diff options
Diffstat (limited to 'arch/um/kernel/irq.c')
| -rw-r--r-- | arch/um/kernel/irq.c | 379 |
1 files changed, 198 insertions, 181 deletions
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index 5c1e611f628..1d8505b1e29 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -1,90 +1,36 @@ -/* - * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) +/* + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) * Licensed under the GPL * Derived (i.e. mostly copied) from arch/i386/kernel/irq.c: * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar */ -#include "linux/kernel.h" -#include "linux/module.h" -#include "linux/smp.h" -#include "linux/kernel_stat.h" -#include "linux/interrupt.h" -#include "linux/random.h" -#include "linux/slab.h" -#include "linux/file.h" -#include "linux/proc_fs.h" -#include "linux/init.h" -#include "linux/seq_file.h" -#include "linux/profile.h" -#include "linux/hardirq.h" -#include "asm/irq.h" -#include "asm/hw_irq.h" -#include "asm/atomic.h" -#include "asm/signal.h" -#include "asm/system.h" -#include "asm/errno.h" -#include "asm/uaccess.h" -#include "user_util.h" -#include "kern_util.h" -#include "irq_user.h" -#include "irq_kern.h" -#include "os.h" -#include "sigio.h" -#include "um_malloc.h" -#include "misc_constants.h" +#include <linux/cpumask.h> +#include <linux/hardirq.h> +#include <linux/interrupt.h> +#include <linux/kernel_stat.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <as-layout.h> +#include <kern_util.h> +#include <os.h> /* - * Generic, controller-independent functions: + * This list is accessed under irq_lock, except in sigio_handler, + * where it is safe from being modified. IRQ handlers won't change it - + * if an IRQ source has vanished, it will be freed by free_irqs just + * before returning from sigio_handler. That will process a separate + * list of irqs to free, with its own locking, coming back here to + * remove list elements, taking the irq_lock to do so. */ - -int show_interrupts(struct seq_file *p, void *v) -{ - int i = *(loff_t *) v, j; - struct irqaction * action; - unsigned long flags; - - if (i == 0) { - seq_printf(p, " "); - for_each_online_cpu(j) - seq_printf(p, "CPU%d ",j); - seq_putc(p, '\n'); - } - - if (i < NR_IRQS) { - spin_lock_irqsave(&irq_desc[i].lock, flags); - action = irq_desc[i].action; - if (!action) - goto skip; - seq_printf(p, "%3d: ",i); -#ifndef CONFIG_SMP - seq_printf(p, "%10u ", kstat_irqs(i)); -#else - for_each_online_cpu(j) - seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]); -#endif - seq_printf(p, " %14s", irq_desc[i].chip->typename); - seq_printf(p, " %s", action->name); - - for (action=action->next; action; action = action->next) - seq_printf(p, ", %s", action->name); - - seq_putc(p, '\n'); -skip: - spin_unlock_irqrestore(&irq_desc[i].lock, flags); - } else if (i == NR_IRQS) { - seq_putc(p, '\n'); - } - - return 0; -} - -struct irq_fd *active_fds = NULL; +static struct irq_fd *active_fds = NULL; static struct irq_fd **last_irq_ptr = &active_fds; extern void free_irqs(void); -void sigio_handler(int sig, union uml_pt_regs *regs) +void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) { struct irq_fd *irq_fd; int n; @@ -95,11 +41,13 @@ void sigio_handler(int sig, union uml_pt_regs *regs) while (1) { n = os_waiting_for_events(active_fds); if (n <= 0) { - if(n == -EINTR) continue; + if (n == -EINTR) + continue; else break; } - for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) { + for (irq_fd = active_fds; irq_fd != NULL; + irq_fd = irq_fd->next) { if (irq_fd->current_events != 0) { irq_fd->current_events = 0; do_IRQ(irq_fd->irq, regs); @@ -112,42 +60,41 @@ void sigio_handler(int sig, union uml_pt_regs *regs) static DEFINE_SPINLOCK(irq_lock); -int activate_fd(int irq, int fd, int type, void *dev_id) +static int activate_fd(int irq, int fd, int type, void *dev_id) { struct pollfd *tmp_pfd; struct irq_fd *new_fd, *irq_fd; unsigned long flags; - int pid, events, err, n; + int events, err, n; - pid = os_getpid(); - err = os_set_fd_async(fd, pid); + err = os_set_fd_async(fd); if (err < 0) goto out; - new_fd = um_kmalloc(sizeof(*new_fd)); err = -ENOMEM; + new_fd = kmalloc(sizeof(struct irq_fd), GFP_KERNEL); if (new_fd == NULL) goto out; if (type == IRQ_READ) events = UM_POLLIN | UM_POLLPRI; - else - events = UM_POLLOUT; + else events = UM_POLLOUT; *new_fd = ((struct irq_fd) { .next = NULL, .id = dev_id, .fd = fd, .type = type, .irq = irq, - .pid = pid, .events = events, .current_events = 0 } ); + err = -EBUSY; spin_lock_irqsave(&irq_lock, flags); for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) { if ((irq_fd->fd == fd) && (irq_fd->type == type)) { - printk("Registering fd %d twice\n", fd); - printk("Irqs : %d, %d\n", irq_fd->irq, irq); - printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id); + printk(KERN_ERR "Registering fd %d twice\n", fd); + printk(KERN_ERR "Irqs : %d, %d\n", irq_fd->irq, irq); + printk(KERN_ERR "Ids : 0x%p, 0x%p\n", irq_fd->id, + dev_id); goto out_unlock; } } @@ -163,7 +110,8 @@ int activate_fd(int irq, int fd, int type, void *dev_id) if (n == 0) break; - /* n > 0 + /* + * n > 0 * It means we couldn't put new pollfd to current pollfds * and tmp_fds is NULL or too small for new pollfds array. * Needed size is equal to n as minimum. @@ -176,9 +124,8 @@ int activate_fd(int irq, int fd, int type, void *dev_id) */ spin_unlock_irqrestore(&irq_lock, flags); kfree(tmp_pfd); - tmp_pfd = NULL; - tmp_pfd = um_kmalloc(n); + tmp_pfd = kmalloc(n, GFP_KERNEL); if (tmp_pfd == NULL) goto out_kfree; @@ -190,7 +137,8 @@ int activate_fd(int irq, int fd, int type, void *dev_id) spin_unlock_irqrestore(&irq_lock, flags); - /* This calls activate_fd, so it has to be outside the critical + /* + * This calls activate_fd, so it has to be outside the critical * section. */ maybe_sigio_broken(fd, (type == IRQ_READ)); @@ -226,7 +174,7 @@ static int same_irq_and_dev(struct irq_fd *irq, void *d) return ((irq->irq == data->irq) && (irq->id == data->dev)); } -void free_irq_by_irq_and_dev(unsigned int irq, void *dev) +static void free_irq_by_irq_and_dev(unsigned int irq, void *dev) { struct irq_and_dev data = ((struct irq_and_dev) { .irq = irq, .dev = dev }); @@ -244,6 +192,7 @@ void free_irq_by_fd(int fd) free_irq_by_cb(same_fd, &fd); } +/* Must be called with irq_lock held */ static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out) { struct irq_fd *irq; @@ -256,13 +205,14 @@ static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out) i++; } if (irq == NULL) { - printk("find_irq_by_fd doesn't have descriptor %d\n", fd); + printk(KERN_ERR "find_irq_by_fd doesn't have descriptor %d\n", + fd); goto out; } fdi = os_get_pollfd(i); if ((fdi != -1) && (fdi != fd)) { - printk("find_irq_by_fd - mismatch between active_fds and " - "pollfds, fd %d vs %d, need %d\n", irq->fd, + printk(KERN_ERR "find_irq_by_fd - mismatch between active_fds " + "and pollfds, fd %d vs %d, need %d\n", irq->fd, fdi, fd); irq = NULL; goto out; @@ -298,7 +248,7 @@ void deactivate_fd(int fd, int irqnum) spin_lock_irqsave(&irq_lock, flags); irq = find_irq_by_fd(fd, irqnum, &i); - if(irq == NULL){ + if (irq == NULL) { spin_unlock_irqrestore(&irq_lock, flags); return; } @@ -308,7 +258,14 @@ void deactivate_fd(int fd, int irqnum) ignore_sigio_fd(fd); } +EXPORT_SYMBOL(deactivate_fd); +/* + * Called just before shutdown in order to provide a clean exec + * environment in case the system is rebooting. No locking because + * that would cause a pointless shutdown hang if something hadn't + * released the lock. + */ int deactivate_all_fds(void) { struct irq_fd *irq; @@ -325,45 +282,28 @@ int deactivate_all_fds(void) return 0; } -#ifdef CONFIG_MODE_TT -void forward_interrupts(int pid) -{ - struct irq_fd *irq; - unsigned long flags; - int err; - - spin_lock_irqsave(&irq_lock, flags); - for (irq = active_fds; irq != NULL; irq = irq->next) { - err = os_set_owner(irq->fd, pid); - if (err < 0) { - /* XXX Just remove the irq rather than - * print out an infinite stream of these - */ - printk("Failed to forward %d to pid %d, err = %d\n", - irq->fd, pid, -err); - } - - irq->pid = pid; - } - spin_unlock_irqrestore(&irq_lock, flags); -} -#endif - /* - * do_IRQ handles all normal device IRQ's (the special + * do_IRQ handles all normal device IRQs (the special * SMP cross-CPU interrupts have their own specific * handlers). */ -unsigned int do_IRQ(int irq, union uml_pt_regs *regs) +unsigned int do_IRQ(int irq, struct uml_pt_regs *regs) { struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)regs); irq_enter(); - __do_IRQ(irq); + generic_handle_irq(irq); irq_exit(); set_irq_regs(old_regs); return 1; } +void um_free_irq(unsigned int irq, void *dev) +{ + free_irq_by_irq_and_dev(irq, dev); + free_irq(irq, dev); +} +EXPORT_SYMBOL(um_free_irq); + int um_request_irq(unsigned int irq, int fd, int type, irq_handler_t handler, unsigned long irqflags, const char * devname, @@ -371,86 +311,163 @@ int um_request_irq(unsigned int irq, int fd, int type, { int err; - err = request_irq(irq, handler, irqflags, devname, dev_id); - if (err) - return err; - - if (fd != -1) + if (fd != -1) { err = activate_fd(irq, fd, type, dev_id); - return err; + if (err) + return err; + } + + return request_irq(irq, handler, irqflags, devname, dev_id); } + EXPORT_SYMBOL(um_request_irq); EXPORT_SYMBOL(reactivate_fd); -/* hw_interrupt_type must define (startup || enable) && - * (shutdown || disable) && end */ -static void dummy(unsigned int irq) +/* + * irq_chip must define at least enable/disable and ack when + * the edge handler is used. + */ +static void dummy(struct irq_data *d) { } /* This is used for everything else than the timer. */ -static struct hw_interrupt_type normal_irq_type = { - .typename = "SIGIO", - .release = free_irq_by_irq_and_dev, - .disable = dummy, - .enable = dummy, - .ack = dummy, - .end = dummy +static struct irq_chip normal_irq_type = { + .name = "SIGIO", + .irq_disable = dummy, + .irq_enable = dummy, + .irq_ack = dummy, + .irq_mask = dummy, + .irq_unmask = dummy, }; -static struct hw_interrupt_type SIGVTALRM_irq_type = { - .typename = "SIGVTALRM", - .release = free_irq_by_irq_and_dev, - .shutdown = dummy, /* never called */ - .disable = dummy, - .enable = dummy, - .ack = dummy, - .end = dummy +static struct irq_chip SIGVTALRM_irq_type = { + .name = "SIGVTALRM", + .irq_disable = dummy, + .irq_enable = dummy, + .irq_ack = dummy, + .irq_mask = dummy, + .irq_unmask = dummy, }; void __init init_IRQ(void) { int i; - irq_desc[TIMER_IRQ].status = IRQ_DISABLED; - irq_desc[TIMER_IRQ].action = NULL; - irq_desc[TIMER_IRQ].depth = 1; - irq_desc[TIMER_IRQ].chip = &SIGVTALRM_irq_type; - enable_irq(TIMER_IRQ); - for (i = 1; i < NR_IRQS; i++) { - irq_desc[i].status = IRQ_DISABLED; - irq_desc[i].action = NULL; - irq_desc[i].depth = 1; - irq_desc[i].chip = &normal_irq_type; - enable_irq(i); - } + irq_set_chip_and_handler(TIMER_IRQ, &SIGVTALRM_irq_type, handle_edge_irq); + + for (i = 1; i < NR_IRQS; i++) + irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq); } -int init_aio_irq(int irq, char *name, irq_handler_t handler) -{ - int fds[2], err; +/* + * IRQ stack entry and exit: + * + * Unlike i386, UML doesn't receive IRQs on the normal kernel stack + * and switch over to the IRQ stack after some preparation. We use + * sigaltstack to receive signals on a separate stack from the start. + * These two functions make sure the rest of the kernel won't be too + * upset by being on a different stack. The IRQ stack has a + * thread_info structure at the bottom so that current et al continue + * to work. + * + * to_irq_stack copies the current task's thread_info to the IRQ stack + * thread_info and sets the tasks's stack to point to the IRQ stack. + * + * from_irq_stack copies the thread_info struct back (flags may have + * been modified) and resets the task's stack pointer. + * + * Tricky bits - + * + * What happens when two signals race each other? UML doesn't block + * signals with sigprocmask, SA_DEFER, or sa_mask, so a second signal + * could arrive while a previous one is still setting up the + * thread_info. + * + * There are three cases - + * The first interrupt on the stack - sets up the thread_info and + * handles the interrupt + * A nested interrupt interrupting the copying of the thread_info - + * can't handle the interrupt, as the stack is in an unknown state + * A nested interrupt not interrupting the copying of the + * thread_info - doesn't do any setup, just handles the interrupt + * + * The first job is to figure out whether we interrupted stack setup. + * This is done by xchging the signal mask with thread_info->pending. + * If the value that comes back is zero, then there is no setup in + * progress, and the interrupt can be handled. If the value is + * non-zero, then there is stack setup in progress. In order to have + * the interrupt handled, we leave our signal in the mask, and it will + * be handled by the upper handler after it has set up the stack. + * + * Next is to figure out whether we are the outer handler or a nested + * one. As part of setting up the stack, thread_info->real_thread is + * set to non-NULL (and is reset to NULL on exit). This is the + * nesting indicator. If it is non-NULL, then the stack is already + * set up and the handler can run. + */ - err = os_pipe(fds, 1, 1); - if (err) { - printk("init_aio_irq - os_pipe failed, err = %d\n", -err); - goto out; +static unsigned long pending_mask; + +unsigned long to_irq_stack(unsigned long *mask_out) +{ + struct thread_info *ti; + unsigned long mask, old; + int nested; + + mask = xchg(&pending_mask, *mask_out); + if (mask != 0) { + /* + * If any interrupts come in at this point, we want to + * make sure that their bits aren't lost by our + * putting our bit in. So, this loop accumulates bits + * until xchg returns the same value that we put in. + * When that happens, there were no new interrupts, + * and pending_mask contains a bit for each interrupt + * that came in. + */ + old = *mask_out; + do { + old |= mask; + mask = xchg(&pending_mask, old); + } while (mask != old); + return 1; } - err = um_request_irq(irq, fds[0], IRQ_READ, handler, - IRQF_DISABLED | IRQF_SAMPLE_RANDOM, name, - (void *) (long) fds[0]); - if (err) { - printk("init_aio_irq - : um_request_irq failed, err = %d\n", - err); - goto out_close; + ti = current_thread_info(); + nested = (ti->real_thread != NULL); + if (!nested) { + struct task_struct *task; + struct thread_info *tti; + + task = cpu_tasks[ti->cpu].task; + tti = task_thread_info(task); + + *ti = *tti; + ti->real_thread = tti; + task->stack = ti; } - err = fds[1]; - goto out; + mask = xchg(&pending_mask, 0); + *mask_out |= mask | nested; + return 0; +} - out_close: - os_close_file(fds[0]); - os_close_file(fds[1]); - out: - return err; +unsigned long from_irq_stack(int nested) +{ + struct thread_info *ti, *to; + unsigned long mask; + + ti = current_thread_info(); + + pending_mask = 1; + + to = ti->real_thread; + current->stack = to; + ti->real_thread = NULL; + *to = *ti; + + mask = xchg(&pending_mask, 0); + return mask & ~1; } + |