1 files changed, 26 insertions, 3 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 7437fa133c02..3260ab044996 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -86,6 +86,29 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
          */
         if (c->x86 == 6 && c->x86_model < 15)
                 clear_cpu_cap(c, X86_FEATURE_PAT);
+
+#ifdef CONFIG_KMEMCHECK
+        /*
+         * P4s have a "fast strings" feature which causes single-
+         * stepping REP instructions to only generate a #DB on
+         * cache-line boundaries.
+         *
+         * Ingo Molnar reported a Pentium D (model 6) and a Xeon
+         * (model 2) with the same problem.
+         */
+        if (c->x86 == 15) {
+                u64 misc_enable;
+
+                rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+
+                if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) {
+                        printk(KERN_INFO "kmemcheck: Disabling fast string operations\n");
+
+                        misc_enable &= ~MSR_IA32_MISC_ENABLE_FAST_STRING;
+                        wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+                }
+        }
+#endif
 }
 
 #ifdef CONFIG_X86_32
@@ -229,12 +252,12 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
 }
 #endif
 
-static void __cpuinit srat_detect_node(void)
+static void __cpuinit srat_detect_node(struct cpuinfo_x86 *c)
 {
 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
         unsigned node;
         int cpu = smp_processor_id();
-        int apicid = hard_smp_processor_id();
+        int apicid = cpu_has_apic ? hard_smp_processor_id() : c->apicid;
 
         /* Don't do the funky fallback heuristics the AMD version employs
            for now. */
@@ -400,7 +423,7 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
         }
 
         /* Work around errata */
-        srat_detect_node();
+        srat_detect_node(c);
 
         if (cpu_has(c, X86_FEATURE_VMX))
                 detect_vmx_virtcap(c);