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* [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning
@ 2021-09-27 21:02 Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 1/4] ARM: 9077/1: PLT: Move struct plt_entries definition to header Florian Fainelli
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Florian Fainelli @ 2021-09-27 21:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: stable, Greg Kroah-Hartman, Sasha Levin, Florian Fainelli,
	Steven Rostedt, Ingo Molnar, Russell King, Alex Sverdlin,
	moderated list:ARM PORT

This patch series is present in v5.14 and fixes warnings seen at insmod
with FTRACE and MODULE_PLTS enabled on ARM/Linux.

Changes in v3:

- resolved build error with allmodconfig enabling CONFIG_OLD_MCOUNT

Changes in v2:

- included build fix without DYNAMIC_FTRACE
- preserved Author's original name in 4.9 submission

Alex Sverdlin (4):
  ARM: 9077/1: PLT: Move struct plt_entries definition to header
  ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link()
  ARM: 9079/1: ftrace: Add MODULE_PLTS support
  ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without
    DYNAMIC_FTRACE

 arch/arm/include/asm/ftrace.h |  3 +++
 arch/arm/include/asm/insn.h   |  8 +++---
 arch/arm/include/asm/module.h | 10 +++++++
 arch/arm/kernel/ftrace.c      | 50 ++++++++++++++++++++++++++++-------
 arch/arm/kernel/insn.c        | 19 ++++++-------
 arch/arm/kernel/module-plts.c | 49 ++++++++++++++++++++++++++--------
 6 files changed, 105 insertions(+), 34 deletions(-)

-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH stable 4.19 v3 1/4] ARM: 9077/1: PLT: Move struct plt_entries definition to header
  2021-09-27 21:02 [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning Florian Fainelli
@ 2021-09-27 21:02 ` Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 2/4] ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link() Florian Fainelli
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Florian Fainelli @ 2021-09-27 21:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: stable, Greg Kroah-Hartman, Sasha Levin, Alex Sverdlin,
	Russell King, Florian Fainelli, Steven Rostedt, Ingo Molnar,
	Russell King, moderated list:ARM PORT

From: Alex Sverdlin <alexander.sverdlin@nokia.com>

commit 4e271701c17dee70c6e1351c4d7d42e70405c6a9 upstream

No functional change, later it will be re-used in several files.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 arch/arm/include/asm/module.h | 9 +++++++++
 arch/arm/kernel/module-plts.c | 9 ---------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index 9e81b7c498d8..56d4c97e578a 100644
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -19,6 +19,15 @@ enum {
 };
 #endif
 
+#define PLT_ENT_STRIDE		L1_CACHE_BYTES
+#define PLT_ENT_COUNT		(PLT_ENT_STRIDE / sizeof(u32))
+#define PLT_ENT_SIZE		(sizeof(struct plt_entries) / PLT_ENT_COUNT)
+
+struct plt_entries {
+	u32	ldr[PLT_ENT_COUNT];
+	u32	lit[PLT_ENT_COUNT];
+};
+
 struct mod_plt_sec {
 	struct elf32_shdr	*plt;
 	int			plt_count;
diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c
index 3d0c2e4dda1d..f272711c411f 100644
--- a/arch/arm/kernel/module-plts.c
+++ b/arch/arm/kernel/module-plts.c
@@ -14,10 +14,6 @@
 #include <asm/cache.h>
 #include <asm/opcodes.h>
 
-#define PLT_ENT_STRIDE		L1_CACHE_BYTES
-#define PLT_ENT_COUNT		(PLT_ENT_STRIDE / sizeof(u32))
-#define PLT_ENT_SIZE		(sizeof(struct plt_entries) / PLT_ENT_COUNT)
-
 #ifdef CONFIG_THUMB2_KERNEL
 #define PLT_ENT_LDR		__opcode_to_mem_thumb32(0xf8dff000 | \
 							(PLT_ENT_STRIDE - 4))
@@ -26,11 +22,6 @@
 						    (PLT_ENT_STRIDE - 8))
 #endif
 
-struct plt_entries {
-	u32	ldr[PLT_ENT_COUNT];
-	u32	lit[PLT_ENT_COUNT];
-};
-
 static bool in_init(const struct module *mod, unsigned long loc)
 {
 	return loc - (u32)mod->init_layout.base < mod->init_layout.size;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH stable 4.19 v3 2/4] ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link()
  2021-09-27 21:02 [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 1/4] ARM: 9077/1: PLT: Move struct plt_entries definition to header Florian Fainelli
@ 2021-09-27 21:02 ` Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 3/4] ARM: 9079/1: ftrace: Add MODULE_PLTS support Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 4/4] ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE Florian Fainelli
  3 siblings, 0 replies; 5+ messages in thread
From: Florian Fainelli @ 2021-09-27 21:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: stable, Greg Kroah-Hartman, Sasha Levin, Alex Sverdlin,
	Russell King, Florian Fainelli, Steven Rostedt, Ingo Molnar,
	Russell King, moderated list:ARM PORT

From: Alex Sverdlin <alexander.sverdlin@nokia.com>

commit 890cb057a46d323fd8c77ebecb6485476614cd21 upstream

Will be used in the following patch. No functional change.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 arch/arm/include/asm/insn.h |  8 ++++----
 arch/arm/kernel/ftrace.c    |  2 +-
 arch/arm/kernel/insn.c      | 19 ++++++++++---------
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/insn.h b/arch/arm/include/asm/insn.h
index f20e08ac85ae..5475cbf9fb6b 100644
--- a/arch/arm/include/asm/insn.h
+++ b/arch/arm/include/asm/insn.h
@@ -13,18 +13,18 @@ arm_gen_nop(void)
 }
 
 unsigned long
-__arm_gen_branch(unsigned long pc, unsigned long addr, bool link);
+__arm_gen_branch(unsigned long pc, unsigned long addr, bool link, bool warn);
 
 static inline unsigned long
 arm_gen_branch(unsigned long pc, unsigned long addr)
 {
-	return __arm_gen_branch(pc, addr, false);
+	return __arm_gen_branch(pc, addr, false, true);
 }
 
 static inline unsigned long
-arm_gen_branch_link(unsigned long pc, unsigned long addr)
+arm_gen_branch_link(unsigned long pc, unsigned long addr, bool warn)
 {
-	return __arm_gen_branch(pc, addr, true);
+	return __arm_gen_branch(pc, addr, true, warn);
 }
 
 #endif
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index ee673c09aa6c..05bf124ae324 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -98,7 +98,7 @@ int ftrace_arch_code_modify_post_process(void)
 
 static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
 {
-	return arm_gen_branch_link(pc, addr);
+	return arm_gen_branch_link(pc, addr, true);
 }
 
 static int ftrace_modify_code(unsigned long pc, unsigned long old,
diff --git a/arch/arm/kernel/insn.c b/arch/arm/kernel/insn.c
index 2e844b70386b..db0acbb7d7a0 100644
--- a/arch/arm/kernel/insn.c
+++ b/arch/arm/kernel/insn.c
@@ -3,8 +3,9 @@
 #include <linux/kernel.h>
 #include <asm/opcodes.h>
 
-static unsigned long
-__arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
+static unsigned long __arm_gen_branch_thumb2(unsigned long pc,
+					     unsigned long addr, bool link,
+					     bool warn)
 {
 	unsigned long s, j1, j2, i1, i2, imm10, imm11;
 	unsigned long first, second;
@@ -12,7 +13,7 @@ __arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
 
 	offset = (long)addr - (long)(pc + 4);
 	if (offset < -16777216 || offset > 16777214) {
-		WARN_ON_ONCE(1);
+		WARN_ON_ONCE(warn);
 		return 0;
 	}
 
@@ -33,8 +34,8 @@ __arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
 	return __opcode_thumb32_compose(first, second);
 }
 
-static unsigned long
-__arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
+static unsigned long __arm_gen_branch_arm(unsigned long pc, unsigned long addr,
+					  bool link, bool warn)
 {
 	unsigned long opcode = 0xea000000;
 	long offset;
@@ -44,7 +45,7 @@ __arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
 
 	offset = (long)addr - (long)(pc + 8);
 	if (unlikely(offset < -33554432 || offset > 33554428)) {
-		WARN_ON_ONCE(1);
+		WARN_ON_ONCE(warn);
 		return 0;
 	}
 
@@ -54,10 +55,10 @@ __arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
 }
 
 unsigned long
-__arm_gen_branch(unsigned long pc, unsigned long addr, bool link)
+__arm_gen_branch(unsigned long pc, unsigned long addr, bool link, bool warn)
 {
 	if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
-		return __arm_gen_branch_thumb2(pc, addr, link);
+		return __arm_gen_branch_thumb2(pc, addr, link, warn);
 	else
-		return __arm_gen_branch_arm(pc, addr, link);
+		return __arm_gen_branch_arm(pc, addr, link, warn);
 }
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH stable 4.19 v3 3/4] ARM: 9079/1: ftrace: Add MODULE_PLTS support
  2021-09-27 21:02 [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 1/4] ARM: 9077/1: PLT: Move struct plt_entries definition to header Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 2/4] ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link() Florian Fainelli
@ 2021-09-27 21:02 ` Florian Fainelli
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 4/4] ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE Florian Fainelli
  3 siblings, 0 replies; 5+ messages in thread
From: Florian Fainelli @ 2021-09-27 21:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: stable, Greg Kroah-Hartman, Sasha Levin, Alex Sverdlin,
	Russell King, Florian Fainelli, Steven Rostedt, Ingo Molnar,
	Russell King, moderated list:ARM PORT

From: Alex Sverdlin <alexander.sverdlin@nokia.com>

commit 79f32b221b18c15a98507b101ef4beb52444cc6f upstream

Teach ftrace_make_call() and ftrace_make_nop() about PLTs.
Teach PLT code about FTRACE and all its callbacks.
Otherwise the following might happen:

------------[ cut here ]------------
WARNING: CPU: 14 PID: 2265 at .../arch/arm/kernel/insn.c:14 __arm_gen_branch+0x83/0x8c()
...
Hardware name: LSI Axxia AXM55XX
[<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14)
[<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8)
[<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90)
[<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c)
[<c03218f3>] (warn_slowpath_null) from [<c03143cf>] (__arm_gen_branch+0x83/0x8c)
[<c03143cf>] (__arm_gen_branch) from [<c0314337>] (ftrace_make_nop+0xf/0x24)
[<c0314337>] (ftrace_make_nop) from [<c038ebcb>] (ftrace_process_locs+0x27b/0x3e8)
[<c038ebcb>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44)
[<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84)
[<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18)
---[ end trace e1b64ced7a89adcc ]---
------------[ cut here ]------------
WARNING: CPU: 14 PID: 2265 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1b1/0x234()
...
Hardware name: LSI Axxia AXM55XX
[<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14)
[<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8)
[<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90)
[<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c)
[<c03218f3>] (warn_slowpath_null) from [<c038e87d>] (ftrace_bug+0x1b1/0x234)
[<c038e87d>] (ftrace_bug) from [<c038ebd5>] (ftrace_process_locs+0x285/0x3e8)
[<c038ebd5>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44)
[<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84)
[<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18)
---[ end trace e1b64ced7a89adcd ]---
ftrace failed to modify [<e9ef7006>] 0xe9ef7006
actual: 02:f0:3b:fa
ftrace record flags: 0
(0) expected tramp: c0314265

[florian: resolved merge conflict with struct
dyn_arch_ftrace::old_mcount]

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 arch/arm/include/asm/ftrace.h |  3 +++
 arch/arm/include/asm/module.h |  1 +
 arch/arm/kernel/ftrace.c      | 50 ++++++++++++++++++++++++++++-------
 arch/arm/kernel/module-plts.c | 44 +++++++++++++++++++++++++++---
 4 files changed, 84 insertions(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
index 9e842ff41768..faeb6b1c0089 100644
--- a/arch/arm/include/asm/ftrace.h
+++ b/arch/arm/include/asm/ftrace.h
@@ -19,6 +19,9 @@ struct dyn_arch_ftrace {
 #ifdef CONFIG_OLD_MCOUNT
 	bool	old_mcount;
 #endif
+#ifdef CONFIG_ARM_MODULE_PLTS
+	struct module *mod;
+#endif
 };
 
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index 56d4c97e578a..6b36656eed83 100644
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -30,6 +30,7 @@ struct plt_entries {
 
 struct mod_plt_sec {
 	struct elf32_shdr	*plt;
+	struct plt_entries	*plt_ent;
 	int			plt_count;
 };
 
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 05bf124ae324..51839250e49a 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -96,9 +96,10 @@ int ftrace_arch_code_modify_post_process(void)
 	return 0;
 }
 
-static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
+static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr,
+					 bool warn)
 {
-	return arm_gen_branch_link(pc, addr, true);
+	return arm_gen_branch_link(pc, addr, warn);
 }
 
 static int ftrace_modify_code(unsigned long pc, unsigned long old,
@@ -137,14 +138,14 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	int ret;
 
 	pc = (unsigned long)&ftrace_call;
-	new = ftrace_call_replace(pc, (unsigned long)func);
+	new = ftrace_call_replace(pc, (unsigned long)func, true);
 
 	ret = ftrace_modify_code(pc, 0, new, false);
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 	if (!ret) {
 		pc = (unsigned long)&ftrace_regs_call;
-		new = ftrace_call_replace(pc, (unsigned long)func);
+		new = ftrace_call_replace(pc, (unsigned long)func, true);
 
 		ret = ftrace_modify_code(pc, 0, new, false);
 	}
@@ -153,7 +154,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 #ifdef CONFIG_OLD_MCOUNT
 	if (!ret) {
 		pc = (unsigned long)&ftrace_call_old;
-		new = ftrace_call_replace(pc, (unsigned long)func);
+		new = ftrace_call_replace(pc, (unsigned long)func, true);
 
 		ret = ftrace_modify_code(pc, 0, new, false);
 	}
@@ -166,10 +167,22 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
 	unsigned long new, old;
 	unsigned long ip = rec->ip;
+	unsigned long aaddr = adjust_address(rec, addr);
+	struct module *mod = NULL;
+
+#ifdef CONFIG_ARM_MODULE_PLTS
+	mod = rec->arch.mod;
+#endif
 
 	old = ftrace_nop_replace(rec);
 
-	new = ftrace_call_replace(ip, adjust_address(rec, addr));
+	new = ftrace_call_replace(ip, aaddr, !mod);
+#ifdef CONFIG_ARM_MODULE_PLTS
+	if (!new && mod) {
+		aaddr = get_module_plt(mod, ip, aaddr);
+		new = ftrace_call_replace(ip, aaddr, true);
+	}
+#endif
 
 	return ftrace_modify_code(rec->ip, old, new, true);
 }
@@ -182,9 +195,9 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 	unsigned long new, old;
 	unsigned long ip = rec->ip;
 
-	old = ftrace_call_replace(ip, adjust_address(rec, old_addr));
+	old = ftrace_call_replace(ip, adjust_address(rec, old_addr), true);
 
-	new = ftrace_call_replace(ip, adjust_address(rec, addr));
+	new = ftrace_call_replace(ip, adjust_address(rec, addr), true);
 
 	return ftrace_modify_code(rec->ip, old, new, true);
 }
@@ -194,12 +207,29 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 int ftrace_make_nop(struct module *mod,
 		    struct dyn_ftrace *rec, unsigned long addr)
 {
+	unsigned long aaddr = adjust_address(rec, addr);
 	unsigned long ip = rec->ip;
 	unsigned long old;
 	unsigned long new;
 	int ret;
 
-	old = ftrace_call_replace(ip, adjust_address(rec, addr));
+#ifdef CONFIG_ARM_MODULE_PLTS
+	/* mod is only supplied during module loading */
+	if (!mod)
+		mod = rec->arch.mod;
+	else
+		rec->arch.mod = mod;
+#endif
+
+	old = ftrace_call_replace(ip, aaddr,
+				  !IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || !mod);
+#ifdef CONFIG_ARM_MODULE_PLTS
+	if (!old && mod) {
+		aaddr = get_module_plt(mod, ip, aaddr);
+		old = ftrace_call_replace(ip, aaddr, true);
+	}
+#endif
+
 	new = ftrace_nop_replace(rec);
 	ret = ftrace_modify_code(ip, old, new, true);
 
@@ -207,7 +237,7 @@ int ftrace_make_nop(struct module *mod,
 	if (ret == -EINVAL && addr == MCOUNT_ADDR) {
 		rec->arch.old_mcount = true;
 
-		old = ftrace_call_replace(ip, adjust_address(rec, addr));
+		old = ftrace_call_replace(ip, adjust_address(rec, addr), true);
 		new = ftrace_nop_replace(rec);
 		ret = ftrace_modify_code(ip, old, new, true);
 	}
diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c
index f272711c411f..6804a145be11 100644
--- a/arch/arm/kernel/module-plts.c
+++ b/arch/arm/kernel/module-plts.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/elf.h>
+#include <linux/ftrace.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sort.h>
@@ -22,19 +23,52 @@
 						    (PLT_ENT_STRIDE - 8))
 #endif
 
+static const u32 fixed_plts[] = {
+#ifdef CONFIG_FUNCTION_TRACER
+	FTRACE_ADDR,
+	MCOUNT_ADDR,
+#endif
+};
+
 static bool in_init(const struct module *mod, unsigned long loc)
 {
 	return loc - (u32)mod->init_layout.base < mod->init_layout.size;
 }
 
+static void prealloc_fixed(struct mod_plt_sec *pltsec, struct plt_entries *plt)
+{
+	int i;
+
+	if (!ARRAY_SIZE(fixed_plts) || pltsec->plt_count)
+		return;
+	pltsec->plt_count = ARRAY_SIZE(fixed_plts);
+
+	for (i = 0; i < ARRAY_SIZE(plt->ldr); ++i)
+		plt->ldr[i] = PLT_ENT_LDR;
+
+	BUILD_BUG_ON(sizeof(fixed_plts) > sizeof(plt->lit));
+	memcpy(plt->lit, fixed_plts, sizeof(fixed_plts));
+}
+
 u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val)
 {
 	struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core :
 							  &mod->arch.init;
+	struct plt_entries *plt;
+	int idx;
+
+	/* cache the address, ELF header is available only during module load */
+	if (!pltsec->plt_ent)
+		pltsec->plt_ent = (struct plt_entries *)pltsec->plt->sh_addr;
+	plt = pltsec->plt_ent;
 
-	struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr;
-	int idx = 0;
+	prealloc_fixed(pltsec, plt);
+
+	for (idx = 0; idx < ARRAY_SIZE(fixed_plts); ++idx)
+		if (plt->lit[idx] == val)
+			return (u32)&plt->ldr[idx];
 
+	idx = 0;
 	/*
 	 * Look for an existing entry pointing to 'val'. Given that the
 	 * relocations are sorted, this will be the last entry we allocated.
@@ -182,8 +216,8 @@ static unsigned int count_plts(const Elf32_Sym *syms, Elf32_Addr base,
 int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
 			      char *secstrings, struct module *mod)
 {
-	unsigned long core_plts = 0;
-	unsigned long init_plts = 0;
+	unsigned long core_plts = ARRAY_SIZE(fixed_plts);
+	unsigned long init_plts = ARRAY_SIZE(fixed_plts);
 	Elf32_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum;
 	Elf32_Sym *syms = NULL;
 
@@ -238,6 +272,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
 	mod->arch.core.plt->sh_size = round_up(core_plts * PLT_ENT_SIZE,
 					       sizeof(struct plt_entries));
 	mod->arch.core.plt_count = 0;
+	mod->arch.core.plt_ent = NULL;
 
 	mod->arch.init.plt->sh_type = SHT_NOBITS;
 	mod->arch.init.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
@@ -245,6 +280,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
 	mod->arch.init.plt->sh_size = round_up(init_plts * PLT_ENT_SIZE,
 					       sizeof(struct plt_entries));
 	mod->arch.init.plt_count = 0;
+	mod->arch.init.plt_ent = NULL;
 
 	pr_debug("%s: plt=%x, init.plt=%x\n", __func__,
 		 mod->arch.core.plt->sh_size, mod->arch.init.plt->sh_size);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH stable 4.19 v3 4/4] ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE
  2021-09-27 21:02 [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning Florian Fainelli
                   ` (2 preceding siblings ...)
  2021-09-27 21:02 ` [PATCH stable 4.19 v3 3/4] ARM: 9079/1: ftrace: Add MODULE_PLTS support Florian Fainelli
@ 2021-09-27 21:02 ` Florian Fainelli
  3 siblings, 0 replies; 5+ messages in thread
From: Florian Fainelli @ 2021-09-27 21:02 UTC (permalink / raw)
  To: linux-kernel
  Cc: stable, Greg Kroah-Hartman, Sasha Levin, Alex Sverdlin,
	kernel test robot, Russell King, Florian Fainelli,
	Steven Rostedt, Ingo Molnar, Russell King,
	moderated list:ARM PORT

From: Alex Sverdlin <alexander.sverdlin@nokia.com>

commit 6fa630bf473827aee48cbf0efbbdf6f03134e890 upstream

FTRACE_ADDR is only defined when CONFIG_DYNAMIC_FTRACE is defined, the
latter is even stronger requirement than CONFIG_FUNCTION_TRACER (which is
enough for MCOUNT_ADDR).

Link: https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/ZUVCQBHDMFVR7CCB7JPESLJEWERZDJ3T/

Fixes: 1f12fb25c5c5d22f ("ARM: 9079/1: ftrace: Add MODULE_PLTS support")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 arch/arm/kernel/module-plts.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c
index 6804a145be11..ed0e09cc735f 100644
--- a/arch/arm/kernel/module-plts.c
+++ b/arch/arm/kernel/module-plts.c
@@ -24,7 +24,7 @@
 #endif
 
 static const u32 fixed_plts[] = {
-#ifdef CONFIG_FUNCTION_TRACER
+#ifdef CONFIG_DYNAMIC_FTRACE
 	FTRACE_ADDR,
 	MCOUNT_ADDR,
 #endif
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-09-27 21:03 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-27 21:02 [PATCH stable 4.19 v3 0/4] ARM: ftrace MODULE_PLTS warning Florian Fainelli
2021-09-27 21:02 ` [PATCH stable 4.19 v3 1/4] ARM: 9077/1: PLT: Move struct plt_entries definition to header Florian Fainelli
2021-09-27 21:02 ` [PATCH stable 4.19 v3 2/4] ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link() Florian Fainelli
2021-09-27 21:02 ` [PATCH stable 4.19 v3 3/4] ARM: 9079/1: ftrace: Add MODULE_PLTS support Florian Fainelli
2021-09-27 21:02 ` [PATCH stable 4.19 v3 4/4] ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE Florian Fainelli

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