[PATCH v4 07/10] irqchip/gic-v3: Improve the maintainability of NMI masking in GIC driver

[Liao Chang]

It has a better maintainability to use the local_nmi_enable() in GIC
driver to unmask NMI and keep regular IRQ and FIQ maskable, instead of
writing raw value into DAIF, PMR and ALLINT directly.

Signed-off-by: Liao Chang <liaochang1@xxxxxxxxxx>
---
 arch/arm64/include/asm/daifflags.h | 14 ++++++++++++++
 drivers/irqchip/irq-gic-v3.c       |  6 ++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h
index b19dfd948704..4eb97241a58f 100644
--- a/arch/arm64/include/asm/daifflags.h
+++ b/arch/arm64/include/asm/daifflags.h
@@ -332,4 +332,18 @@ static inline void local_nmi_serror_enable(void)
 	irqflags.fields.allint = 0;
 	local_allint_restore_notrace(irqflags);
 }
+
+/*
+ * local_nmi_enable - Enable NMI with or without superpriority.
+ */
+static inline void local_nmi_enable(void)
+{
+	if (system_uses_irq_prio_masking()) {
+		gic_pmr_mask_irqs();
+		asm volatile ("msr daifclr, #3" : : : "memory");
+	} else if (system_uses_nmi()) {
+		asm volatile ("msr daifset, #3" : : : "memory");
+		msr_pstate_allint(0);
+	}
+}
 #endif
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 6fb276504bcc..ed7d8d87768f 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -33,6 +33,7 @@
 #include <asm/exception.h>
 #include <asm/smp_plat.h>
 #include <asm/virt.h>
+#include <asm/daifflags.h>
 
 #include "irq-gic-common.h"
 
@@ -813,10 +814,7 @@ static void __gic_handle_irq_from_irqson(struct pt_regs *regs)
 		nmi_exit();
 	}
 
-	if (gic_prio_masking_enabled()) {
-		gic_pmr_mask_irqs();
-		gic_arch_enable_irqs();
-	}
+	local_nmi_enable();
 
 	if (!is_nmi)
 		__gic_handle_irq(irqnr, regs);
-- 
2.34.1