From: Behan Webster <[email protected]>
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
From: Behan Webster <[email protected]>
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 <[email protected]>
Signed-off-by: Behan Webster <[email protected]>
Reviewed-by: Jan-Simon Möller <[email protected]>
---
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
On Fri, Sep 06, 2013 at 05:42:41PM -0400, [email protected] wrote:
> From: Behan Webster <[email protected]>
>
> 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?