From 50f98784b124df9e33fc55ca6ddfa00c779b2300 Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Thu, 30 Jul 2020 18:03:21 +0100 Subject: [PATCH] BACKPORT: FROMGIT: irqchip/gic-v2, v3: Prevent SW resends entirely The GIC irqchips can now use a HW resend when a retrigger is invoked by check_irq_resend(). However, should the HW resend fail, check_irq_resend() will still attempt to trigger a SW resend, which is still a bad idea for the GICs. Prevent this from happening by setting IRQD_HANDLE_ENFORCE_IRQCTX on all GIC IRQs. Technically per-cpu IRQs do not need this, as their flow handlers never set IRQS_PENDING, but this aligns all IRQs wrt context enforcement: this also forces all GIC IRQ handling to happen in IRQ context (as defined by in_irq()). Signed-off-by: Valentin Schneider Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200730170321.31228-3-valentin.schneider@arm.com Bug: 140053385 (cherry picked from commit 1b57d91b969cda1d2c3530f2e829ca366a9c7df7 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: I26d068ff58660627b4fd02f2d0483f81f0cd2094 Signed-off-by: Eric Biggers --- drivers/irqchip/irq-gic-v3.c | 5 ++++- drivers/irqchip/irq-gic.c | 6 +++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index a23645182245..3120c2c5905c 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -1314,6 +1314,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) { struct irq_chip *chip = &gic_chip; + struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(irq)); if (static_branch_likely(&supports_deactivate_key)) chip = &gic_eoimode1_chip; @@ -1338,7 +1339,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, irq_domain_set_info(d, irq, hw, chip, d->host_data, handle_fasteoi_irq, NULL, NULL); irq_set_probe(irq); - irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq))); + irqd_set_single_target(irqd); break; case LPI_RANGE: @@ -1352,6 +1353,8 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, return -EPERM; } + /* Prevents SW retriggers which mess up the ACK/EOI ordering */ + irqd_set_handle_enforce_irqctx(irqd); return 0; } diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index f285cb325a8f..6053245a4754 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -1002,6 +1002,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) { struct gic_chip_data *gic = d->host_data; + struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(irq)); switch (hw) { case 0 ... 15: @@ -1019,9 +1020,12 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq, irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data, handle_fasteoi_irq, NULL, NULL); irq_set_probe(irq); - irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq))); + irqd_set_single_target(irqd); break; } + + /* Prevents SW retriggers which mess up the ACK/EOI ordering */ + irqd_set_handle_enforce_irqctx(irqd); return 0; }