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| author | Rusty Russell <rusty@rustcorp.com.au> | 2009-10-26 06:56:04 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-26 14:33:02 +0300 |
| commit | ae1b22f6e46c03cede7cea234d0bf2253b4261cf (patch) | |
| tree | 3a38eb7c35cf3fad8816f87cfbb0c19c079d7101 | |
| parent | 14a3f40aafacde1dfd6912327ae14df4baf10304 (diff) | |
| download | linux-ae1b22f6e46c03cede7cea234d0bf2253b4261cf.tar.xz | |
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>
| -rw-r--r-- | arch/x86/Kconfig.cpu | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index f2824fb8c79c..2649840d888f 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. |