Messages in this thread | | | From | Marc Zyngier <> | Subject | [PATCH 00/15] arm/arm64: fix use of irq_find_mapping outside of legal RCU context | Date | Tue, 8 Jul 2014 14:10:23 +0100 |
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A number of irqchip drivers are directly calling irq_find_mapping, which may use a rcu_read_lock call when walking the radix tree.
Turns out that if you hit that point with CONFIG_PROVE_RCU enabled, the kernel will shout at you, as using RCU in this context may be illegal (specially if coming from the idle state, where RCU would be in a quiescent state).
A possible fix would be to wrap calls to irq_find_mapping into a RCU_NONIDLE macro, but that really looks ugly.
This patch series introduce another IRQ entry point on arm and arm64 (handle_domain_irq), which has the exact same behaviour as handle_IRQ, except that it also takes a irq_domain pointer. This allows the logical IRQ lookup to be done inside the irq_{enter,exit} section, which contains a rcu_irq_{enter,exit}, making it safe.
A number of irqchips are then converted to this new entry point. I've converted all the direct users of irq_find_mapping, except for the cases where it was used as a chained handler (chained_irq_{enter,exit} makes it safe). Users of irq_linear_revmap are safe as well.
I've given it some light testing on arm64. The series is also available in my tree:
git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git handle_domain_irq
Marc Zyngier (15): arm64: pass IRQ domain to the core IRQ handler ARM: pass IRQ domain to the core IRQ handler irqchip: GIC: convert to handle_domain_irq irqchip: armada-370-xp: convert to handle_domain_irq irqchip: clps711x: convert to handle_domain_irq irqchip: mmp: convert to handle_domain_irq irqchip: mxs: convert to handle_domain_irq irqchip: orion: convert to handle_domain_irq irqchip: s3c24xx: convert to handle_domain_irq irqchip: sirfsoc: convert to handle_domain_irq irqchip: sun4i: convert to handle_domain_irq irqchip: versatile-fpga: convert to handle_domain_irq irqchip: vic: convert to handle_domain_irq irqchip: vt8500: convert to handle_domain_irq irqchip: zevio: convert to handle_domain_irq
arch/arm/include/asm/irq.h | 2 ++ arch/arm/kernel/irq.c | 23 +++++++++++++++++++---- arch/arm64/include/asm/hardirq.h | 4 ++++ arch/arm64/kernel/irq.c | 23 ++++++++++++++++++++--- drivers/irqchip/irq-armada-370-xp.c | 19 ++++++++++--------- drivers/irqchip/irq-clps711x.c | 18 +++++++----------- drivers/irqchip/irq-gic.c | 3 +-- drivers/irqchip/irq-mmp.c | 10 ++++------ drivers/irqchip/irq-mxs.c | 3 +-- drivers/irqchip/irq-orion.c | 5 ++--- drivers/irqchip/irq-s3c24xx.c | 4 +--- drivers/irqchip/irq-sirfsoc.c | 6 ++---- drivers/irqchip/irq-sun4i.c | 5 ++--- drivers/irqchip/irq-versatile-fpga.c | 2 +- drivers/irqchip/irq-vic.c | 2 +- drivers/irqchip/irq-vt8500.c | 5 ++--- drivers/irqchip/irq-zevio.c | 3 +-- 17 files changed, 80 insertions(+), 57 deletions(-)
-- 2.0.0
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