21 @@ test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
>  static int __kprobes
>  test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
>  {
> +	struct test_arg *args;
> +
>  	if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
>  		return 0; /* Already run for this test instance */
>  
>  	result_regs = *regs;
> +
> +	/* Mask out results which are indeterminate */
>  	result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
> +	for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
> +		if (args[0].type == ARG_TYPE_REG_MASKED) {
> +			struct test_arg_regptr *arg =
> +				(struct test_arg_regptr *)args;
> +			result_regs.uregs[arg->reg] &= arg->val;
> +		}
>  
>  	/* Undo any changes done to SP by the test case */
>  	regs->ARM_sp = (unsigned long)current_stack;
> diff --git a/arch/arm/probes/kprobes/test-core.h b/arch/arm/probes/kprobes/test-core.h
> index 9991754..32f7aa7 100644
> --- a/arch/arm/probes/kprobes/test-core.h
> +++ b/arch/arm/probes/kprobes/test-core.h
> @@ -45,10 +45,11 @@ extern int kprobe_test_cc_position;
>   *
>   */
>  
> -#define	ARG_TYPE_END	0
> -#define	ARG_TYPE_REG	1
> -#define	ARG_TYPE_PTR	2
> -#define	ARG_TYPE_MEM	3
> +#define	ARG_TYPE_END		0
> +#define	ARG_TYPE_REG		1
> +#define	ARG_TYPE_PTR		2
> +#define	ARG_TYPE_MEM		3
> +#define	ARG_TYPE_REG_MASKED	4
>  
>  #define ARG_FLAG_UNSUPPORTED	0x01
>  #define ARG_FLAG_SUPPORTED	0x02
> @@ -61,7 +62,7 @@ struct test_arg {
>  };
>  
>  struct test_arg_regptr {
> -	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR */
> +	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR or ARG_TYPE_REG_MASKED */
>  	u8	reg;
>  	u8	_padding[2];
>  	u32	val;
> @@ -138,6 +139,12 @@ struct test_arg_end {
>  	".short	0					\n\t"	\
>  	".word	"#val"					\n\t"
>  
> +#define	TEST_ARG_REG_MASKED(reg, val)				\
> +	".byte	"__stringify(ARG_TYPE_REG_MASKED)"	\n\t"	\
> +	".byte	"#reg"					\n\t"	\
> +	".short	0					\n\t"	\
> +	".word	"#val"					\n\t"
> +
>  #define	TEST_ARG_END(flags)					\
>  	".byte	"__stringify(ARG_TYPE_END)"		\n\t"	\
>  	".byte	"TEST_ISA flags"			\n\t"	\
> @@ -395,6 +402,22 @@ struct test_arg_end {
>  	"	"codex"			\n\t"					\
>  	TESTCASE_END
>  
> +#define TEST_RMASKED(code1, reg, mask, code2)		\
> +	TESTCASE_START(code1 #reg code2)		\
> +	TEST_ARG_REG_MASKED(reg, mask)			\
> +	TEST_ARG_END("")				\
> +	TEST_INSTRUCTION(code1 #reg code2)		\
> +	TESTCASE_END
> +
> +/*
> + * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
> + * can change randomly as the kernel doesn't take care to preserve or initialise
> + * this across context switches. Also, with Security Extensions, the flag may
> + * not be under control of the kernel; for this reason we ignore the state of
> + * the FIQ disable flag CPSR.F as well.
> + */
> +#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
> +
>  
>  /*
>   * Macros for defining space directives spread over multiple lines.
> diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
> index e8cf193..b683b45 100644
> --- a/arch/arm/probes/kprobes/test-thumb.c
> +++ b/arch/arm/probes/kprobes/test-thumb.c
> @@ -778,8 +778,8 @@ CONDITION_INSTRUCTIONS(22,
>  
>  	TEST_UNSUPPORTED("subs	pc, lr, #4")
>  
> -	TEST("mrs	r0, cpsr")
> -	TEST("mrs	r14, cpsr")
> +	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
> +	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8d00) "	@ mrs	sp, spsr")
>  	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8f00) "	@ mrs	pc, spsr")
>  	TEST_UNSUPPORTED("mrs	r0, spsr")
> 

Well, I'm just working on a patch which introducing a TEST_INTOFF and disable interrupts
for "MRS" testcase. Do you think it is inappropriate? I'll use your patch test for a night
in my hardware, and will let you know the result tomorrow.

Thank you!


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe
  2014-12-08 14:09 ` [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe Wang Nan
@ 2014-12-10 13:23   ` Jon Medhurst (Tixy)
  0 siblings, 0 replies; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-10 13:23 UTC (permalink / raw)
  To: masami.hiramatsu.pt
  Cc: Wang Nan, linux, lizefan, linux-kernel, linux-arm-kernel

Hi Masami Hiramatsu

How should this patch find its way into the mainline? Is it OK to submit
this as part of the ARM kprobe changes (which presumably will go in via
Russell's tree)?
 
-- 
Tixy

On Mon, 2014-12-08 at 22:09 +0800, Wang Nan wrote:
> From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> 
> Pass the original kprobe for preparing an optimized kprobe arch-dep
> part, since for some architecture (e.g. ARM32) requires the information
> in original kprobe.
> 
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> ---
>  arch/x86/kernel/kprobes/opt.c | 3 ++-
>  include/linux/kprobes.h       | 3 ++-
>  kernel/kprobes.c              | 4 ++--
>  3 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
> index f1314d0..7028296 100644
> --- a/arch/x86/kernel/kprobes/opt.c
> +++ b/arch/x86/kernel/kprobes/opt.c
> @@ -320,7 +320,8 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
>   * Target instructions MUST be relocatable (checked inside)
>   * This is called when new aggr(opt)probe is allocated or reused.
>   */
> -int arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
> +int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
> +				  struct kprobe *__unused)
>  {
>  	u8 *buf;
>  	int ret;
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index f7296e5..7ab2c93 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -308,7 +308,8 @@ struct optimized_kprobe {
>  /* Architecture dependent functions for direct jump optimization */
>  extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
>  extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
> -extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
> +extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
> +					 struct kprobe *orig);
>  extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
>  extern void arch_optimize_kprobes(struct list_head *oplist);
>  extern void arch_unoptimize_kprobes(struct list_head *oplist,
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3995f54..9f28aa7 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -717,7 +717,7 @@ static void prepare_optimized_kprobe(struct kprobe *p)
>  	struct optimized_kprobe *op;
>  
>  	op = container_of(p, struct optimized_kprobe, kp);
> -	arch_prepare_optimized_kprobe(op);
> +	arch_prepare_optimized_kprobe(op, p);
>  }
>  
>  /* Allocate new optimized_kprobe and try to prepare optimized instructions */
> @@ -731,7 +731,7 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
>  
>  	INIT_LIST_HEAD(&op->list);
>  	op->kp.addr = p->addr;
> -	arch_prepare_optimized_kprobe(op);
> +	arch_prepare_optimized_kprobe(op, p);
>  
>  	return &op->kp;
>  }



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-10 13:18           ` Wang Nan
@ 2014-12-10 13:49             ` Jon Medhurst (Tixy)
  2014-12-11  9:56             ` Wang Nan
  1 sibling, 0 replies; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-10 13:49 UTC (permalink / raw)
  To: Wang Nan
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

On Wed, 2014-12-10 at 21:18 +0800, Wang Nan wrote:
[...]
> Well, I'm just working on a patch which introducing a TEST_INTOFF and disable interrupts
> for "MRS" testcase. Do you think it is inappropriate?

That's what I started to do, implementing in a similar way to
DONT_TEST_IN_ITBLOCK, and thought the same ints off feature could be
used for the stack consuming instructions checks as well.

Then I realised that for the MRS case it's no use turning ints off for a
single iteration of a test, because the next iteration could see
different results, so that would mean turning interrupts off for all
iterations, which we can't do.

Also, the FIQ flag may not be under our control if Linux isn't running
in secure mode, and I was worried that in such cases we could see the
value of the flag change if secure mode code chose to do so. (Though
perhaps non-secure mode will always read FIQ flag as zero in such a
case?)

So in the end I thought the only robust way of writing the tests would
be to ignore the values of the A and F flags.

-- 
Tixy



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v3] ARM: kprobes: Add test cases for stack consuming instructions
  2014-12-10 13:18           ` Wang Nan
  2014-12-10 13:49             ` Jon Medhurst (Tixy)
@ 2014-12-11  9:56             ` Wang Nan
  1 sibling, 0 replies; 22+ messages in thread
From: Wang Nan @ 2014-12-11  9:56 UTC (permalink / raw)
  To: Jon Medhurst (Tixy)
  Cc: masami.hiramatsu.pt, lizefan, linux, linux-kernel, linux-arm-kernel

On 2014/12/10 21:18, Wang Nan wrote:
> On 2014/12/10 20:34, Jon Medhurst (Tixy) wrote:
>> On Wed, 2014-12-10 at 16:23 +0800, Wang Nan wrote:
>>> Hi Tixy,
>>>
>>> I experienced another FAIL during test:
>>>
>>> [11567.220477] Miscellaneous instructions
>>> [11567.265397] ---------------------------------------------------------
>>> [11567.342626] mrs	r0, cpsr	@ e10f0000
>>> [11568.612656] FAIL: registers differ
>>> [11568.653414] FAIL: Test mrs	r0, cpsr
>>> [11568.695210] FAIL: Scenario 5
>>> [11568.729709] initial_regs:
>>> [11568.761083] r0  21522152 | r1  21522052 | r2  21522352 | r3  21522252
>>> [11568.838301] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>>> [11568.915526] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>>> [11568.992748] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f590
>>> [11569.069969] cpsr 58050013
>>> [11569.101336] expected_regs:
>>> [11569.133750] r0  58050013 | r1  21522052 | r2  21522352 | r3  21522252
>>> [11569.210975] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>>> [11569.288197] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>>> [11569.365417] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
>>> [11569.442634] cpsr 58050013
>>> [11569.474010] result_regs:
>>> [11569.504337] r0  58050113 | r1  21522052 | r2  21522352 | r3  21522252     <--- see R0 in this line
>>> [11569.581556] r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
>>> [11569.658776] r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
>>> [11569.736000] r12 21522d52 | sp  ed343cf0 | lr  21522f52 | pc  bf11f594
>>> [11569.813222] cpsr 58050013
>>> [11569.844593] mrspl	r7, cpsr	@ 510f7000
>>> [11571.842652] mrs	r14, cpsr	@ e10fe000
>>>
>>> The failure is raise when testing in "mrs r0, cpsr". The added bit is PSR_A_BIT, which
>>> should be ignored.
>>>
>>> So looks like this is also a problem in your test framework. If you don't have
>>> enough time, you can give me some hints to deal with it.
>>
>> The problem is that the A bit can change randomly when interrupts or
>> reschedules happen (I'm not sure it should, and it may be a bug). For
>> the purposes of this test code, we can't disable interrupts and
>> scheduling around all the iterations of a test case, because inserting
>> and removing probes requires them to be enabled. So we need a method of
>> ignoring bits in cpsr, how about the following patch...
>>
>> ----------------------------------------------------------------------------
>>
>> From: Jon Medhurst <tixy@linaro.org>
>> Subject: [PATCH] ARM: kprobes: Fix unreliable MRS instruction tests
>>
>> For the instruction 'mrs Rn, cpsr' the resulting value of Rn can vary due to
>> external factors we can't control. So get the test code to mask out these
>> indeterminate bits.
>>
>> Signed-off-by: Jon Medhurst <tixy@linaro.org>
>> ---
>>  arch/arm/probes/kprobes/test-arm.c   |  6 +++---
>>  arch/arm/probes/kprobes/test-core.c  | 19 ++++++++++---------
>>  arch/arm/probes/kprobes/test-core.h  | 33 ++++++++++++++++++++++++++++-----
>>  arch/arm/probes/kprobes/test-thumb.c |  4 ++--
>>  4 files changed, 43 insertions(+), 19 deletions(-)
>>
>> diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c
>> index 9b3b1b4..e72b07e 100644
>> --- a/arch/arm/probes/kprobes/test-arm.c
>> +++ b/arch/arm/probes/kprobes/test-arm.c
>> @@ -204,9 +204,9 @@ void kprobe_arm_test_cases(void)
>>  #endif
>>  	TEST_GROUP("Miscellaneous instructions")
>>  
>> -	TEST("mrs	r0, cpsr")
>> -	TEST("mrspl	r7, cpsr")
>> -	TEST("mrs	r14, cpsr")
>> +	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
>> +	TEST_RMASKED("mrspl	r",7,~PSR_IGNORE_BITS,", cpsr")
>> +	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
>>  	TEST_UNSUPPORTED(__inst_arm(0xe10ff000) "	@ mrs r15, cpsr")
>>  	TEST_UNSUPPORTED("mrs	r0, spsr")
>>  	TEST_UNSUPPORTED("mrs	lr, spsr")
>> diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
>> index 7c5ddd5..e495127 100644
>> --- a/arch/arm/probes/kprobes/test-core.c
>> +++ b/arch/arm/probes/kprobes/test-core.c
>> @@ -1056,15 +1056,6 @@ static int test_case_run_count;
>>  static bool test_case_is_thumb;
>>  static int test_instance;
>>  
>> -/*
>> - * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
>> - * can change randomly as the kernel doesn't take care to preserve or initialise
>> - * this across context switches. Also, with Security Extentions, the flag may
>> - * not be under control of the kernel; for this reason we ignore the state of
>> - * the FIQ disable flag CPSR.F as well.
>> - */
>> -#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
>> -
>>  static unsigned long test_check_cc(int cc, unsigned long cpsr)
>>  {
>>  	int ret = arm_check_condition(cc << 28, cpsr);
>> @@ -1271,11 +1262,21 @@ test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
>>  static int __kprobes
>>  test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
>>  {
>> +	struct test_arg *args;
>> +
>>  	if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
>>  		return 0; /* Already run for this test instance */
>>  
>>  	result_regs = *regs;
>> +
>> +	/* Mask out results which are indeterminate */
>>  	result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
>> +	for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
>> +		if (args[0].type == ARG_TYPE_REG_MASKED) {
>> +			struct test_arg_regptr *arg =
>> +				(struct test_arg_regptr *)args;
>> +			result_regs.uregs[arg->reg] &= arg->val;
>> +		}
>>  
>>  	/* Undo any changes done to SP by the test case */
>>  	regs->ARM_sp = (unsigned long)current_stack;
>> diff --git a/arch/arm/probes/kprobes/test-core.h b/arch/arm/probes/kprobes/test-core.h
>> index 9991754..32f7aa7 100644
>> --- a/arch/arm/probes/kprobes/test-core.h
>> +++ b/arch/arm/probes/kprobes/test-core.h
>> @@ -45,10 +45,11 @@ extern int kprobe_test_cc_position;
>>   *
>>   */
>>  
>> -#define	ARG_TYPE_END	0
>> -#define	ARG_TYPE_REG	1
>> -#define	ARG_TYPE_PTR	2
>> -#define	ARG_TYPE_MEM	3
>> +#define	ARG_TYPE_END		0
>> +#define	ARG_TYPE_REG		1
>> +#define	ARG_TYPE_PTR		2
>> +#define	ARG_TYPE_MEM		3
>> +#define	ARG_TYPE_REG_MASKED	4
>>  
>>  #define ARG_FLAG_UNSUPPORTED	0x01
>>  #define ARG_FLAG_SUPPORTED	0x02
>> @@ -61,7 +62,7 @@ struct test_arg {
>>  };
>>  
>>  struct test_arg_regptr {
>> -	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR */
>> +	u8	type;		/* ARG_TYPE_REG or ARG_TYPE_PTR or ARG_TYPE_REG_MASKED */
>>  	u8	reg;
>>  	u8	_padding[2];
>>  	u32	val;
>> @@ -138,6 +139,12 @@ struct test_arg_end {
>>  	".short	0					\n\t"	\
>>  	".word	"#val"					\n\t"
>>  
>> +#define	TEST_ARG_REG_MASKED(reg, val)				\
>> +	".byte	"__stringify(ARG_TYPE_REG_MASKED)"	\n\t"	\
>> +	".byte	"#reg"					\n\t"	\
>> +	".short	0					\n\t"	\
>> +	".word	"#val"					\n\t"
>> +
>>  #define	TEST_ARG_END(flags)					\
>>  	".byte	"__stringify(ARG_TYPE_END)"		\n\t"	\
>>  	".byte	"TEST_ISA flags"			\n\t"	\
>> @@ -395,6 +402,22 @@ struct test_arg_end {
>>  	"	"codex"			\n\t"					\
>>  	TESTCASE_END
>>  
>> +#define TEST_RMASKED(code1, reg, mask, code2)		\
>> +	TESTCASE_START(code1 #reg code2)		\
>> +	TEST_ARG_REG_MASKED(reg, mask)			\
>> +	TEST_ARG_END("")				\
>> +	TEST_INSTRUCTION(code1 #reg code2)		\
>> +	TESTCASE_END
>> +
>> +/*
>> + * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
>> + * can change randomly as the kernel doesn't take care to preserve or initialise
>> + * this across context switches. Also, with Security Extensions, the flag may
>> + * not be under control of the kernel; for this reason we ignore the state of
>> + * the FIQ disable flag CPSR.F as well.
>> + */
>> +#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
>> +
>>  
>>  /*
>>   * Macros for defining space directives spread over multiple lines.
>> diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
>> index e8cf193..b683b45 100644
>> --- a/arch/arm/probes/kprobes/test-thumb.c
>> +++ b/arch/arm/probes/kprobes/test-thumb.c
>> @@ -778,8 +778,8 @@ CONDITION_INSTRUCTIONS(22,
>>  
>>  	TEST_UNSUPPORTED("subs	pc, lr, #4")
>>  
>> -	TEST("mrs	r0, cpsr")
>> -	TEST("mrs	r14, cpsr")
>> +	TEST_RMASKED("mrs	r",0,~PSR_IGNORE_BITS,", cpsr")
>> +	TEST_RMASKED("mrs	r",14,~PSR_IGNORE_BITS,", cpsr")
>>  	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8d00) "	@ mrs	sp, spsr")
>>  	TEST_UNSUPPORTED(__inst_thumb32(0xf3ef8f00) "	@ mrs	pc, spsr")
>>  	TEST_UNSUPPORTED("mrs	r0, spsr")
>>
> 
> Well, I'm just working on a patch which introducing a TEST_INTOFF and disable interrupts
> for "MRS" testcase. Do you think it is inappropriate? I'll use your patch test for a night
> in my hardware, and will let you know the result tomorrow.
> 
> Thank you!
> 

Hi Tixy,

I'd like to let you know that I have tested your v3 patch in an ARM cortex A15 board
for 8 hours and nothing bad happened. I'll post a v16 patch series to merge your patch.

Thank you!

> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
  2014-12-09  2:14 Wang Nan
@ 2014-12-09  9:38 ` Jon Medhurst (Tixy)
  0 siblings, 0 replies; 22+ messages in thread
From: Jon Medhurst (Tixy) @ 2014-12-09  9:38 UTC (permalink / raw)
  To: Wang Nan
  Cc: Masami Hiramatsu, Russell King, Li Zefan, linux-kernel,
	Linux ARM Kernel List

On Tue, 2014-12-09 at 10:14 +0800, Wang Nan wrote:
> Hi all,
> 
> Looks like v15 patch solves the problems found in patch v13 and v14. I run Tixy's test
> cases in a loop for a whole night on two real unpublished Hisilicon ARM A15 SoCs (I
> backported kprobes to 3.10 kernel), no problem arise, they are still running now.


I get a reproducible failure (below), but I believe it is a flaw in the
test code. Now that we have optimised probes there is a window of
opportunity for and interrupt to happen between the the kprobe which
sets up the test preconditions and the tested probe executing. That will
change the contents of stack memory below SP and make it inconsistent
between test runs.

This recent flurry of kprobes work has been eating up my time somewhat
and I have other urgent matters I should attend to, so I won't be
looking at this problem for a few days.

That test failure...

strh	r3, [r13, #-64]!	@ e16d34b0
FAIL: test memory differs
FAIL: Test strh	r3, [r13, #-64]!
FAIL: Scenario 1
initial_regs:
r0  21522152 | r1  21522052 | r2  21522352 | r3  12345678
r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
r12 21522d52 | sp  bf053ea0 | lr  21522f52 | pc  80028cf0
cpsr 18010013
expected_regs:
r0  21522152 | r1  21522052 | r2  21522352 | r3  12345678
r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
r12 21522d52 | sp  bf053e60 | lr  21522f52 | pc  80028cf4
cpsr 18010013
result_regs:
r0  21522152 | r1  21522052 | r2  21522352 | r3  12345678
r4  21522552 | r5  21522452 | r6  21522752 | r7  21522652
r8  21522952 | r9  21522852 | r10 21522b52 | r11 21522a52
r12 21522d52 | sp  bf053e60 | lr  21522f52 | pc  80028cf4
cpsr 18010013
current_stack=bf053da0
expected_memory:
21525678 12345678 21522552 21522452
21522752 21522652 21522952 21522852
21522b52 21522a52 21522d52 bf053ea0
21522f52 80028cf0 18010113 ffffffff
result_memory:
45675678 4567baab 4567bbab 4567bcab
4567bdab 4567beab 4567bfab 4567c0ab
4567c1ab 4567c2ab 4567c3ab 4567c4ab
4567c5ab 4567c6ab 4567c7ab 4567c8ab
strh r3, [r13, #-64-8]!	@ e16d34b8
strh	r4, [r14, #-64-8]!	@ e16e44b8

-- 
Tixy



^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32
@ 2014-12-09  2:14 Wang Nan
  2014-12-09  9:38 ` Jon Medhurst (Tixy)
  0 siblings, 1 reply; 22+ messages in thread
From: Wang Nan @ 2014-12-09  2:14 UTC (permalink / raw)
  To: Masami Hiramatsu, Jon Medhurst (Tixy), Russell King
  Cc: Li Zefan, linux-kernel, Linux ARM Kernel List

Hi all,

Looks like v15 patch solves the problems found in patch v13 and v14. I run Tixy's test
cases in a loop for a whole night on two real unpublished Hisilicon ARM A15 SoCs (I
backported kprobes to 3.10 kernel), no problem arise, they are still running now.


^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, other threads:[~2014-12-11  9:57 UTC | newest]

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-12-08 14:09 [RESEND][PATCH v15 0/7] ARM: kprobes: OPTPROBES and other improvements Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 1/7] ARM: probes: move all probe code to dedicate directory Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 2/7] ARM: kprobes: introduces checker Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 3/7] ARM: kprobes: collects stack consumption for store instructions Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 4/7] ARM: kprobes: disallow probing stack consuming instructions Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 5/7] ARM: kprobes: Add test cases for " Wang Nan
2014-12-09 16:43   ` [PATCH v2] " Jon Medhurst (Tixy)
2014-12-09 17:11     ` [PATCH v3] " Jon Medhurst (Tixy)
2014-12-10  8:23       ` Wang Nan
2014-12-10 12:34         ` Jon Medhurst (Tixy)
2014-12-10 13:18           ` Wang Nan
2014-12-10 13:49             ` Jon Medhurst (Tixy)
2014-12-11  9:56             ` Wang Nan
2014-12-08 14:09 ` [RESEND][PATCH v15 6/7] kprobes: Pass the original kprobe for preparing optimized kprobe Wang Nan
2014-12-10 13:23   ` Jon Medhurst (Tixy)
2014-12-08 14:09 ` [RESEND][PATCH v15 7/7] ARM: kprobes: enable OPTPROBES for ARM 32 Wang Nan
2014-12-09  6:47   ` Masami Hiramatsu
2014-12-09  9:14     ` Jon Medhurst (Tixy)
2014-12-09 10:25       ` Masami Hiramatsu
2014-12-09 10:12     ` Wang Nan
2014-12-09  2:14 Wang Nan
2014-12-09  9:38 ` Jon Medhurst (Tixy)

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