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                                         free_irq_by_irq_and_dev(irq_fd->irq,
  89                                                                 irq_fd->id);
  90                                 }
  91                         }
  92                 }
  93         }
  94 }
  95
  96 int activate_ipi(int fd, int pid)
  97 {
  98         return(os_set_fd_async(fd, pid));
  99 }
 100
 101 static void maybe_sigio_broken(int fd, int type)
 102 {
 103         if(isatty(fd)){
 104                 if((type == IRQ_WRITE) && !pty_output_sigio){
 105                         write_sigio_workaround();
 106                         add_sigio_fd(fd, 0);
 107                 }
 108                 else if((type == IRQ_READ) && !pty_close_sigio){
 109                         write_sigio_workaround();
 110                         add_sigio_fd(fd, 1);
 111                 }
 112         }
 113 }
 114
 115 int activate_fd(int irq, int fd, int type, void *dev_id)
 116 {
 117         struct pollfd *tmp_pfd;
 118         struct irq_fd *new_fd, *irq_fd;
 119         unsigned long flags;
 120         int pid, events, err, n, size;
 121
 122         pid = os_getpid();
 123         err = os_set_fd_async(fd, pid);
 124         if(err < 0)
 125                 goto out;
 126
 127         new_fd = um_kmalloc(sizeof(*new_fd));
 128         err = -ENOMEM;
 129         if(new_fd == NULL)
 130                 goto out;
 131
 132         if(type == IRQ_READ) events = POLLIN | POLLPRI;
 133         else events = POLLOUT;
 134         *new_fd = ((struct irq_fd) { .next              = NULL,
 135                                      .id                = dev_id,
 136                                      .fd                = fd,
 137                                      .type              = type,
 138                                      .irq               = irq,
 139                                      .pid               = pid,
 140                                      .events            = events,
 141                                      .current_events    = 0,
 142                                      .freed             = 0  } );
 143
 144         /* Critical section - locked by a spinlock because this stuff can
 145          * be changed from interrupt handlers.  The stuff above is done
 146          * outside the lock because it allocates memory.
 147          */
 148
 149         /* Actually, it only looks like it can be called from interrupt
 150          * context.  The culprit is reactivate_fd, which calls
 151          * maybe_sigio_broken, which calls write_sigio_workaround,
 152          * which calls activate_fd.  However, write_sigio_workaround should
 153          * only be called once, at boot time.  That would make it clear that
 154          * this is called only from process context, and can be locked with
 155          * a semaphore.
 156          */
 157         flags = irq_lock();
 158         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 159                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
 160                         printk("Registering fd %d twice\n", fd);
 161                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 162                         printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
 163                         goto out_unlock;
 164                 }
 165         }
 166
 167         n = pollfds_num;
 168         if(n == pollfds_size){
 169                 while(1){
 170                         /* Here we have to drop the lock in order to call
 171                          * kmalloc, which might sleep.  If something else
 172                          * came in and changed the pollfds array, we free
 173                          * the buffer and try again.
 174                          */
 175                         irq_unlock(flags);
 176                         size = (pollfds_num + 1) * sizeof(pollfds[0]);
 177                         tmp_pfd = um_kmalloc(size);
 178                         flags = irq_lock();
 179                         if(tmp_pfd == NULL)
 180                                 goto out_unlock;
 181                         if(n == pollfds_size)
 182                                 break;
 183                         kfree(tmp_pfd);
 184                 }
 185                 if(pollfds != NULL){
 186                         memcpy(tmp_pfd, pollfds,
 187                                sizeof(pollfds[0]) * pollfds_size);
 188                         kfree(pollfds);
 189                 }
 190                 pollfds = tmp_pfd;
 191                 pollfds_size++;
 192         }
 193
 194         if(type == IRQ_WRITE)
 195                 fd = -1;
 196
 197         pollfds[pollfds_num] = ((struct pollfd) { .fd   = fd,
 198                                                   .events       = events,
 199                                                   .revents      = 0 });
 200         pollfds_num++;
 201
 202         *last_irq_ptr = new_fd;
 203         last_irq_ptr = &new_fd->next;
 204
 205         irq_unlock(flags);
 206
 207         /* This calls activate_fd, so it has to be outside the critical
 208          * section.
 209          */
 210         maybe_sigio_broken(fd, type);
 211
 212         return(0);
 213
 214  out_unlock:
 215         irq_unlock(flags);
 216         kfree(new_fd);
 217  out:
 218         return(err);
 219 }
 220
 221 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 222 {
 223         struct irq_fd **prev;
 224         unsigned long flags;
 225         int i = 0;
 226
 227         flags = irq_lock();
 228         prev = &active_fds;
 229         while(*prev != NULL){
 230                 if((*test)(*prev, arg)){
 231                         struct irq_fd *old_fd = *prev;
 232                         if((pollfds[i].fd != -1) &&
 233                            (pollfds[i].fd != (*prev)->fd)){
 234                                 printk("free_irq_by_cb - mismatch between "
 235                                        "active_fds and pollfds, fd %d vs %d\n",
 236                                        (*prev)->fd, pollfds[i].fd);
 237                                 goto out;
 238                         }
 239
 240                         pollfds_num--;
 241
 242                         /* This moves the *whole* array after pollfds[i] (though
 243                          * it doesn't spot as such)! */
 244
 245                         memmove(&pollfds[i], &pollfds[i + 1],
 246                                (pollfds_num - i) * sizeof(pollfds[0]));
 247
 248                         if(last_irq_ptr == &old_fd->next)
 249                                 last_irq_ptr = prev;
 250                         *prev = (*prev)->next;
 251                         if(old_fd->type == IRQ_WRITE)
 252                                 ignore_sigio_fd(old_fd->fd);
 253                         kfree(old_fd);
 254                         continue;
 255                 }
 256                 prev = &(*prev)->next;
 257                 i++;
 258         }
 259  out:
 260         irq_unlock(flags);
 261 }
 262
 263 struct irq_and_dev {
 264         int irq;
 265         void *dev;
 266 };
 267
 268 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 269 {
 270         struct irq_and_dev *data = d;
 271
 272         return((irq->irq == data->irq) && (irq->id == data->dev));
 273 }
 274
 275 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 276 {
 277         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 278                                                           .dev  = dev });
 279
 280         free_irq_by_cb(same_irq_and_dev, &data);
 281 }
 282
 283 static int same_fd(struct irq_fd *irq, void *fd)
 284 {
 285         return(irq->fd == *((int *) fd));
 286 }
 287
 288 void free_irq_by_fd(int fd)
 289 {
 290         free_irq_by_cb(same_fd, &fd);
 291 }
 292
 293 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 294 {
 295         struct irq_fd *irq;
 296         int i = 0;
 297
 298         for(irq=active_fds; irq != NULL; irq = irq->next){
 299                 if((irq->fd == fd) && (irq->irq == irqnum)) break;
 300                 i++;
 301         }
 302         if(irq == NULL){
 303                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 304                 goto out;
 305         }
 306         if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
 307                 printk("find_irq_by_fd - mismatch between active_fds and "
 308                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 309                        pollfds[i].fd, fd);
 310                 irq = NULL;
 311                 goto out;
 312         }
 313         *index_out = i;
 314  out:
 315         return(irq);
 316 }
 317
 318 void free_irq_later(int irq, void *dev_id)
 319 {
 320         struct irq_fd *irq_fd;
 321         unsigned long flags;
 322
 323         flags = irq_lock();
 324         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 325                 if((irq_fd->irq == irq) && (irq_fd->id == dev_id))
 326                         break;
 327         }
 328         if(irq_fd == NULL){
 329                 printk("free_irq_later found no irq, irq = %d, "
 330                        "dev_id = 0x%p\n", irq, dev_id);
 331                 goto out;
 332         }
 333         irq_fd->freed = 1;
 334  out:
 335         irq_unlock(flags);
 336 }
 337
 338 void reactivate_fd(int fd, int irqnum)
 339 {
 340         struct irq_fd *irq;
 341         unsigned long flags;
 342         int i;
 343
 344         flags = irq_lock();
 345         irq = find_irq_by_fd(fd, irqnum, &i);
 346         if(irq == NULL){
 347                 irq_unlock(flags);
 348                 return;
 349         }
 350
 351         pollfds[i].fd = irq->fd;
 352
 353         irq_unlock(flags);
 354
 355         /* This calls activate_fd, so it has to be outside the critical
 356          * section.
 357          */
 358         maybe_sigio_broken(fd, irq->type);
 359 }
 360
 361 void deactivate_fd(int fd, int irqnum)
 362 {
 363         struct irq_fd *irq;
 364         unsigned long flags;
 365         int i;
 366
 367         flags = irq_lock();
 368         irq = find_irq_by_fd(fd, irqnum, &i);
 369         if(irq == NULL)
 370                 goto out;
 371         pollfds[i].fd = -1;
 372  out:
 373         irq_unlock(flags);
 374 }
 375
 376 int deactivate_all_fds(void)
 377 {
 378         struct irq_fd *irq;
 379         int err;
 380
 381         for(irq=active_fds;irq != NULL;irq = irq->next){
 382                 err = os_clear_fd_async(irq->fd);
 383                 if(err)
 384                         return(err);
 385         }
 386         /* If there is a signal already queued, after unblocking ignore it */
 387         set_handler(SIGIO, SIG_IGN, 0, -1);
 388
 389         return(0);
 390 }
 391
 392 void forward_ipi(int fd, int pid)
 393 {
 394         int err;
 395
 396         err = os_set_owner(fd, pid);
 397         if(err < 0)
 398                 printk("forward_ipi: set_owner failed, fd = %d, me = %d, "
 399                        "target = %d, err = %d\n", fd, os_getpid(), pid, -err);
 400 }
 401
 402 void forward_interrupts(int pid)
 403 {
 404         struct irq_fd *irq;
 405         unsigned long flags;
 406         int err;
 407
 408         flags = irq_lock();
 409         for(irq=active_fds;irq != NULL;irq = irq->next){
 410                 err = os_set_owner(irq->fd, pid);
 411                 if(err < 0){
 412                         /* XXX Just remove the irq rather than
 413                          * print out an infinite stream of these
 414                          */
 415                         printk("Failed to forward %d to pid %d, err = %d\n",
 416                                irq->fd, pid, -err);
 417                 }
 418
 419                 irq->pid = pid;
 420         }
 421         irq_unlock(flags);
 422 }
 423
 424 void init_irq_signals(int on_sigstack)
 425 {
 426         __sighandler_t h;
 427         int flags;
 428
 429         flags = on_sigstack ? SA_ONSTACK : 0;
 430         if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
 431         else h = boot_timer_handler;
 432
 433         set_handler(SIGVTALRM, h, flags | SA_RESTART,
 434                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 435         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
 436                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 437         signal(SIGWINCH, SIG_IGN);
 438 }
 439
 440 /*
 441  * Overrides for Emacs so that we follow Linus's tabbing style.
 442  * Emacs will notice this stuff at the end of the file and automatically
 443  * adjust the settings for this buffer only.  This must remain at the end
 444  * of the file.
 445  * ---------------------------------------------------------------------------
 446  * Local variables:
 447  * c-file-style: "linux"
 448  * End:
 449  */