x86: Don't generate cmpxchg8b_emu if CONFIG_X86_CMPXCHG64=y

Conditionaly compile cmpxchg8b_emu.o and EXPORT_SYMBOL(cmpxchg8b_emu).

This reduces the kernel size a bit.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4AC43E7E.1000600@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c
index 1736c5a725aa..9c3bd4a2050e 100644
--- a/arch/x86/kernel/i386_ksyms_32.c
+++ b/arch/x86/kernel/i386_ksyms_32.c
@@ -15,8 +15,10 @@ EXPORT_SYMBOL(mcount);
  * the export, but dont use it from C code, it is used
  * by assembly code and is not using C calling convention!
  */
+#ifndef CONFIG_X86_CMPXCHG64
 extern void cmpxchg8b_emu(void);
 EXPORT_SYMBOL(cmpxchg8b_emu);
+#endif
 
 /* Networking helper routines. */
 EXPORT_SYMBOL(csum_partial_copy_generic);