arm64: Unmask PMR before going idle

CPU does not received signals for interrupts with a priority masked by
ICC_PMR_EL1. This means the CPU might not come back from a WFI
instruction.

Make sure ICC_PMR_EL1 does not mask interrupts when doing a WFI.

Since the logic of cpu_do_idle is becoming a bit more complex than just
two instructions, lets turn it from ASM to C.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 6d410fc2849babbf0746e214af495a996d17318e..3767fb21a5b8037fa898242fa3ea8d1442d21d02 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -51,6 +51,7 @@
 #include <linux/thread_info.h>
 
 #include <asm/alternative.h>
+#include <asm/arch_gicv3.h>
 #include <asm/compat.h>
 #include <asm/cacheflush.h>
 #include <asm/exec.h>
@@ -74,6 +75,50 @@ EXPORT_SYMBOL_GPL(pm_power_off);
 
 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 
+static void __cpu_do_idle(void)
+{
+       dsb(sy);
+       wfi();
+}
+
+static void __cpu_do_idle_irqprio(void)
+{
+       unsigned long pmr;
+       unsigned long daif_bits;
+
+       daif_bits = read_sysreg(daif);
+       write_sysreg(daif_bits | PSR_I_BIT, daif);
+
+       /*
+        * Unmask PMR before going idle to make sure interrupts can
+        * be raised.
+        */
+       pmr = gic_read_pmr();
+       gic_write_pmr(GIC_PRIO_IRQON);
+
+       __cpu_do_idle();
+
+       gic_write_pmr(pmr);
+       write_sysreg(daif_bits, daif);
+}
+
+/*
+ *     cpu_do_idle()
+ *
+ *     Idle the processor (wait for interrupt).
+ *
+ *     If the CPU supports priority masking we must do additional work to
+ *     ensure that interrupts are not masked at the PMR (because the core will
+ *     not wake up if we block the wake up signal in the interrupt controller).
+ */
+void cpu_do_idle(void)
+{
+       if (system_uses_irq_prio_masking())
+               __cpu_do_idle_irqprio();
+       else
+               __cpu_do_idle();
+}
+
 /*
  * This is our default idle handler.
  */

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 73886a5f1f3048cc22149834c0fd91e94a5a48d7..3ea4f3b84a8bdc3806b43ef20d93dacbe969254b 100644 (file)
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -55,17 +55,6 @@
 
 #define MAIR(attr, mt) ((attr) << ((mt) * 8))
 
-/*
- *     cpu_do_idle()
- *
- *     Idle the processor (wait for interrupt).
- */
-ENTRY(cpu_do_idle)
-       dsb     sy                              // WFI may enter a low-power mode
-       wfi
-       ret
-ENDPROC(cpu_do_idle)
-
 #ifdef CONFIG_CPU_PM
 /**
  * cpu_do_suspend - save CPU registers context