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authorArjan van de Ven <arjan@infradead.org>2009-09-30 17:07:54 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-30 22:55:59 +0200
commit79e1dd05d1a22e95ab6d54d21836f478b3b56976 (patch)
tree03f9ff44af91de79c33abec468dd278d9cde83d4 /arch/x86/lib/Makefile
parent17d857be649a21ca90008c6dc425d849fa83db5c (diff)
downloadlinux-79e1dd05d1a22e95ab6d54d21836f478b3b56976.tar.bz2
x86: Provide an alternative() based cmpxchg64()
cmpxchg64() today generates, to quote Linus, "barf bag" code. cmpxchg64() is about to get used in the scheduler to fix a bug there, but it's a prerequisite that cmpxchg64() first be made non-sucking. This patch turns cmpxchg64() into an efficient implementation that uses the alternative() mechanism to just use the raw instruction on all modern systems. Note: the fallback is NOT smp safe, just like the current fallback is not SMP safe. (Interested parties with i486 based SMP systems are welcome to submit fix patches for that.) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> [ fixed asm constraint bug ] Fixed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090930170754.0886ff2e@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/Makefile')
-rw-r--r--arch/x86/lib/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 9e609206fac9..3e549b8ec8c9 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -15,7 +15,7 @@ ifeq ($(CONFIG_X86_32),y)
obj-y += atomic64_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
- lib-y += semaphore_32.o string_32.o
+ lib-y += semaphore_32.o string_32.o cmpxchg8b_emu.o
lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
else