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authorEmanuel Czirai <icanrealizeum@gmail.com>2016-09-02 07:35:50 +0200
committerSasha Levin <alexander.levin@verizon.com>2016-09-15 18:53:30 -0400
commit706f890792bcc8abb5ca894e7c00bb415c903ad3 (patch)
tree6cd7ea5259799836afc2ee53cd2cdbf9e65c968b
parent8fdbea47fa4873884fe06a24669cf1d4138b53ab (diff)
x86/AMD: Apply erratum 665 on machines without a BIOS fix
[ Upstream commit d1992996753132e2dafe955cccb2fb0714d3cfc4 ] 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> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-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 e4cf63301ff4..c6c4248ab138 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -618,6 +618,17 @@ 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;
@@ -675,6 +686,7 @@ 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;
}