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![Marc Zyngier](/assets/img/avatar_default.png)
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>
596 lines
13 KiB
C
596 lines
13 KiB
C
/*
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* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
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* Copyright (C) 2005-2006, Thomas Gleixner, Russell King
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*
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* This file contains the interrupt descriptor management code
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*
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* Detailed information is available in Documentation/DocBook/genericirq
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*
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*/
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#include <linux/irq.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/interrupt.h>
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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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/*
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* lockdep: we want to handle all irq_desc locks as a single lock-class:
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*/
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static struct lock_class_key irq_desc_lock_class;
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#if defined(CONFIG_SMP)
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static void __init init_irq_default_affinity(void)
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{
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alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
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cpumask_setall(irq_default_affinity);
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}
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#else
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static void __init init_irq_default_affinity(void)
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{
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}
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#endif
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#ifdef CONFIG_SMP
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static int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node)
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{
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if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
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return -ENOMEM;
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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if (!zalloc_cpumask_var_node(&desc->pending_mask, gfp, node)) {
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free_cpumask_var(desc->irq_data.affinity);
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return -ENOMEM;
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}
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#endif
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return 0;
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}
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static void desc_smp_init(struct irq_desc *desc, int node)
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{
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desc->irq_data.node = node;
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cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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cpumask_clear(desc->pending_mask);
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#endif
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}
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static inline int desc_node(struct irq_desc *desc)
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{
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return desc->irq_data.node;
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}
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#else
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static inline int
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alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
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static inline void desc_smp_init(struct irq_desc *desc, int node) { }
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static inline int desc_node(struct irq_desc *desc) { return 0; }
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#endif
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static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
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struct module *owner)
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{
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int cpu;
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desc->irq_data.irq = irq;
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desc->irq_data.chip = &no_irq_chip;
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desc->irq_data.chip_data = NULL;
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desc->irq_data.handler_data = NULL;
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desc->irq_data.msi_desc = NULL;
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irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
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irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
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desc->handle_irq = handle_bad_irq;
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desc->depth = 1;
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desc->irq_count = 0;
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desc->irqs_unhandled = 0;
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desc->name = NULL;
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desc->owner = owner;
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for_each_possible_cpu(cpu)
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*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
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desc_smp_init(desc, node);
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}
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int nr_irqs = NR_IRQS;
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EXPORT_SYMBOL_GPL(nr_irqs);
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static DEFINE_MUTEX(sparse_irq_lock);
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static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
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#ifdef CONFIG_SPARSE_IRQ
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static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
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static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
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{
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radix_tree_insert(&irq_desc_tree, irq, desc);
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}
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struct irq_desc *irq_to_desc(unsigned int irq)
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{
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return radix_tree_lookup(&irq_desc_tree, irq);
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}
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EXPORT_SYMBOL(irq_to_desc);
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static void delete_irq_desc(unsigned int irq)
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{
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radix_tree_delete(&irq_desc_tree, irq);
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}
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#ifdef CONFIG_SMP
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static void free_masks(struct irq_desc *desc)
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{
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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free_cpumask_var(desc->pending_mask);
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#endif
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free_cpumask_var(desc->irq_data.affinity);
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}
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#else
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static inline void free_masks(struct irq_desc *desc) { }
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#endif
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static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)
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{
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struct irq_desc *desc;
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gfp_t gfp = GFP_KERNEL;
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desc = kzalloc_node(sizeof(*desc), gfp, node);
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if (!desc)
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return NULL;
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/* allocate based on nr_cpu_ids */
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desc->kstat_irqs = alloc_percpu(unsigned int);
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if (!desc->kstat_irqs)
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goto err_desc;
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if (alloc_masks(desc, gfp, node))
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goto err_kstat;
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raw_spin_lock_init(&desc->lock);
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lockdep_set_class(&desc->lock, &irq_desc_lock_class);
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desc_set_defaults(irq, desc, node, owner);
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return desc;
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err_kstat:
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free_percpu(desc->kstat_irqs);
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err_desc:
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kfree(desc);
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return NULL;
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}
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static void free_desc(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unregister_irq_proc(irq, desc);
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mutex_lock(&sparse_irq_lock);
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delete_irq_desc(irq);
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mutex_unlock(&sparse_irq_lock);
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free_masks(desc);
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free_percpu(desc->kstat_irqs);
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kfree(desc);
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}
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static int alloc_descs(unsigned int start, unsigned int cnt, int node,
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struct module *owner)
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{
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struct irq_desc *desc;
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int i;
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for (i = 0; i < cnt; i++) {
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desc = alloc_desc(start + i, node, owner);
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if (!desc)
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goto err;
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mutex_lock(&sparse_irq_lock);
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irq_insert_desc(start + i, desc);
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mutex_unlock(&sparse_irq_lock);
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}
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return start;
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err:
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for (i--; i >= 0; i--)
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free_desc(start + i);
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mutex_lock(&sparse_irq_lock);
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bitmap_clear(allocated_irqs, start, cnt);
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mutex_unlock(&sparse_irq_lock);
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return -ENOMEM;
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}
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static int irq_expand_nr_irqs(unsigned int nr)
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{
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if (nr > IRQ_BITMAP_BITS)
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return -ENOMEM;
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nr_irqs = nr;
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return 0;
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}
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int __init early_irq_init(void)
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{
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int i, initcnt, node = first_online_node;
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struct irq_desc *desc;
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init_irq_default_affinity();
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/* Let arch update nr_irqs and return the nr of preallocated irqs */
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initcnt = arch_probe_nr_irqs();
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printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs, initcnt);
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if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
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nr_irqs = IRQ_BITMAP_BITS;
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if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
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initcnt = IRQ_BITMAP_BITS;
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if (initcnt > nr_irqs)
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nr_irqs = initcnt;
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for (i = 0; i < initcnt; i++) {
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desc = alloc_desc(i, node, NULL);
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set_bit(i, allocated_irqs);
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irq_insert_desc(i, desc);
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}
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return arch_early_irq_init();
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}
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#else /* !CONFIG_SPARSE_IRQ */
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struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
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[0 ... NR_IRQS-1] = {
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.handle_irq = handle_bad_irq,
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.depth = 1,
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.lock = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
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}
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};
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int __init early_irq_init(void)
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{
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int count, i, node = first_online_node;
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struct irq_desc *desc;
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init_irq_default_affinity();
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printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
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desc = irq_desc;
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count = ARRAY_SIZE(irq_desc);
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for (i = 0; i < count; i++) {
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desc[i].kstat_irqs = alloc_percpu(unsigned int);
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alloc_masks(&desc[i], GFP_KERNEL, node);
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raw_spin_lock_init(&desc[i].lock);
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lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
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desc_set_defaults(i, &desc[i], node, NULL);
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}
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return arch_early_irq_init();
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}
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struct irq_desc *irq_to_desc(unsigned int irq)
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{
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return (irq < NR_IRQS) ? irq_desc + irq : NULL;
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}
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EXPORT_SYMBOL(irq_to_desc);
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static void free_desc(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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raw_spin_lock_irqsave(&desc->lock, flags);
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desc_set_defaults(irq, desc, desc_node(desc), NULL);
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raw_spin_unlock_irqrestore(&desc->lock, flags);
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}
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static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
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struct module *owner)
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{
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u32 i;
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for (i = 0; i < cnt; i++) {
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struct irq_desc *desc = irq_to_desc(start + i);
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desc->owner = owner;
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}
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return start;
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}
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static int irq_expand_nr_irqs(unsigned int nr)
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{
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return -ENOMEM;
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}
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void irq_mark_irq(unsigned int irq)
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{
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mutex_lock(&sparse_irq_lock);
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bitmap_set(allocated_irqs, irq, 1);
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mutex_unlock(&sparse_irq_lock);
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}
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#ifdef CONFIG_GENERIC_IRQ_LEGACY
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void irq_init_desc(unsigned int irq)
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{
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free_desc(irq);
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}
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#endif
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#endif /* !CONFIG_SPARSE_IRQ */
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/**
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* generic_handle_irq - Invoke the handler for a particular irq
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* @irq: The irq number to handle
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*
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*/
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int generic_handle_irq(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (!desc)
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return -EINVAL;
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generic_handle_irq_desc(irq, desc);
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return 0;
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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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* irq_free_descs - free irq descriptors
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* @from: Start of descriptor range
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* @cnt: Number of consecutive irqs to free
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*/
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void irq_free_descs(unsigned int from, unsigned int cnt)
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{
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int i;
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if (from >= nr_irqs || (from + cnt) > nr_irqs)
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return;
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for (i = 0; i < cnt; i++)
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free_desc(from + i);
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mutex_lock(&sparse_irq_lock);
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bitmap_clear(allocated_irqs, from, cnt);
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mutex_unlock(&sparse_irq_lock);
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}
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EXPORT_SYMBOL_GPL(irq_free_descs);
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/**
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* irq_alloc_descs - allocate and initialize a range of irq descriptors
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* @irq: Allocate for specific irq number if irq >= 0
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* @from: Start the search from this irq number
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* @cnt: Number of consecutive irqs to allocate.
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* @node: Preferred node on which the irq descriptor should be allocated
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* @owner: Owning module (can be NULL)
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*
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* Returns the first irq number or error code
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*/
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int __ref
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__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
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struct module *owner)
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{
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int start, ret;
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if (!cnt)
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return -EINVAL;
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if (irq >= 0) {
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if (from > irq)
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return -EINVAL;
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from = irq;
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} else {
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/*
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* For interrupts which are freely allocated the
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* architecture can force a lower bound to the @from
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* argument. x86 uses this to exclude the GSI space.
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*/
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from = arch_dynirq_lower_bound(from);
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}
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mutex_lock(&sparse_irq_lock);
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start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
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from, cnt, 0);
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ret = -EEXIST;
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if (irq >=0 && start != irq)
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goto err;
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if (start + cnt > nr_irqs) {
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ret = irq_expand_nr_irqs(start + cnt);
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if (ret)
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goto err;
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}
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bitmap_set(allocated_irqs, start, cnt);
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mutex_unlock(&sparse_irq_lock);
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return alloc_descs(start, cnt, node, owner);
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err:
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mutex_unlock(&sparse_irq_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(__irq_alloc_descs);
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#ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
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/**
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* irq_alloc_hwirqs - Allocate an irq descriptor and initialize the hardware
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* @cnt: number of interrupts to allocate
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* @node: node on which to allocate
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*
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* Returns an interrupt number > 0 or 0, if the allocation fails.
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*/
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unsigned int irq_alloc_hwirqs(int cnt, int node)
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{
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int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL);
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if (irq < 0)
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return 0;
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for (i = irq; cnt > 0; i++, cnt--) {
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if (arch_setup_hwirq(i, node))
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goto err;
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irq_clear_status_flags(i, _IRQ_NOREQUEST);
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}
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return irq;
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err:
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for (i--; i >= irq; i--) {
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irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
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arch_teardown_hwirq(i);
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}
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irq_free_descs(irq, cnt);
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return 0;
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}
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EXPORT_SYMBOL_GPL(irq_alloc_hwirqs);
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/**
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* irq_free_hwirqs - Free irq descriptor and cleanup the hardware
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* @from: Free from irq number
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* @cnt: number of interrupts to free
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*
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*/
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void irq_free_hwirqs(unsigned int from, int cnt)
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{
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int i, j;
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for (i = from, j = cnt; j > 0; i++, j--) {
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irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
|
|
arch_teardown_hwirq(i);
|
|
}
|
|
irq_free_descs(from, cnt);
|
|
}
|
|
EXPORT_SYMBOL_GPL(irq_free_hwirqs);
|
|
#endif
|
|
|
|
/**
|
|
* irq_get_next_irq - get next allocated irq number
|
|
* @offset: where to start the search
|
|
*
|
|
* Returns next irq number after offset or nr_irqs if none is found.
|
|
*/
|
|
unsigned int irq_get_next_irq(unsigned int offset)
|
|
{
|
|
return find_next_bit(allocated_irqs, nr_irqs, offset);
|
|
}
|
|
|
|
struct irq_desc *
|
|
__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
|
|
unsigned int check)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
|
|
if (desc) {
|
|
if (check & _IRQ_DESC_CHECK) {
|
|
if ((check & _IRQ_DESC_PERCPU) &&
|
|
!irq_settings_is_per_cpu_devid(desc))
|
|
return NULL;
|
|
|
|
if (!(check & _IRQ_DESC_PERCPU) &&
|
|
irq_settings_is_per_cpu_devid(desc))
|
|
return NULL;
|
|
}
|
|
|
|
if (bus)
|
|
chip_bus_lock(desc);
|
|
raw_spin_lock_irqsave(&desc->lock, *flags);
|
|
}
|
|
return desc;
|
|
}
|
|
|
|
void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
|
|
{
|
|
raw_spin_unlock_irqrestore(&desc->lock, flags);
|
|
if (bus)
|
|
chip_bus_sync_unlock(desc);
|
|
}
|
|
|
|
int irq_set_percpu_devid(unsigned int irq)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
|
|
if (!desc)
|
|
return -EINVAL;
|
|
|
|
if (desc->percpu_enabled)
|
|
return -EINVAL;
|
|
|
|
desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
|
|
|
|
if (!desc->percpu_enabled)
|
|
return -ENOMEM;
|
|
|
|
irq_set_percpu_devid_flags(irq);
|
|
return 0;
|
|
}
|
|
|
|
void kstat_incr_irq_this_cpu(unsigned int irq)
|
|
{
|
|
kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
|
|
}
|
|
|
|
unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
|
|
return desc && desc->kstat_irqs ?
|
|
*per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
|
|
}
|
|
|
|
unsigned int kstat_irqs(unsigned int irq)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
int cpu;
|
|
int sum = 0;
|
|
|
|
if (!desc || !desc->kstat_irqs)
|
|
return 0;
|
|
for_each_possible_cpu(cpu)
|
|
sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
|
|
return sum;
|
|
}
|