Messages in this thread Patch in this message | | | Date | Fri, 09 Jul 2021 09:23:05 -0000 | From | "irqchip-bot for Marc Zyngier" <> | Subject | [irqchip: irq/irqchip-fixes] irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry |
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The following commit has been merged into the irq/irqchip-fixes branch of irqchip:
Commit-ID: 1fee9db9b42d821e8007289d4eea74bdf85b1543 Gitweb: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/1fee9db9b42d821e8007289d4eea74bdf85b1543 Author: Marc Zyngier <maz@kernel.org> AuthorDate: Tue, 06 Jul 2021 11:38:59 +01:00 Committer: Marc Zyngier <maz@kernel.org> CommitterDate: Fri, 09 Jul 2021 10:18:58 +01:00
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 --- arch/mips/include/asm/irq.h | 3 +++ arch/mips/kernel/irq.c | 16 ++++++++++++++++ drivers/irqchip/irq-mips-cpu.c | 10 ++++++---- drivers/irqchip/irq-mips-gic.c | 8 ++++---- drivers/irqchip/irq-pic32-evic.c | 5 ++--- 5 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h index d1477ec..57561e0 100644 --- a/arch/mips/include/asm/irq.h +++ b/arch/mips/include/asm/irq.h @@ -57,6 +57,9 @@ asmlinkage void plat_irq_dispatch(void); extern void do_IRQ(unsigned int irq); +struct irq_domain; +extern void do_domain_IRQ(struct irq_domain *domain, unsigned int irq); + extern void arch_init_irq(void); extern void spurious_interrupt(void); diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c index 85b6c60..d20e002 100644 --- a/arch/mips/kernel/irq.c +++ b/arch/mips/kernel/irq.c @@ -21,6 +21,7 @@ #include <linux/kallsyms.h> #include <linux/kgdb.h> #include <linux/ftrace.h> +#include <linux/irqdomain.h> #include <linux/atomic.h> #include <linux/uaccess.h> @@ -107,3 +108,18 @@ void __irq_entry do_IRQ(unsigned int irq) irq_exit(); } +#ifdef CONFIG_IRQ_DOMAIN +void __irq_entry do_domain_IRQ(struct irq_domain *domain, unsigned int hwirq) +{ + struct irq_desc *desc; + + irq_enter(); + check_stack_overflow(); + + desc = irq_resolve_mapping(domain, hwirq); + if (likely(desc)) + handle_irq_desc(desc); + + irq_exit(); +} +#endif diff --git a/drivers/irqchip/irq-mips-cpu.c b/drivers/irqchip/irq-mips-cpu.c index 0bbb0b2..0c7ae71 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 b146e06..54c7092 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 34c4b4f..1d9bb28 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)
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