arm64: suspend: Use cpuidle context helpers in cpu_suspend()

Use cpuidle context helpers to switch to using DAIF.IF instead
of PMR to mask interrupts, ensuring that we suspend with
interrupts being able to reach the CPU interface.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20210615111227.2454465-5-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

Author: Marc Zyngier

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();
 
 	/*