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From: Dave Jones <davej@redhat.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
Subject: [PATCH] Don't enable F00F workaround on Intel Quark processors.
Date: Tue, 28 Oct 2014 13:57:53 -0400	[thread overview]
Message-ID: <20141028175753.GA12743@redhat.com> (raw)

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.

Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Dave Jones <davej@redhat.com>

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef456273172..9cc6b6f25f42 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);

             reply	other threads:[~2014-10-28 17:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-28 17:57 Dave Jones [this message]
2014-10-28 18:33 ` [tip:x86/urgent] x86: Don' t enable F00F workaround on Intel Quark processors tip-bot for Dave Jones
2014-10-29  0:02 ` [PATCH] Don't " Bryan O'Donoghue
2014-10-29  9:10 ` [tip:x86/urgent] x86: Don' t " tip-bot for Dave Jones

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