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 "user_util.h"
  29 #include "kern_util.h"
  30 #include "irq_user.h"
  31 #include "irq_kern.h"
  32 #include "os.h"
  33 #include "sigio.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 struct irq_fd *active_fds = NULL;
  82 static struct irq_fd **last_irq_ptr = &active_fds;
  83
  84 extern void free_irqs(void);
  85
  86 void sigio_handler(int sig, union uml_pt_regs *regs)
  87 {
  88         struct irq_fd *irq_fd;
  89         int n;
  90
  91         if (smp_sigio_handler())
  92                 return;
  93
  94         while (1) {
  95                 n = os_waiting_for_events(active_fds);
  96                 if (n <= 0) {
  97                         if(n == -EINTR) continue;
  98                         else break;
  99                 }
 100
 101                 for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 102                         if (irq_fd->current_events != 0) {
 103                                 irq_fd->current_events = 0;
 104                                 do_IRQ(irq_fd->irq, regs);
 105                         }
 106                 }
 107         }
 108
 109         free_irqs();
 110 }
 111
 112 static DEFINE_SPINLOCK(irq_lock);
 113
 114 int activate_fd(int irq, int fd, int type, void *dev_id)
 115 {
 116         struct pollfd *tmp_pfd;
 117         struct irq_fd *new_fd, *irq_fd;
 118         unsigned long flags;
 119         int pid, events, err, n;
 120
 121         pid = os_getpid();
 122         err = os_set_fd_async(fd, pid);
 123         if (err < 0)
 124                 goto out;
 125
 126         new_fd = um_kmalloc(sizeof(*new_fd));
 127         err = -ENOMEM;
 128         if (new_fd == NULL)
 129                 goto out;
 130
 131         if (type == IRQ_READ)
 132                 events = UM_POLLIN | UM_POLLPRI;
 133         else
 134                 events = UM_POLLOUT;
 135         *new_fd = ((struct irq_fd) { .next              = NULL,
 136                                      .id                = dev_id,
 137                                      .fd                = fd,
 138                                      .type              = type,
 139                                      .irq               = irq,
 140                                      .pid               = pid,
 141                                      .events            = events,
 142                                      .current_events    = 0 } );
 143
 144         /* Critical section - locked by a spinlock because this stuff can
 145          * be changed from interrupt handlers.  The stuff above is done
 146          * outside the lock because it allocates memory.
 147          */
 148
 149         /* Actually, it only looks like it can be called from interrupt
 150          * context.  The culprit is reactivate_fd, which calls
 151          * maybe_sigio_broken, which calls write_sigio_workaround,
 152          * which calls activate_fd.  However, write_sigio_workaround should
 153          * only be called once, at boot time.  That would make it clear that
 154          * this is called only from process context, and can be locked with
 155          * a semaphore.
 156          */
 157         spin_lock_irqsave(&irq_lock, flags);
 158         for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
 159                 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
 160                         printk("Registering fd %d twice\n", fd);
 161                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 162                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 163                         goto out_unlock;
 164                 }
 165         }
 166
 167         /*-------------*/
 168         if (type == IRQ_WRITE)
 169                 fd = -1;
 170
 171         tmp_pfd = NULL;
 172         n = 0;
 173
 174         while (1) {
 175                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 176                 if (n == 0)
 177                         break;
 178
 179                 /* n > 0
 180                  * It means we couldn't put new pollfd to current pollfds
 181                  * and tmp_fds is NULL or too small for new pollfds array.
 182                  * Needed size is equal to n as minimum.
 183                  *
 184                  * Here we have to drop the lock in order to call
 185                  * kmalloc, which might sleep.
 186                  * If something else came in and changed the pollfds array
 187                  * so we will not be able to put new pollfd struct to pollfds
 188                  * then we free the buffer tmp_fds and try again.
 189                  */
 190                 spin_unlock_irqrestore(&irq_lock, flags);
 191                 kfree(tmp_pfd);
 192                 tmp_pfd = NULL;
 193
 194                 tmp_pfd = um_kmalloc(n);
 195                 if (tmp_pfd == NULL)
 196                         goto out_kfree;
 197
 198                 spin_lock_irqsave(&irq_lock, flags);
 199         }
 200         /*-------------*/
 201
 202         *last_irq_ptr = new_fd;
 203         last_irq_ptr = &new_fd->next;
 204
 205         spin_unlock_irqrestore(&irq_lock, flags);
 206
 207         /* This calls activate_fd, so it has to be outside the critical
 208          * section.
 209          */
 210         maybe_sigio_broken(fd, (type == IRQ_READ));
 211
 212         return(0);
 213
 214  out_unlock:
 215         spin_unlock_irqrestore(&irq_lock, flags);
 216  out_kfree:
 217         kfree(new_fd);
 218  out:
 219         return(err);
 220 }
 221
 222 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
 223 {
 224         unsigned long flags;
 225
 226         spin_lock_irqsave(&irq_lock, flags);
 227         os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
 228         spin_unlock_irqrestore(&irq_lock, flags);
 229 }
 230
 231 struct irq_and_dev {
 232         int irq;
 233         void *dev;
 234 };
 235
 236 static int same_irq_and_dev(struct irq_fd *irq, void *d)
 237 {
 238         struct irq_and_dev *data = d;
 239
 240         return ((irq->irq == data->irq) && (irq->id == data->dev));
 241 }
 242
 243 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
 244 {
 245         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
 246                                                           .dev  = dev });
 247
 248         free_irq_by_cb(same_irq_and_dev, &data);
 249 }
 250
 251 static int same_fd(struct irq_fd *irq, void *fd)
 252 {
 253         return (irq->fd == *((int *)fd));
 254 }
 255
 256 void free_irq_by_fd(int fd)
 257 {
 258         free_irq_by_cb(same_fd, &fd);
 259 }
 260
 261 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
 262 {
 263         struct irq_fd *irq;
 264         int i = 0;
 265         int fdi;
 266
 267         for (irq = active_fds; irq != NULL; irq = irq->next) {
 268                 if ((irq->fd == fd) && (irq->irq == irqnum))
 269                         break;
 270                 i++;
 271         }
 272         if (irq == NULL) {
 273                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 274                 goto out;
 275         }
 276         fdi = os_get_pollfd(i);
 277         if ((fdi != -1) && (fdi != fd)) {
 278                 printk("find_irq_by_fd - mismatch between active_fds and "
 279                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 280                        fdi, fd);
 281                 irq = NULL;
 282                 goto out;
 283         }
 284         *index_out = i;
 285  out:
 286         return irq;
 287 }
 288
 289 void reactivate_fd(int fd, int irqnum)
 290 {
 291         struct irq_fd *irq;
 292         unsigned long flags;
 293         int i;
 294
 295         spin_lock_irqsave(&irq_lock, flags);
 296         irq = find_irq_by_fd(fd, irqnum, &i);
 297         if (irq == NULL) {
 298                 spin_unlock_irqrestore(&irq_lock, flags);
 299                 return;
 300         }
 301         os_set_pollfd(i, irq->fd);
 302         spin_unlock_irqrestore(&irq_lock, flags);
 303
 304         /* This calls activate_fd, so it has to be outside the critical
 305          * section.
 306          */
 307         maybe_sigio_broken(fd, (irq->type == IRQ_READ));
 308 }
 309
 310 void deactivate_fd(int fd, int irqnum)
 311 {
 312         struct irq_fd *irq;
 313         unsigned long flags;
 314         int i;
 315
 316         spin_lock_irqsave(&irq_lock, flags);
 317         irq = find_irq_by_fd(fd, irqnum, &i);
 318         if (irq == NULL)
 319                 goto out;
 320         os_set_pollfd(i, -1);
 321  out:
 322         spin_unlock_irqrestore(&irq_lock, flags);
 323 }
 324
 325 int deactivate_all_fds(void)
 326 {
 327         struct irq_fd *irq;
 328         int err;
 329
 330         for (irq = active_fds; irq != NULL; irq = irq->next) {
 331                 err = os_clear_fd_async(irq->fd);
 332                 if (err)
 333                         return err;
 334         }
 335         /* If there is a signal already queued, after unblocking ignore it */
 336         os_set_ioignore();
 337
 338         return 0;
 339 }
 340
 341 #ifdef CONFIG_MODE_TT
 342 void forward_interrupts(int pid)
 343 {
 344         struct irq_fd *irq;
 345         unsigned long flags;
 346         int err;
 347
 348         spin_lock_irqsave(&irq_lock, flags);
 349         for (irq = active_fds; irq != NULL; irq = irq->next) {
 350                 err = os_set_owner(irq->fd, pid);
 351                 if (err < 0) {
 352                         /* XXX Just remove the irq rather than
 353                          * print out an infinite stream of these
 354                          */
 355                         printk("Failed to forward %d to pid %d, err = %d\n",
 356                                irq->fd, pid, -err);
 357                 }
 358
 359                 irq->pid = pid;
 360         }
 361         spin_unlock_irqrestore(&irq_lock, flags);
 362 }
 363 #endif
 364
 365 /*
 366  * do_IRQ handles all normal device IRQ's (the special
 367  * SMP cross-CPU interrupts have their own specific
 368  * handlers).
 369  */
 370 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 371 {
 372         irq_enter();
 373
 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 }