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[PATCH] x86/asm: Merge KSTK_ESP() implementations

Brian Gerst posted 1 patch 11 months, 1 week ago
There is a newer version of this series
arch/x86/include/asm/processor.h | 5 +----
arch/x86/kernel/process_64.c     | 5 -----
2 files changed, 1 insertion(+), 9 deletions(-)
[PATCH] x86/asm: Merge KSTK_ESP() implementations
Posted by Brian Gerst 11 months, 1 week ago 
Commit 263042e4630a ("Save user RSP in pt_regs->sp on SYSCALL64
fastpath") simplified the 64-bit implementation of KSTK_ESP() which is
now identical to 32-bit.  Merge them into a common definition.

No functional change.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
 arch/x86/include/asm/processor.h | 5 +----
 arch/x86/kernel/process_64.c     | 5 -----
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a969bea1ed07..55f0e48413b0 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -652,8 +652,6 @@ static __always_inline void prefetchw(const void *x)
 	.sysenter_cs		= __KERNEL_CS,				  \
 }
 
-#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
-
 #else
 extern unsigned long __top_init_kernel_stack[];
 
@@ -661,8 +659,6 @@ extern unsigned long __top_init_kernel_stack[];
 	.sp	= (unsigned long)&__top_init_kernel_stack,		\
 }
 
-extern unsigned long KSTK_ESP(struct task_struct *task);
-
 #endif /* CONFIG_X86_64 */
 
 extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
@@ -676,6 +672,7 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
 #define TASK_UNMAPPED_BASE		__TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
 
 #define KSTK_EIP(task)		(task_pt_regs(task)->ip)
+#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
 
 /* Get/set a process' ability to use the timestamp counter instruction */
 #define GET_TSC_CTL(adr)	get_tsc_mode((adr))
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4ca73ddfb30b..f983d2a57ac3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -979,8 +979,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 
 	return ret;
 }
-
-unsigned long KSTK_ESP(struct task_struct *task)
-{
-	return task_pt_regs(task)->sp;
-}

base-commit: 693c8502970a533363e9ece482c80bb6db0c12a5
-- 
2.48.1
Re: [PATCH] x86/asm: Merge KSTK_ESP() implementations
Posted by H. Peter Anvin 11 months, 1 week ago 
On March 3, 2025 10:31:11 AM PST, Brian Gerst <brgerst@gmail.com> wrote:
>Commit 263042e4630a ("Save user RSP in pt_regs->sp on SYSCALL64
>fastpath") simplified the 64-bit implementation of KSTK_ESP() which is
>now identical to 32-bit.  Merge them into a common definition.
>
>No functional change.
>
>Signed-off-by: Brian Gerst <brgerst@gmail.com>
>---
> arch/x86/include/asm/processor.h | 5 +----
> arch/x86/kernel/process_64.c     | 5 -----
> 2 files changed, 1 insertion(+), 9 deletions(-)
>
>diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
>index a969bea1ed07..55f0e48413b0 100644
>--- a/arch/x86/include/asm/processor.h
>+++ b/arch/x86/include/asm/processor.h
>@@ -652,8 +652,6 @@ static __always_inline void prefetchw(const void *x)
> 	.sysenter_cs		= __KERNEL_CS,				  \
> }
> 
>-#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
>-
> #else
> extern unsigned long __top_init_kernel_stack[];
> 
>@@ -661,8 +659,6 @@ extern unsigned long __top_init_kernel_stack[];
> 	.sp	= (unsigned long)&__top_init_kernel_stack,		\
> }
> 
>-extern unsigned long KSTK_ESP(struct task_struct *task);
>-
> #endif /* CONFIG_X86_64 */
> 
> extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
>@@ -676,6 +672,7 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
> #define TASK_UNMAPPED_BASE		__TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
> 
> #define KSTK_EIP(task)		(task_pt_regs(task)->ip)
>+#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
> 
> /* Get/set a process' ability to use the timestamp counter instruction */
> #define GET_TSC_CTL(adr)	get_tsc_mode((adr))
>diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
>index 4ca73ddfb30b..f983d2a57ac3 100644
>--- a/arch/x86/kernel/process_64.c
>+++ b/arch/x86/kernel/process_64.c
>@@ -979,8 +979,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
> 
> 	return ret;
> }
>-
>-unsigned long KSTK_ESP(struct task_struct *task)
>-{
>-	return task_pt_regs(task)->sp;
>-}
>
>base-commit: 693c8502970a533363e9ece482c80bb6db0c12a5

Why using the macro version?
Re: [PATCH] x86/asm: Merge KSTK_ESP() implementations
Posted by Brian Gerst 11 months, 1 week ago 
On Mon, Mar 3, 2025 at 7:01 PM H. Peter Anvin <hpa@zytor.com> wrote:
>
> On March 3, 2025 10:31:11 AM PST, Brian Gerst <brgerst@gmail.com> wrote:
> >Commit 263042e4630a ("Save user RSP in pt_regs->sp on SYSCALL64
> >fastpath") simplified the 64-bit implementation of KSTK_ESP() which is
> >now identical to 32-bit.  Merge them into a common definition.
> >
> >No functional change.
> >
> >Signed-off-by: Brian Gerst <brgerst@gmail.com>
> >---
> > arch/x86/include/asm/processor.h | 5 +----
> > arch/x86/kernel/process_64.c     | 5 -----
> > 2 files changed, 1 insertion(+), 9 deletions(-)
> >
> >diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> >index a969bea1ed07..55f0e48413b0 100644
> >--- a/arch/x86/include/asm/processor.h
> >+++ b/arch/x86/include/asm/processor.h
> >@@ -652,8 +652,6 @@ static __always_inline void prefetchw(const void *x)
> >       .sysenter_cs            = __KERNEL_CS,                            \
> > }
> >
> >-#define KSTK_ESP(task)                (task_pt_regs(task)->sp)
> >-
> > #else
> > extern unsigned long __top_init_kernel_stack[];
> >
> >@@ -661,8 +659,6 @@ extern unsigned long __top_init_kernel_stack[];
> >       .sp     = (unsigned long)&__top_init_kernel_stack,              \
> > }
> >
> >-extern unsigned long KSTK_ESP(struct task_struct *task);
> >-
> > #endif /* CONFIG_X86_64 */
> >
> > extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
> >@@ -676,6 +672,7 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
> > #define TASK_UNMAPPED_BASE            __TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
> >
> > #define KSTK_EIP(task)                (task_pt_regs(task)->ip)
> >+#define KSTK_ESP(task)                (task_pt_regs(task)->sp)
> >
> > /* Get/set a process' ability to use the timestamp counter instruction */
> > #define GET_TSC_CTL(adr)      get_tsc_mode((adr))
> >diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> >index 4ca73ddfb30b..f983d2a57ac3 100644
> >--- a/arch/x86/kernel/process_64.c
> >+++ b/arch/x86/kernel/process_64.c
> >@@ -979,8 +979,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
> >
> >       return ret;
> > }
> >-
> >-unsigned long KSTK_ESP(struct task_struct *task)
> >-{
> >-      return task_pt_regs(task)->sp;
> >-}
> >
> >base-commit: 693c8502970a533363e9ece482c80bb6db0c12a5
>
> Why using the macro version?

Why call an out-of-line function?  I guess it could be an inline
function (along with KSK_EIP()).


Brian Gerst
Re: [PATCH] x86/asm: Merge KSTK_ESP() implementations
Posted by H. Peter Anvin 11 months, 1 week ago 
On March 3, 2025 4:25:06 PM PST, Brian Gerst <brgerst@gmail.com> wrote:
>On Mon, Mar 3, 2025 at 7:01 PM H. Peter Anvin <hpa@zytor.com> wrote:
>>
>> On March 3, 2025 10:31:11 AM PST, Brian Gerst <brgerst@gmail.com> wrote:
>> >Commit 263042e4630a ("Save user RSP in pt_regs->sp on SYSCALL64
>> >fastpath") simplified the 64-bit implementation of KSTK_ESP() which is
>> >now identical to 32-bit.  Merge them into a common definition.
>> >
>> >No functional change.
>> >
>> >Signed-off-by: Brian Gerst <brgerst@gmail.com>
>> >---
>> > arch/x86/include/asm/processor.h | 5 +----
>> > arch/x86/kernel/process_64.c     | 5 -----
>> > 2 files changed, 1 insertion(+), 9 deletions(-)
>> >
>> >diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
>> >index a969bea1ed07..55f0e48413b0 100644
>> >--- a/arch/x86/include/asm/processor.h
>> >+++ b/arch/x86/include/asm/processor.h
>> >@@ -652,8 +652,6 @@ static __always_inline void prefetchw(const void *x)
>> >       .sysenter_cs            = __KERNEL_CS,                            \
>> > }
>> >
>> >-#define KSTK_ESP(task)                (task_pt_regs(task)->sp)
>> >-
>> > #else
>> > extern unsigned long __top_init_kernel_stack[];
>> >
>> >@@ -661,8 +659,6 @@ extern unsigned long __top_init_kernel_stack[];
>> >       .sp     = (unsigned long)&__top_init_kernel_stack,              \
>> > }
>> >
>> >-extern unsigned long KSTK_ESP(struct task_struct *task);
>> >-
>> > #endif /* CONFIG_X86_64 */
>> >
>> > extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
>> >@@ -676,6 +672,7 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
>> > #define TASK_UNMAPPED_BASE            __TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
>> >
>> > #define KSTK_EIP(task)                (task_pt_regs(task)->ip)
>> >+#define KSTK_ESP(task)                (task_pt_regs(task)->sp)
>> >
>> > /* Get/set a process' ability to use the timestamp counter instruction */
>> > #define GET_TSC_CTL(adr)      get_tsc_mode((adr))
>> >diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
>> >index 4ca73ddfb30b..f983d2a57ac3 100644
>> >--- a/arch/x86/kernel/process_64.c
>> >+++ b/arch/x86/kernel/process_64.c
>> >@@ -979,8 +979,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
>> >
>> >       return ret;
>> > }
>> >-
>> >-unsigned long KSTK_ESP(struct task_struct *task)
>> >-{
>> >-      return task_pt_regs(task)->sp;
>> >-}
>> >
>> >base-commit: 693c8502970a533363e9ece482c80bb6db0c12a5
>>
>> Why using the macro version?
>
>Why call an out-of-line function?  I guess it could be an inline
>function (along with KSK_EIP()).
>
>
>Brian Gerst
>

Ah yes, not out of line obviously.
[tip: x86/core] x86/asm: Merge KSTK_ESP() implementations
Posted by tip-bot2 for Brian Gerst 11 months, 1 week ago 
The following commit has been merged into the x86/core branch of tip:

Commit-ID:     399fd7a26441586021ca3722f6a98ff33ed32caf
Gitweb:        https://git.kernel.org/tip/399fd7a26441586021ca3722f6a98ff33ed32caf
Author:        Brian Gerst <brgerst@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 13:31:11 -05:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 03 Mar 2025 20:28:33 +01:00

x86/asm: Merge KSTK_ESP() implementations

Commit:

  263042e4630a ("Save user RSP in pt_regs->sp on SYSCALL64 fastpath")

simplified the 64-bit implementation of KSTK_ESP() which is
now identical to 32-bit.  Merge them into a common definition.

No functional change.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250303183111.2245129-1-brgerst@gmail.com
---
 arch/x86/include/asm/processor.h | 5 +----
 arch/x86/kernel/process_64.c     | 5 -----
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c0cd101..0c91108 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -668,8 +668,6 @@ static __always_inline void prefetchw(const void *x)
 	.sysenter_cs		= __KERNEL_CS,				  \
 }
 
-#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
-
 #else
 extern unsigned long __top_init_kernel_stack[];
 
@@ -677,8 +675,6 @@ extern unsigned long __top_init_kernel_stack[];
 	.sp	= (unsigned long)&__top_init_kernel_stack,		\
 }
 
-extern unsigned long KSTK_ESP(struct task_struct *task);
-
 #endif /* CONFIG_X86_64 */
 
 extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
@@ -692,6 +688,7 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
 #define TASK_UNMAPPED_BASE		__TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
 
 #define KSTK_EIP(task)		(task_pt_regs(task)->ip)
+#define KSTK_ESP(task)		(task_pt_regs(task)->sp)
 
 /* Get/set a process' ability to use the timestamp counter instruction */
 #define GET_TSC_CTL(adr)	get_tsc_mode((adr))
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4ca73dd..f983d2a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -979,8 +979,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 
 	return ret;
 }
-
-unsigned long KSTK_ESP(struct task_struct *task)
-{
-	return task_pt_regs(task)->sp;
-}

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