From: Rusty Russell Date: Tue, 5 Jan 2010 02:18:49 +0000 (+1030) Subject: Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium" X-Git-Tag: firefly_0821_release~11625^2~379 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b7e5f77916291b3c80fdf34dd2a649d8d10138e8;p=firefly-linux-kernel-4.4.55.git Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium" commit db677ffa5f5a4f15b9dad4d132b3477b80766d82 upstream. This reverts commit ae1b22f6e46c03cede7cea234d0bf2253b4261cf. As Linus said in 982d007a6ee: "There was something really messy about cmpxchg8b and clone CPU's, so if you enable it on other CPUs later, do it carefully." This breaks lguest for those configs, but we can fix that by emulating if we have to. Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14884 Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 2649840d888f..f2824fb8c79c 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 !M386 && !M486 + depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM # this should be set for all -march=.. options where the compiler # generates cmov.