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authorMarc Zyngier <maz@kernel.org>2021-07-06 13:38:59 +0300
committerMarc Zyngier <maz@kernel.org>2021-07-09 12:18:58 +0300
commit1fee9db9b42d821e8007289d4eea74bdf85b1543 (patch)
tree6f5b28725cd0b60ac05ccc13b073328b13eec4a2 /drivers/irqchip
parent0e3c1f30b03599f2ee8ff3327eca53c99564ba13 (diff)
downloadlinux-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.c10
-rw-r--r--drivers/irqchip/irq-mips-gic.c8
-rw-r--r--drivers/irqchip/irq-pic32-evic.c5
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)