| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.7 062/184] x86/AMD: Apply erratum 665 on machines without a BIOS fix | Date | Thu, 22 Sep 2016 19:39:56 +0200 |
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4.7-stable review patch. If anyone has any objections, please let me know.
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From: Emanuel Czirai <icanrealizeum@gmail.com>
commit d1992996753132e2dafe955cccb2fb0714d3cfc4 upstream.
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> Link: http://lkml.kernel.org/r/20160902053550.18097-1-bp@alien8.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kernel/cpu/amd.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
--- 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_x 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 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; }
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