Merge branch 'for-next/cpuidle' into for-next/core

Fix resume from idle when pNMI is being used.

* for-next/cpuidle:
  arm64: suspend: Use cpuidle context helpers in cpu_suspend()
  PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()
  arm64: Convert cpu_do_idle() to using cpuidle context helpers
  arm64: Add cpuidle context save/restore helpers

Author: willdeacon

arch/arm/include/asm/cpuidle.h

@@ -49,4 +49,9 @@ extern int arm_cpuidle_suspend(int index);
 
 extern int arm_cpuidle_init(int cpu);
 
+struct arm_cpuidle_irq_context { };
+
+#define arm_cpuidle_save_irq_context(c)		(void)c
+#define arm_cpuidle_restore_irq_context(c)	(void)c
+
 #endif

arch/arm64/include/asm/cpuidle.h

@@ -18,4 +18,39 @@ static inline int arm_cpuidle_suspend(int index)
 	return -EOPNOTSUPP;
 }
 #endif
+
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+#include <asm/arch_gicv3.h>
+
+struct arm_cpuidle_irq_context {
+	unsigned long pmr;
+	unsigned long daif_bits;
+};
+
+#define arm_cpuidle_save_irq_context(__c)				\
+	do {								\
+		struct arm_cpuidle_irq_context *c = __c;		\
+		if (system_uses_irq_prio_masking()) {			\
+			c->daif_bits = read_sysreg(daif);		\
+			write_sysreg(c->daif_bits | PSR_I_BIT | PSR_F_BIT, \
+				     daif);				\
+			c->pmr = gic_read_pmr();			\
+			gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); \
+		}							\
+	} while (0)
+
+#define arm_cpuidle_restore_irq_context(__c)				\
+	do {								\
+		struct arm_cpuidle_irq_context *c = __c;		\
+		if (system_uses_irq_prio_masking()) {			\
+			gic_write_pmr(c->pmr);				\
+			write_sysreg(c->daif_bits, daif);		\
+		}							\
+	} while (0)
+#else
+struct arm_cpuidle_irq_context { };
+
+#define arm_cpuidle_save_irq_context(c)		(void)c
+#define arm_cpuidle_restore_irq_context(c)	(void)c
+#endif
 #endif

arch/arm64/kernel/process.c

@@ -46,9 +46,9 @@
 #include <linux/prctl.h>
 
 #include <asm/alternative.h>
-#include <asm/arch_gicv3.h>
 #include <asm/compat.h>
 #include <asm/cpufeature.h>
+#include <asm/cpuidle.h>
 #include <asm/cacheflush.h>
 #include <asm/exec.h>
 #include <asm/fpsimd.h>
@@ -74,33 +74,6 @@ EXPORT_SYMBOL_GPL(pm_power_off);
 
 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 
-static void noinstr __cpu_do_idle(void)
-{
-	dsb(sy);
-	wfi();
-}
-
-static void noinstr __cpu_do_idle_irqprio(void)
-{
-	unsigned long pmr;
-	unsigned long daif_bits;
-
-	daif_bits = read_sysreg(daif);
-	write_sysreg(daif_bits | PSR_I_BIT | PSR_F_BIT, daif);
-
-	/*
-	 * Unmask PMR before going idle to make sure interrupts can
-	 * be raised.
-	 */
-	pmr = gic_read_pmr();
-	gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
-
-	__cpu_do_idle();
-
-	gic_write_pmr(pmr);
-	write_sysreg(daif_bits, daif);
-}
-
 /*
  *	cpu_do_idle()
  *
@@ -112,10 +85,14 @@ static void noinstr __cpu_do_idle_irqprio(void)
  */
 void noinstr cpu_do_idle(void)
 {
-	if (system_uses_irq_prio_masking())
-		__cpu_do_idle_irqprio();
-	else
-		__cpu_do_idle();
+	struct arm_cpuidle_irq_context context;
+
+	arm_cpuidle_save_irq_context(&context);
+
+	dsb(sy);
+	wfi();
+
+	arm_cpuidle_restore_irq_context(&context);
 }
 
 /*

arch/arm64/kernel/suspend.c

@@ -7,6 +7,7 @@
 #include <asm/alternative.h>
 #include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
+#include <asm/cpuidle.h>
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
 #include <asm/exec.h>
@@ -91,6 +92,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	int ret = 0;
 	unsigned long flags;
 	struct sleep_stack_data state;
+	struct arm_cpuidle_irq_context context;
 
 	/* Report any MTE async fault before going to suspend */
 	mte_suspend_enter();
@@ -103,12 +105,18 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	flags = local_daif_save();
 
 	/*
-	 * Function graph tracer state gets incosistent when the kernel
+	 * Function graph tracer state gets inconsistent when the kernel
 	 * calls functions that never return (aka suspend finishers) hence
 	 * disable graph tracing during their execution.
 	 */
 	pause_graph_tracing();
 
+	/*
+	 * Switch to using DAIF.IF instead of PMR in order to reliably
+	 * resume if we're using pseudo-NMIs.
+	 */
+	arm_cpuidle_save_irq_context(&context);
+
 	if (__cpu_suspend_enter(&state)) {
 		/* Call the suspend finisher */
 		ret = fn(arg);
@@ -126,6 +134,8 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 		RCU_NONIDLE(__cpu_suspend_exit());
 	}
 
+	arm_cpuidle_restore_irq_context(&context);
+
 	unpause_graph_tracing();
 
 	/*

drivers/firmware/psci/psci.c

@@ -335,10 +335,15 @@ int psci_cpu_suspend_enter(u32 state)
 {
 	int ret;
 
-	if (!psci_power_state_loses_context(state))
+	if (!psci_power_state_loses_context(state)) {
+		struct arm_cpuidle_irq_context context;
+
+		arm_cpuidle_save_irq_context(&context);
 		ret = psci_ops.cpu_suspend(state, 0);
-	else
+		arm_cpuidle_restore_irq_context(&context);
+	} else {
 		ret = cpu_suspend(state, psci_suspend_finisher);
+	}
 
 	return ret;
 }