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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef4562..9cc6b6f 100644 (file)
--- 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);