[RFC PATCH 08/36] irqchip/gic-v3: make the unmasking of pseudo-NMIs explicit when handling IRQs

[Vladimir Murzin <vladimir.murzin@arm.com>]

From: Ada Couprie Diaz <ada.coupriediaz@arm.com>

`gic_arch_enable_irqs()` is only used when handling IRQs (which could
be pseudo-NMIs) and unmasking pseudo-NMIs.

The chain of `gic_pmr_mask_irqs()` and `gic_arch_enable_irqs()` for it
is slightly confusing without further explanation.

Remove `gic_arch_enable_irqs()` and instead do the whole pseudo-NMI
umasking in `gic_unmask_pnmis()`, making the operation explicit.

Signed-off-by: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 arch/arm/include/asm/arch_gicv3.h     | 6 +-----
 arch/arm64/include/asm/arch_gicv3.h   | 7 +++++--
 arch/arm64/include/asm/entry-common.h | 2 +-
 drivers/irqchip/irq-gic-v3.c          | 5 +----
 4 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/arch/arm/include/asm/arch_gicv3.h b/arch/arm/include/asm/arch_gicv3.h
index 847590df7551..d4ac8d3271b1 100644
--- a/arch/arm/include/asm/arch_gicv3.h
+++ b/arch/arm/include/asm/arch_gicv3.h
@@ -246,11 +246,7 @@ static inline void gic_pmr_mask_irqs(void)
 	WARN_ON_ONCE(true);
 }
 
-static inline void gic_arch_enable_irqs(void)
-{
-	/* Should not get called. */
-	WARN_ON_ONCE(true);
-}
+static inline void gic_unmask_pnmis(void) {}
 
 static inline bool gic_has_relaxed_pmr_sync(void)
 {
diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h
index d20b03931a8d..3dcb7b8309d9 100644
--- a/arch/arm64/include/asm/arch_gicv3.h
+++ b/arch/arm64/include/asm/arch_gicv3.h
@@ -178,9 +178,12 @@ static inline void gic_pmr_mask_irqs(void)
 	gic_write_pmr(GIC_PRIO_IRQOFF);
 }
 
-static inline void gic_arch_enable_irqs(void)
+static inline void gic_unmask_pnmis(void)
 {
-	asm volatile ("msr daifclr, #3" : : : "memory");
+	if (gic_prio_masking_enabled()) {
+		gic_pmr_mask_irqs();
+		asm volatile ("msr daifclr, #3" : : : "memory");
+	}
 }
 
 static inline bool gic_has_relaxed_pmr_sync(void)
diff --git a/arch/arm64/include/asm/entry-common.h b/arch/arm64/include/asm/entry-common.h
index cab8cd78f693..1905765159aa 100644
--- a/arch/arm64/include/asm/entry-common.h
+++ b/arch/arm64/include/asm/entry-common.h
@@ -32,7 +32,7 @@ static inline bool arch_irqentry_exit_need_resched(void)
 	/*
 	 * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
 	 * priority masking is used the GIC irqchip driver will clear DAIF.IF
-	 * using gic_arch_enable_irqs() for normal IRQs. If anything is set in
+	 * in gic_unmask_pnmis() for normal IRQs. If anything is set in
 	 * DAIF we must have handled an NMI, so skip preemption.
 	 */
 	if (system_uses_irq_prio_masking() && read_sysreg(daif))
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 99444a1b2ffa..94c6a3f2b009 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -867,10 +867,7 @@ 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();
-	}
+	gic_unmask_pnmis();
 
 	if (!is_nmi)
 		__gic_handle_irq(irqnr, regs);
-- 
2.34.1