From: Andi Kleen <a...@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: x...@kernel.org
Signed-off-by: Andi Kleen <a...@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
--
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