diff options
author | Marc Zyngier <maz@kernel.org> | 2021-07-06 13:38:59 +0300 |
---|---|---|
committer | Marc Zyngier <maz@kernel.org> | 2021-07-09 12:18:58 +0300 |
commit | 1fee9db9b42d821e8007289d4eea74bdf85b1543 (patch) | |
tree | 6f5b28725cd0b60ac05ccc13b073328b13eec4a2 /drivers/irqchip | |
parent | 0e3c1f30b03599f2ee8ff3327eca53c99564ba13 (diff) | |
download | linux-1fee9db9b42d821e8007289d4eea74bdf85b1543.tar.xz |
irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry
Since d4a45c68dc81 ("irqdomain: Protect the linear revmap with RCU"),
any irqdomain lookup requires the RCU read lock to be held.
This assumes that the architecture code will be structured such as
irq_enter() will be called *before* the interrupt is looked up
in the irq domain. However, this isn't the case for MIPS, and a number
of drivers are structured to do it the other way around when handling
an interrupt in their root irqchip (secondary irqchips are OK by
construction).
This results in a RCU splat on a lockdep-enabled kernel when the kernel
takes an interrupt from idle, as reported by Guenter Roeck.
Note that this could have fired previously if any driver had used
tree-based irqdomain, which always had the RCU requirement.
To solve this, provide a MIPS-specific helper (do_domain_IRQ())
as the pendent of do_IRQ() that will do thing in the right order
(and maybe save some cycles in the process).
Ideally, MIPS would be moved over to using handle_domain_irq(),
but that's much more ambitious.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
[maz: add dependency on CONFIG_IRQ_DOMAIN after report from the kernelci bot]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20210705172352.GA56304@roeck-us.net
Link: https://lore.kernel.org/r/20210706110647.3979002-1-maz@kernel.org
Diffstat (limited to 'drivers/irqchip')
-rw-r--r-- | drivers/irqchip/irq-mips-cpu.c | 10 | ||||
-rw-r--r-- | drivers/irqchip/irq-mips-gic.c | 8 | ||||
-rw-r--r-- | drivers/irqchip/irq-pic32-evic.c | 5 |
3 files changed, 12 insertions, 11 deletions
diff --git a/drivers/irqchip/irq-mips-cpu.c b/drivers/irqchip/irq-mips-cpu.c index 0bbb0b2d0dd5..0c7ae71a0af0 100644 --- a/drivers/irqchip/irq-mips-cpu.c +++ b/drivers/irqchip/irq-mips-cpu.c @@ -127,7 +127,6 @@ static struct irq_chip mips_mt_cpu_irq_controller = { asmlinkage void __weak plat_irq_dispatch(void) { unsigned long pending = read_c0_cause() & read_c0_status() & ST0_IM; - unsigned int virq; int irq; if (!pending) { @@ -137,12 +136,15 @@ asmlinkage void __weak plat_irq_dispatch(void) pending >>= CAUSEB_IP; while (pending) { + struct irq_domain *d; + irq = fls(pending) - 1; if (IS_ENABLED(CONFIG_GENERIC_IRQ_IPI) && irq < 2) - virq = irq_linear_revmap(ipi_domain, irq); + d = ipi_domain; else - virq = irq_linear_revmap(irq_domain, irq); - do_IRQ(virq); + d = irq_domain; + + do_domain_IRQ(d, irq); pending &= ~BIT(irq); } } diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index b146e069bf5b..54c7092cc61d 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -169,8 +169,8 @@ static void gic_handle_shared_int(bool chained) generic_handle_domain_irq(gic_irq_domain, GIC_SHARED_TO_HWIRQ(intr)); else - do_IRQ(irq_find_mapping(gic_irq_domain, - GIC_SHARED_TO_HWIRQ(intr))); + do_domain_IRQ(gic_irq_domain, + GIC_SHARED_TO_HWIRQ(intr)); } } @@ -320,8 +320,8 @@ static void gic_handle_local_int(bool chained) generic_handle_domain_irq(gic_irq_domain, GIC_LOCAL_TO_HWIRQ(intr)); else - do_IRQ(irq_find_mapping(gic_irq_domain, - GIC_LOCAL_TO_HWIRQ(intr))); + do_domain_IRQ(gic_irq_domain, + GIC_LOCAL_TO_HWIRQ(intr)); } } diff --git a/drivers/irqchip/irq-pic32-evic.c b/drivers/irqchip/irq-pic32-evic.c index 34c4b4ffacd1..1d9bb28d13e5 100644 --- a/drivers/irqchip/irq-pic32-evic.c +++ b/drivers/irqchip/irq-pic32-evic.c @@ -42,11 +42,10 @@ static void __iomem *evic_base; asmlinkage void __weak plat_irq_dispatch(void) { - unsigned int irq, hwirq; + unsigned int hwirq; hwirq = readl(evic_base + REG_INTSTAT) & 0xFF; - irq = irq_linear_revmap(evic_irq_domain, hwirq); - do_IRQ(irq); + do_domain_IRQ(evic_irq_domain, hwirq); } static struct evic_chip_data *irqd_to_priv(struct irq_data *data) |