linux-kernel - [PATCH 9/9] irqchip/gic-v3: Improve the maintainability of NMI masking in GIC driver

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Date: Tue, 9 Apr 2024 01:23:44 +0000
From: Liao Chang <liaochang1@...wei.com>
To: <catalin.marinas@....com>, <will@...nel.org>, <maz@...nel.org>,
	<oliver.upton@...ux.dev>, <james.morse@....com>, <suzuki.poulose@....com>,
	<yuzenghui@...wei.com>, <tglx@...utronix.de>, <mark.rutland@....com>,
	<ardb@...nel.org>, <broonie@...nel.org>, <liaochang1@...wei.com>,
	<anshuman.khandual@....com>, <miguel.luis@...cle.com>, <joey.gouly@....com>,
	<ryan.roberts@....com>, <jeremy.linton@....com>, <liwei391@...wei.com>,
	<daniel.thompson@...aro.org>, <sumit.garg@...aro.org>,
	<kristina.martsenko@....com>, <jpoimboe@...nel.org>, <ericchancf@...gle.com>,
	<robh@...nel.org>, <scott@...amperecomputing.com>,
	<songshuaishuai@...ylab.org>, <shijie@...amperecomputing.com>,
	<bhe@...hat.com>, <akpm@...ux-foundation.org>, <thunder.leizhen@...wei.com>,
	<horms@...nel.org>, <rmk+kernel@...linux.org.uk>, <takakura@...inux.co.jp>,
	<dianders@...omium.org>, <swboyd@...omium.org>, <frederic@...nel.org>,
	<reijiw@...gle.com>, <akihiko.odaki@...nix.com>, <ruanjinjie@...wei.com>
CC: <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	<kvmarm@...ts.linux.dev>
Subject: [PATCH 9/9] irqchip/gic-v3: Improve the maintainability of NMI masking in GIC driver

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@...wei.com>
---
 arch/arm64/include/asm/daifflags.h | 13 +++++++++++++
 drivers/irqchip/irq-gic-v3.c       |  6 ++----
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h
index b831def08bb3..1196eb85aa8d 100644
--- a/arch/arm64/include/asm/daifflags.h
+++ b/arch/arm64/include/asm/daifflags.h
@@ -330,4 +330,17 @@ static inline void local_errnmi_enable(void)
 	irqflags.fields.allint = 0;
 	local_allint_restore(irqflags);
 }
+
+/*
+ * local_nmi_enable - Enable NMI with or without superpriority.
+ */
+static inline void local_nmi_enable(void)
+{
+	arch_irqflags_t irqflags;
+
+	irqflags.fields.daif = read_sysreg(daif);
+	irqflags.fields.pmr = GIC_PRIO_IRQOFF;
+	irqflags.fields.allint = 0;
+	local_allint_restore(irqflags);
+}
 #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