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