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Don't enable F00F workaround on Intel Quark processors.

PATCH In review Dave Jones 3 participants 4 messages Oct 28, 2014 – Oct 29, 2014 x86

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Dave Jones

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#0 lore raw

PATCH 1/1 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.

Cc Bryan O'Donoghue <[email protected]>
arch/x86/kernel/cpu/intel.c +3 -2
index 1ef456273172..9cc6b6f25f42 100644
@@ -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);
#1 lore raw

[tip:x86/urgent] x86: Don' t enable F00F workaround on Intel Quark processors

x86: Don't enable F00F workaround on Intel Quark processors
Commit-ID:  c1dd2d38a55119e1611a9ea3ee30bcf8902e2b04
Gitweb:     http://git.kernel.org/tip/c1dd2d38a55119e1611a9ea3ee30bcf8902e2b04
Author:     Dave Jones <[email protected]>
AuthorDate: Tue, 28 Oct 2014 13:57:53 -0400
Committer:  Thomas Gleixner <[email protected]>
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.

---
 arch/x86/kernel/cpu/intel.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
arch/x86/kernel/cpu/intel.c +3 -2
index 1ef4562..9cc6b6f 100644
@@ -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);
#2 lore raw
In reply to Dave Jones
Quoted 4 lines · Dave Jones

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.

Tested - works, F00F removed from list of bugs in /proc/cpuinfo

BOD

#3 lore raw

[tip:x86/urgent] x86: Don' t enable F00F workaround on Intel Quark processors

In reply to Dave Jones
x86: Don't enable F00F workaround on Intel Quark processors
Commit-ID:  d4e1a0af1d3a88cdfc8c954d3005eb8745ec518d
Gitweb:     http://git.kernel.org/tip/d4e1a0af1d3a88cdfc8c954d3005eb8745ec518d
Author:     Dave Jones <[email protected]>
AuthorDate: Tue, 28 Oct 2014 13:57:53 -0400
Committer:  Ingo Molnar <[email protected]>
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.

---
 arch/x86/kernel/cpu/intel.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
arch/x86/kernel/cpu/intel.c +3 -2
index 1ef4562..9cc6b6f 100644
@@ -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);