[PATCH v2 00/26] genirq: fix use of irq_find_mapping outside of legal RCU context

Marc Zyngier
2014-08-26T10:03:49Z

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 generic IRQ entry point
(handle_domain_irq), which has the exact same behaviour as handle_IRQ
(as defined on arm, arm64 and openrisc), 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

>From v1 [1]:
- Made handle_domain_irq a generic function
- Added OpenRISC to the list of affected architectures
- Converted more interrupt controllers
- Rebased on v3.17-rc1

[1]: https://lkml.org/lkml/2014/7/8/381

Marc Zyngier (26):
genirq: add irq_domain-aware core IRQ handler
arm64: convert handle_IRQ to use __handle_domain_irq
ARM: convert handle_IRQ to use __handle_domain_irq
openrisc: convert handle_IRQ to use __handle_domain_irq
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
irqchip: GICv3: convert to handle_domain_irq
irqchip: atmel-aic: convert to handle_domain_irq
irqchip: atmel-aic5: convert to handle_domain_irq
irqchip: or1k-pic: convert to handle_domain_irq
ARM: imx: avic: convert to handle_domain_irq
ARM: imx: tzic: convert to handle_domain_irq
ARM: omap2: irq: convert to handle_domain_irq
arm64: get rid of handle_IRQ
openrisc: get rid of handle_IRQ

arch/arm/Kconfig | 1 +
arch/arm/kernel/irq.c | 19 +---------------
arch/arm/mach-imx/avic.c | 2 +-
arch/arm/mach-imx/tzic.c | 3 +--
arch/arm/mach-omap2/irq.c | 3 +--
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/hardirq.h | 2 --
arch/arm64/kernel/irq.c | 27 -----------------------
arch/openrisc/Kconfig | 1 +
arch/openrisc/include/asm/irq.h | 1 -
arch/openrisc/kernel/irq.c | 12 -----------
drivers/irqchip/irq-armada-370-xp.c | 19 ++++++++--------
drivers/irqchip/irq-atmel-aic.c | 4 +---
drivers/irqchip/irq-atmel-aic5.c | 4 +---
drivers/irqchip/irq-clps711x.c | 18 ++++++----------
drivers/irqchip/irq-gic-v3.c | 13 ++++++-----
drivers/irqchip/irq-gic.c | 3 +--
drivers/irqchip/irq-mmp.c | 10 ++++-----
drivers/irqchip/irq-mxs.c | 3 +--
drivers/irqchip/irq-or1k-pic.c | 4 ++--
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 +--
include/linux/irqdesc.h | 19 ++++++++++++++++
kernel/irq/Kconfig | 3 +++
kernel/irq/irqdesc.c | 42 ++++++++++++++++++++++++++++++++++++
31 files changed, 116 insertions(+), 130 deletions(-)

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2.0.4