arch/um/kernel/irq_user.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <signal.h>
  10 #include <string.h>
  11 #include <sys/poll.h>
  12 #include <sys/types.h>
  13 #include <sys/time.h>
  14 #include "user_util.h"
  15 #include "kern_util.h"
  16 #include "user.h"
  17 #include "process.h"
  18 #include "signal_user.h"
  19 #include "sigio.h"
  20 #include "irq_user.h"
  21 #include "os.h"
  22
  23 struct irq_fd {
  24         struct irq_fd *next;
  25         void *id;
  26         int fd;
  27         int type;
  28         int irq;
  29         int pid;
  30         int events;
  31         int current_events;
  32 };
  33
  34 static struct irq_fd *active_fds = NULL;
  35 static struct irq_fd **last_irq_ptr = &active_fds;
  36
  37 static struct pollfd *pollfds = NULL;
  38 static int pollfds_num = 0;
  39 static int pollfds_size = 0;
  40
  41 extern int io_count, intr_count;
  42
  43 extern void free_irqs(void);
  44
  45 void sigio_handler(int sig, union uml_pt_regs *regs)
  46 {
  47         struct irq_fd *irq_fd;
  48         int i, n;
  49
  50         if(smp_sigio_handler()) return;
  51         while(1){
  52                 n = poll(pollfds, pollfds_num, 0);
  53                 if(n < 0){
  54                         if(errno == EINTR) continue;
  55                         printk("sigio_handler : poll returned %d, "
  56                                "errno = %d\n", n, errno);
  57                         break;
  58                 }
  59                 if(n == 0) break;
  60
  61                 irq_fd = active_fds;
  62                 for(i = 0; i < pollfds_num; i++){
  63                         if(pollfds[i].revents != 0){
  64                                 irq_fd->current_events = pollfds[i].revents;
  65                                 pollfds[i].fd = -1;
  66                         }
  67                         irq_fd = irq_fd->next;
  68                 }
  69
  70                 for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
  71                         if(irq_fd->current_events != 0){
  72                                 irq_fd->current_events = 0;
  73                                 do_IRQ(irq_fd->irq, regs);
  74                         }
  75                 }
  76         }
  77
  78         free_irqs();
  79 }
  80
  81 int activate_ipi(int fd, int pid)
  82 {
  83         return(os_set_fd_async(fd, pid));
  84 }
  85
  86 static void maybe_sigio_broken(int fd, int type)
  87 {
  88         if(isatty(fd)){
  89                 if((type == IRQ_WRITE) && !pty_output_sigio){
  90                         write_sigio_workaround();
  91                         add_sigio_fd(fd, 0);
  92                 }
  93                 else if((type == IRQ_READ) && !pty_close_sigio){
  94                         write_sigio_workaround();
  95                         add_sigio_fd(fd, 1);
  96                 }
  97         }
  98 }
  99
 100 int activate_fd(int irq, int fd, int type, void *dev_id)
 101 {
 102         struct pollfd *tmp_pfd;
 103         struct irq_fd *new_fd, *irq_fd;
 104         unsigned long flags;
 105         int pid, events, err, n, size;
 106
 107         pid = os_getpid();
 108         err = os_set_fd_async(fd, pid);
 109         if(err < 0)
 110                 goto out;
 111
 112         new_fd = um_kmalloc(sizeof(*new_fd));
 113         err = -ENOMEM;
 114         if(new_fd == NULL)
 115                 goto out;
 116
 117         if(type == IRQ_READ) events = POLLIN | POLLPRI;
 118         else events = POLLOUT;
 119         *new_fd = ((struct irq_fd) { .next              = NULL,
 120                                      .id                = dev_id,
 121                                      .fd                = fd,
 122                                      .type              = type,
 123                                      .irq               = irq,
 124                                      .pid               = pid,
 125                                      .events            = events,
 126                                      .current_events    = 0 } );
 127
 128         /* Critical section - locked by a spinlock because this stuff can
 129          * be changed from interrupt handlers.  The stuff above is done
 130          * outside the lock because it allocates memory.
 131          */
 132
 133         /* Actually, it only looks like it can be called from interrupt
 134          * context.  The culprit is reactivate_fd, which calls
 135          * maybe_sigio_broken, which calls write_sigio_workaround,
 136          * which calls activate_fd.  However, write_sigio_workaround should
 137          * only be called once, at boot time.  That would make it clear that
 138          * this is called only from process context, and can be locked with
 139          * a semaphore.
 140          */
 141         flags = irq_lock();
 142         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 143                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
 144                         printk("Registering fd %d twice\n", fd);
 145                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 146                         printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
 147                         goto out_unlock;
 148                 }
 149         }
 150
 151         n = pollfds_num;
 152         if(n == pollfds_size){
 153                 while(1){
 154                         /* Here we have to drop the lock in order to call
 155                          * kmalloc, which might sleep.  If something else
 156                          * came in and changed the pollfds array, we free
 157                          * the buffer and try again.
 158                          */
 159                         irq_unlock(flags);
 160                         size = (pollfds_num + 1) * sizeof(pollfds[0]);
 161                         tmp_pfd = um_kmalloc(size);
 162                         flags = irq_lock();
 163                         if(tmp_pfd == NULL)
 164                                 goto out_unlock;
 165                         if(n == pollfds_size)
 166                                 break;
 167                         kfree(tmp_pfd);
 168                 }
 169                 if(pollfds != NULL){
 170                         memcpy(tmp_pfd, pollfds,
 171                                sizeof(pollfds[0]) * pollfds_size);
 172                         kfree(pollfds);
 173                 }
 174                 pollfds = tmp_pfd;
 175                 pollfds_size++;
 176         }
 177
 178         if(type == IRQ_WRITE)
 179                 fd = -1;
 180
 181         pollfds[pollfds_num] = ((struct pollfd) { .fd   = fd,
 182                                                   .events       = events,
 183                                                   .revents      = 0 });
 184         pollfds_num++;
 185
 186         *last_irq_ptr = new_fd;
 187         last_irq_ptr = &new_fd->next;
 188
 189         irq_unlock(flags);
 190
 191         /* This calls activate_fd, so it has to be outside the critical
 192          * section.
 193          */
 194         maybe_sigio_broken(fd, type);
 195
 196         return(0);
 197
 198  out_unlock:
 199         irq_unlock(flags);
 200         kfree(new_fd);
 201  out:
 202         return(err);
 203 }
 204
 205 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 206 {
 207         struct irq_fd **prev;
 208         unsigned long flags;
 209         int i = 0;
 210
 211         flags = irq_lock();
 212         prev = &active_fds;
 213         while(*prev != NULL){
 214                 if((*test)(*prev, arg)){
 215                         struct irq_fd *old_fd = *prev;
 216                         if((pollfds[i].fd != -1) &&
 217                            (pollfds[i].fd != (*prev)->fd)){
 218                                 printk("free_irq_by_cb - mismatch between "
 219                                        "active_fds and pollfds, fd %d vs %d\n",
 220                                        (*prev)->fd, pollfds[i].fd);
 221                                 goto out;
 222                         }
 223
 224                         pollfds_num--;
 225
 226                         /* This moves the *whole* array after pollfds[i] (though
 227                          * it doesn't spot as such)! */
 228
 229                         memmove(&pollfds[i], &pollfds[i + 1],
 230                                (pollfds_num - i) * sizeof(pollfds[0]));
 231
 232                         if(last_irq_ptr == &old_fd->next)
 233                                 last_irq_ptr = prev;
 234                         *prev = (*prev)->next;
 235                         if(old_fd->type == IRQ_WRITE)
 236                                 ignore_sigio_fd(old_fd->fd);
 237                         kfree(old_fd);
 238                         continue;
 239                 }
 240                 prev = &(*prev)->next;
 241                 i++;
 242         }
 243  out:
 244         irq_unlock(flags);
 245 }
 246
 247 struct irq_and_dev {
 248         int irq;
 249         void *dev;
 250 };
 251
 252 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 253 {
 254         struct irq_and_dev *data = d;
 255
 256         return((irq->irq == data->irq) && (irq->id == data->dev));
 257 }
 258
 259 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 260 {
 261         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 262                                                           .dev  = dev });
 263
 264         free_irq_by_cb(same_irq_and_dev, &data);
 265 }
 266
 267 static int same_fd(struct irq_fd *irq, void *fd)
 268 {
 269         return(irq->fd == *((int *) fd));
 270 }
 271
 272 void free_irq_by_fd(int fd)
 273 {
 274         free_irq_by_cb(same_fd, &fd);
 275 }
 276
 277 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 278 {
 279         struct irq_fd *irq;
 280         int i = 0;
 281
 282         for(irq=active_fds; irq != NULL; irq = irq->next){
 283                 if((irq->fd == fd) && (irq->irq == irqnum)) break;
 284                 i++;
 285         }
 286         if(irq == NULL){
 287                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 288                 goto out;
 289         }
 290         if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
 291                 printk("find_irq_by_fd - mismatch between active_fds and "
 292                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 293                        pollfds[i].fd, fd);
 294                 irq = NULL;
 295                 goto out;
 296         }
 297         *index_out = i;
 298  out:
 299         return(irq);
 300 }
 301
 302 void reactivate_fd(int fd, int irqnum)
 303 {
 304         struct irq_fd *irq;
 305         unsigned long flags;
 306         int i;
 307
 308         flags = irq_lock();
 309         irq = find_irq_by_fd(fd, irqnum, &i);
 310         if(irq == NULL){
 311                 irq_unlock(flags);
 312                 return;
 313         }
 314
 315         pollfds[i].fd = irq->fd;
 316
 317         irq_unlock(flags);
 318
 319         /* This calls activate_fd, so it has to be outside the critical
 320          * section.
 321          */
 322         maybe_sigio_broken(fd, irq->type);
 323 }
 324
 325 void deactivate_fd(int fd, int irqnum)
 326 {
 327         struct irq_fd *irq;
 328         unsigned long flags;
 329         int i;
 330
 331         flags = irq_lock();
 332         irq = find_irq_by_fd(fd, irqnum, &i);
 333         if(irq == NULL)
 334                 goto out;
 335         pollfds[i].fd = -1;
 336  out:
 337         irq_unlock(flags);
 338 }
 339
 340 int deactivate_all_fds(void)
 341 {
 342         struct irq_fd *irq;
 343         int err;
 344
 345         for(irq=active_fds;irq != NULL;irq = irq->next){
 346                 err = os_clear_fd_async(irq->fd);
 347                 if(err)
 348                         return(err);
 349         }
 350         /* If there is a signal already queued, after unblocking ignore it */
 351         set_handler(SIGIO, SIG_IGN, 0, -1);
 352
 353         return(0);
 354 }
 355
 356 void forward_ipi(int fd, int pid)
 357 {
 358         int err;
 359
 360         err = os_set_owner(fd, pid);
 361         if(err < 0)
 362                 printk("forward_ipi: set_owner failed, fd = %d, me = %d, "
 363                        "target = %d, err = %d\n", fd, os_getpid(), pid, -err);
 364 }
 365
 366 void forward_interrupts(int pid)
 367 {
 368         struct irq_fd *irq;
 369         unsigned long flags;
 370         int err;
 371
 372         flags = irq_lock();
 373         for(irq=active_fds;irq != NULL;irq = irq->next){
 374                 err = os_set_owner(irq->fd, pid);
 375                 if(err < 0){
 376                         /* XXX Just remove the irq rather than
 377                          * print out an infinite stream of these
 378                          */
 379                         printk("Failed to forward %d to pid %d, err = %d\n",
 380                                irq->fd, pid, -err);
 381                 }
 382
 383                 irq->pid = pid;
 384         }
 385         irq_unlock(flags);
 386 }
 387
 388 void init_irq_signals(int on_sigstack)
 389 {
 390         __sighandler_t h;
 391         int flags;
 392
 393         flags = on_sigstack ? SA_ONSTACK : 0;
 394         if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
 395         else h = boot_timer_handler;
 396
 397         set_handler(SIGVTALRM, h, flags | SA_RESTART,
 398                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 399         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
 400                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 401         signal(SIGWINCH, SIG_IGN);
 402 }
 403
 404 /*
 405  * Overrides for Emacs so that we follow Linus's tabbing style.
 406  * Emacs will notice this stuff at the end of the file and automatically
 407  * adjust the settings for this buffer only.  This must remain at the end
 408  * of the file.
 409  * ---------------------------------------------------------------------------
 410  * Local variables:
 411  * c-file-style: "linux"
 412  * End:
 413  */