* [PATCH] arm: LLVMLinux: Use __builtin_frame_address instead of named registers
@ 2013-09-06 21:42 ` behanw at converseincode.com
0 siblings, 0 replies; 7+ messages in thread
From: behanw @ 2013-09-06 21:42 UTC (permalink / raw)
To: linux, linux-arm-kernel, linux-kernel
Cc: behanw, Paul E. McKenney, David Howells, Catalin Marinas, Dave Jones
From: Behan Webster <behanw@converseincode.com>
The LLVMLinux Project is working to be able to build the Linux kernel with
clang/LLVM. With the release of LLVM 3.3 clang is now able to compile the Linux
kernel with a number of small patches (available from the LLVMLinux git repo).
Use the frame pointer to calculate the end of the stack for current_pt_regs()
The existing code uses the stack pointer to do this calculation.
Using the frame pointer yeilds the same value in a more portable way.
This change supports being able to compile the kernel with gcc and clang.
Behan Webster (1):
arm: LLVMLinux: Calculate pt_regs address from fp
arch/arm/include/asm/ptrace.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--
1.8.1.2
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] arm: LLVMLinux: Use __builtin_frame_address instead of named registers
@ 2013-09-06 21:42 ` behanw at converseincode.com
0 siblings, 0 replies; 7+ messages in thread
From: behanw at converseincode.com @ 2013-09-06 21:42 UTC (permalink / raw)
To: linux-arm-kernel
From: Behan Webster <behanw@converseincode.com>
The LLVMLinux Project is working to be able to build the Linux kernel with
clang/LLVM. With the release of LLVM 3.3 clang is now able to compile the Linux
kernel with a number of small patches (available from the LLVMLinux git repo).
Use the frame pointer to calculate the end of the stack for current_pt_regs()
The existing code uses the stack pointer to do this calculation.
Using the frame pointer yeilds the same value in a more portable way.
This change supports being able to compile the kernel with gcc and clang.
Behan Webster (1):
arm: LLVMLinux: Calculate pt_regs address from fp
arch/arm/include/asm/ptrace.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--
1.8.1.2
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp
2013-09-06 21:42 ` behanw at converseincode.com
@ 2013-09-06 21:42 ` behanw at converseincode.com
-1 siblings, 0 replies; 7+ messages in thread
From: behanw @ 2013-09-06 21:42 UTC (permalink / raw)
To: linux
Cc: behanw, Mark Charlebois, Paul E. McKenney, David Howells,
Catalin Marinas, Dave Jones, moderated list:ARM PORT, open list
From: Behan Webster <behanw@converseincode.com>
Use the frame pointer to calculate the end of the stack for current_pt_regs()
The existing code uses the stack pointer to do this calculation.
Using the frame pointer yeilds the same value in a more portable way.
This change supports being able to compile the kernel with gcc and clang.
Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
arch/arm/include/asm/ptrace.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 04c99f3..8aec2db 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -138,9 +138,9 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs)
return regs->ARM_sp;
}
-#define current_pt_regs(void) ({ \
- register unsigned long sp asm ("sp"); \
- (struct pt_regs *)((sp | (THREAD_SIZE - 1)) - 7) - 1; \
+#define current_pt_regs(void) ({ \
+ (struct pt_regs *)(((unsigned long)(__builtin_frame_address(0)) \
+ | (THREAD_SIZE - 1)) - 7) - 1; \
})
#endif /* __ASSEMBLY__ */
--
1.8.1.2
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp
@ 2013-09-06 21:42 ` behanw at converseincode.com
0 siblings, 0 replies; 7+ messages in thread
From: behanw at converseincode.com @ 2013-09-06 21:42 UTC (permalink / raw)
To: linux-arm-kernel
From: Behan Webster <behanw@converseincode.com>
Use the frame pointer to calculate the end of the stack for current_pt_regs()
The existing code uses the stack pointer to do this calculation.
Using the frame pointer yeilds the same value in a more portable way.
This change supports being able to compile the kernel with gcc and clang.
Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Jan-Simon M?ller <dl9pf@gmx.de>
---
arch/arm/include/asm/ptrace.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 04c99f3..8aec2db 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -138,9 +138,9 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs)
return regs->ARM_sp;
}
-#define current_pt_regs(void) ({ \
- register unsigned long sp asm ("sp"); \
- (struct pt_regs *)((sp | (THREAD_SIZE - 1)) - 7) - 1; \
+#define current_pt_regs(void) ({ \
+ (struct pt_regs *)(((unsigned long)(__builtin_frame_address(0)) \
+ | (THREAD_SIZE - 1)) - 7) - 1; \
})
#endif /* __ASSEMBLY__ */
--
1.8.1.2
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp
2013-09-06 21:42 ` behanw at converseincode.com
@ 2013-09-06 22:18 ` Russell King - ARM Linux
-1 siblings, 0 replies; 7+ messages in thread
From: Russell King - ARM Linux @ 2013-09-06 22:18 UTC (permalink / raw)
To: behanw
Cc: Mark Charlebois, Paul E. McKenney, David Howells,
Catalin Marinas, Dave Jones, moderated list:ARM PORT, open list
On Fri, Sep 06, 2013 at 05:42:41PM -0400, behanw@converseincode.com wrote:
> From: Behan Webster <behanw@converseincode.com>
>
> Use the frame pointer to calculate the end of the stack for current_pt_regs()
> The existing code uses the stack pointer to do this calculation.
> Using the frame pointer yeilds the same value in a more portable way.
> This change supports being able to compile the kernel with gcc and clang.
What happens when frame pointers are disabled on gcc?
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp
@ 2013-09-06 22:18 ` Russell King - ARM Linux
0 siblings, 0 replies; 7+ messages in thread
From: Russell King - ARM Linux @ 2013-09-06 22:18 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Sep 06, 2013 at 05:42:41PM -0400, behanw at converseincode.com wrote:
> From: Behan Webster <behanw@converseincode.com>
>
> Use the frame pointer to calculate the end of the stack for current_pt_regs()
> The existing code uses the stack pointer to do this calculation.
> Using the frame pointer yeilds the same value in a more portable way.
> This change supports being able to compile the kernel with gcc and clang.
What happens when frame pointers are disabled on gcc?
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp
2013-09-06 22:18 ` Russell King - ARM Linux
(?)
@ 2013-09-06 23:02 ` Behan Webster
-1 siblings, 0 replies; 7+ messages in thread
From: Behan Webster @ 2013-09-06 23:02 UTC (permalink / raw)
To: linux-arm-kernel
On 09/06/13 18:18, Russell King - ARM Linux wrote:
> On Fri, Sep 06, 2013 at 05:42:41PM -0400, behanw at converseincode.com wrote:
>> From: Behan Webster <behanw@converseincode.com>
>>
>> Use the frame pointer to calculate the end of the stack for current_pt_regs()
>> The existing code uses the stack pointer to do this calculation.
>> Using the frame pointer yeilds the same value in a more portable way.
>> This change supports being able to compile the kernel with gcc and clang.
> What happens when frame pointers are disabled on gcc?
Drat. Good point. Didn't think of that.
Could be rewritten to use current_stack_pointer (assuming the patch
series that implements that would be amenable).
Thanks,
Behan
--
Behan Webster
behanw at converseincode.com
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2013-09-06 23:02 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-09-06 21:42 [PATCH] arm: LLVMLinux: Use __builtin_frame_address instead of named registers behanw
2013-09-06 21:42 ` behanw at converseincode.com
2013-09-06 21:42 ` [PATCH] arm: LLVMLinux: Calculate pt_regs address from fp behanw
2013-09-06 21:42 ` behanw at converseincode.com
2013-09-06 22:18 ` Russell King - ARM Linux
2013-09-06 22:18 ` Russell King - ARM Linux
2013-09-06 23:02 ` Behan Webster
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