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* [PATCH] x86: simplify task_pt_regs() macro definition
@ 2015-03-13 14:09 Denys Vlasenko
  2015-03-13 18:26 ` Steven Rostedt
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Denys Vlasenko @ 2015-03-13 14:09 UTC (permalink / raw)
  To: Andy Lutomirski
  Cc: Denys Vlasenko, Linus Torvalds, Steven Rostedt, Ingo Molnar,
	Borislav Petkov, H. Peter Anvin, Oleg Nesterov,
	Frederic Weisbecker, Alexei Starovoitov, Will Drewry, Kees Cook,
	x86, linux-kernel

Before this change, task_pt_regs() was using KSTK_TOP(),
and it was the only use of that macro. In turn, KSTK_TOP used
THREAD_SIZE_LONGS, and it was the only use of that macro too.

Fold these macros into task_pt_regs(). Tweak comment
about "- 8" - we now use a symbolic constant, not literal 8.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
 arch/x86/include/asm/processor.h | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 87474b2..d42c959 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -847,15 +847,8 @@ static inline void spin_lock_prefetch(const void *x)
 
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
-#define THREAD_SIZE_LONGS      (THREAD_SIZE/sizeof(unsigned long))
-#define KSTK_TOP(info)                                                 \
-({                                                                     \
-       unsigned long *__ptr = (unsigned long *)(info);                 \
-       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \
-})
-
 /*
- * The below -8 is to reserve 8 bytes on top of the ring0 stack.
+ * TOP_OF_KERNEL_STACK_PADDING reserves 8 bytes on top of the ring0 stack.
  * This is necessary to guarantee that the entire "struct pt_regs"
  * is accessible even if the CPU haven't stored the SS/ESP registers
  * on the stack (interrupt gate does not save these registers
@@ -864,12 +857,11 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
  * "struct pt_regs" is possible, but they may contain the
  * completely wrong values.
  */
-#define task_pt_regs(task)                                             \
-({                                                                     \
-       struct pt_regs *__regs__;                                       \
-       __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \
-				     TOP_OF_KERNEL_STACK_PADDING);     \
-       __regs__ - 1;                                                   \
+#define task_pt_regs(task) \
+({									\
+	unsigned long __ptr = (unsigned long)task_stack_page(task);	\
+	__ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;		\
+	((struct pt_regs *)__ptr) - 1;					\
 })
 
 #define KSTK_ESP(task)		(task_pt_regs(task)->sp)
-- 
1.8.1.4


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] x86: simplify task_pt_regs() macro definition
  2015-03-13 14:09 [PATCH] x86: simplify task_pt_regs() macro definition Denys Vlasenko
@ 2015-03-13 18:26 ` Steven Rostedt
  2015-03-16 12:09 ` [tip:x86/asm] x86/asm/entry: Simplify " tip-bot for Denys Vlasenko
  2015-03-17  8:46 ` tip-bot for Denys Vlasenko
  2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2015-03-13 18:26 UTC (permalink / raw)
  To: Denys Vlasenko
  Cc: Andy Lutomirski, Linus Torvalds, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, Oleg Nesterov, Frederic Weisbecker,
	Alexei Starovoitov, Will Drewry, Kees Cook, x86, linux-kernel

On Fri, 13 Mar 2015 15:09:03 +0100
Denys Vlasenko <dvlasenk@redhat.com> wrote:

> Before this change, task_pt_regs() was using KSTK_TOP(),
> and it was the only use of that macro. In turn, KSTK_TOP used
> THREAD_SIZE_LONGS, and it was the only use of that macro too.
> 
> Fold these macros into task_pt_regs(). Tweak comment
> about "- 8" - we now use a symbolic constant, not literal 8.

I wonder if we should mention "8" at all?

As for the patch, from what I can tell, it keeps the same logic.

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: Ingo Molnar <mingo@kernel.org>
> CC: Borislav Petkov <bp@alien8.de>
> CC: "H. Peter Anvin" <hpa@zytor.com>
> CC: Andy Lutomirski <luto@amacapital.net>
> CC: Oleg Nesterov <oleg@redhat.com>
> CC: Frederic Weisbecker <fweisbec@gmail.com>
> CC: Alexei Starovoitov <ast@plumgrid.com>
> CC: Will Drewry <wad@chromium.org>
> CC: Kees Cook <keescook@chromium.org>
> CC: x86@kernel.org
> CC: linux-kernel@vger.kernel.org
> ---
>  arch/x86/include/asm/processor.h | 20 ++++++--------------
>  1 file changed, 6 insertions(+), 14 deletions(-)


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [tip:x86/asm] x86/asm/entry: Simplify task_pt_regs() macro definition
  2015-03-13 14:09 [PATCH] x86: simplify task_pt_regs() macro definition Denys Vlasenko
  2015-03-13 18:26 ` Steven Rostedt
@ 2015-03-16 12:09 ` tip-bot for Denys Vlasenko
  2015-03-17  8:46 ` tip-bot for Denys Vlasenko
  2 siblings, 0 replies; 4+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-03-16 12:09 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: hpa, rostedt, oleg, tglx, keescook, dvlasenk, wad, torvalds, bp,
	ast, mingo, linux-kernel, fweisbec, luto

Commit-ID:  42503341cde213c5928a19f7c6e1eb8c85f2df3d
Gitweb:     http://git.kernel.org/tip/42503341cde213c5928a19f7c6e1eb8c85f2df3d
Author:     Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Fri, 13 Mar 2015 15:09:03 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 16 Mar 2015 11:05:36 +0100

x86/asm/entry: Simplify task_pt_regs() macro definition

Before this change, task_pt_regs() was using KSTK_TOP(),
and it was the only use of that macro. In turn, KSTK_TOP used
THREAD_SIZE_LONGS, and it was the only use of that macro too.

Fold these macros into task_pt_regs(). Tweak comment
about "- 8" - we now use a symbolic constant, not literal 8.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426255743-5394-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/processor.h | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c3a037b..d157f94 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -846,15 +846,8 @@ static inline void spin_lock_prefetch(const void *x)
 
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
-#define THREAD_SIZE_LONGS      (THREAD_SIZE/sizeof(unsigned long))
-#define KSTK_TOP(info)                                                 \
-({                                                                     \
-       unsigned long *__ptr = (unsigned long *)(info);                 \
-       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \
-})
-
 /*
- * The below -8 is to reserve 8 bytes on top of the ring0 stack.
+ * TOP_OF_KERNEL_STACK_PADDING reserves 8 bytes on top of the ring0 stack.
  * This is necessary to guarantee that the entire "struct pt_regs"
  * is accessible even if the CPU haven't stored the SS/ESP registers
  * on the stack (interrupt gate does not save these registers
@@ -863,12 +856,11 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
  * "struct pt_regs" is possible, but they may contain the
  * completely wrong values.
  */
-#define task_pt_regs(task)                                             \
-({                                                                     \
-       struct pt_regs *__regs__;                                       \
-       __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \
-				     TOP_OF_KERNEL_STACK_PADDING);     \
-       __regs__ - 1;                                                   \
+#define task_pt_regs(task) \
+({									\
+	unsigned long __ptr = (unsigned long)task_stack_page(task);	\
+	__ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;		\
+	((struct pt_regs *)__ptr) - 1;					\
 })
 
 #define KSTK_ESP(task)		(task_pt_regs(task)->sp)

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [tip:x86/asm] x86/asm/entry: Simplify task_pt_regs() macro definition
  2015-03-13 14:09 [PATCH] x86: simplify task_pt_regs() macro definition Denys Vlasenko
  2015-03-13 18:26 ` Steven Rostedt
  2015-03-16 12:09 ` [tip:x86/asm] x86/asm/entry: Simplify " tip-bot for Denys Vlasenko
@ 2015-03-17  8:46 ` tip-bot for Denys Vlasenko
  2 siblings, 0 replies; 4+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-03-17  8:46 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: dvlasenk, keescook, hpa, rostedt, mingo, wad, linux-kernel, oleg,
	fweisbec, torvalds, ast, bp, luto, tglx

Commit-ID:  5c39403e004bec75ce0c549541be5479595d6ad0
Gitweb:     http://git.kernel.org/tip/5c39403e004bec75ce0c549541be5479595d6ad0
Author:     Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Fri, 13 Mar 2015 15:09:03 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Mar 2015 09:25:28 +0100

x86/asm/entry: Simplify task_pt_regs() macro definition

Before this change, task_pt_regs() was using KSTK_TOP(),
and it was the only use of that macro. In turn, KSTK_TOP used
THREAD_SIZE_LONGS, and it was the only use of that macro too.

Fold these macros into task_pt_regs(). Tweak comment
about "- 8" - we now use a symbolic constant, not literal 8.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426255743-5394-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/processor.h | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b262089..6a5c0ec 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -847,15 +847,8 @@ static inline void spin_lock_prefetch(const void *x)
 
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
-#define THREAD_SIZE_LONGS      (THREAD_SIZE/sizeof(unsigned long))
-#define KSTK_TOP(info)                                                 \
-({                                                                     \
-       unsigned long *__ptr = (unsigned long *)(info);                 \
-       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \
-})
-
 /*
- * The below -8 is to reserve 8 bytes on top of the ring0 stack.
+ * TOP_OF_KERNEL_STACK_PADDING reserves 8 bytes on top of the ring0 stack.
  * This is necessary to guarantee that the entire "struct pt_regs"
  * is accessible even if the CPU haven't stored the SS/ESP registers
  * on the stack (interrupt gate does not save these registers
@@ -864,12 +857,11 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
  * "struct pt_regs" is possible, but they may contain the
  * completely wrong values.
  */
-#define task_pt_regs(task)                                             \
-({                                                                     \
-       struct pt_regs *__regs__;                                       \
-       __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \
-				     TOP_OF_KERNEL_STACK_PADDING);     \
-       __regs__ - 1;                                                   \
+#define task_pt_regs(task) \
+({									\
+	unsigned long __ptr = (unsigned long)task_stack_page(task);	\
+	__ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;		\
+	((struct pt_regs *)__ptr) - 1;					\
 })
 
 #define KSTK_ESP(task)		(task_pt_regs(task)->sp)

^ permalink raw reply	[flat|nested] 4+ messages in thread

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2015-03-13 18:26 ` Steven Rostedt
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