#include <linux/sched.h>
#include <linux/module.h>
#include <linux/pm.h>
+#include <linux/clockchips.h>
struct kmem_cache *task_xstate_cachep;
SLAB_PANIC, NULL);
}
+/*
+ * Idle related variables and functions
+ */
+unsigned long boot_option_idle_override = 0;
+EXPORT_SYMBOL(boot_option_idle_override);
+
+/*
+ * Powermanagement idle function, if any..
+ */
+void (*pm_idle)(void);
+EXPORT_SYMBOL(pm_idle);
+
+#ifdef CONFIG_X86_32
+/*
+ * This halt magic was a workaround for ancient floppy DMA
+ * wreckage. It should be safe to remove.
+ */
+static int hlt_counter;
+void disable_hlt(void)
+{
+ hlt_counter++;
+}
+EXPORT_SYMBOL(disable_hlt);
+
+void enable_hlt(void)
+{
+ hlt_counter--;
+}
+EXPORT_SYMBOL(enable_hlt);
+
+static inline int hlt_use_halt(void)
+{
+ return (!hlt_counter && boot_cpu_data.hlt_works_ok);
+}
+#else
+static inline int hlt_use_halt(void)
+{
+ return 1;
+}
+#endif
+
+/*
+ * We use this if we don't have any better
+ * idle routine..
+ */
+void default_idle(void)
+{
+ if (hlt_use_halt()) {
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+
+ if (!need_resched())
+ safe_halt(); /* enables interrupts racelessly */
+ else
+ local_irq_enable();
+ current_thread_info()->status |= TS_POLLING;
+ } else {
+ local_irq_enable();
+ /* loop is done by the caller */
+ cpu_relax();
+ }
+}
+#ifdef CONFIG_APM_MODULE
+EXPORT_SYMBOL(default_idle);
+#endif
+
static void do_nothing(void *unused)
{
}
local_irq_enable();
}
+/*
+ * On SMP it's slightly faster (but much more power-consuming!)
+ * to poll the ->work.need_resched flag instead of waiting for the
+ * cross-CPU IPI to arrive. Use this option with caution.
+ */
+static void poll_idle(void)
+{
+ local_irq_enable();
+ cpu_relax();
+}
+
+/*
+ * mwait selection logic:
+ *
+ * It depends on the CPU. For AMD CPUs that support MWAIT this is
+ * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings
+ * then depend on a clock divisor and current Pstate of the core. If
+ * all cores of a processor are in halt state (C1) the processor can
+ * enter the C1E (C1 enhanced) state. If mwait is used this will never
+ * happen.
+ *
+ * idle=mwait overrides this decision and forces the usage of mwait.
+ */
+
+#define MWAIT_INFO 0x05
+#define MWAIT_ECX_EXTENDED_INFO 0x01
+#define MWAIT_EDX_C1 0xf0
static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
{
+ u32 eax, ebx, ecx, edx;
+
if (force_mwait)
return 1;
- /* Any C1 states supported? */
- return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0;
+
+ if (c->cpuid_level < MWAIT_INFO)
+ return 0;
+
+ cpuid(MWAIT_INFO, &eax, &ebx, &ecx, &edx);
+ /* Check, whether EDX has extended info about MWAIT */
+ if (!(ecx & MWAIT_ECX_EXTENDED_INFO))
+ return 1;
+
+ /*
+ * edx enumeratios MONITOR/MWAIT extensions. Check, whether
+ * C1 supports MWAIT
+ */
+ return (edx & MWAIT_EDX_C1);
}
/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->work.need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
+ * Check for AMD CPUs, which have potentially C1E support
*/
-static void poll_idle(void)
+static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
{
- local_irq_enable();
- cpu_relax();
+ 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;
}
-void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
+/*
+ * 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 int selected;
+ static cpumask_t c1e_mask = CPU_MASK_NONE;
+ static int c1e_detected;
- if (selected)
+ 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. Needs
+ * to run with interrupts enabled as it uses
+ * smp_function_call.
+ */
+ local_irq_enable();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
+ &cpu);
+ printk(KERN_INFO "Switch to broadcast mode on CPU%d\n",
+ cpu);
+ local_irq_disable();
+ }
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
+
+ default_idle();
+
+ /*
+ * The switch back from broadcast mode needs to be
+ * called with interrupts disabled.
+ */
+ 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
if (pm_idle == poll_idle && smp_num_siblings > 1) {
printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
" performance may degrade.\n");
}
#endif
+ if (pm_idle)
+ return;
+
if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
/*
- * Skip, if setup has overridden idle.
* One CPU supports mwait => All CPUs supports mwait
*/
- if (!pm_idle) {
- printk(KERN_INFO "using mwait in idle threads.\n");
- pm_idle = mwait_idle;
- }
- }
- selected = 1;
+ 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;
}
static int __init idle_setup(char *str)
git.openpandora.org / pandora-kernel.git / blobdiff