x86: Fix vsyscall on gcc 4.5 with -Os

This fixes the -Os breaks with gcc 4.5 bug.  rdtsc_barrier needs to be
force inlined, otherwise user space will jump into kernel space and
kill init.

This also addresses http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44129
I believe.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <20100618210859.GA10913@basil.fritz.box>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@kernel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index b8fe48ee2ed9..e7f4d33c55ed 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -451,7 +451,7 @@ void stop_this_cpu(void *dummy);
  *
  * (Could use an alternative three way for this if there was one.)
  */
-static inline void rdtsc_barrier(void)
+static __always_inline void rdtsc_barrier(void)
 {
         alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
         alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);