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/kernel.h"
   9 #include "linux/module.h"
  10 #include "linux/smp.h"
  11 #include "linux/kernel_stat.h"
  12 #include "linux/interrupt.h"
  13 #include "linux/random.h"
  14 #include "linux/slab.h"
  15 #include "linux/file.h"
  16 #include "linux/proc_fs.h"
  17 #include "linux/init.h"
  18 #include "linux/seq_file.h"
  19 #include "linux/profile.h"
  20 #include "linux/hardirq.h"
  21 #include "asm/irq.h"
  22 #include "asm/hw_irq.h"
  23 #include "asm/atomic.h"
  24 #include "asm/signal.h"
  25 #include "asm/system.h"
  26 #include "asm/errno.h"
  27 #include "asm/uaccess.h"
  28 #include "kern_util.h"
  29 #include "irq_user.h"
  30 #include "irq_kern.h"
  31 #include "os.h"
  32 #include "sigio.h"
  33 #include "um_malloc.h"
  34 #include "misc_constants.h"
  35
  36 /*
  37  * Generic, controller-independent functions:
  38  */
  39
  40 int show_interrupts(struct seq_file *p, void *v)
  41 {
  42         int i = *(loff_t *) v, j;
  43         struct irqaction * action;
  44         unsigned long flags;
  45
  46         if (i == 0) {
  47                 seq_printf(p, "           ");
  48                 for_each_online_cpu(j)
  49                         seq_printf(p, "CPU%d       ",j);
  50                 seq_putc(p, '\n');
  51         }
  52
  53         if (i < NR_IRQS) {
  54                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  55                 action = irq_desc[i].action;
  56                 if (!action)
  57                         goto skip;
  58                 seq_printf(p, "%3d: ",i);
  59 #ifndef CONFIG_SMP
  60                 seq_printf(p, "%10u ", kstat_irqs(i));
  61 #else
  62                 for_each_online_cpu(j)
  63                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  64 #endif
  65                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
  66                 seq_printf(p, "  %s", action->name);
  67
  68                 for (action=action->next; action; action = action->next)
  69                         seq_printf(p, ", %s", action->name);
  70
  71                 seq_putc(p, '\n');
  72 skip:
  73                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  74         } else if (i == NR_IRQS) {
  75                 seq_putc(p, '\n');
  76         }
  77
  78         return 0;
  79 }
  80
  81 /*
  82  * This list is accessed under irq_lock, except in sigio_handler,
  83  * where it is safe from being modified.  IRQ handlers won't change it -
  84  * if an IRQ source has vanished, it will be freed by free_irqs just
  85  * before returning from sigio_handler.  That will process a separate
  86  * list of irqs to free, with its own locking, coming back here to
  87  * remove list elements, taking the irq_lock to do so.
  88  */
  89 static struct irq_fd *active_fds = NULL;
  90 static struct irq_fd **last_irq_ptr = &active_fds;
  91
  92 extern void free_irqs(void);
  93
  94 void sigio_handler(int sig, union uml_pt_regs *regs)
  95 {
  96         struct irq_fd *irq_fd;
  97         int n;
  98
  99         if (smp_sigio_handler())
 100                 return;
 101
 102         while (1) {
 103                 n = os_waiting_for_events(active_fds);
 104                 if (n <= 0) {
 105                         if(n == -EINTR) continue;
 106                         else break;
 107                 }
 108
 109                 for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 110                         if (irq_fd->current_events != 0) {
 111                                 irq_fd->current_events = 0;
 112                                 do_IRQ(irq_fd->irq, regs);
 113                         }
 114                 }
 115         }
 116
 117         free_irqs();
 118 }
 119
 120 static DEFINE_SPINLOCK(irq_lock);
 121
 122 int activate_fd(int irq, int fd, int type, void *dev_id)
 123 {
 124         struct pollfd *tmp_pfd;
 125         struct irq_fd *new_fd, *irq_fd;
 126         unsigned long flags;
 127         int pid, events, err, n;
 128
 129         pid = os_getpid();
 130         err = os_set_fd_async(fd, pid);
 131         if (err < 0)
 132                 goto out;
 133
 134         err = -ENOMEM;
 135         new_fd = kmalloc(sizeof(struct irq_fd), GFP_KERNEL);
 136         if (new_fd == NULL)
 137                 goto out;
 138
 139         if (type == IRQ_READ)
 140                 events = UM_POLLIN | UM_POLLPRI;
 141         else
 142                 events = UM_POLLOUT;
 143         *new_fd = ((struct irq_fd) { .next              = NULL,
 144                                      .id                = dev_id,
 145                                      .fd                = fd,
 146                                      .type              = type,
 147                                      .irq               = irq,
 148                                      .pid               = pid,
 149                                      .events            = events,
 150                                      .current_events    = 0 } );
 151
 152         err = -EBUSY;
 153         spin_lock_irqsave(&irq_lock, flags);
 154         for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 155                 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
 156                         printk("Registering fd %d twice\n", fd);
 157                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 158                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 159                         goto out_unlock;
 160                 }
 161         }
 162
 163         if (type == IRQ_WRITE)
 164                 fd = -1;
 165
 166         tmp_pfd = NULL;
 167         n = 0;
 168
 169         while (1) {
 170                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 171                 if (n == 0)
 172                         break;
 173
 174                 /* n > 0
 175                  * It means we couldn't put new pollfd to current pollfds
 176                  * and tmp_fds is NULL or too small for new pollfds array.
 177                  * Needed size is equal to n as minimum.
 178                  *
 179                  * Here we have to drop the lock in order to call
 180                  * kmalloc, which might sleep.
 181                  * If something else came in and changed the pollfds array
 182                  * so we will not be able to put new pollfd struct to pollfds
 183                  * then we free the buffer tmp_fds and try again.
 184                  */
 185                 spin_unlock_irqrestore(&irq_lock, flags);
 186                 kfree(tmp_pfd);
 187
 188                 tmp_pfd = kmalloc(n, GFP_KERNEL);
 189                 if (tmp_pfd == NULL)
 190                         goto out_kfree;
 191
 192                 spin_lock_irqsave(&irq_lock, flags);
 193         }
 194
 195         *last_irq_ptr = new_fd;
 196         last_irq_ptr = &new_fd->next;
 197
 198         spin_unlock_irqrestore(&irq_lock, flags);
 199
 200         /* This calls activate_fd, so it has to be outside the critical
 201          * section.
 202          */
 203         maybe_sigio_broken(fd, (type == IRQ_READ));
 204
 205         return 0;
 206
 207  out_unlock:
 208         spin_unlock_irqrestore(&irq_lock, flags);
 209  out_kfree:
 210         kfree(new_fd);
 211  out:
 212         return err;
 213 }
 214
 215 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 216 {
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&irq_lock, flags);
 220         os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
 221         spin_unlock_irqrestore(&irq_lock, flags);
 222 }
 223
 224 struct irq_and_dev {
 225         int irq;
 226         void *dev;
 227 };
 228
 229 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 230 {
 231         struct irq_and_dev *data = d;
 232
 233         return ((irq->irq == data->irq) && (irq->id == data->dev));
 234 }
 235
 236 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 237 {
 238         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 239                                                           .dev  = dev });
 240
 241         free_irq_by_cb(same_irq_and_dev, &data);
 242 }
 243
 244 static int same_fd(struct irq_fd *irq, void *fd)
 245 {
 246         return (irq->fd == *((int *)fd));
 247 }
 248
 249 void free_irq_by_fd(int fd)
 250 {
 251         free_irq_by_cb(same_fd, &fd);
 252 }
 253
 254 /* Must be called with irq_lock held */
 255 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 256 {
 257         struct irq_fd *irq;
 258         int i = 0;
 259         int fdi;
 260
 261         for (irq = active_fds; irq != NULL; irq = irq->next) {
 262                 if ((irq->fd == fd) && (irq->irq == irqnum))
 263                         break;
 264                 i++;
 265         }
 266         if (irq == NULL) {
 267                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 268                 goto out;
 269         }
 270         fdi = os_get_pollfd(i);
 271         if ((fdi != -1) && (fdi != fd)) {
 272                 printk("find_irq_by_fd - mismatch between active_fds and "
 273                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 274                        fdi, fd);
 275                 irq = NULL;
 276                 goto out;
 277         }
 278         *index_out = i;
 279  out:
 280         return irq;
 281 }
 282
 283 void reactivate_fd(int fd, int irqnum)
 284 {
 285         struct irq_fd *irq;
 286         unsigned long flags;
 287         int i;
 288
 289         spin_lock_irqsave(&irq_lock, flags);
 290         irq = find_irq_by_fd(fd, irqnum, &i);
 291         if (irq == NULL) {
 292                 spin_unlock_irqrestore(&irq_lock, flags);
 293                 return;
 294         }
 295         os_set_pollfd(i, irq->fd);
 296         spin_unlock_irqrestore(&irq_lock, flags);
 297
 298         add_sigio_fd(fd);
 299 }
 300
 301 void deactivate_fd(int fd, int irqnum)
 302 {
 303         struct irq_fd *irq;
 304         unsigned long flags;
 305         int i;
 306
 307         spin_lock_irqsave(&irq_lock, flags);
 308         irq = find_irq_by_fd(fd, irqnum, &i);
 309         if(irq == NULL){
 310                 spin_unlock_irqrestore(&irq_lock, flags);
 311                 return;
 312         }
 313
 314         os_set_pollfd(i, -1);
 315         spin_unlock_irqrestore(&irq_lock, flags);
 316
 317         ignore_sigio_fd(fd);
 318 }
 319
 320 /*
 321  * Called just before shutdown in order to provide a clean exec
 322  * environment in case the system is rebooting.  No locking because
 323  * that would cause a pointless shutdown hang if something hadn't
 324  * released the lock.
 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         struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)regs);
 374         irq_enter();
 375         __do_IRQ(irq);
 376         irq_exit();
 377         set_irq_regs(old_regs);
 378         return 1;
 379 }
 380
 381 int um_request_irq(unsigned int irq, int fd, int type,
 382                    irq_handler_t handler,
 383                    unsigned long irqflags, const char * devname,
 384                    void *dev_id)
 385 {
 386         int err;
 387
 388         err = request_irq(irq, handler, irqflags, devname, dev_id);
 389         if (err)
 390                 return err;
 391
 392         if (fd != -1)
 393                 err = activate_fd(irq, fd, type, dev_id);
 394         return err;
 395 }
 396 EXPORT_SYMBOL(um_request_irq);
 397 EXPORT_SYMBOL(reactivate_fd);
 398
 399 /* hw_interrupt_type must define (startup || enable) &&
 400  * (shutdown || disable) && end */
 401 static void dummy(unsigned int irq)
 402 {
 403 }
 404
 405 /* This is used for everything else than the timer. */
 406 static struct hw_interrupt_type normal_irq_type = {
 407         .typename = "SIGIO",
 408         .release = free_irq_by_irq_and_dev,
 409         .disable = dummy,
 410         .enable = dummy,
 411         .ack = dummy,
 412         .end = dummy
 413 };
 414
 415 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 416         .typename = "SIGVTALRM",
 417         .release = free_irq_by_irq_and_dev,
 418         .shutdown = dummy, /* never called */
 419         .disable = dummy,
 420         .enable = dummy,
 421         .ack = dummy,
 422         .end = dummy
 423 };
 424
 425 void __init init_IRQ(void)
 426 {
 427         int i;
 428
 429         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 430         irq_desc[TIMER_IRQ].action = NULL;
 431         irq_desc[TIMER_IRQ].depth = 1;
 432         irq_desc[TIMER_IRQ].chip = &SIGVTALRM_irq_type;
 433         enable_irq(TIMER_IRQ);
 434         for (i = 1; i < NR_IRQS; i++) {
 435                 irq_desc[i].status = IRQ_DISABLED;
 436                 irq_desc[i].action = NULL;
 437                 irq_desc[i].depth = 1;
 438                 irq_desc[i].chip = &normal_irq_type;
 439                 enable_irq(i);
 440         }
 441 }
 442
 443 int init_aio_irq(int irq, char *name, irq_handler_t handler)
 444 {
 445         int fds[2], err;
 446
 447         err = os_pipe(fds, 1, 1);
 448         if (err) {
 449                 printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
 450                 goto out;
 451         }
 452
 453         err = um_request_irq(irq, fds[0], IRQ_READ, handler,
 454                              IRQF_DISABLED | IRQF_SAMPLE_RANDOM, name,
 455                              (void *) (long) fds[0]);
 456         if (err) {
 457                 printk("init_aio_irq - : um_request_irq failed, err = %d\n",
 458                        err);
 459                 goto out_close;
 460         }
 461
 462         err = fds[1];
 463         goto out;
 464
 465  out_close:
 466         os_close_file(fds[0]);
 467         os_close_file(fds[1]);
 468  out:
 469         return err;
 470 }