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-rw-r--r--arch/x86/kernel/process.c32
1 files changed, 24 insertions, 8 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ad9540676fcc..28ad9f4d8b94 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -526,21 +526,37 @@ static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
526} 526}
527 527
528/* 528/*
529 * Check for AMD CPUs, which have potentially C1E support 529 * Check for AMD CPUs, where APIC timer interrupt does not wake up CPU from C1e.
530 * For more information see
531 * - Erratum #400 for NPT family 0xf and family 0x10 CPUs
532 * - Erratum #365 for family 0x11 (not affected because C1e not in use)
530 */ 533 */
531static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c) 534static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
532{ 535{
536 u64 val;
533 if (c->x86_vendor != X86_VENDOR_AMD) 537 if (c->x86_vendor != X86_VENDOR_AMD)
534 return 0; 538 goto no_c1e_idle;
535
536 if (c->x86 < 0x0F)
537 return 0;
538 539
539 /* Family 0x0f models < rev F do not have C1E */ 540 /* Family 0x0f models < rev F do not have C1E */
540 if (c->x86 == 0x0f && c->x86_model < 0x40) 541 if (c->x86 == 0x0F && c->x86_model >= 0x40)
541 return 0; 542 return 1;
542 543
543 return 1; 544 if (c->x86 == 0x10) {
545 /*
546 * check OSVW bit for CPUs that are not affected
547 * by erratum #400
548 */
549 rdmsrl(MSR_AMD64_OSVW_ID_LENGTH, val);
550 if (val >= 2) {
551 rdmsrl(MSR_AMD64_OSVW_STATUS, val);
552 if (!(val & BIT(1)))
553 goto no_c1e_idle;
554 }
555 return 1;
556 }
557
558no_c1e_idle:
559 return 0;
544} 560}
545 561
546static cpumask_var_t c1e_mask; 562static cpumask_var_t c1e_mask;