Commit-ID: d1992996753132e2dafe955cccb2fb0714d3cfc4 Gitweb: http://git.kernel.org/tip/d1992996753132e2dafe955cccb2fb0714d3cfc4 Author: Emanuel Czirai <icanrealiz...@gmail.com> AuthorDate: Fri, 2 Sep 2016 07:35:50 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 2 Sep 2016 20:42:28 +0200
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 <icanrealiz...@gmail.com> Signed-off-by: Borislav Petkov <b...@suse.de> Cc: Yaowu Xu <ya...@google.com> Cc: sta...@vger.kernel.org Link: http://lkml.kernel.org/r/20160902053550.18097-1...@alien8.de Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/kernel/cpu/amd.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index f5c69d8..b81fe2d 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; }
