powernv/cpuidle: Redesign idle states management

[cascardo/linux.git] / arch / powerpc / platforms / powernv / smp.c

diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 4753958..c0691d0 100644 (file)
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -149,6 +149,8 @@ static int pnv_smp_cpu_disable(void)
 static void pnv_smp_cpu_kill_self(void)
 {
        unsigned int cpu;
+       unsigned long srr1;
+       u32 idle_states;
 
        /* Standard hot unplug procedure */
        local_irq_disable();
@@ -159,19 +161,36 @@ static void pnv_smp_cpu_kill_self(void)
        generic_set_cpu_dead(cpu);
        smp_wmb();
 
+       idle_states = pnv_get_supported_cpuidle_states();
        /* We don't want to take decrementer interrupts while we are offline,
         * so clear LPCR:PECE1. We keep PECE2 enabled.
         */
        mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1);
        while (!generic_check_cpu_restart(cpu)) {
                ppc64_runlatch_off();
-               power7_nap(1);
+               if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
+                               (idle_states & OPAL_PM_SLEEP_ENABLED_ER1))
+                       srr1 = power7_sleep();
+               else
+                       srr1 = power7_nap(1);
                ppc64_runlatch_on();
 
-               /* Clear the IPI that woke us up */
-               icp_native_flush_interrupt();
-               local_paca->irq_happened &= PACA_IRQ_HARD_DIS;
-               mb();
+               /*
+                * If the SRR1 value indicates that we woke up due to
+                * an external interrupt, then clear the interrupt.
+                * We clear the interrupt before checking for the
+                * reason, so as to avoid a race where we wake up for
+                * some other reason, find nothing and clear the interrupt
+                * just as some other cpu is sending us an interrupt.
+                * If we returned from power7_nap as a result of
+                * having finished executing in a KVM guest, then srr1
+                * contains 0.
+                */
+               if ((srr1 & SRR1_WAKEMASK) == SRR1_WAKEEE) {
+                       icp_native_flush_interrupt();
+                       local_paca->irq_happened &= PACA_IRQ_HARD_DIS;
+                       smp_mb();
+               }
 
                if (cpu_core_split_required())
                        continue;