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 <fcntl.h>
  10 #include <signal.h>
  11 #include <string.h>
  12 #include <sys/poll.h>
  13 #include <sys/types.h>
  14 #include <sys/time.h>
  15 #include "user_util.h"
  16 #include "kern_util.h"
  17 #include "user.h"
  18 #include "process.h"
  19 #include "signal_user.h"
  20 #include "sigio.h"
  21 #include "irq_user.h"
  22 #include "os.h"
  23
  24 struct irq_fd {
  25         struct irq_fd *next;
  26         void *id;
  27         int fd;
  28         int type;
  29         int irq;
  30         int pid;
  31         int events;
  32         int current_events;
  33         int freed;
  34 };
  35
  36 static struct irq_fd *active_fds = NULL;
  37 static struct irq_fd **last_irq_ptr = &active_fds;
  38
  39 static struct pollfd *pollfds = NULL;
  40 static int pollfds_num = 0;
  41 static int pollfds_size = 0;
  42
  43 extern int io_count, intr_count;
  44
  45 void sigio_handler(int sig, union uml_pt_regs *regs)
  46 {
  47         struct irq_fd *irq_fd, *next;
  48         int i, n;
  49
  50         if(smp_sigio_handler()) return;
  51         while(1){
  52                 if((n = poll(pollfds, pollfds_num, 0)) < 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 int activate_ipi(int fd, int pid)
  94 {
  95         return(os_set_fd_async(fd, pid));
  96 }
  97
  98 static void maybe_sigio_broken(int fd, int type)
  99 {
 100         if(isatty(fd)){
 101                 if((type == IRQ_WRITE) && !pty_output_sigio){
 102                         write_sigio_workaround();
 103                         add_sigio_fd(fd, 0);
 104                 }
 105                 else if((type == IRQ_READ) && !pty_close_sigio){
 106                         write_sigio_workaround();
 107                         add_sigio_fd(fd, 1);
 108                 }
 109         }
 110 }
 111
 112 int activate_fd(int irq, int fd, int type, void *dev_id)
 113 {
 114         struct pollfd *tmp_pfd;
 115         struct irq_fd *new_fd, *irq_fd;
 116         unsigned long flags;
 117         int pid, events, err, n, size;
 118
 119         pid = os_getpid();
 120         err = os_set_fd_async(fd, pid);
 121         if(err < 0)
 122                 goto out;
 123
 124         new_fd = um_kmalloc(sizeof(*new_fd));
 125         err = -ENOMEM;
 126         if(new_fd == NULL)
 127                 goto out;
 128
 129         if(type == IRQ_READ) events = POLLIN | POLLPRI;
 130         else events = POLLOUT;
 131         *new_fd = ((struct irq_fd) { .next              = NULL,
 132                                      .id                = dev_id,
 133                                      .fd                = fd,
 134                                      .type              = type,
 135                                      .irq               = irq,
 136                                      .pid               = pid,
 137                                      .events            = events,
 138                                      .current_events    = 0,
 139                                      .freed             = 0  } );
 140
 141         /* Critical section - locked by a spinlock because this stuff can
 142          * be changed from interrupt handlers.  The stuff above is done
 143          * outside the lock because it allocates memory.
 144          */
 145
 146         /* Actually, it only looks like it can be called from interrupt
 147          * context.  The culprit is reactivate_fd, which calls
 148          * maybe_sigio_broken, which calls write_sigio_workaround,
 149          * which calls activate_fd.  However, write_sigio_workaround should
 150          * only be called once, at boot time.  That would make it clear that
 151          * this is called only from process context, and can be locked with
 152          * a semaphore.
 153          */
 154         flags = irq_lock();
 155         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 156                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
 157                         printk("Registering fd %d twice\n", fd);
 158                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 159                         printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
 160                         goto out_unlock;
 161                 }
 162         }
 163
 164         n = pollfds_num;
 165         if(n == pollfds_size){
 166                 while(1){
 167                         /* Here we have to drop the lock in order to call
 168                          * kmalloc, which might sleep.  If something else
 169                          * came in and changed the pollfds array, we free
 170                          * the buffer and try again.
 171                          */
 172                         irq_unlock(flags);
 173                         size = (pollfds_num + 1) * sizeof(pollfds[0]);
 174                         tmp_pfd = um_kmalloc(size);
 175                         flags = irq_lock();
 176                         if(tmp_pfd == NULL)
 177                                 goto out_unlock;
 178                         if(n == pollfds_size)
 179                                 break;
 180                         kfree(tmp_pfd);
 181                 }
 182                 if(pollfds != NULL){
 183                         memcpy(tmp_pfd, pollfds,
 184                                sizeof(pollfds[0]) * pollfds_size);
 185                         kfree(pollfds);
 186                 }
 187                 pollfds = tmp_pfd;
 188                 pollfds_size++;
 189         }
 190
 191         if(type == IRQ_WRITE)
 192                 fd = -1;
 193
 194         pollfds[pollfds_num] = ((struct pollfd) { .fd   = fd,
 195                                                   .events       = events,
 196                                                   .revents      = 0 });
 197         pollfds_num++;
 198
 199         *last_irq_ptr = new_fd;
 200         last_irq_ptr = &new_fd->next;
 201
 202         irq_unlock(flags);
 203
 204         /* This calls activate_fd, so it has to be outside the critical
 205          * section.
 206          */
 207         maybe_sigio_broken(fd, type);
 208
 209         return(0);
 210
 211  out_unlock:
 212         irq_unlock(flags);
 213         kfree(new_fd);
 214  out:
 215         return(err);
 216 }
 217
 218 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 219 {
 220         struct irq_fd **prev;
 221         unsigned long flags;
 222         int i = 0;
 223
 224         flags = irq_lock();
 225         prev = &active_fds;
 226         while(*prev != NULL){
 227                 if((*test)(*prev, arg)){
 228                         struct irq_fd *old_fd = *prev;
 229                         if((pollfds[i].fd != -1) &&
 230                            (pollfds[i].fd != (*prev)->fd)){
 231                                 printk("free_irq_by_cb - mismatch between "
 232                                        "active_fds and pollfds, fd %d vs %d\n",
 233                                        (*prev)->fd, pollfds[i].fd);
 234                                 goto out;
 235                         }
 236                         memcpy(&pollfds[i], &pollfds[i + 1],
 237                                (pollfds_num - i - 1) * sizeof(pollfds[0]));
 238                         pollfds_num--;
 239                         if(last_irq_ptr == &old_fd->next)
 240                                 last_irq_ptr = prev;
 241                         *prev = (*prev)->next;
 242                         if(old_fd->type == IRQ_WRITE)
 243                                 ignore_sigio_fd(old_fd->fd);
 244                         kfree(old_fd);
 245                         continue;
 246                 }
 247                 prev = &(*prev)->next;
 248                 i++;
 249         }
 250  out:
 251         irq_unlock(flags);
 252 }
 253
 254 struct irq_and_dev {
 255         int irq;
 256         void *dev;
 257 };
 258
 259 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 260 {
 261         struct irq_and_dev *data = d;
 262
 263         return((irq->irq == data->irq) && (irq->id == data->dev));
 264 }
 265
 266 void free_irq_by_irq_and_dev(int irq, void *dev)
 267 {
 268         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 269                                                           .dev  = dev });
 270
 271         free_irq_by_cb(same_irq_and_dev, &data);
 272 }
 273
 274 static int same_fd(struct irq_fd *irq, void *fd)
 275 {
 276         return(irq->fd == *((int *) fd));
 277 }
 278
 279 void free_irq_by_fd(int fd)
 280 {
 281         free_irq_by_cb(same_fd, &fd);
 282 }
 283
 284 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 285 {
 286         struct irq_fd *irq;
 287         int i = 0;
 288
 289         for(irq=active_fds; irq != NULL; irq = irq->next){
 290                 if((irq->fd == fd) && (irq->irq == irqnum)) break;
 291                 i++;
 292         }
 293         if(irq == NULL){
 294                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 295                 goto out;
 296         }
 297         if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
 298                 printk("find_irq_by_fd - mismatch between active_fds and "
 299                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 300                        pollfds[i].fd, fd);
 301                 irq = NULL;
 302                 goto out;
 303         }
 304         *index_out = i;
 305  out:
 306         return(irq);
 307 }
 308
 309 void free_irq_later(int irq, void *dev_id)
 310 {
 311         struct irq_fd *irq_fd;
 312         unsigned long flags;
 313
 314         flags = irq_lock();
 315         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 316                 if((irq_fd->irq == irq) && (irq_fd->id == dev_id))
 317                         break;
 318         }
 319         if(irq_fd == NULL){
 320                 printk("free_irq_later found no irq, irq = %d, "
 321                        "dev_id = 0x%p\n", irq, dev_id);
 322                 goto out;
 323         }
 324         irq_fd->freed = 1;
 325  out:
 326         irq_unlock(flags);
 327 }
 328
 329 void reactivate_fd(int fd, int irqnum)
 330 {
 331         struct irq_fd *irq;
 332         unsigned long flags;
 333         int i;
 334
 335         flags = irq_lock();
 336         irq = find_irq_by_fd(fd, irqnum, &i);
 337         if(irq == NULL){
 338                 irq_unlock(flags);
 339                 return;
 340         }
 341
 342         pollfds[i].fd = irq->fd;
 343
 344         irq_unlock(flags);
 345
 346         /* This calls activate_fd, so it has to be outside the critical
 347          * section.
 348          */
 349         maybe_sigio_broken(fd, irq->type);
 350 }
 351
 352 void deactivate_fd(int fd, int irqnum)
 353 {
 354         struct irq_fd *irq;
 355         unsigned long flags;
 356         int i;
 357
 358         flags = irq_lock();
 359         irq = find_irq_by_fd(fd, irqnum, &i);
 360         if(irq == NULL)
 361                 goto out;
 362         pollfds[i].fd = -1;
 363  out:
 364         irq_unlock(flags);
 365 }
 366
 367 void forward_ipi(int fd, int pid)
 368 {
 369         if(fcntl(fd, F_SETOWN, pid) < 0){
 370                 int save_errno = errno;
 371                 if(fcntl(fd, F_GETOWN, 0) != pid){
 372                         printk("forward_ipi: F_SETOWN failed, fd = %d, "
 373                                "me = %d, target = %d, errno = %d\n", fd,
 374                                os_getpid(), pid, save_errno);
 375                 }
 376         }
 377 }
 378
 379 void forward_interrupts(int pid)
 380 {
 381         struct irq_fd *irq;
 382         unsigned long flags;
 383
 384         flags = irq_lock();
 385         for(irq=active_fds;irq != NULL;irq = irq->next){
 386                 if(fcntl(irq->fd, F_SETOWN, pid) < 0){
 387                         int save_errno = errno;
 388                         if(fcntl(irq->fd, F_GETOWN, 0) != pid){
 389                                 /* XXX Just remove the irq rather than
 390                                  * print out an infinite stream of these
 391                                  */
 392                                 printk("Failed to forward %d to pid %d, "
 393                                        "errno = %d\n", irq->fd, pid,
 394                                        save_errno);
 395                         }
 396                 }
 397                 irq->pid = pid;
 398         }
 399         irq_unlock(flags);
 400 }
 401
 402 void init_irq_signals(int on_sigstack)
 403 {
 404         __sighandler_t h;
 405         int flags;
 406
 407         flags = on_sigstack ? SA_ONSTACK : 0;
 408         if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
 409         else h = boot_timer_handler;
 410
 411         set_handler(SIGVTALRM, h, flags | SA_RESTART,
 412                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 413         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
 414                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 415         signal(SIGWINCH, SIG_IGN);
 416 }
 417
 418 /*
 419  * Overrides for Emacs so that we follow Linus's tabbing style.
 420  * Emacs will notice this stuff at the end of the file and automatically
 421  * adjust the settings for this buffer only.  This must remain at the end
 422  * of the file.
 423  * ---------------------------------------------------------------------------
 424  * Local variables:
 425  * c-file-style: "linux"
 426  * End:
 427  */