[PATCH] i386: add idle notifier

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / i386 / kernel / process.c

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 05be774..7845d48 100644 (file)
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -48,6 +48,7 @@
 #include <asm/i387.h>
 #include <asm/desc.h>
 #include <asm/vm86.h>
+#include <asm/idle.h>
 #ifdef CONFIG_MATH_EMULATION
 #include <asm/math_emu.h>
 #endif
@@ -80,6 +81,42 @@ void (*pm_idle)(void);
 EXPORT_SYMBOL(pm_idle);
 static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
 
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+       atomic_notifier_chain_register(&idle_notifier, n);
+}
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+       atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+
+static DEFINE_PER_CPU(volatile unsigned long, idle_state);
+
+void enter_idle(void)
+{
+       /* needs to be atomic w.r.t. interrupts, not against other CPUs */
+       __set_bit(0, &__get_cpu_var(idle_state));
+       atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+       /* needs to be atomic w.r.t. interrupts, not against other CPUs */
+       if (__test_and_clear_bit(0, &__get_cpu_var(idle_state)) == 0)
+               return;
+       atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+void exit_idle(void)
+{
+       if (current->pid)
+               return;
+       __exit_idle();
+}
+
 void disable_hlt(void)
 {
        hlt_counter++;
@@ -130,6 +167,7 @@ EXPORT_SYMBOL(default_idle);
  */
 static void poll_idle (void)
 {
+       local_irq_enable();
        cpu_relax();
 }
 
@@ -189,7 +227,16 @@ void cpu_idle(void)
                                play_dead();
 
                        __get_cpu_var(irq_stat).idle_timestamp = jiffies;
+
+                       /*
+                        * Idle routines should keep interrupts disabled
+                        * from here on, until they go to idle.
+                        * Otherwise, idle callbacks can misfire.
+                        */
+                       local_irq_disable();
+                       enter_idle();
                        idle();
+                       __exit_idle();
                }
                preempt_enable_no_resched();
                schedule();
@@ -243,7 +290,11 @@ void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
                __monitor((void *)&current_thread_info()->flags, 0, 0);
                smp_mb();
                if (!need_resched())
-                       __mwait(eax, ecx);
+                       __sti_mwait(eax, ecx);
+               else
+                       local_irq_enable();
+       } else {
+               local_irq_enable();
        }
 }