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authorJulien Thierry <julien.thierry@arm.com>2019-01-31 14:58:47 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2019-02-06 10:05:18 +0000
commita9806aa259feb2f6fd582b6342c835a3482fccc6 (patch)
tree432ea57e608d7d2f0ecd0a477813f471c4f6a3eb /arch/arm64/kernel
parent133d05186325ce04494ea6488a6b86e50a446c12 (diff)
downloadlinux-a9806aa259feb2f6fd582b6342c835a3482fccc6.tar.bz2
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>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/process.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 6d410fc2849b..3767fb21a5b8 100644
--- 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.
*/