From fb79d22e1d4b06385796cc0db0084a2e07beccee Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 12 Oct 2007 23:04:07 +0200 Subject: [PATCH] x86: disable apic timer for AMD C1E enabled CPUs AMDs C1E enabled CPUs stop the local apic timer, when both cores are idle. This is a hardware feature which breaks highres/dynticks. Add the same quirk as we have for 32 bit already. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven --- arch/x86/kernel/apic_64.c | 2 +- arch/x86/kernel/setup_64.c | 34 ++++++++++++++++++++++++++++++++++ include/asm-x86/apic_64.h | 1 + 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c index b0237ca..118830c 100644 --- a/arch/x86/kernel/apic_64.c +++ b/arch/x86/kernel/apic_64.c @@ -44,7 +44,7 @@ int apic_verbosity; int apic_runs_main_timer; int apic_calibrate_pmtmr __initdata; -int disable_apic_timer __initdata; +int disable_apic_timer __cpuinitdata; /* Local APIC timer works in C2? */ int local_apic_timer_c2_ok; diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c index af838f6..32054bf 100644 --- a/arch/x86/kernel/setup_64.c +++ b/arch/x86/kernel/setup_64.c @@ -546,6 +546,37 @@ static void __init amd_detect_cmp(struct cpuinfo_x86 *c) #endif } +#define ENABLE_C1E_MASK 0x18000000 +#define CPUID_PROCESSOR_SIGNATURE 1 +#define CPUID_XFAM 0x0ff00000 +#define CPUID_XFAM_K8 0x00000000 +#define CPUID_XFAM_10H 0x00100000 +#define CPUID_XFAM_11H 0x00200000 +#define CPUID_XMOD 0x000f0000 +#define CPUID_XMOD_REV_F 0x00040000 + +/* AMD systems with C1E don't have a working lAPIC timer. Check for that. */ +static __cpuinit int amd_apic_timer_broken(void) +{ + u32 lo, hi; + u32 eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE); + switch (eax & CPUID_XFAM) { + case CPUID_XFAM_K8: + if ((eax & CPUID_XMOD) < CPUID_XMOD_REV_F) + break; + case CPUID_XFAM_10H: + case CPUID_XFAM_11H: + rdmsr(MSR_K8_ENABLE_C1E, lo, hi); + if (lo & ENABLE_C1E_MASK) + return 1; + break; + default: + /* err on the side of caution */ + return 1; + } + return 0; +} + static void __cpuinit init_amd(struct cpuinfo_x86 *c) { unsigned level; @@ -617,6 +648,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) /* Family 10 doesn't support C states in MWAIT so don't use it */ if (c->x86 == 0x10 && !force_mwait) clear_bit(X86_FEATURE_MWAIT, &c->x86_capability); + + if (amd_apic_timer_broken()) + disable_apic_timer = 1; } static void __cpuinit detect_ht(struct cpuinfo_x86 *c) diff --git a/include/asm-x86/apic_64.h b/include/asm-x86/apic_64.h index 81335e9..f32f654 100644 --- a/include/asm-x86/apic_64.h +++ b/include/asm-x86/apic_64.h @@ -19,6 +19,7 @@ extern int apic_verbosity; extern int apic_runs_main_timer; extern int ioapic_force; +extern int disable_apic_timer; /* * Define the default level of output to be very little -- 2.7.4