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 <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

2 files changed, 35 insertions, 1 deletions

diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index b0237caff712..118830cba1ae 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 af838f6b0b7f..32054bf5ba40 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)