arch/um/kernel/irq.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  * Derived (i.e. mostly copied) from arch/i386/kernel/irq.c:
   5  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   6  */
   7
   8 #include "linux/config.h"
   9 #include "linux/kernel.h"
  10 #include "linux/module.h"
  11 #include "linux/smp.h"
  12 #include "linux/kernel_stat.h"
  13 #include "linux/interrupt.h"
  14 #include "linux/random.h"
  15 #include "linux/slab.h"
  16 #include "linux/file.h"
  17 #include "linux/proc_fs.h"
  18 #include "linux/init.h"
  19 #include "linux/seq_file.h"
  20 #include "linux/profile.h"
  21 #include "linux/hardirq.h"
  22 #include "asm/irq.h"
  23 #include "asm/hw_irq.h"
  24 #include "asm/atomic.h"
  25 #include "asm/signal.h"
  26 #include "asm/system.h"
  27 #include "asm/errno.h"
  28 #include "asm/uaccess.h"
  29 #include "user_util.h"
  30 #include "kern_util.h"
  31 #include "irq_user.h"
  32 #include "irq_kern.h"
  33 #include "os.h"
  34 #include "sigio.h"
  35 #include "misc_constants.h"
  36
  37 /*
  38  * Generic, controller-independent functions:
  39  */
  40
  41 int show_interrupts(struct seq_file *p, void *v)
  42 {
  43         int i = *(loff_t *) v, j;
  44         struct irqaction * action;
  45         unsigned long flags;
  46
  47         if (i == 0) {
  48                 seq_printf(p, "           ");
  49                 for_each_online_cpu(j)
  50                         seq_printf(p, "CPU%d       ",j);
  51                 seq_putc(p, '\n');
  52         }
  53
  54         if (i < NR_IRQS) {
  55                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  56                 action = irq_desc[i].action;
  57                 if (!action)
  58                         goto skip;
  59                 seq_printf(p, "%3d: ",i);
  60 #ifndef CONFIG_SMP
  61                 seq_printf(p, "%10u ", kstat_irqs(i));
  62 #else
  63                 for_each_online_cpu(j)
  64                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  65 #endif
  66                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
  67                 seq_printf(p, "  %s", action->name);
  68
  69                 for (action=action->next; action; action = action->next)
  70                         seq_printf(p, ", %s", action->name);
  71
  72                 seq_putc(p, '\n');
  73 skip:
  74                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  75         } else if (i == NR_IRQS) {
  76                 seq_putc(p, '\n');
  77         }
  78
  79         return 0;
  80 }
  81
  82 struct irq_fd *active_fds = NULL;
  83 static struct irq_fd **last_irq_ptr = &active_fds;
  84
  85 extern void free_irqs(void);
  86
  87 void sigio_handler(int sig, union uml_pt_regs *regs)
  88 {
  89         struct irq_fd *irq_fd;
  90         int n;
  91
  92         if (smp_sigio_handler())
  93                 return;
  94
  95         while (1) {
  96                 n = os_waiting_for_events(active_fds);
  97                 if (n <= 0) {
  98                         if(n == -EINTR) continue;
  99                         else break;
 100                 }
 101
 102                 for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 103                         if (irq_fd->current_events != 0) {
 104                                 irq_fd->current_events = 0;
 105                                 do_IRQ(irq_fd->irq, regs);
 106                         }
 107                 }
 108         }
 109
 110         free_irqs();
 111 }
 112
 113 static void maybe_sigio_broken(int fd, int type)
 114 {
 115         if (os_isatty(fd)) {
 116                 if ((type == IRQ_WRITE) && !pty_output_sigio) {
 117                         write_sigio_workaround();
 118                         add_sigio_fd(fd, 0);
 119                 } else if ((type == IRQ_READ) && !pty_close_sigio) {
 120                         write_sigio_workaround();
 121                         add_sigio_fd(fd, 1);
 122                 }
 123         }
 124 }
 125
 126 int activate_fd(int irq, int fd, int type, void *dev_id)
 127 {
 128         struct pollfd *tmp_pfd;
 129         struct irq_fd *new_fd, *irq_fd;
 130         unsigned long flags;
 131         int pid, events, err, n;
 132
 133         pid = os_getpid();
 134         err = os_set_fd_async(fd, pid);
 135         if (err < 0)
 136                 goto out;
 137
 138         new_fd = um_kmalloc(sizeof(*new_fd));
 139         err = -ENOMEM;
 140         if (new_fd == NULL)
 141                 goto out;
 142
 143         if (type == IRQ_READ)
 144                 events = UM_POLLIN | UM_POLLPRI;
 145         else
 146                 events = UM_POLLOUT;
 147         *new_fd = ((struct irq_fd) { .next              = NULL,
 148                                      .id                = dev_id,
 149                                      .fd                = fd,
 150                                      .type              = type,
 151                                      .irq               = irq,
 152                                      .pid               = pid,
 153                                      .events            = events,
 154                                      .current_events    = 0 } );
 155
 156         /* Critical section - locked by a spinlock because this stuff can
 157          * be changed from interrupt handlers.  The stuff above is done
 158          * outside the lock because it allocates memory.
 159          */
 160
 161         /* Actually, it only looks like it can be called from interrupt
 162          * context.  The culprit is reactivate_fd, which calls
 163          * maybe_sigio_broken, which calls write_sigio_workaround,
 164          * which calls activate_fd.  However, write_sigio_workaround should
 165          * only be called once, at boot time.  That would make it clear that
 166          * this is called only from process context, and can be locked with
 167          * a semaphore.
 168          */
 169         flags = irq_lock();
 170         for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 171                 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
 172                         printk("Registering fd %d twice\n", fd);
 173                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 174                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 175                         goto out_unlock;
 176                 }
 177         }
 178
 179         /*-------------*/
 180         if (type == IRQ_WRITE)
 181                 fd = -1;
 182
 183         tmp_pfd = NULL;
 184         n = 0;
 185
 186         while (1) {
 187                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 188                 if (n == 0)
 189                         break;
 190
 191                 /* n > 0
 192                  * It means we couldn't put new pollfd to current pollfds
 193                  * and tmp_fds is NULL or too small for new pollfds array.
 194                  * Needed size is equal to n as minimum.
 195                  *
 196                  * Here we have to drop the lock in order to call
 197                  * kmalloc, which might sleep.
 198                  * If something else came in and changed the pollfds array
 199                  * so we will not be able to put new pollfd struct to pollfds
 200                  * then we free the buffer tmp_fds and try again.
 201                  */
 202                 irq_unlock(flags);
 203                 kfree(tmp_pfd);
 204                 tmp_pfd = NULL;
 205
 206                 tmp_pfd = um_kmalloc(n);
 207                 if (tmp_pfd == NULL)
 208                         goto out_kfree;
 209
 210                 flags = irq_lock();
 211         }
 212         /*-------------*/
 213
 214         *last_irq_ptr = new_fd;
 215         last_irq_ptr = &new_fd->next;
 216
 217         irq_unlock(flags);
 218
 219         /* This calls activate_fd, so it has to be outside the critical
 220          * section.
 221          */
 222         maybe_sigio_broken(fd, type);
 223
 224         return(0);
 225
 226  out_unlock:
 227         irq_unlock(flags);
 228  out_kfree:
 229         kfree(new_fd);
 230  out:
 231         return(err);
 232 }
 233
 234 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 235 {
 236         unsigned long flags;
 237
 238         flags = irq_lock();
 239         os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
 240         irq_unlock(flags);
 241 }
 242
 243 struct irq_and_dev {
 244         int irq;
 245         void *dev;
 246 };
 247
 248 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 249 {
 250         struct irq_and_dev *data = d;
 251
 252         return ((irq->irq == data->irq) && (irq->id == data->dev));
 253 }
 254
 255 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 256 {
 257         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 258                                                           .dev  = dev });
 259
 260         free_irq_by_cb(same_irq_and_dev, &data);
 261 }
 262
 263 static int same_fd(struct irq_fd *irq, void *fd)
 264 {
 265         return (irq->fd == *((int *)fd));
 266 }
 267
 268 void free_irq_by_fd(int fd)
 269 {
 270         free_irq_by_cb(same_fd, &fd);
 271 }
 272
 273 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 274 {
 275         struct irq_fd *irq;
 276         int i = 0;
 277         int fdi;
 278
 279         for (irq = active_fds; irq != NULL; irq = irq->next) {
 280                 if ((irq->fd == fd) && (irq->irq == irqnum))
 281                         break;
 282                 i++;
 283         }
 284         if (irq == NULL) {
 285                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 286                 goto out;
 287         }
 288         fdi = os_get_pollfd(i);
 289         if ((fdi != -1) && (fdi != fd)) {
 290                 printk("find_irq_by_fd - mismatch between active_fds and "
 291                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 292                        fdi, 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         os_set_pollfd(i, irq->fd);
 314         irq_unlock(flags);
 315
 316         /* This calls activate_fd, so it has to be outside the critical
 317          * section.
 318          */
 319         maybe_sigio_broken(fd, irq->type);
 320 }
 321
 322 void deactivate_fd(int fd, int irqnum)
 323 {
 324         struct irq_fd *irq;
 325         unsigned long flags;
 326         int i;
 327
 328         flags = irq_lock();
 329         irq = find_irq_by_fd(fd, irqnum, &i);
 330         if (irq == NULL)
 331                 goto out;
 332         os_set_pollfd(i, -1);
 333  out:
 334         irq_unlock(flags);
 335 }
 336
 337 int deactivate_all_fds(void)
 338 {
 339         struct irq_fd *irq;
 340         int err;
 341
 342         for (irq = active_fds; irq != NULL; irq = irq->next) {
 343                 err = os_clear_fd_async(irq->fd);
 344                 if (err)
 345                         return err;
 346         }
 347         /* If there is a signal already queued, after unblocking ignore it */
 348         os_set_ioignore();
 349
 350         return 0;
 351 }
 352
 353 void forward_interrupts(int pid)
 354 {
 355         struct irq_fd *irq;
 356         unsigned long flags;
 357         int err;
 358
 359         flags = irq_lock();
 360         for (irq = active_fds; irq != NULL; irq = irq->next) {
 361                 err = os_set_owner(irq->fd, pid);
 362                 if (err < 0) {
 363                         /* XXX Just remove the irq rather than
 364                          * print out an infinite stream of these
 365                          */
 366                         printk("Failed to forward %d to pid %d, err = %d\n",
 367                                irq->fd, pid, -err);
 368                 }
 369
 370                 irq->pid = pid;
 371         }
 372         irq_unlock(flags);
 373 }
 374
 375 /*
 376  * do_IRQ handles all normal device IRQ's (the special
 377  * SMP cross-CPU interrupts have their own specific
 378  * handlers).
 379  */
 380 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 381 {
 382        irq_enter();
 383        __do_IRQ(irq, (struct pt_regs *)regs);
 384        irq_exit();
 385        return 1;
 386 }
 387
 388 int um_request_irq(unsigned int irq, int fd, int type,
 389                    irqreturn_t (*handler)(int, void *, struct pt_regs *),
 390                    unsigned long irqflags, const char * devname,
 391                    void *dev_id)
 392 {
 393         int err;
 394
 395         err = request_irq(irq, handler, irqflags, devname, dev_id);
 396         if (err)
 397                 return err;
 398
 399         if (fd != -1)
 400                 err = activate_fd(irq, fd, type, dev_id);
 401         return err;
 402 }
 403 EXPORT_SYMBOL(um_request_irq);
 404 EXPORT_SYMBOL(reactivate_fd);
 405
 406 static DEFINE_SPINLOCK(irq_spinlock);
 407
 408 unsigned long irq_lock(void)
 409 {
 410         unsigned long flags;
 411
 412         spin_lock_irqsave(&irq_spinlock, flags);
 413         return flags;
 414 }
 415
 416 void irq_unlock(unsigned long flags)
 417 {
 418         spin_unlock_irqrestore(&irq_spinlock, flags);
 419 }
 420
 421 /* hw_interrupt_type must define (startup || enable) &&
 422  * (shutdown || disable) && end */
 423 static void dummy(unsigned int irq)
 424 {
 425 }
 426
 427 /* This is used for everything else than the timer. */
 428 static struct hw_interrupt_type normal_irq_type = {
 429         .typename = "SIGIO",
 430         .release = free_irq_by_irq_and_dev,
 431         .disable = dummy,
 432         .enable = dummy,
 433         .ack = dummy,
 434         .end = dummy
 435 };
 436
 437 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 438         .typename = "SIGVTALRM",
 439         .release = free_irq_by_irq_and_dev,
 440         .shutdown = dummy, /* never called */
 441         .disable = dummy,
 442         .enable = dummy,
 443         .ack = dummy,
 444         .end = dummy
 445 };
 446
 447 void __init init_IRQ(void)
 448 {
 449         int i;
 450
 451         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 452         irq_desc[TIMER_IRQ].action = NULL;
 453         irq_desc[TIMER_IRQ].depth = 1;
 454         irq_desc[TIMER_IRQ].handler = &SIGVTALRM_irq_type;
 455         enable_irq(TIMER_IRQ);
 456         for (i = 1; i < NR_IRQS; i++) {
 457                 irq_desc[i].status = IRQ_DISABLED;
 458                 irq_desc[i].action = NULL;
 459                 irq_desc[i].depth = 1;
 460                 irq_desc[i].handler = &normal_irq_type;
 461                 enable_irq(i);
 462         }
 463 }
 464
 465 int init_aio_irq(int irq, char *name, irqreturn_t (*handler)(int, void *,
 466                                                              struct pt_regs *))
 467 {
 468         int fds[2], err;
 469
 470         err = os_pipe(fds, 1, 1);
 471         if (err) {
 472                 printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
 473                 goto out;
 474         }
 475
 476         err = um_request_irq(irq, fds[0], IRQ_READ, handler,
 477                              SA_INTERRUPT | SA_SAMPLE_RANDOM, name,
 478                              (void *) (long) fds[0]);
 479         if (err) {
 480                 printk("init_aio_irq - : um_request_irq failed, err = %d\n",
 481                        err);
 482                 goto out_close;
 483         }
 484
 485         err = fds[1];
 486         goto out;
 487
 488  out_close:
 489         os_close_file(fds[0]);
 490         os_close_file(fds[1]);
 491  out:
 492         return err;
 493 }