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 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 static DEFINE_SPINLOCK(irq_lock);
 127
 128 int activate_fd(int irq, int fd, int type, void *dev_id)
 129 {
 130         struct pollfd *tmp_pfd;
 131         struct irq_fd *new_fd, *irq_fd;
 132         unsigned long flags;
 133         int pid, events, err, n;
 134
 135         pid = os_getpid();
 136         err = os_set_fd_async(fd, pid);
 137         if (err < 0)
 138                 goto out;
 139
 140         new_fd = um_kmalloc(sizeof(*new_fd));
 141         err = -ENOMEM;
 142         if (new_fd == NULL)
 143                 goto out;
 144
 145         if (type == IRQ_READ)
 146                 events = UM_POLLIN | UM_POLLPRI;
 147         else
 148                 events = UM_POLLOUT;
 149         *new_fd = ((struct irq_fd) { .next              = NULL,
 150                                      .id                = dev_id,
 151                                      .fd                = fd,
 152                                      .type              = type,
 153                                      .irq               = irq,
 154                                      .pid               = pid,
 155                                      .events            = events,
 156                                      .current_events    = 0 } );
 157
 158         /* Critical section - locked by a spinlock because this stuff can
 159          * be changed from interrupt handlers.  The stuff above is done
 160          * outside the lock because it allocates memory.
 161          */
 162
 163         /* Actually, it only looks like it can be called from interrupt
 164          * context.  The culprit is reactivate_fd, which calls
 165          * maybe_sigio_broken, which calls write_sigio_workaround,
 166          * which calls activate_fd.  However, write_sigio_workaround should
 167          * only be called once, at boot time.  That would make it clear that
 168          * this is called only from process context, and can be locked with
 169          * a semaphore.
 170          */
 171         spin_lock_irqsave(&irq_lock, flags);
 172         for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 173                 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
 174                         printk("Registering fd %d twice\n", fd);
 175                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 176                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 177                         goto out_unlock;
 178                 }
 179         }
 180
 181         /*-------------*/
 182         if (type == IRQ_WRITE)
 183                 fd = -1;
 184
 185         tmp_pfd = NULL;
 186         n = 0;
 187
 188         while (1) {
 189                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 190                 if (n == 0)
 191                         break;
 192
 193                 /* n > 0
 194                  * It means we couldn't put new pollfd to current pollfds
 195                  * and tmp_fds is NULL or too small for new pollfds array.
 196                  * Needed size is equal to n as minimum.
 197                  *
 198                  * Here we have to drop the lock in order to call
 199                  * kmalloc, which might sleep.
 200                  * If something else came in and changed the pollfds array
 201                  * so we will not be able to put new pollfd struct to pollfds
 202                  * then we free the buffer tmp_fds and try again.
 203                  */
 204                 spin_unlock_irqrestore(&irq_lock, flags);
 205                 kfree(tmp_pfd);
 206                 tmp_pfd = NULL;
 207
 208                 tmp_pfd = um_kmalloc(n);
 209                 if (tmp_pfd == NULL)
 210                         goto out_kfree;
 211
 212                 spin_lock_irqsave(&irq_lock, flags);
 213         }
 214         /*-------------*/
 215
 216         *last_irq_ptr = new_fd;
 217         last_irq_ptr = &new_fd->next;
 218
 219         spin_unlock_irqrestore(&irq_lock, flags);
 220
 221         /* This calls activate_fd, so it has to be outside the critical
 222          * section.
 223          */
 224         maybe_sigio_broken(fd, type);
 225
 226         return(0);
 227
 228  out_unlock:
 229         spin_unlock_irqrestore(&irq_lock, flags);
 230  out_kfree:
 231         kfree(new_fd);
 232  out:
 233         return(err);
 234 }
 235
 236 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 237 {
 238         unsigned long flags;
 239
 240         spin_lock_irqsave(&irq_lock, flags);
 241         os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
 242         spin_unlock_irqrestore(&irq_lock, flags);
 243 }
 244
 245 struct irq_and_dev {
 246         int irq;
 247         void *dev;
 248 };
 249
 250 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 251 {
 252         struct irq_and_dev *data = d;
 253
 254         return ((irq->irq == data->irq) && (irq->id == data->dev));
 255 }
 256
 257 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 258 {
 259         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 260                                                           .dev  = dev });
 261
 262         free_irq_by_cb(same_irq_and_dev, &data);
 263 }
 264
 265 static int same_fd(struct irq_fd *irq, void *fd)
 266 {
 267         return (irq->fd == *((int *)fd));
 268 }
 269
 270 void free_irq_by_fd(int fd)
 271 {
 272         free_irq_by_cb(same_fd, &fd);
 273 }
 274
 275 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 276 {
 277         struct irq_fd *irq;
 278         int i = 0;
 279         int fdi;
 280
 281         for (irq = active_fds; irq != NULL; irq = irq->next) {
 282                 if ((irq->fd == fd) && (irq->irq == irqnum))
 283                         break;
 284                 i++;
 285         }
 286         if (irq == NULL) {
 287                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 288                 goto out;
 289         }
 290         fdi = os_get_pollfd(i);
 291         if ((fdi != -1) && (fdi != fd)) {
 292                 printk("find_irq_by_fd - mismatch between active_fds and "
 293                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 294                        fdi, fd);
 295                 irq = NULL;
 296                 goto out;
 297         }
 298         *index_out = i;
 299  out:
 300         return irq;
 301 }
 302
 303 void reactivate_fd(int fd, int irqnum)
 304 {
 305         struct irq_fd *irq;
 306         unsigned long flags;
 307         int i;
 308
 309         spin_lock_irqsave(&irq_lock, flags);
 310         irq = find_irq_by_fd(fd, irqnum, &i);
 311         if (irq == NULL) {
 312                 spin_unlock_irqrestore(&irq_lock, flags);
 313                 return;
 314         }
 315         os_set_pollfd(i, irq->fd);
 316         spin_unlock_irqrestore(&irq_lock, 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         spin_lock_irqsave(&irq_lock, flags);
 331         irq = find_irq_by_fd(fd, irqnum, &i);
 332         if (irq == NULL)
 333                 goto out;
 334         os_set_pollfd(i, -1);
 335  out:
 336         spin_unlock_irqrestore(&irq_lock, 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         os_set_ioignore();
 351
 352         return 0;
 353 }
 354
 355 #ifdef CONFIG_MODE_TT
 356 void forward_interrupts(int pid)
 357 {
 358         struct irq_fd *irq;
 359         unsigned long flags;
 360         int err;
 361
 362         spin_lock_irqsave(&irq_lock, flags);
 363         for (irq = active_fds; irq != NULL; irq = irq->next) {
 364                 err = os_set_owner(irq->fd, pid);
 365                 if (err < 0) {
 366                         /* XXX Just remove the irq rather than
 367                          * print out an infinite stream of these
 368                          */
 369                         printk("Failed to forward %d to pid %d, err = %d\n",
 370                                irq->fd, pid, -err);
 371                 }
 372
 373                 irq->pid = pid;
 374         }
 375         spin_unlock_irqrestore(&irq_lock, flags);
 376 }
 377 #endif
 378
 379 /*
 380  * do_IRQ handles all normal device IRQ's (the special
 381  * SMP cross-CPU interrupts have their own specific
 382  * handlers).
 383  */
 384 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 385 {
 386        irq_enter();
 387        __do_IRQ(irq, (struct pt_regs *)regs);
 388        irq_exit();
 389        return 1;
 390 }
 391
 392 int um_request_irq(unsigned int irq, int fd, int type,
 393                    irqreturn_t (*handler)(int, void *, struct pt_regs *),
 394                    unsigned long irqflags, const char * devname,
 395                    void *dev_id)
 396 {
 397         int err;
 398
 399         err = request_irq(irq, handler, irqflags, devname, dev_id);
 400         if (err)
 401                 return err;
 402
 403         if (fd != -1)
 404                 err = activate_fd(irq, fd, type, dev_id);
 405         return err;
 406 }
 407 EXPORT_SYMBOL(um_request_irq);
 408 EXPORT_SYMBOL(reactivate_fd);
 409
 410 /* hw_interrupt_type must define (startup || enable) &&
 411  * (shutdown || disable) && end */
 412 static void dummy(unsigned int irq)
 413 {
 414 }
 415
 416 /* This is used for everything else than the timer. */
 417 static struct hw_interrupt_type normal_irq_type = {
 418         .typename = "SIGIO",
 419         .release = free_irq_by_irq_and_dev,
 420         .disable = dummy,
 421         .enable = dummy,
 422         .ack = dummy,
 423         .end = dummy
 424 };
 425
 426 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 427         .typename = "SIGVTALRM",
 428         .release = free_irq_by_irq_and_dev,
 429         .shutdown = dummy, /* never called */
 430         .disable = dummy,
 431         .enable = dummy,
 432         .ack = dummy,
 433         .end = dummy
 434 };
 435
 436 void __init init_IRQ(void)
 437 {
 438         int i;
 439
 440         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 441         irq_desc[TIMER_IRQ].action = NULL;
 442         irq_desc[TIMER_IRQ].depth = 1;
 443         irq_desc[TIMER_IRQ].chip = &SIGVTALRM_irq_type;
 444         enable_irq(TIMER_IRQ);
 445         for (i = 1; i < NR_IRQS; i++) {
 446                 irq_desc[i].status = IRQ_DISABLED;
 447                 irq_desc[i].action = NULL;
 448                 irq_desc[i].depth = 1;
 449                 irq_desc[i].chip = &normal_irq_type;
 450                 enable_irq(i);
 451         }
 452 }
 453
 454 int init_aio_irq(int irq, char *name, irqreturn_t (*handler)(int, void *,
 455                                                              struct pt_regs *))
 456 {
 457         int fds[2], err;
 458
 459         err = os_pipe(fds, 1, 1);
 460         if (err) {
 461                 printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
 462                 goto out;
 463         }
 464
 465         err = um_request_irq(irq, fds[0], IRQ_READ, handler,
 466                              IRQF_DISABLED | IRQF_SAMPLE_RANDOM, name,
 467                              (void *) (long) fds[0]);
 468         if (err) {
 469                 printk("init_aio_irq - : um_request_irq failed, err = %d\n",
 470                        err);
 471                 goto out_close;
 472         }
 473
 474         err = fds[1];
 475         goto out;
 476
 477  out_close:
 478         os_close_file(fds[0]);
 479         os_close_file(fds[1]);
 480  out:
 481         return err;
 482 }