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-rw-r--r--arch/x86/kernel/process.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 9fea14607df..68ad3539b14 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -6,6 +6,7 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/pm.h>
+#include <linux/clockchips.h>
struct kmem_cache *task_xstate_cachep;
@@ -219,6 +220,68 @@ static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
return (edx & MWAIT_EDX_C1);
}
+/*
+ * Check for AMD CPUs, which have potentially C1E support
+ */
+static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
+{
+ if (c->x86_vendor != X86_VENDOR_AMD)
+ return 0;
+
+ if (c->x86 < 0x0F)
+ return 0;
+
+ /* Family 0x0f models < rev F do not have C1E */
+ if (c->x86 == 0x0f && c->x86_model < 0x40)
+ return 0;
+
+ return 1;
+}
+
+/*
+ * C1E aware idle routine. We check for C1E active in the interrupt
+ * pending message MSR. If we detect C1E, then we handle it the same
+ * way as C3 power states (local apic timer and TSC stop)
+ */
+static void c1e_idle(void)
+{
+ static cpumask_t c1e_mask = CPU_MASK_NONE;
+ static int c1e_detected;
+
+ if (need_resched())
+ return;
+
+ if (!c1e_detected) {
+ u32 lo, hi;
+
+ rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
+ if (lo & K8_INTP_C1E_ACTIVE_MASK) {
+ c1e_detected = 1;
+ mark_tsc_unstable("TSC halt in C1E");
+ printk(KERN_INFO "System has C1E enabled\n");
+ }
+ }
+
+ if (c1e_detected) {
+ int cpu = smp_processor_id();
+
+ if (!cpu_isset(cpu, c1e_mask)) {
+ cpu_set(cpu, c1e_mask);
+ /* Force broadcast so ACPI can not interfere */
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
+ &cpu);
+ printk(KERN_INFO "Switch to broadcast mode on CPU%d\n",
+ cpu);
+ }
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
+ default_idle();
+ local_irq_disable();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
+ local_irq_enable();
+ } else
+ default_idle();
+}
+
void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_SMP
@@ -236,6 +299,9 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
*/
printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
+ } else if (check_c1e_idle(c)) {
+ printk(KERN_INFO "using C1E aware idle routine\n");
+ pm_idle = c1e_idle;
} else
pm_idle = default_idle;
}