Messages in this thread Patch in this message | | | From | Marc Zyngier <> | Subject | [PATCH 01/15] arm64: pass IRQ domain to the core IRQ handler | Date | Tue, 8 Jul 2014 14:10:24 +0100 |
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Calling irq_find_mapping from outside a irq_{enter,exit} section is unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled: If coming from the idle state, the rcu_read_lock call in irq_find_mapping will generate an an unpleasant warning:
<quote> =============================== [ INFO: suspicious RCU usage. ] 3.16.0-rc1+ #135 Not tainted ------------------------------- include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle!
other info that might help us debug this:
RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 1 lock held by swapper/0/0: #0: (rcu_read_lock){......}, at: [<ffffffc00010206c>] irq_find_mapping+0x4c/0x198 </quote>
A solution is to add a new handle_domain_irq entry point into the arm64 code that the interrupt controller code can call. This new function takes an irq_domain, and calls into irq_find_domain inside the irq_{enter,exit} block.
Interrupt controllers can then be updated to use the new mechanism.
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/include/asm/hardirq.h | 4 ++++ arch/arm64/kernel/irq.c | 23 ++++++++++++++++++++--- 2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h index 0be6782..fb3e318 100644 --- a/arch/arm64/include/asm/hardirq.h +++ b/arch/arm64/include/asm/hardirq.h @@ -49,6 +49,10 @@ static inline void ack_bad_irq(unsigned int irq) extern void handle_IRQ(unsigned int, struct pt_regs *); +struct irq_domain; +extern void handle_domain_irq(struct irq_domain *, + unsigned int, struct pt_regs *); + /* * No arch-specific IRQ flags. */ diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index 0f08dfd..cb487ad 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -23,6 +23,7 @@ #include <linux/kernel_stat.h> #include <linux/irq.h> +#include <linux/irqdomain.h> #include <linux/smp.h> #include <linux/init.h> #include <linux/irqchip.h> @@ -45,19 +46,30 @@ int arch_show_interrupts(struct seq_file *p, int prec) * not come via this function. Instead, they should provide their * own 'handler'. Used by platform code implementing C-based 1st * level decoding. + * + * handle_domain_irq does the same thing, but also converts the HW + * interrupt number into a logical one using the provided domain. A + * NULL domain indicates that this conversion has already been done. */ -void handle_IRQ(unsigned int irq, struct pt_regs *regs) +void handle_domain_irq(struct irq_domain *domain, + unsigned int hwirq, struct pt_regs *regs) { struct pt_regs *old_regs = set_irq_regs(regs); + unsigned int irq; irq_enter(); + if (domain) + irq = irq_find_mapping(domain, hwirq); + else + irq = hwirq; + /* * Some hardware gives randomly wrong interrupts. Rather * than crashing, do something sensible. */ - if (unlikely(irq >= nr_irqs)) { - pr_warn_ratelimited("Bad IRQ%u\n", irq); + if (unlikely(!irq || irq >= nr_irqs)) { + pr_warn_ratelimited("Bad IRQ%u (%u)\n", irq, hwirq); ack_bad_irq(irq); } else { generic_handle_irq(irq); @@ -67,6 +79,11 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs) set_irq_regs(old_regs); } +void handle_IRQ(unsigned int irq, struct pt_regs *regs) +{ + handle_domain_irq(NULL, irq, regs); +} + void __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) { if (handle_arch_irq) -- 2.0.0
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