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: <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> 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 <vladimir.murzin@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/1409047421-27649-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Jason Cooper <jason@lakedaemon.net>
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@ -12,6 +12,8 @@ struct irq_affinity_notify;
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struct proc_dir_entry;
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struct module;
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struct irq_desc;
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struct irq_domain;
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struct pt_regs;
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/**
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* struct irq_desc - interrupt descriptor
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@ -118,6 +120,23 @@ static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *de
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int generic_handle_irq(unsigned int irq);
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#ifdef CONFIG_HANDLE_DOMAIN_IRQ
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/*
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* Convert a HW interrupt number to a logical one using a IRQ domain,
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* and handle the result interrupt number. Return -EINVAL if
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* conversion failed. Providing a NULL domain indicates that the
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* conversion has already been done.
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*/
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int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
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bool lookup, struct pt_regs *regs);
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static inline int handle_domain_irq(struct irq_domain *domain,
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unsigned int hwirq, struct pt_regs *regs)
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{
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return __handle_domain_irq(domain, hwirq, true, regs);
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}
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#endif
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/* Test to see if a driver has successfully requested an irq */
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static inline int irq_has_action(unsigned int irq)
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{
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@ -55,6 +55,9 @@ config GENERIC_IRQ_CHIP
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config IRQ_DOMAIN
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bool
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config HANDLE_DOMAIN_IRQ
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bool
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config IRQ_DOMAIN_DEBUG
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bool "Expose hardware/virtual IRQ mapping via debugfs"
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depends on IRQ_DOMAIN && DEBUG_FS
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@ -14,6 +14,7 @@
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#include <linux/kernel_stat.h>
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#include <linux/radix-tree.h>
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#include <linux/bitmap.h>
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#include <linux/irqdomain.h>
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#include "internals.h"
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@ -336,6 +337,47 @@ int generic_handle_irq(unsigned int irq)
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}
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EXPORT_SYMBOL_GPL(generic_handle_irq);
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#ifdef CONFIG_HANDLE_DOMAIN_IRQ
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/**
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* __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
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* @domain: The domain where to perform the lookup
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* @hwirq: The HW irq number to convert to a logical one
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* @lookup: Whether to perform the domain lookup or not
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* @regs: Register file coming from the low-level handling code
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*
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* Returns: 0 on success, or -EINVAL if conversion has failed
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*/
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int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
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bool lookup, struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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unsigned int irq = hwirq;
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int ret = 0;
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irq_enter();
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#ifdef CONFIG_IRQ_DOMAIN
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if (lookup)
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irq = irq_find_mapping(domain, hwirq);
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#endif
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/*
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* Some hardware gives randomly wrong interrupts. Rather
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* than crashing, do something sensible.
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*/
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if (unlikely(!irq || irq >= nr_irqs)) {
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ack_bad_irq(irq);
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ret = -EINVAL;
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} else {
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generic_handle_irq(irq);
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}
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irq_exit();
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set_irq_regs(old_regs);
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return ret;
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}
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#endif
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/* Dynamic interrupt handling */
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/**
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