Commit f4b825bd authored Jan 05, 2010 by Rusty Russell Committed by H. Peter Anvin Jan 04, 2010

Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium"

This reverts commit ae1b22f6.

As Linus said in 982d007a: "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 <rusty@rustcorp.com.au>
LKML-Reference: <201001051248.49700.rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

parent a557aae2

arch/x86/Kconfig.cpu

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -396,7 +396,7 @@ config X86_TSC

	config X86_CMPXCHG64		config X86_CMPXCHG64
	def_bool y		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		# this should be set for all -march=.. options where the compiler
	# generates cmov.		# generates cmov.