releases/2.6.32.17/x86-fix-vsyscall-on-gcc-4.5-with-os.patch

   1 From 124482935fb7fb9303c8a8ab930149c6a93d9910 Mon Sep 17 00:00:00 2001
   2 From: Andi Kleen <andi@firstfloor.org>
   3 Date: Fri, 18 Jun 2010 23:09:00 +0200
   4 Subject: x86: Fix vsyscall on gcc 4.5 with -Os
   5
   6 From: Andi Kleen <andi@firstfloor.org>
   7
   8 commit 124482935fb7fb9303c8a8ab930149c6a93d9910 upstream.
   9
  10 This fixes the -Os breaks with gcc 4.5 bug.  rdtsc_barrier needs to be
  11 force inlined, otherwise user space will jump into kernel space and
  12 kill init.
  13
  14 This also addresses http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44129
  15 I believe.
  16
  17 Signed-off-by: Andi Kleen <ak@linux.intel.com>
  18 LKML-Reference: <20100618210859.GA10913@basil.fritz.box>
  19 Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  21
  22 ---
  23  arch/x86/include/asm/system.h |    2 +-
  24  1 file changed, 1 insertion(+), 1 deletion(-)
  25
  26 --- a/arch/x86/include/asm/system.h
  27 +++ b/arch/x86/include/asm/system.h
  28 @@ -449,7 +449,7 @@ void stop_this_cpu(void *dummy);
  29   *
  30   * (Could use an alternative three way for this if there was one.)
  31   */
  32 -static inline void rdtsc_barrier(void)
  33 +static __always_inline void rdtsc_barrier(void)
  34  {
  35         alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
  36         alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);