From 76ba59f8366f2d9282cb5bda9de75b4b68cbe55f Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 26 Aug 2014 11:03:16 +0100 Subject: [PATCH] genirq: Add irq_domain-aware core IRQ handler 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 unpleasant warning: =============================== [ 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: [] irq_find_mapping+0x4c/0x198 As this issue is fairly widespread and involves at least three different architectures, a possible solution is to add a new handle_domain_irq entry point into the generic IRQ 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. An additional "lookup" parameter is used to allow non-domain architecture code to be replaced by this as well. Interrupt controllers can then be updated to use the new mechanism. This code is sitting behind a new CONFIG_HANDLE_DOMAIN_IRQ, as not all architectures implement set_irq_regs (yes, mn10300, I'm looking at you...). Reported-by: Vladimir Murzin Signed-off-by: Marc Zyngier Link: https://lkml.kernel.org/r/1409047421-27649-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Jason Cooper --- include/linux/irqdesc.h | 19 +++++++++++++++++++ kernel/irq/Kconfig | 3 +++ kernel/irq/irqdesc.c | 42 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 64 insertions(+) diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 472c021a2d4f..ff24667cd86c 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -12,6 +12,8 @@ struct irq_affinity_notify; struct proc_dir_entry; struct module; struct irq_desc; +struct irq_domain; +struct pt_regs; /** * struct irq_desc - interrupt descriptor @@ -118,6 +120,23 @@ static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *de int generic_handle_irq(unsigned int irq); +#ifdef CONFIG_HANDLE_DOMAIN_IRQ +/* + * Convert a HW interrupt number to a logical one using a IRQ domain, + * and handle the result interrupt number. Return -EINVAL if + * conversion failed. Providing a NULL domain indicates that the + * conversion has already been done. + */ +int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, + bool lookup, struct pt_regs *regs); + +static inline int handle_domain_irq(struct irq_domain *domain, + unsigned int hwirq, struct pt_regs *regs) +{ + return __handle_domain_irq(domain, hwirq, true, regs); +} +#endif + /* Test to see if a driver has successfully requested an irq */ static inline int irq_has_action(unsigned int irq) { diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index d269cecdfbf0..225086b2652e 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -55,6 +55,9 @@ config GENERIC_IRQ_CHIP config IRQ_DOMAIN bool +config HANDLE_DOMAIN_IRQ + bool + config IRQ_DOMAIN_DEBUG bool "Expose hardware/virtual IRQ mapping via debugfs" depends on IRQ_DOMAIN && DEBUG_FS diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 1487a123db5c..a1782f88f0af 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internals.h" @@ -336,6 +337,47 @@ int generic_handle_irq(unsigned int irq) } EXPORT_SYMBOL_GPL(generic_handle_irq); +#ifdef CONFIG_HANDLE_DOMAIN_IRQ +/** + * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain + * @domain: The domain where to perform the lookup + * @hwirq: The HW irq number to convert to a logical one + * @lookup: Whether to perform the domain lookup or not + * @regs: Register file coming from the low-level handling code + * + * Returns: 0 on success, or -EINVAL if conversion has failed + */ +int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, + bool lookup, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + unsigned int irq = hwirq; + int ret = 0; + + irq_enter(); + +#ifdef CONFIG_IRQ_DOMAIN + if (lookup) + irq = irq_find_mapping(domain, hwirq); +#endif + + /* + * Some hardware gives randomly wrong interrupts. Rather + * than crashing, do something sensible. + */ + if (unlikely(!irq || irq >= nr_irqs)) { + ack_bad_irq(irq); + ret = -EINVAL; + } else { + generic_handle_irq(irq); + } + + irq_exit(); + set_irq_regs(old_regs); + return ret; +} +#endif + /* Dynamic interrupt handling */ /**