diff options
Diffstat (limited to 'arch/x86/kernel/cpu/intel.c')
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 08b95a35b5cb..e7656cbef68d 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -311,16 +311,18 @@ static void early_init_intel(struct cpuinfo_x86 *c) } /* - * There is a known erratum on Pentium III and Core Solo - * and Core Duo CPUs. - * " Page with PAT set to WC while associated MTRR is UC - * may consolidate to UC " - * Because of this erratum, it is better to stick with - * setting WC in MTRR rather than using PAT on these CPUs. + * PAT is broken on early family 6 CPUs, the last of which + * is "Yonah" where the erratum is named "AN7": * - * Enable PAT WC only on P4, Core 2 or later CPUs. + * Page with PAT (Page Attribute Table) Set to USWC + * (Uncacheable Speculative Write Combine) While + * Associated MTRR (Memory Type Range Register) Is UC + * (Uncacheable) May Consolidate to UC + * + * Disable PAT and fall back to MTRR on these CPUs. */ - if (c->x86 == 6 && c->x86_model < 15) + if (c->x86_vfm >= INTEL_PENTIUM_PRO && + c->x86_vfm <= INTEL_CORE_YONAH) clear_cpu_cap(c, X86_FEATURE_PAT); /* |