/* * linux/kernel/irq/handle.c * * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar * Copyright (C) 2005-2006, Thomas Gleixner, Russell King * * This file contains the core interrupt handling code. * * Detailed information is available in Documentation/DocBook/genericirq * */ #include #include #include #include #include #include #include "internals.h" /** * handle_bad_irq - handle spurious and unhandled irqs * @desc: description of the interrupt * * Handles spurious and unhandled IRQ's. It also prints a debugmessage. */ void handle_bad_irq(struct irq_desc *desc) { unsigned int irq = irq_desc_get_irq(desc); print_irq_desc(irq, desc); kstat_incr_irqs_this_cpu(desc); ack_bad_irq(irq); } EXPORT_SYMBOL_GPL(handle_bad_irq); /* * Special, empty irq handler: */ irqreturn_t no_action(int cpl, void *dev_id) { return IRQ_NONE; } EXPORT_SYMBOL_GPL(no_action); static void warn_no_thread(unsigned int irq, struct irqaction *action) { if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) return; printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " "but no thread function available.", irq, action->name); } void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) { /* * In case the thread crashed and was killed we just pretend that * we handled the interrupt. The hardirq handler has disabled the * device interrupt, so no irq storm is lurking. */ if (action->thread->flags & PF_EXITING) return; /* * Wake up the handler thread for this action. If the * RUNTHREAD bit is already set, nothing to do. */ if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags)) return; /* * It's safe to OR the mask lockless here. We have only two * places which write to threads_oneshot: This code and the * irq thread. * * This code is the hard irq context and can never run on two * cpus in parallel. If it ever does we have more serious * problems than this bitmask. * * The irq threads of this irq which clear their "running" bit * in threads_oneshot are serialized via desc->lock against * each other and they are serialized against this code by * IRQS_INPROGRESS. * * Hard irq handler: * * spin_lock(desc->lock); * desc->state |= IRQS_INPROGRESS; * spin_unlock(desc->lock); * set_bit(IRQTF_RUNTHREAD, &action->thread_flags); * desc->threads_oneshot |= mask; * spin_lock(desc->lock); * desc->state &= ~IRQS_INPROGRESS; * spin_unlock(desc->lock); * * irq thread: * * again: * spin_lock(desc->lock); * if (desc->state & IRQS_INPROGRESS) { * spin_unlock(desc->lock); * while(desc->state & IRQS_INPROGRESS) * cpu_relax(); * goto again; * } * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) * desc->threads_oneshot &= ~mask; * spin_unlock(desc->lock); * * So either the thread waits for us to clear IRQS_INPROGRESS * or we are waiting in the flow handler for desc->lock to be * released before we reach this point. The thread also checks * IRQTF_RUNTHREAD under desc->lock. If set it leaves * threads_oneshot untouched and runs the thread another time. */ desc->threads_oneshot |= action->thread_mask; /* * We increment the threads_active counter in case we wake up * the irq thread. The irq thread decrements the counter when * it returns from the handler or in the exit path and wakes * up waiters which are stuck in synchronize_irq() when the * active count becomes zero. synchronize_irq() is serialized * against this code (hard irq handler) via IRQS_INPROGRESS * like the finalize_oneshot() code. See comment above. */ atomic_inc(&desc->threads_active); wake_up_process(action->thread); } irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags) { irqreturn_t retval = IRQ_NONE; unsigned int irq = desc->irq_data.irq; struct irqaction *action; for_each_action_of_desc(desc, action) { irqreturn_t res; trace_irq_handler_entry(irq, action); res = action->handler(irq, action->dev_id); trace_irq_handler_exit(irq, action, res); if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n", irq, action->handler)) local_irq_disable(); switch (res) { case IRQ_WAKE_THREAD: /* * Catch drivers which return WAKE_THREAD but * did not set up a thread function */ if (unlikely(!action->thread_fn)) { warn_no_thread(irq, action); break; } __irq_wake_thread(desc, action); /* Fall through to add to randomness */ case IRQ_HANDLED: *flags |= action->flags; break; default: break; } retval |= res; } return retval; } irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) { irqreturn_t retval; unsigned int flags = 0; retval = __handle_irq_event_percpu(desc, &flags); add_interrupt_randomness(desc->irq_data.irq, flags); if (!noirqdebug) note_interrupt(desc, retval); return retval; } irqreturn_t handle_irq_event(struct irq_desc *desc) { irqreturn_t ret; desc->istate &= ~IRQS_PENDING; irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); raw_spin_unlock(&desc->lock); ret = handle_irq_event_percpu(desc); raw_spin_lock(&desc->lock); irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); return ret; } oid'>6ba22924faa1b82ef2f0277db10a3f5abdc44157 /drivers/usb/host/sl811_cs.c parent3705ccfdd1e8b539225ce20e3925a945cc788d67 (diff)
mm: do not export ioremap_page_range symbol for external module
Recently, I've found cases in which ioremap_page_range was used incorrectly, in external modules, leading to crashes. This can be partly attributed to the fact that ioremap_page_range is lower-level, with fewer protections, as compared to the other functions that an external module would typically call. Those include: ioremap_cache ioremap_nocache ioremap_prot ioremap_uc ioremap_wc ioremap_wt ...each of which wraps __ioremap_caller, which in turn provides a safer way to achieve the mapping. Therefore, stop EXPORT-ing ioremap_page_range. Link: http://lkml.kernel.org/r/1485173220-29010-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/usb/host/sl811_cs.c')