Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH 5/7] x86: Use inline assembler instead of global register variable to get sp v2 | Date | Tue, 22 Oct 2013 09:07:57 -0700 |
| |
From: Andi Kleen <ak@linux.intel.com>
LTO in gcc 4.6/47. has trouble with global register variables. They were used to read the stack pointer. Use a simple inline assembler statement with a mov instead.
This also helps LLVM/clang, who do not support global register variables.
v2: More general asm constraint. Fix description (Jan Beulich) Cc: x86@kernel.org Signed-off-by: Andi Kleen <ak@linux.intel.com> --- arch/x86/include/asm/thread_info.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 2781119..ffda484 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -166,9 +166,11 @@ struct thread_info { */ #ifndef __ASSEMBLY__ - -/* how to get the current stack pointer from C */ -register unsigned long current_stack_pointer asm("esp") __used; +#define current_stack_pointer ({ \ + unsigned long sp; \ + asm("mov %%esp,%0" : "=g" (sp)); \ + sp; \ +}) /* how to get the thread information struct from C */ static inline struct thread_info *current_thread_info(void) -- 1.8.3.1
| |