diff options
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index daed39ba261..3260ab04499 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 |