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Subject[tip:x86/urgent] x86: Don' t enable F00F workaround on Intel Quark processors
Commit-ID:  c1dd2d38a55119e1611a9ea3ee30bcf8902e2b04
Gitweb: http://git.kernel.org/tip/c1dd2d38a55119e1611a9ea3ee30bcf8902e2b04
Author: Dave Jones <davej@redhat.com>
AuthorDate: Tue, 28 Oct 2014 13:57:53 -0400
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 28 Oct 2014 19:31:23 +0100

x86: Don't enable F00F workaround on Intel Quark processors

The Intel Quark processor is a part of family 5, but does not have the
F00F bug present in Pentiums of the same family.

Pentiums were models 0 through 8, Quark is model 9.

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Link: http://lkml.kernel.org/r/20141028175753.GA12743@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
arch/x86/kernel/cpu/intel.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef4562..9cc6b6f 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -213,12 +213,13 @@ static void intel_workarounds(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_F00F_BUG
/*
- * All current models of Pentium and Pentium with MMX technology CPUs
+ * All models of Pentium and Pentium with MMX technology CPUs
* have the F0 0F bug, which lets nonprivileged users lock up the
* system. Announce that the fault handler will be checking for it.
+ * The Quark is also family 5, but does not have the same bug.
*/
clear_cpu_bug(c, X86_BUG_F00F);
- if (!paravirt_enabled() && c->x86 == 5) {
+ if (!paravirt_enabled() && c->x86 == 5 && c->x86_model < 9) {
static int f00f_workaround_enabled;

set_cpu_bug(c, X86_BUG_F00F);

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