Commit-ID: dff38e3e93bbc10653a232f68077e5d031624464 Gitweb: http://git.kernel.org/tip/dff38e3e93bbc10653a232f68077e5d031624464 Author: Andi Kleen <a...@linux.intel.com> AuthorDate: Tue, 22 Oct 2013 09:07:57 -0700 Committer: H. Peter Anvin <h...@linux.intel.com> CommitDate: Wed, 29 Jan 2014 22:17:17 -0800
x86: Use inline assembler instead of global register variable to get sp 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, which does not support global register variables. [ hpa: Ideally this should become a builtin in both gcc and clang. ] v2: More general asm constraint. Fix description (Jan Beulich) Signed-off-by: Andi Kleen <a...@linux.intel.com> Link: http://lkml.kernel.org/r/1382458079-24450-6-git-send-email-a...@firstfloor.org Signed-off-by: H. Peter Anvin <h...@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 3ba3de4..e1940c0 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -163,9 +163,11 @@ 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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
