From 6d86d53d07dccfb4539e2c69a47b5d4d3a678282 Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Thu, 30 Jul 2020 18:03:20 +0100 Subject: [PATCH] BACKPORT: FROMGIT: irqchip/gic-v2, v3: Implement irq_chip->irq_retrigger() While digging around IRQCHIP_EOI_IF_HANDLED and irq/resend.c, it has come to my attention that the IRQ resend situation seems a bit precarious for the GIC(s). When marking an IRQ with IRQS_PENDING, handle_fasteoi_irq() will bail out and issue an irq_eoi(). Should the IRQ in question be re-enabled, check_irq_resend() will trigger a SW resend, which will go through the flow handler again and issue *another* irq_eoi() on the *same* IRQ activation. This is something the GIC spec clearly describes as a bad idea: any EOI must match a previous ACK. Implement irq_chip.irq_retrigger() for the GIC chips by setting the GIC pending bit of the relevant IRQ. After being called by check_irq_resend(), this will eventually trigger a *new* interrupt which we will handle as usual. Signed-off-by: Valentin Schneider Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200730170321.31228-2-valentin.schneider@arm.com Bug: 140053385 (cherry picked from commit 17f644e949ffb14e9c8870d99bc574066d8b685c https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git irq/gic-retrigger) (resolved trivial merge conflict in drivers/irqchip/irq-gic.c) Change-Id: I1c5e81c7cf33155e81ba31615e5eaf3f578350c2 Signed-off-by: Eric Biggers --- drivers/irqchip/irq-gic-v3.c | 7 +++++++ drivers/irqchip/irq-gic.c | 6 ++++++ 2 files changed, 13 insertions(+) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 6c9b93700955..a23645182245 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -1220,6 +1220,11 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val, #define gic_smp_init() do { } while(0) #endif +static int gic_retrigger(struct irq_data *data) +{ + return !gic_irq_set_irqchip_state(data, IRQCHIP_STATE_PENDING, true); +} + #ifdef CONFIG_CPU_PM static int gic_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, void *v) @@ -1275,6 +1280,7 @@ static struct irq_chip gic_chip = { .irq_eoi = gic_eoi_irq, .irq_set_type = gic_set_type, .irq_set_affinity = gic_set_affinity, + .irq_retrigger = gic_retrigger, .irq_get_irqchip_state = gic_irq_get_irqchip_state, .irq_set_irqchip_state = gic_irq_set_irqchip_state, .irq_nmi_setup = gic_irq_nmi_setup, @@ -1292,6 +1298,7 @@ static struct irq_chip gic_eoimode1_chip = { .irq_eoi = gic_eoimode1_eoi_irq, .irq_set_type = gic_set_type, .irq_set_affinity = gic_set_affinity, + .irq_retrigger = gic_retrigger, .irq_get_irqchip_state = gic_irq_get_irqchip_state, .irq_set_irqchip_state = gic_irq_set_irqchip_state, .irq_set_vcpu_affinity = gic_irq_set_vcpu_affinity, diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 30edcca627d6..f285cb325a8f 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -326,6 +326,11 @@ static int gic_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu) return 0; } +static int gic_retrigger(struct irq_data *data) +{ + return !gic_irq_set_irqchip_state(data, IRQCHIP_STATE_PENDING, true); +} + static void __exception_irq_entry gic_handle_irq(struct pt_regs *regs) { u32 irqstat, irqnr; @@ -398,6 +403,7 @@ static const struct irq_chip gic_chip = { .irq_unmask = gic_unmask_irq, .irq_eoi = gic_eoi_irq, .irq_set_type = gic_set_type, + .irq_retrigger = gic_retrigger, .irq_get_irqchip_state = gic_irq_get_irqchip_state, .irq_set_irqchip_state = gic_irq_set_irqchip_state, .flags = IRQCHIP_SET_TYPE_MASKED |