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authorRusty Russell <rusty@rustcorp.com.au>2009-10-26 14:26:04 +1030
committerIngo Molnar <mingo@elte.hu>2009-10-26 12:33:02 +0100
commitae1b22f6e46c03cede7cea234d0bf2253b4261cf (patch)
tree3a38eb7c35cf3fad8816f87cfbb0c19c079d7101 /arch
parent14a3f40aafacde1dfd6912327ae14df4baf10304 (diff)
x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium
Commit 79e1dd05d1a22 "x86: Provide an alternative() based cmpxchg64()" broke lguest, even on systems which have cmpxchg8b support. The emulation code gets used until alternatives get run, but it contains native instructions, not their paravirt alternatives. The simplest fix is to turn this code off except for 386 and 486 builds. Reported-by: Johannes Stezenbach <js@sig21.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: lguest@ozlabs.org Cc: Arjan van de Ven <arjan@infradead.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <200910261426.05769.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig.cpu2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index f2824fb8c79..2649840d888 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -400,7 +400,7 @@ config X86_TSC
config X86_CMPXCHG64
def_bool y
- depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM
+ depends on !M386 && !M486
# this should be set for all -march=.. options where the compiler
# generates cmov.