[PATCHv3 3/4] irqchip: GICv3: expose pNMI discriminator

[Pingfan Liu <kernelfans@gmail.com>]

Arch level code is ready to take over the nmi_enter()/nmi_exit()
housekeeping.

GICv3 can expose the pNMI discriminator, then simply remove the
housekeeping.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Yuichi Ito <ito-yuichi@fujitsu.com>
Cc: rcu@vger.kernel.org
To: linux-arm-kernel@lists.infradead.org
---
 drivers/irqchip/irq-gic-v3.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index daec3309b014..aa2bcb47b47e 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -646,12 +646,8 @@ static void gic_deactivate_unhandled(u32 irqnr)
 
 static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs)
 {
-	bool irqs_enabled = interrupts_enabled(regs);
 	int err;
 
-	if (irqs_enabled)
-		nmi_enter();
-
 	if (static_branch_likely(&supports_deactivate_key))
 		gic_write_eoir(irqnr);
 	/*
@@ -664,8 +660,6 @@ static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs)
 	if (err)
 		gic_deactivate_unhandled(irqnr);
 
-	if (irqs_enabled)
-		nmi_exit();
 }
 
 static u32 do_read_iar(struct pt_regs *regs)
@@ -702,6 +696,15 @@ static u32 do_read_iar(struct pt_regs *regs)
 	return iar;
 }
 
+static bool gic_is_in_nmi(void)
+{
+	if (gic_supports_nmi() &&
+	    unlikely(gic_read_rpr() == GICD_INT_RPR_PRI(GICD_INT_NMI_PRI)))
+		return true;
+
+	return false;
+}
+
 static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
 {
 	u32 irqnr;
@@ -1791,6 +1794,9 @@ static int __init gic_init_bases(void __iomem *dist_base,
 	}
 
 	set_handle_irq(gic_handle_irq);
+#if IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI)
+	set_nmi_discriminator(gic_is_in_nmi);
+#endif
 
 	gic_update_rdist_properties();
 
-- 
2.31.1