[tip:x86/urgent] x86: Don' t enable F00F workaround on Intel Quark processors
From: tip-bot for Dave Jones
Date: Wed Oct 29 2014 - 05:10:52 EST
Commit-ID: d4e1a0af1d3a88cdfc8c954d3005eb8745ec518d
Gitweb: http://git.kernel.org/tip/d4e1a0af1d3a88cdfc8c954d3005eb8745ec518d
Author: Dave Jones <davej@xxxxxxxxxx>
AuthorDate: Tue, 28 Oct 2014 13:57:53 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 29 Oct 2014 08:52:09 +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@xxxxxxxxxx>
Cc: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20141028175753.GA12743@xxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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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