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].chip->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 DEFINE_SPINLOCK(irq_lock);
 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;
 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)
 133                 events = UM_POLLIN | UM_POLLPRI;
 134         else
 135                 events = UM_POLLOUT;
 136         *new_fd = ((struct irq_fd) { .next              = NULL,
 137                                      .id                = dev_id,
 138                                      .fd                = fd,
 139                                      .type              = type,
 140                                      .irq               = irq,
 141                                      .pid               = pid,
 142                                      .events            = events,
 143                                      .current_events    = 0 } );
 144
 145         /* Critical section - locked by a spinlock because this stuff can
 146          * be changed from interrupt handlers.  The stuff above is done
 147          * outside the lock because it allocates memory.
 148          */
 149
 150         /* Actually, it only looks like it can be called from interrupt
 151          * context.  The culprit is reactivate_fd, which calls
 152          * maybe_sigio_broken, which calls write_sigio_workaround,
 153          * which calls activate_fd.  However, write_sigio_workaround should
 154          * only be called once, at boot time.  That would make it clear that
 155          * this is called only from process context, and can be locked with
 156          * a semaphore.
 157          */
 158         spin_lock_irqsave(&irq_lock, flags);
 159         for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 160                 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
 161                         printk("Registering fd %d twice\n", fd);
 162                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 163                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 164                         goto out_unlock;
 165                 }
 166         }
 167
 168         /*-------------*/
 169         if (type == IRQ_WRITE)
 170                 fd = -1;
 171
 172         tmp_pfd = NULL;
 173         n = 0;
 174
 175         while (1) {
 176                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 177                 if (n == 0)
 178                         break;
 179
 180                 /* n > 0
 181                  * It means we couldn't put new pollfd to current pollfds
 182                  * and tmp_fds is NULL or too small for new pollfds array.
 183                  * Needed size is equal to n as minimum.
 184                  *
 185                  * Here we have to drop the lock in order to call
 186                  * kmalloc, which might sleep.
 187                  * If something else came in and changed the pollfds array
 188                  * so we will not be able to put new pollfd struct to pollfds
 189                  * then we free the buffer tmp_fds and try again.
 190                  */
 191                 spin_unlock_irqrestore(&irq_lock, flags);
 192                 kfree(tmp_pfd);
 193                 tmp_pfd = NULL;
 194
 195                 tmp_pfd = um_kmalloc(n);
 196                 if (tmp_pfd == NULL)
 197                         goto out_kfree;
 198
 199                 spin_lock_irqsave(&irq_lock, flags);
 200         }
 201         /*-------------*/
 202
 203         *last_irq_ptr = new_fd;
 204         last_irq_ptr = &new_fd->next;
 205
 206         spin_unlock_irqrestore(&irq_lock, flags);
 207
 208         /* This calls activate_fd, so it has to be outside the critical
 209          * section.
 210          */
 211         maybe_sigio_broken(fd, (type == IRQ_READ));
 212
 213         return(0);
 214
 215  out_unlock:
 216         spin_unlock_irqrestore(&irq_lock, flags);
 217  out_kfree:
 218         kfree(new_fd);
 219  out:
 220         return(err);
 221 }
 222
 223 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 224 {
 225         unsigned long flags;
 226
 227         spin_lock_irqsave(&irq_lock, flags);
 228         os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
 229         spin_unlock_irqrestore(&irq_lock, flags);
 230 }
 231
 232 struct irq_and_dev {
 233         int irq;
 234         void *dev;
 235 };
 236
 237 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 238 {
 239         struct irq_and_dev *data = d;
 240
 241         return ((irq->irq == data->irq) && (irq->id == data->dev));
 242 }
 243
 244 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 245 {
 246         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 247                                                           .dev  = dev });
 248
 249         free_irq_by_cb(same_irq_and_dev, &data);
 250 }
 251
 252 static int same_fd(struct irq_fd *irq, void *fd)
 253 {
 254         return (irq->fd == *((int *)fd));
 255 }
 256
 257 void free_irq_by_fd(int fd)
 258 {
 259         free_irq_by_cb(same_fd, &fd);
 260 }
 261
 262 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 263 {
 264         struct irq_fd *irq;
 265         int i = 0;
 266         int fdi;
 267
 268         for (irq = active_fds; irq != NULL; irq = irq->next) {
 269                 if ((irq->fd == fd) && (irq->irq == irqnum))
 270                         break;
 271                 i++;
 272         }
 273         if (irq == NULL) {
 274                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 275                 goto out;
 276         }
 277         fdi = os_get_pollfd(i);
 278         if ((fdi != -1) && (fdi != fd)) {
 279                 printk("find_irq_by_fd - mismatch between active_fds and "
 280                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 281                        fdi, fd);
 282                 irq = NULL;
 283                 goto out;
 284         }
 285         *index_out = i;
 286  out:
 287         return irq;
 288 }
 289
 290 void reactivate_fd(int fd, int irqnum)
 291 {
 292         struct irq_fd *irq;
 293         unsigned long flags;
 294         int i;
 295
 296         spin_lock_irqsave(&irq_lock, flags);
 297         irq = find_irq_by_fd(fd, irqnum, &i);
 298         if (irq == NULL) {
 299                 spin_unlock_irqrestore(&irq_lock, flags);
 300                 return;
 301         }
 302         os_set_pollfd(i, irq->fd);
 303         spin_unlock_irqrestore(&irq_lock, flags);
 304
 305         /* This calls activate_fd, so it has to be outside the critical
 306          * section.
 307          */
 308         maybe_sigio_broken(fd, (irq->type == IRQ_READ));
 309 }
 310
 311 void deactivate_fd(int fd, int irqnum)
 312 {
 313         struct irq_fd *irq;
 314         unsigned long flags;
 315         int i;
 316
 317         spin_lock_irqsave(&irq_lock, flags);
 318         irq = find_irq_by_fd(fd, irqnum, &i);
 319         if (irq == NULL)
 320                 goto out;
 321         os_set_pollfd(i, -1);
 322  out:
 323         spin_unlock_irqrestore(&irq_lock, flags);
 324 }
 325
 326 int deactivate_all_fds(void)
 327 {
 328         struct irq_fd *irq;
 329         int err;
 330
 331         for (irq = active_fds; irq != NULL; irq = irq->next) {
 332                 err = os_clear_fd_async(irq->fd);
 333                 if (err)
 334                         return err;
 335         }
 336         /* If there is a signal already queued, after unblocking ignore it */
 337         os_set_ioignore();
 338
 339         return 0;
 340 }
 341
 342 #ifdef CONFIG_MODE_TT
 343 void forward_interrupts(int pid)
 344 {
 345         struct irq_fd *irq;
 346         unsigned long flags;
 347         int err;
 348
 349         spin_lock_irqsave(&irq_lock, flags);
 350         for (irq = active_fds; irq != NULL; irq = irq->next) {
 351                 err = os_set_owner(irq->fd, pid);
 352                 if (err < 0) {
 353                         /* XXX Just remove the irq rather than
 354                          * print out an infinite stream of these
 355                          */
 356                         printk("Failed to forward %d to pid %d, err = %d\n",
 357                                irq->fd, pid, -err);
 358                 }
 359
 360                 irq->pid = pid;
 361         }
 362         spin_unlock_irqrestore(&irq_lock, flags);
 363 }
 364 #endif
 365
 366 /*
 367  * do_IRQ handles all normal device IRQ's (the special
 368  * SMP cross-CPU interrupts have their own specific
 369  * handlers).
 370  */
 371 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 372 {
 373        irq_enter();
 374        __do_IRQ(irq, (struct pt_regs *)regs);
 375        irq_exit();
 376        return 1;
 377 }
 378
 379 int um_request_irq(unsigned int irq, int fd, int type,
 380                    irqreturn_t (*handler)(int, void *, struct pt_regs *),
 381                    unsigned long irqflags, const char * devname,
 382                    void *dev_id)
 383 {
 384         int err;
 385
 386         err = request_irq(irq, handler, irqflags, devname, dev_id);
 387         if (err)
 388                 return err;
 389
 390         if (fd != -1)
 391                 err = activate_fd(irq, fd, type, dev_id);
 392         return err;
 393 }
 394 EXPORT_SYMBOL(um_request_irq);
 395 EXPORT_SYMBOL(reactivate_fd);
 396
 397 /* hw_interrupt_type must define (startup || enable) &&
 398  * (shutdown || disable) && end */
 399 static void dummy(unsigned int irq)
 400 {
 401 }
 402
 403 /* This is used for everything else than the timer. */
 404 static struct hw_interrupt_type normal_irq_type = {
 405         .typename = "SIGIO",
 406         .release = free_irq_by_irq_and_dev,
 407         .disable = dummy,
 408         .enable = dummy,
 409         .ack = dummy,
 410         .end = dummy
 411 };
 412
 413 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 414         .typename = "SIGVTALRM",
 415         .release = free_irq_by_irq_and_dev,
 416         .shutdown = dummy, /* never called */
 417         .disable = dummy,
 418         .enable = dummy,
 419         .ack = dummy,
 420         .end = dummy
 421 };
 422
 423 void __init init_IRQ(void)
 424 {
 425         int i;
 426
 427         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 428         irq_desc[TIMER_IRQ].action = NULL;
 429         irq_desc[TIMER_IRQ].depth = 1;
 430         irq_desc[TIMER_IRQ].chip = &SIGVTALRM_irq_type;
 431         enable_irq(TIMER_IRQ);
 432         for (i = 1; i < NR_IRQS; i++) {
 433                 irq_desc[i].status = IRQ_DISABLED;
 434                 irq_desc[i].action = NULL;
 435                 irq_desc[i].depth = 1;
 436                 irq_desc[i].chip = &normal_irq_type;
 437                 enable_irq(i);
 438         }
 439 }
 440
 441 int init_aio_irq(int irq, char *name, irqreturn_t (*handler)(int, void *,
 442                                                              struct pt_regs *))
 443 {
 444         int fds[2], err;
 445
 446         err = os_pipe(fds, 1, 1);
 447         if (err) {
 448                 printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
 449                 goto out;
 450         }
 451
 452         err = um_request_irq(irq, fds[0], IRQ_READ, handler,
 453                              IRQF_DISABLED | IRQF_SAMPLE_RANDOM, name,
 454                              (void *) (long) fds[0]);
 455         if (err) {
 456                 printk("init_aio_irq - : um_request_irq failed, err = %d\n",
 457                        err);
 458                 goto out_close;
 459         }
 460
 461         err = fds[1];
 462         goto out;
 463
 464  out_close:
 465         os_close_file(fds[0]);
 466         os_close_file(fds[1]);
 467  out:
 468         return err;
 469 }