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-rw-r--r--arch/powerpc/include/asm/hw_irq.h2
-rw-r--r--arch/powerpc/kernel/irq.c46
-rw-r--r--arch/powerpc/platforms/cell/pervasive.c11
-rw-r--r--arch/powerpc/platforms/pseries/processor_idle.c17
4 files changed, 64 insertions, 12 deletions
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 6eb75b8..92224b7 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -125,6 +125,8 @@ static inline bool arch_irq_disabled_regs(struct pt_regs *regs)
return !regs->softe;
}
+extern bool prep_irq_for_idle(void);
+
#else /* CONFIG_PPC64 */
#define SET_MSR_EE(x) mtmsr(x)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 1b41502..9270a39 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -286,6 +286,52 @@ void notrace restore_interrupts(void)
__hard_irq_enable();
}
+/*
+ * This is a helper to use when about to go into idle low-power
+ * when the latter has the side effect of re-enabling interrupts
+ * (such as calling H_CEDE under pHyp).
+ *
+ * You call this function with interrupts soft-disabled (this is
+ * already the case when ppc_md.power_save is called). The function
+ * will return whether to enter power save or just return.
+ *
+ * In the former case, it will have notified lockdep of interrupts
+ * being re-enabled and generally sanitized the lazy irq state,
+ * and in the latter case it will leave with interrupts hard
+ * disabled and marked as such, so the local_irq_enable() call
+ * in cpu_idle() will properly re-enable everything.
+ */
+bool prep_irq_for_idle(void)
+{
+ /*
+ * First we need to hard disable to ensure no interrupt
+ * occurs before we effectively enter the low power state
+ */
+ hard_irq_disable();
+
+ /*
+ * If anything happened while we were soft-disabled,
+ * we return now and do not enter the low power state.
+ */
+ if (lazy_irq_pending())
+ return false;
+
+ /* Tell lockdep we are about to re-enable */
+ trace_hardirqs_on();
+
+ /*
+ * Mark interrupts as soft-enabled and clear the
+ * PACA_IRQ_HARD_DIS from the pending mask since we
+ * are about to hard enable as well as a side effect
+ * of entering the low power state.
+ */
+ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+ local_paca->soft_enabled = 1;
+
+ /* Tell the caller to enter the low power state */
+ return true;
+}
+
#endif /* CONFIG_PPC64 */
int arch_show_interrupts(struct seq_file *p, int prec)
diff --git a/arch/powerpc/platforms/cell/pervasive.c b/arch/powerpc/platforms/cell/pervasive.c
index efdacc8..d17e98b 100644
--- a/arch/powerpc/platforms/cell/pervasive.c
+++ b/arch/powerpc/platforms/cell/pervasive.c
@@ -42,11 +42,9 @@ static void cbe_power_save(void)
{
unsigned long ctrl, thread_switch_control;
- /*
- * We need to hard disable interrupts, the local_irq_enable() done by
- * our caller upon return will hard re-enable.
- */
- hard_irq_disable();
+ /* Ensure our interrupt state is properly tracked */
+ if (!prep_irq_for_idle())
+ return;
ctrl = mfspr(SPRN_CTRLF);
@@ -81,6 +79,9 @@ static void cbe_power_save(void)
*/
ctrl &= ~(CTRL_RUNLATCH | CTRL_TE);
mtspr(SPRN_CTRLT, ctrl);
+
+ /* Re-enable interrupts in MSR */
+ __hard_irq_enable();
}
static int cbe_system_reset_exception(struct pt_regs *regs)
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
index e61483e..c71be66 100644
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ b/arch/powerpc/platforms/pseries/processor_idle.c
@@ -99,15 +99,18 @@ out:
static void check_and_cede_processor(void)
{
/*
- * Interrupts are soft-disabled at this point,
- * but not hard disabled. So an interrupt might have
- * occurred before entering NAP, and would be potentially
- * lost (edge events, decrementer events, etc...) unless
- * we first hard disable then check.
+ * Ensure our interrupt state is properly tracked,
+ * also checks if no interrupt has occurred while we
+ * were soft-disabled
*/
- hard_irq_disable();
- if (!lazy_irq_pending())
+ if (prep_irq_for_idle()) {
cede_processor();
+#ifdef CONFIG_TRACE_IRQFLAGS
+ /* Ensure that H_CEDE returns with IRQs on */
+ if (WARN_ON(!(mfmsr() & MSR_EE)))
+ __hard_irq_enable();
+#endif
+ }
}
static int dedicated_cede_loop(struct cpuidle_device *dev,