diff options
| author | Andi Kleen <ak@linux.intel.com> | 2013-10-22 09:07:57 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-01-29 22:17:17 -0800 |
| commit | dff38e3e93bbc10653a232f68077e5d031624464 (patch) | |
| tree | 084ea355a1f7d84e3d1a33759e3105ff116e2d28 /arch | |
| parent | a2e7f0e3a4f0f23fe4cd8cc22da547872f0170bb (diff) | |
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 <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-6-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 3ba3de457d05..e1940c06ed02 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) |