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authorEmanuel Czirai <icanrealizeum@gmail.com>2016-09-02 07:35:50 +0200
committerThomas Gleixner <tglx@linutronix.de>2016-09-02 20:42:28 +0200
commitd1992996753132e2dafe955cccb2fb0714d3cfc4 (patch)
tree92a0102f68353c85730b99faf1f83e08451f12c6 /arch
parent3eab887a55424fc2c27553b7bfe32330df83f7b8 (diff)
x86/AMD: Apply erratum 665 on machines without a BIOS fix
AMD F12h machines have an erratum which can cause DIV/IDIV to behave unpredictably. The workaround is to set MSRC001_1029[31] but sometimes there is no BIOS update containing that workaround so let's do it ourselves unconditionally. It is simple enough. [ Borislav: Wrote commit message. ] Signed-off-by: Emanuel Czirai <icanrealizeum@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Yaowu Xu <yaowu@google.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20160902053550.18097-1-bp@alien8.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/amd.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index f5c69d8974e1..b81fe2d63e15 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -669,6 +669,17 @@ static void init_amd_gh(struct cpuinfo_x86 *c)
set_cpu_bug(c, X86_BUG_AMD_TLB_MMATCH);
}
+#define MSR_AMD64_DE_CFG 0xC0011029
+
+static void init_amd_ln(struct cpuinfo_x86 *c)
+{
+ /*
+ * Apply erratum 665 fix unconditionally so machines without a BIOS
+ * fix work.
+ */
+ msr_set_bit(MSR_AMD64_DE_CFG, 31);
+}
+
static void init_amd_bd(struct cpuinfo_x86 *c)
{
u64 value;
@@ -726,6 +737,7 @@ static void init_amd(struct cpuinfo_x86 *c)
case 6: init_amd_k7(c); break;
case 0xf: init_amd_k8(c); break;
case 0x10: init_amd_gh(c); break;
+ case 0x12: init_amd_ln(c); break;
case 0x15: init_amd_bd(c); break;
}