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