From a8d6829044901a67732904be5f1eacdf8539604f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 22 Sep 2008 19:02:25 +0200 Subject: [PATCH] x86: prevent C-states hang on AMD C1E enabled machines Impact: System hang when AMD C1E machines switch into C2/C3 AMD C1E enabled systems do not work with normal ACPI C-states even if the BIOS is advertising them. Limit the C-states to C1 for the ACPI processor idle code. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process.c | 1 + include/asm-x86/acpi.h | 2 ++ include/asm-x86/cpufeature.h | 1 + 3 files changed, 4 insertions(+) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 2e2247117f6..d8c2a299bfe 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -272,6 +272,7 @@ static void c1e_idle(void) c1e_detected = 1; mark_tsc_unstable("TSC halt in C1E"); printk(KERN_INFO "System has C1E enabled\n"); + set_cpu_cap(&boot_cpu_data, X86_FEATURE_AMDC1E); } } diff --git a/include/asm-x86/acpi.h b/include/asm-x86/acpi.h index 635d764dc13..35d1743b57a 100644 --- a/include/asm-x86/acpi.h +++ b/include/asm-x86/acpi.h @@ -140,6 +140,8 @@ static inline unsigned int acpi_processor_cstate_check(unsigned int max_cstate) boot_cpu_data.x86_model <= 0x05 && boot_cpu_data.x86_mask < 0x0A) return 1; + else if (boot_cpu_has(X86_FEATURE_AMDC1E)) + return 1; else return max_cstate; } diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h index 9489283a4bc..cfcfb0a806b 100644 --- a/include/asm-x86/cpufeature.h +++ b/include/asm-x86/cpufeature.h @@ -81,6 +81,7 @@ #define X86_FEATURE_LFENCE_RDTSC (3*32+18) /* Lfence synchronizes RDTSC */ #define X86_FEATURE_11AP (3*32+19) /* Bad local APIC aka 11AP */ #define X86_FEATURE_NOPL (3*32+20) /* The NOPL (0F 1F) instructions */ +#define X86_FEATURE_AMDC1E (3*32+21) /* AMD C1E detected */ /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ #define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */ -- 2.41.1