2014-10-28 17:58:10

by Dave Jones

[permalink] [raw]
Subject: [PATCH] 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]>
Signed-off-by: Dave Jones <[email protected]>

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);


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 <[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.

Signed-off-by: Dave Jones <[email protected]>
Cc: Bryan O'Donoghue <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

---
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);

2014-10-29 00:02:14

by Bryan O'Donoghue

[permalink] [raw]
Subject: Re: [PATCH] Don't enable F00F workaround on Intel Quark processors.

On 28/10/14 17:57, Dave Jones wrote:
> 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

Subject: [tip:x86/urgent] 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.

Signed-off-by: Dave Jones <[email protected]>
Cc: Bryan O'Donoghue <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
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);