diff options
Diffstat (limited to 'arch/um/kernel/irq.c')
| -rw-r--r-- | arch/um/kernel/irq.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index bbf94bf2921e..c39ea3abeda4 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -31,6 +31,8 @@ #include "irq_user.h" #include "irq_kern.h" #include "os.h" +#include "sigio.h" +#include "misc_constants.h" /* * Generic, controller-independent functions: @@ -77,6 +79,298 @@ skip: return 0; } +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) +{ + 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 void maybe_sigio_broken(int fd, int type) +{ + if(os_isatty(fd)){ + if((type == IRQ_WRITE) && !pty_output_sigio){ + write_sigio_workaround(); + add_sigio_fd(fd, 0); + } + else if((type == IRQ_READ) && !pty_close_sigio){ + write_sigio_workaround(); + add_sigio_fd(fd, 1); + } + } +} + + +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; + + pid = os_getpid(); + err = os_set_fd_async(fd, pid); + if(err < 0) + goto out; + + new_fd = um_kmalloc(sizeof(*new_fd)); + err = -ENOMEM; + 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, + .pid = pid, + .events = events, + .current_events = 0 } ); + + /* Critical section - locked by a spinlock because this stuff can + * be changed from interrupt handlers. The stuff above is done + * outside the lock because it allocates memory. + */ + + /* Actually, it only looks like it can be called from interrupt + * context. The culprit is reactivate_fd, which calls + * maybe_sigio_broken, which calls write_sigio_workaround, + * which calls activate_fd. However, write_sigio_workaround should + * only be called once, at boot time. That would make it clear that + * this is called only from process context, and can be locked with + * a semaphore. + */ + flags = irq_lock(); + 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); + 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. + */ + irq_unlock(flags); + if (tmp_pfd != NULL) { + kfree(tmp_pfd); + tmp_pfd = NULL; + } + + tmp_pfd = um_kmalloc(n); + if (tmp_pfd == NULL) + goto out_kfree; + + flags = irq_lock(); + } + /*-------------*/ + + *last_irq_ptr = new_fd; + last_irq_ptr = &new_fd->next; + + irq_unlock(flags); + + /* This calls activate_fd, so it has to be outside the critical + * section. + */ + maybe_sigio_broken(fd, type); + + return(0); + + out_unlock: + irq_unlock(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; + + flags = irq_lock(); + os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr); + irq_unlock(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)); +} + +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); +} + +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("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, + 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; + + flags = irq_lock(); + irq = find_irq_by_fd(fd, irqnum, &i); + if(irq == NULL){ + irq_unlock(flags); + return; + } + os_set_pollfd(i, irq->fd); + irq_unlock(flags); + + /* This calls activate_fd, so it has to be outside the critical + * section. + */ + maybe_sigio_broken(fd, irq->type); +} + +void deactivate_fd(int fd, int irqnum) +{ + struct irq_fd *irq; + unsigned long flags; + int i; + + flags = irq_lock(); + irq = find_irq_by_fd(fd, irqnum, &i); + if(irq == NULL) + goto out; + os_set_pollfd(i, -1); + out: + irq_unlock(flags); +} + +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); +} + +void forward_interrupts(int pid) +{ + struct irq_fd *irq; + unsigned long flags; + int err; + + flags = irq_lock(); + 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; + } + irq_unlock(flags); +} + /* * do_IRQ handles all normal device IRQ's (the special * SMP cross-CPU interrupts have their own specific |