4c182ae781
Make activate_fd() and free_irq_by_irq_and_dev() static. Remove init_aio_irq() since it has no users. Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
517 lines
12 KiB
C
517 lines
12 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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* Derived (i.e. mostly copied) from arch/i386/kernel/irq.c:
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* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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*/
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#include "linux/cpumask.h"
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#include "linux/hardirq.h"
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#include "linux/interrupt.h"
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#include "linux/kernel_stat.h"
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#include "linux/module.h"
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#include "linux/seq_file.h"
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#include "as-layout.h"
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#include "kern_util.h"
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#include "os.h"
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/*
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* Generic, controller-independent functions:
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*/
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int show_interrupts(struct seq_file *p, void *v)
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{
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int i = *(loff_t *) v, j;
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struct irqaction * action;
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unsigned long flags;
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if (i == 0) {
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seq_printf(p, " ");
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for_each_online_cpu(j)
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seq_printf(p, "CPU%d ",j);
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seq_putc(p, '\n');
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}
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if (i < NR_IRQS) {
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spin_lock_irqsave(&irq_desc[i].lock, flags);
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action = irq_desc[i].action;
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if (!action)
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goto skip;
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seq_printf(p, "%3d: ",i);
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#ifndef CONFIG_SMP
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seq_printf(p, "%10u ", kstat_irqs(i));
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#else
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for_each_online_cpu(j)
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seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
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#endif
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seq_printf(p, " %14s", irq_desc[i].chip->typename);
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seq_printf(p, " %s", action->name);
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for (action=action->next; action; action = action->next)
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seq_printf(p, ", %s", action->name);
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seq_putc(p, '\n');
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skip:
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spin_unlock_irqrestore(&irq_desc[i].lock, flags);
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} else if (i == NR_IRQS)
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seq_putc(p, '\n');
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return 0;
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}
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/*
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* This list is accessed under irq_lock, except in sigio_handler,
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* where it is safe from being modified. IRQ handlers won't change it -
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* if an IRQ source has vanished, it will be freed by free_irqs just
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* before returning from sigio_handler. That will process a separate
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* list of irqs to free, with its own locking, coming back here to
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* remove list elements, taking the irq_lock to do so.
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*/
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static struct irq_fd *active_fds = NULL;
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static struct irq_fd **last_irq_ptr = &active_fds;
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extern void free_irqs(void);
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void sigio_handler(int sig, struct uml_pt_regs *regs)
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{
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struct irq_fd *irq_fd;
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int n;
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if (smp_sigio_handler())
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return;
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while (1) {
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n = os_waiting_for_events(active_fds);
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if (n <= 0) {
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if (n == -EINTR)
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continue;
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else break;
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}
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for (irq_fd = active_fds; irq_fd != NULL;
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irq_fd = irq_fd->next) {
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if (irq_fd->current_events != 0) {
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irq_fd->current_events = 0;
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do_IRQ(irq_fd->irq, regs);
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}
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}
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}
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free_irqs();
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}
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static DEFINE_SPINLOCK(irq_lock);
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static int activate_fd(int irq, int fd, int type, void *dev_id)
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{
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struct pollfd *tmp_pfd;
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struct irq_fd *new_fd, *irq_fd;
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unsigned long flags;
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int events, err, n;
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err = os_set_fd_async(fd);
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if (err < 0)
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goto out;
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err = -ENOMEM;
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new_fd = kmalloc(sizeof(struct irq_fd), GFP_KERNEL);
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if (new_fd == NULL)
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goto out;
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if (type == IRQ_READ)
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events = UM_POLLIN | UM_POLLPRI;
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else events = UM_POLLOUT;
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*new_fd = ((struct irq_fd) { .next = NULL,
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.id = dev_id,
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.fd = fd,
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.type = type,
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.irq = irq,
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.events = events,
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.current_events = 0 } );
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err = -EBUSY;
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spin_lock_irqsave(&irq_lock, flags);
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for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
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if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
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printk(KERN_ERR "Registering fd %d twice\n", fd);
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printk(KERN_ERR "Irqs : %d, %d\n", irq_fd->irq, irq);
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printk(KERN_ERR "Ids : 0x%p, 0x%p\n", irq_fd->id,
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dev_id);
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goto out_unlock;
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}
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}
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if (type == IRQ_WRITE)
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fd = -1;
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tmp_pfd = NULL;
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n = 0;
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while (1) {
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n = os_create_pollfd(fd, events, tmp_pfd, n);
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if (n == 0)
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break;
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/*
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* n > 0
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* It means we couldn't put new pollfd to current pollfds
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* and tmp_fds is NULL or too small for new pollfds array.
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* Needed size is equal to n as minimum.
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*
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* Here we have to drop the lock in order to call
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* kmalloc, which might sleep.
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* If something else came in and changed the pollfds array
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* so we will not be able to put new pollfd struct to pollfds
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* then we free the buffer tmp_fds and try again.
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*/
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spin_unlock_irqrestore(&irq_lock, flags);
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kfree(tmp_pfd);
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tmp_pfd = kmalloc(n, GFP_KERNEL);
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if (tmp_pfd == NULL)
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goto out_kfree;
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spin_lock_irqsave(&irq_lock, flags);
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}
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*last_irq_ptr = new_fd;
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last_irq_ptr = &new_fd->next;
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spin_unlock_irqrestore(&irq_lock, flags);
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/*
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* This calls activate_fd, so it has to be outside the critical
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* section.
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*/
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maybe_sigio_broken(fd, (type == IRQ_READ));
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return 0;
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out_unlock:
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spin_unlock_irqrestore(&irq_lock, flags);
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out_kfree:
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kfree(new_fd);
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out:
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return err;
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}
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static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
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{
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unsigned long flags;
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spin_lock_irqsave(&irq_lock, flags);
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os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
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spin_unlock_irqrestore(&irq_lock, flags);
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}
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struct irq_and_dev {
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int irq;
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void *dev;
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};
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static int same_irq_and_dev(struct irq_fd *irq, void *d)
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{
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struct irq_and_dev *data = d;
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return ((irq->irq == data->irq) && (irq->id == data->dev));
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}
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static void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
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{
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struct irq_and_dev data = ((struct irq_and_dev) { .irq = irq,
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.dev = dev });
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free_irq_by_cb(same_irq_and_dev, &data);
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}
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static int same_fd(struct irq_fd *irq, void *fd)
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{
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return (irq->fd == *((int *)fd));
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}
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void free_irq_by_fd(int fd)
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{
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free_irq_by_cb(same_fd, &fd);
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}
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/* Must be called with irq_lock held */
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static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
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{
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struct irq_fd *irq;
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int i = 0;
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int fdi;
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for (irq = active_fds; irq != NULL; irq = irq->next) {
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if ((irq->fd == fd) && (irq->irq == irqnum))
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break;
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i++;
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}
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if (irq == NULL) {
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printk(KERN_ERR "find_irq_by_fd doesn't have descriptor %d\n",
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fd);
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goto out;
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}
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fdi = os_get_pollfd(i);
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if ((fdi != -1) && (fdi != fd)) {
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printk(KERN_ERR "find_irq_by_fd - mismatch between active_fds "
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"and pollfds, fd %d vs %d, need %d\n", irq->fd,
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fdi, fd);
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irq = NULL;
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goto out;
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}
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*index_out = i;
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out:
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return irq;
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}
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void reactivate_fd(int fd, int irqnum)
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{
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struct irq_fd *irq;
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unsigned long flags;
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int i;
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spin_lock_irqsave(&irq_lock, flags);
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irq = find_irq_by_fd(fd, irqnum, &i);
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if (irq == NULL) {
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spin_unlock_irqrestore(&irq_lock, flags);
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return;
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}
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os_set_pollfd(i, irq->fd);
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spin_unlock_irqrestore(&irq_lock, flags);
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add_sigio_fd(fd);
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}
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void deactivate_fd(int fd, int irqnum)
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{
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struct irq_fd *irq;
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unsigned long flags;
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int i;
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spin_lock_irqsave(&irq_lock, flags);
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irq = find_irq_by_fd(fd, irqnum, &i);
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if (irq == NULL) {
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spin_unlock_irqrestore(&irq_lock, flags);
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return;
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}
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os_set_pollfd(i, -1);
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spin_unlock_irqrestore(&irq_lock, flags);
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ignore_sigio_fd(fd);
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}
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/*
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* Called just before shutdown in order to provide a clean exec
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* environment in case the system is rebooting. No locking because
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* that would cause a pointless shutdown hang if something hadn't
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* released the lock.
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*/
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int deactivate_all_fds(void)
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{
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struct irq_fd *irq;
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int err;
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for (irq = active_fds; irq != NULL; irq = irq->next) {
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err = os_clear_fd_async(irq->fd);
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if (err)
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return err;
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}
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/* If there is a signal already queued, after unblocking ignore it */
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os_set_ioignore();
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return 0;
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}
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/*
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* do_IRQ handles all normal device IRQs (the special
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* SMP cross-CPU interrupts have their own specific
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* handlers).
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*/
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unsigned int do_IRQ(int irq, struct uml_pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)regs);
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irq_enter();
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__do_IRQ(irq);
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irq_exit();
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set_irq_regs(old_regs);
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return 1;
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}
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int um_request_irq(unsigned int irq, int fd, int type,
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irq_handler_t handler,
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unsigned long irqflags, const char * devname,
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void *dev_id)
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{
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int err;
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if (fd != -1) {
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err = activate_fd(irq, fd, type, dev_id);
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if (err)
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return err;
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}
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return request_irq(irq, handler, irqflags, devname, dev_id);
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}
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EXPORT_SYMBOL(um_request_irq);
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EXPORT_SYMBOL(reactivate_fd);
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/*
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* hw_interrupt_type must define (startup || enable) &&
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* (shutdown || disable) && end
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*/
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static void dummy(unsigned int irq)
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{
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}
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/* This is used for everything else than the timer. */
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static struct hw_interrupt_type normal_irq_type = {
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.typename = "SIGIO",
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.release = free_irq_by_irq_and_dev,
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.disable = dummy,
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.enable = dummy,
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.ack = dummy,
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.end = dummy
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};
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static struct hw_interrupt_type SIGVTALRM_irq_type = {
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.typename = "SIGVTALRM",
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.release = free_irq_by_irq_and_dev,
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.shutdown = dummy, /* never called */
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.disable = dummy,
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.enable = dummy,
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.ack = dummy,
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.end = dummy
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};
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void __init init_IRQ(void)
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{
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int i;
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irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
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irq_desc[TIMER_IRQ].action = NULL;
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irq_desc[TIMER_IRQ].depth = 1;
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irq_desc[TIMER_IRQ].chip = &SIGVTALRM_irq_type;
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enable_irq(TIMER_IRQ);
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for (i = 1; i < NR_IRQS; i++) {
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irq_desc[i].status = IRQ_DISABLED;
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irq_desc[i].action = NULL;
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irq_desc[i].depth = 1;
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irq_desc[i].chip = &normal_irq_type;
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enable_irq(i);
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}
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}
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/*
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* IRQ stack entry and exit:
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*
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* Unlike i386, UML doesn't receive IRQs on the normal kernel stack
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* and switch over to the IRQ stack after some preparation. We use
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* sigaltstack to receive signals on a separate stack from the start.
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* These two functions make sure the rest of the kernel won't be too
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* upset by being on a different stack. The IRQ stack has a
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* thread_info structure at the bottom so that current et al continue
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* to work.
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*
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* to_irq_stack copies the current task's thread_info to the IRQ stack
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* thread_info and sets the tasks's stack to point to the IRQ stack.
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*
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* from_irq_stack copies the thread_info struct back (flags may have
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* been modified) and resets the task's stack pointer.
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*
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* Tricky bits -
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*
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* What happens when two signals race each other? UML doesn't block
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* signals with sigprocmask, SA_DEFER, or sa_mask, so a second signal
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* could arrive while a previous one is still setting up the
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* thread_info.
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*
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* There are three cases -
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* The first interrupt on the stack - sets up the thread_info and
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* handles the interrupt
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* A nested interrupt interrupting the copying of the thread_info -
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* can't handle the interrupt, as the stack is in an unknown state
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* A nested interrupt not interrupting the copying of the
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* thread_info - doesn't do any setup, just handles the interrupt
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*
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* The first job is to figure out whether we interrupted stack setup.
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* This is done by xchging the signal mask with thread_info->pending.
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* If the value that comes back is zero, then there is no setup in
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* progress, and the interrupt can be handled. If the value is
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* non-zero, then there is stack setup in progress. In order to have
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* the interrupt handled, we leave our signal in the mask, and it will
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* be handled by the upper handler after it has set up the stack.
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*
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* Next is to figure out whether we are the outer handler or a nested
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* one. As part of setting up the stack, thread_info->real_thread is
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* set to non-NULL (and is reset to NULL on exit). This is the
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* nesting indicator. If it is non-NULL, then the stack is already
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* set up and the handler can run.
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*/
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static unsigned long pending_mask;
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unsigned long to_irq_stack(unsigned long *mask_out)
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{
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struct thread_info *ti;
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unsigned long mask, old;
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int nested;
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mask = xchg(&pending_mask, *mask_out);
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if (mask != 0) {
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/*
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* If any interrupts come in at this point, we want to
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* make sure that their bits aren't lost by our
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* putting our bit in. So, this loop accumulates bits
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* until xchg returns the same value that we put in.
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* When that happens, there were no new interrupts,
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* and pending_mask contains a bit for each interrupt
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* that came in.
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*/
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old = *mask_out;
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do {
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old |= mask;
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mask = xchg(&pending_mask, old);
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} while (mask != old);
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return 1;
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}
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ti = current_thread_info();
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nested = (ti->real_thread != NULL);
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if (!nested) {
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struct task_struct *task;
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struct thread_info *tti;
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task = cpu_tasks[ti->cpu].task;
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tti = task_thread_info(task);
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*ti = *tti;
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ti->real_thread = tti;
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task->stack = ti;
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}
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mask = xchg(&pending_mask, 0);
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*mask_out |= mask | nested;
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return 0;
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}
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unsigned long from_irq_stack(int nested)
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{
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struct thread_info *ti, *to;
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unsigned long mask;
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ti = current_thread_info();
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pending_mask = 1;
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to = ti->real_thread;
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current->stack = to;
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ti->real_thread = NULL;
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*to = *ti;
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mask = xchg(&pending_mask, 0);
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return mask & ~1;
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}
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