1 files changed, 14 insertions, 3 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 5fff00c70de0..1a89a2b68d15 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -25,7 +25,6 @@
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/mpspec.h>
 #include <asm/apic.h>
-#include <mach_apic.h>
 #endif
 
 static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
@@ -69,6 +68,18 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
                 sched_clock_stable = 1;
         }
 
+        /*
+         * 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.
+         *
+         * Enable PAT WC only on P4, Core 2 or later CPUs.
+         */
+        if (c->x86 == 6 && c->x86_model < 15)
+                clear_cpu_cap(c, X86_FEATURE_PAT);
 }
 
 #ifdef CONFIG_X86_32
@@ -141,10 +152,10 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
          */
         if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_mask == 1)) {
                 rdmsr(MSR_IA32_MISC_ENABLE, lo, hi);
-                if ((lo & (1<<9)) == 0) {
+                if ((lo & MSR_IA32_MISC_ENABLE_PREFETCH_DISABLE) == 0) {
                         printk (KERN_INFO "CPU: C0 stepping P4 Xeon detected.\n");
                         printk (KERN_INFO "CPU: Disabling hardware prefetching (Errata 037)\n");
-                        lo |= (1<<9);   /* Disable hw prefetching */
+                        lo |= MSR_IA32_MISC_ENABLE_PREFETCH_DISABLE;
                         wrmsr (MSR_IA32_MISC_ENABLE, lo, hi);
                 }
         }