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         int freed;
  33 };
  34
  35 static struct irq_fd *active_fds = NULL;
  36 static struct irq_fd **last_irq_ptr = &active_fds;
  37
  38 static struct pollfd *pollfds = NULL;
  39 static int pollfds_num = 0;
  40 static int pollfds_size = 0;
  41
  42 extern int io_count, intr_count;
  43
  44 void sigio_handler(int sig, union uml_pt_regs *regs)
  45 {
  46         struct irq_fd *irq_fd, *next;
  47         int i, n;
  48
  49         if(smp_sigio_handler()) return;
  50         while(1){
  51                 n = poll(pollfds, pollfds_num, 0);
  52                 if(n < 0){
  53                         if(errno == EINTR) continue;
  54                         printk("sigio_handler : poll returned %d, "
  55                                "errno = %d\n", n, errno);
  56                         break;
  57                 }
  58                 if(n == 0) break;
  59
  60                 irq_fd = active_fds;
  61                 for(i = 0; i < pollfds_num; i++){
  62                         if(pollfds[i].revents != 0){
  63                                 irq_fd->current_events = pollfds[i].revents;
  64                                 pollfds[i].fd = -1;
  65                         }
  66                         irq_fd = irq_fd->next;
  67                 }
  68
  69                 for(irq_fd = active_fds; irq_fd != NULL; irq_fd = next){
  70                         next = 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                                 /* This is here because the next irq may be
  76                                  * freed in the handler.  If a console goes
  77                                  * away, both the read and write irqs will be
  78                                  * freed.  After do_IRQ, ->next will point to
  79                                  * a good IRQ.
  80                                  * Irqs can't be freed inside their handlers,
  81                                  * so the next best thing is to have them
  82                                  * marked as needing freeing, so that they
  83                                  * can be freed here.
  84                                  */
  85                                 next = irq_fd->next;
  86                                 if(irq_fd->freed){
  87                                         free_irq(irq_fd->irq, irq_fd->id);
  88                                 }
  89                         }
  90                 }
  91         }
  92 }
  93
  94 int activate_ipi(int fd, int pid)
  95 {
  96         return(os_set_fd_async(fd, pid));
  97 }
  98
  99 static void maybe_sigio_broken(int fd, int type)
 100 {
 101         if(isatty(fd)){
 102                 if((type == IRQ_WRITE) && !pty_output_sigio){
 103                         write_sigio_workaround();
 104                         add_sigio_fd(fd, 0);
 105                 }
 106                 else if((type == IRQ_READ) && !pty_close_sigio){
 107                         write_sigio_workaround();
 108                         add_sigio_fd(fd, 1);
 109                 }
 110         }
 111 }
 112
 113 int activate_fd(int irq, int fd, int type, void *dev_id)
 114 {
 115         struct pollfd *tmp_pfd;
 116         struct irq_fd *new_fd, *irq_fd;
 117         unsigned long flags;
 118         int pid, events, err, n, size;
 119
 120         pid = os_getpid();
 121         err = os_set_fd_async(fd, pid);
 122         if(err < 0)
 123                 goto out;
 124
 125         new_fd = um_kmalloc(sizeof(*new_fd));
 126         err = -ENOMEM;
 127         if(new_fd == NULL)
 128                 goto out;
 129
 130         if(type == IRQ_READ) events = POLLIN | POLLPRI;
 131         else events = POLLOUT;
 132         *new_fd = ((struct irq_fd) { .next              = NULL,
 133                                      .id                = dev_id,
 134                                      .fd                = fd,
 135                                      .type              = type,
 136                                      .irq               = irq,
 137                                      .pid               = pid,
 138                                      .events            = events,
 139                                      .current_events    = 0,
 140                                      .freed             = 0  } );
 141
 142         /* Critical section - locked by a spinlock because this stuff can
 143          * be changed from interrupt handlers.  The stuff above is done
 144          * outside the lock because it allocates memory.
 145          */
 146
 147         /* Actually, it only looks like it can be called from interrupt
 148          * context.  The culprit is reactivate_fd, which calls
 149          * maybe_sigio_broken, which calls write_sigio_workaround,
 150          * which calls activate_fd.  However, write_sigio_workaround should
 151          * only be called once, at boot time.  That would make it clear that
 152          * this is called only from process context, and can be locked with
 153          * a semaphore.
 154          */
 155         flags = irq_lock();
 156         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 157                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
 158                         printk("Registering fd %d twice\n", fd);
 159                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 160                         printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
 161                         goto out_unlock;
 162                 }
 163         }
 164
 165         n = pollfds_num;
 166         if(n == pollfds_size){
 167                 while(1){
 168                         /* Here we have to drop the lock in order to call
 169                          * kmalloc, which might sleep.  If something else
 170                          * came in and changed the pollfds array, we free
 171                          * the buffer and try again.
 172                          */
 173                         irq_unlock(flags);
 174                         size = (pollfds_num + 1) * sizeof(pollfds[0]);
 175                         tmp_pfd = um_kmalloc(size);
 176                         flags = irq_lock();
 177                         if(tmp_pfd == NULL)
 178                                 goto out_unlock;
 179                         if(n == pollfds_size)
 180                                 break;
 181                         kfree(tmp_pfd);
 182                 }
 183                 if(pollfds != NULL){
 184                         memcpy(tmp_pfd, pollfds,
 185                                sizeof(pollfds[0]) * pollfds_size);
 186                         kfree(pollfds);
 187                 }
 188                 pollfds = tmp_pfd;
 189                 pollfds_size++;
 190         }
 191
 192         if(type == IRQ_WRITE)
 193                 fd = -1;
 194
 195         pollfds[pollfds_num] = ((struct pollfd) { .fd   = fd,
 196                                                   .events       = events,
 197                                                   .revents      = 0 });
 198         pollfds_num++;
 199
 200         *last_irq_ptr = new_fd;
 201         last_irq_ptr = &new_fd->next;
 202
 203         irq_unlock(flags);
 204
 205         /* This calls activate_fd, so it has to be outside the critical
 206          * section.
 207          */
 208         maybe_sigio_broken(fd, type);
 209
 210         return(0);
 211
 212  out_unlock:
 213         irq_unlock(flags);
 214         kfree(new_fd);
 215  out:
 216         return(err);
 217 }
 218
 219 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 220 {
 221         struct irq_fd **prev;
 222         unsigned long flags;
 223         int i = 0;
 224
 225         flags = irq_lock();
 226         prev = &active_fds;
 227         while(*prev != NULL){
 228                 if((*test)(*prev, arg)){
 229                         struct irq_fd *old_fd = *prev;
 230                         if((pollfds[i].fd != -1) &&
 231                            (pollfds[i].fd != (*prev)->fd)){
 232                                 printk("free_irq_by_cb - mismatch between "
 233                                        "active_fds and pollfds, fd %d vs %d\n",
 234                                        (*prev)->fd, pollfds[i].fd);
 235                                 goto out;
 236                         }
 237
 238                         pollfds_num--;
 239
 240                         /* This moves the *whole* array after pollfds[i] (though
 241                          * it doesn't spot as such)! */
 242
 243                         memmove(&pollfds[i], &pollfds[i + 1],
 244                                (pollfds_num - i) * sizeof(pollfds[0]));
 245
 246                         if(last_irq_ptr == &old_fd->next)
 247                                 last_irq_ptr = prev;
 248                         *prev = (*prev)->next;
 249                         if(old_fd->type == IRQ_WRITE)
 250                                 ignore_sigio_fd(old_fd->fd);
 251                         kfree(old_fd);
 252                         continue;
 253                 }
 254                 prev = &(*prev)->next;
 255                 i++;
 256         }
 257  out:
 258         irq_unlock(flags);
 259 }
 260
 261 struct irq_and_dev {
 262         int irq;
 263         void *dev;
 264 };
 265
 266 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 267 {
 268         struct irq_and_dev *data = d;
 269
 270         return((irq->irq == data->irq) && (irq->id == data->dev));
 271 }
 272
 273 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 274 {
 275         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 276                                                           .dev  = dev });
 277
 278         free_irq_by_cb(same_irq_and_dev, &data);
 279 }
 280
 281 static int same_fd(struct irq_fd *irq, void *fd)
 282 {
 283         return(irq->fd == *((int *) fd));
 284 }
 285
 286 void free_irq_by_fd(int fd)
 287 {
 288         free_irq_by_cb(same_fd, &fd);
 289 }
 290
 291 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 292 {
 293         struct irq_fd *irq;
 294         int i = 0;
 295
 296         for(irq=active_fds; irq != NULL; irq = irq->next){
 297                 if((irq->fd == fd) && (irq->irq == irqnum)) break;
 298                 i++;
 299         }
 300         if(irq == NULL){
 301                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 302                 goto out;
 303         }
 304         if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
 305                 printk("find_irq_by_fd - mismatch between active_fds and "
 306                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 307                        pollfds[i].fd, fd);
 308                 irq = NULL;
 309                 goto out;
 310         }
 311         *index_out = i;
 312  out:
 313         return(irq);
 314 }
 315
 316 void free_irq_later(int irq, void *dev_id)
 317 {
 318         struct irq_fd *irq_fd;
 319         unsigned long flags;
 320
 321         flags = irq_lock();
 322         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 323                 if((irq_fd->irq == irq) && (irq_fd->id == dev_id))
 324                         break;
 325         }
 326         if(irq_fd == NULL){
 327                 printk("free_irq_later found no irq, irq = %d, "
 328                        "dev_id = 0x%p\n", irq, dev_id);
 329                 goto out;
 330         }
 331         irq_fd->freed = 1;
 332  out:
 333         irq_unlock(flags);
 334 }
 335
 336 void reactivate_fd(int fd, int irqnum)
 337 {
 338         struct irq_fd *irq;
 339         unsigned long flags;
 340         int i;
 341
 342         flags = irq_lock();
 343         irq = find_irq_by_fd(fd, irqnum, &i);
 344         if(irq == NULL){
 345                 irq_unlock(flags);
 346                 return;
 347         }
 348
 349         pollfds[i].fd = irq->fd;
 350
 351         irq_unlock(flags);
 352
 353         /* This calls activate_fd, so it has to be outside the critical
 354          * section.
 355          */
 356         maybe_sigio_broken(fd, irq->type);
 357 }
 358
 359 void deactivate_fd(int fd, int irqnum)
 360 {
 361         struct irq_fd *irq;
 362         unsigned long flags;
 363         int i;
 364
 365         flags = irq_lock();
 366         irq = find_irq_by_fd(fd, irqnum, &i);
 367         if(irq == NULL)
 368                 goto out;
 369         pollfds[i].fd = -1;
 370  out:
 371         irq_unlock(flags);
 372 }
 373
 374 int deactivate_all_fds(void)
 375 {
 376         struct irq_fd *irq;
 377         int err;
 378
 379         for(irq=active_fds;irq != NULL;irq = irq->next){
 380                 err = os_clear_fd_async(irq->fd);
 381                 if(err)
 382                         return(err);
 383         }
 384         /* If there is a signal already queued, after unblocking ignore it */
 385         set_handler(SIGIO, SIG_IGN, 0, -1);
 386
 387         return(0);
 388 }
 389
 390 void forward_ipi(int fd, int pid)
 391 {
 392         int err;
 393
 394         err = os_set_owner(fd, pid);
 395         if(err < 0)
 396                 printk("forward_ipi: set_owner failed, fd = %d, me = %d, "
 397                        "target = %d, err = %d\n", fd, os_getpid(), pid, -err);
 398 }
 399
 400 void forward_interrupts(int pid)
 401 {
 402         struct irq_fd *irq;
 403         unsigned long flags;
 404         int err;
 405
 406         flags = irq_lock();
 407         for(irq=active_fds;irq != NULL;irq = irq->next){
 408                 err = os_set_owner(irq->fd, pid);
 409                 if(err < 0){
 410                         /* XXX Just remove the irq rather than
 411                          * print out an infinite stream of these
 412                          */
 413                         printk("Failed to forward %d to pid %d, err = %d\n",
 414                                irq->fd, pid, -err);
 415                 }
 416
 417                 irq->pid = pid;
 418         }
 419         irq_unlock(flags);
 420 }
 421
 422 void init_irq_signals(int on_sigstack)
 423 {
 424         __sighandler_t h;
 425         int flags;
 426
 427         flags = on_sigstack ? SA_ONSTACK : 0;
 428         if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
 429         else h = boot_timer_handler;
 430
 431         set_handler(SIGVTALRM, h, flags | SA_RESTART,
 432                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 433         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
 434                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 435         signal(SIGWINCH, SIG_IGN);
 436 }
 437
 438 /*
 439  * Overrides for Emacs so that we follow Linus's tabbing style.
 440  * Emacs will notice this stuff at the end of the file and automatically
 441  * adjust the settings for this buffer only.  This must remain at the end
 442  * of the file.
 443  * ---------------------------------------------------------------------------
 444  * Local variables:
 445  * c-file-style: "linux"
 446  * End:
 447  */