| /* |
| * 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/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" |
| |
| /* |
| * 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. |
| */ |
| 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, struct uml_pt_regs *regs) |
| { |
| struct irq_fd *irq_fd; |
| int n; |
| |
| if (smp_sigio_handler()) |
| return; |
| |
| while (1) { |
| n = os_waiting_for_events(active_fds); |
| if (n <= 0) { |
| if (n == -EINTR) |
| continue; |
| else break; |
| } |
| |
| 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); |
| } |
| } |
| } |
| |
| free_irqs(); |
| } |
| |
| static DEFINE_SPINLOCK(irq_lock); |
| |
| 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 events, err, n; |
| |
| err = os_set_fd_async(fd); |
| if (err < 0) |
| goto out; |
| |
| 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; |
| *new_fd = ((struct irq_fd) { .next = NULL, |
| .id = dev_id, |
| .fd = fd, |
| .type = type, |
| .irq = irq, |
| .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(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; |
| } |
| } |
| |
| if (type == IRQ_WRITE) |
| fd = -1; |
| |
| tmp_pfd = NULL; |
| n = 0; |
| |
| while (1) { |
| n = os_create_pollfd(fd, events, tmp_pfd, n); |
| if (n == 0) |
| break; |
| |
| /* |
| * 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. |
| * |
| * Here we have to drop the lock in order to call |
| * kmalloc, which might sleep. |
| * If something else came in and changed the pollfds array |
| * so we will not be able to put new pollfd struct to pollfds |
| * then we free the buffer tmp_fds and try again. |
| */ |
| spin_unlock_irqrestore(&irq_lock, flags); |
| kfree(tmp_pfd); |
| |
| tmp_pfd = kmalloc(n, GFP_KERNEL); |
| if (tmp_pfd == NULL) |
| goto out_kfree; |
| |
| spin_lock_irqsave(&irq_lock, flags); |
| } |
| |
| *last_irq_ptr = new_fd; |
| last_irq_ptr = &new_fd->next; |
| |
| spin_unlock_irqrestore(&irq_lock, flags); |
| |
| /* |
| * This calls activate_fd, so it has to be outside the critical |
| * section. |
| */ |
| maybe_sigio_broken(fd, (type == IRQ_READ)); |
| |
| return 0; |
| |
| out_unlock: |
| spin_unlock_irqrestore(&irq_lock, flags); |
| out_kfree: |
| kfree(new_fd); |
| out: |
| return err; |
| } |
| |
| static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&irq_lock, flags); |
| os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr); |
| spin_unlock_irqrestore(&irq_lock, flags); |
| } |
| |
| struct irq_and_dev { |
| int irq; |
| void *dev; |
| }; |
| |
| static int same_irq_and_dev(struct irq_fd *irq, void *d) |
| { |
| struct irq_and_dev *data = d; |
| |
| return ((irq->irq == data->irq) && (irq->id == data->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 }); |
| |
| free_irq_by_cb(same_irq_and_dev, &data); |
| } |
| |
| static int same_fd(struct irq_fd *irq, void *fd) |
| { |
| return (irq->fd == *((int *)fd)); |
| } |
| |
| 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; |
| int i = 0; |
| int fdi; |
| |
| for (irq = active_fds; irq != NULL; irq = irq->next) { |
| if ((irq->fd == fd) && (irq->irq == irqnum)) |
| break; |
| i++; |
| } |
| if (irq == NULL) { |
| 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(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; |
| } |
| *index_out = i; |
| out: |
| return irq; |
| } |
| |
| void reactivate_fd(int fd, int irqnum) |
| { |
| struct irq_fd *irq; |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&irq_lock, flags); |
| irq = find_irq_by_fd(fd, irqnum, &i); |
| if (irq == NULL) { |
| spin_unlock_irqrestore(&irq_lock, flags); |
| return; |
| } |
| os_set_pollfd(i, irq->fd); |
| spin_unlock_irqrestore(&irq_lock, flags); |
| |
| add_sigio_fd(fd); |
| } |
| |
| void deactivate_fd(int fd, int irqnum) |
| { |
| struct irq_fd *irq; |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&irq_lock, flags); |
| irq = find_irq_by_fd(fd, irqnum, &i); |
| if (irq == NULL) { |
| spin_unlock_irqrestore(&irq_lock, flags); |
| return; |
| } |
| |
| os_set_pollfd(i, -1); |
| spin_unlock_irqrestore(&irq_lock, flags); |
| |
| 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; |
| int err; |
| |
| for (irq = active_fds; irq != NULL; irq = irq->next) { |
| err = os_clear_fd_async(irq->fd); |
| if (err) |
| return err; |
| } |
| /* If there is a signal already queued, after unblocking ignore it */ |
| os_set_ioignore(); |
| |
| return 0; |
| } |
| |
| /* |
| * do_IRQ handles all normal device IRQs (the special |
| * SMP cross-CPU interrupts have their own specific |
| * handlers). |
| */ |
| 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(); |
| generic_handle_irq(irq); |
| irq_exit(); |
| set_irq_regs(old_regs); |
| return 1; |
| } |
| |
| int um_request_irq(unsigned int irq, int fd, int type, |
| irq_handler_t handler, |
| unsigned long irqflags, const char * devname, |
| void *dev_id) |
| { |
| int err; |
| |
| if (fd != -1) { |
| err = activate_fd(irq, fd, type, dev_id); |
| if (err) |
| return err; |
| } |
| |
| return request_irq(irq, handler, irqflags, devname, dev_id); |
| } |
| |
| EXPORT_SYMBOL(um_request_irq); |
| EXPORT_SYMBOL(reactivate_fd); |
| |
| /* |
| * 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 irq_chip normal_irq_type = { |
| .name = "SIGIO", |
| .release = free_irq_by_irq_and_dev, |
| .irq_disable = dummy, |
| .irq_enable = dummy, |
| .irq_ack = dummy, |
| }; |
| |
| static struct irq_chip SIGVTALRM_irq_type = { |
| .name = "SIGVTALRM", |
| .release = free_irq_by_irq_and_dev, |
| .irq_disable = dummy, |
| .irq_enable = dummy, |
| .irq_ack = dummy, |
| }; |
| |
| void __init init_IRQ(void) |
| { |
| int 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); |
| } |
| |
| /* |
| * 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. |
| */ |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| mask = xchg(&pending_mask, 0); |
| *mask_out |= mask | nested; |
| return 0; |
| } |
| |
| 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; |
| } |
| |