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()) return;
  93         while(1){
  94                 n = os_waiting_for_events(active_fds);
  95                 if (n <= 0) {
  96                         if(n == -EINTR) continue;
  97                         else break;
  98                 }
  99
 100                 for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 101                         if(irq_fd->current_events != 0){
 102                                 irq_fd->current_events = 0;
 103                                 do_IRQ(irq_fd->irq, regs);
 104                         }
 105                 }
 106         }
 107
 108         free_irqs();
 109 }
 110
 111 static void maybe_sigio_broken(int fd, int type)
 112 {
 113         if(os_isatty(fd)){
 114                 if((type == IRQ_WRITE) && !pty_output_sigio){
 115                         write_sigio_workaround();
 116                         add_sigio_fd(fd, 0);
 117                 }
 118                 else if((type == IRQ_READ) && !pty_close_sigio){
 119                         write_sigio_workaround();
 120                         add_sigio_fd(fd, 1);
 121                 }
 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) events = UM_POLLIN | UM_POLLPRI;
 144         else events = UM_POLLOUT;
 145         *new_fd = ((struct irq_fd) { .next              = NULL,
 146                                      .id                = dev_id,
 147                                      .fd                = fd,
 148                                      .type              = type,
 149                                      .irq               = irq,
 150                                      .pid               = pid,
 151                                      .events            = events,
 152                                      .current_events    = 0 } );
 153
 154         /* Critical section - locked by a spinlock because this stuff can
 155          * be changed from interrupt handlers.  The stuff above is done
 156          * outside the lock because it allocates memory.
 157          */
 158
 159         /* Actually, it only looks like it can be called from interrupt
 160          * context.  The culprit is reactivate_fd, which calls
 161          * maybe_sigio_broken, which calls write_sigio_workaround,
 162          * which calls activate_fd.  However, write_sigio_workaround should
 163          * only be called once, at boot time.  That would make it clear that
 164          * this is called only from process context, and can be locked with
 165          * a semaphore.
 166          */
 167         flags = irq_lock();
 168         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
 169                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
 170                         printk("Registering fd %d twice\n", fd);
 171                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
 172                         printk("Ids : 0x%p, 0x%p\n", irq_fd->id, dev_id);
 173                         goto out_unlock;
 174                 }
 175         }
 176
 177         /*-------------*/
 178         if(type == IRQ_WRITE)
 179                 fd = -1;
 180
 181         tmp_pfd = NULL;
 182         n = 0;
 183
 184         while(1){
 185                 n = os_create_pollfd(fd, events, tmp_pfd, n);
 186                 if (n == 0)
 187                         break;
 188
 189                 /* n > 0
 190                  * It means we couldn't put new pollfd to current pollfds
 191                  * and tmp_fds is NULL or too small for new pollfds array.
 192                  * Needed size is equal to n as minimum.
 193                  *
 194                  * Here we have to drop the lock in order to call
 195                  * kmalloc, which might sleep.
 196                  * If something else came in and changed the pollfds array
 197                  * so we will not be able to put new pollfd struct to pollfds
 198                  * then we free the buffer tmp_fds and try again.
 199                  */
 200                 irq_unlock(flags);
 201                 if (tmp_pfd != NULL) {
 202                         kfree(tmp_pfd);
 203                         tmp_pfd = NULL;
 204                 }
 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)) break;
 281                 i++;
 282         }
 283         if(irq == NULL){
 284                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
 285                 goto out;
 286         }
 287         fdi = os_get_pollfd(i);
 288         if((fdi != -1) && (fdi != fd)){
 289                 printk("find_irq_by_fd - mismatch between active_fds and "
 290                        "pollfds, fd %d vs %d, need %d\n", irq->fd,
 291                        fdi, fd);
 292                 irq = NULL;
 293                 goto out;
 294         }
 295         *index_out = i;
 296  out:
 297         return(irq);
 298 }
 299
 300 void reactivate_fd(int fd, int irqnum)
 301 {
 302         struct irq_fd *irq;
 303         unsigned long flags;
 304         int i;
 305
 306         flags = irq_lock();
 307         irq = find_irq_by_fd(fd, irqnum, &i);
 308         if(irq == NULL){
 309                 irq_unlock(flags);
 310                 return;
 311         }
 312         os_set_pollfd(i, irq->fd);
 313         irq_unlock(flags);
 314
 315         /* This calls activate_fd, so it has to be outside the critical
 316          * section.
 317          */
 318         maybe_sigio_broken(fd, irq->type);
 319 }
 320
 321 void deactivate_fd(int fd, int irqnum)
 322 {
 323         struct irq_fd *irq;
 324         unsigned long flags;
 325         int i;
 326
 327         flags = irq_lock();
 328         irq = find_irq_by_fd(fd, irqnum, &i);
 329         if(irq == NULL)
 330                 goto out;
 331         os_set_pollfd(i, -1);
 332  out:
 333         irq_unlock(flags);
 334 }
 335
 336 int deactivate_all_fds(void)
 337 {
 338         struct irq_fd *irq;
 339         int err;
 340
 341         for(irq=active_fds;irq != NULL;irq = irq->next){
 342                 err = os_clear_fd_async(irq->fd);
 343                 if(err)
 344                         return(err);
 345         }
 346         /* If there is a signal already queued, after unblocking ignore it */
 347         os_set_ioignore();
 348
 349         return(0);
 350 }
 351
 352 void forward_interrupts(int pid)
 353 {
 354         struct irq_fd *irq;
 355         unsigned long flags;
 356         int err;
 357
 358         flags = irq_lock();
 359         for(irq=active_fds;irq != NULL;irq = irq->next){
 360                 err = os_set_owner(irq->fd, pid);
 361                 if(err < 0){
 362                         /* XXX Just remove the irq rather than
 363                          * print out an infinite stream of these
 364                          */
 365                         printk("Failed to forward %d to pid %d, err = %d\n",
 366                                irq->fd, pid, -err);
 367                 }
 368
 369                 irq->pid = pid;
 370         }
 371         irq_unlock(flags);
 372 }
 373
 374 /*
 375  * do_IRQ handles all normal device IRQ's (the special
 376  * SMP cross-CPU interrupts have their own specific
 377  * handlers).
 378  */
 379 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 380 {
 381        irq_enter();
 382        __do_IRQ(irq, (struct pt_regs *) regs);
 383        irq_exit();
 384        return 1;
 385 }
 386
 387 int um_request_irq(unsigned int irq, int fd, int type,
 388                    irqreturn_t (*handler)(int, void *, struct pt_regs *),
 389                    unsigned long irqflags, const char * devname,
 390                    void *dev_id)
 391 {
 392         int err;
 393
 394         err = request_irq(irq, handler, irqflags, devname, dev_id);
 395         if(err)
 396                 return(err);
 397
 398         if(fd != -1)
 399                 err = activate_fd(irq, fd, type, dev_id);
 400         return(err);
 401 }
 402 EXPORT_SYMBOL(um_request_irq);
 403 EXPORT_SYMBOL(reactivate_fd);
 404
 405 static DEFINE_SPINLOCK(irq_spinlock);
 406
 407 unsigned long irq_lock(void)
 408 {
 409         unsigned long flags;
 410
 411         spin_lock_irqsave(&irq_spinlock, flags);
 412         return(flags);
 413 }
 414
 415 void irq_unlock(unsigned long flags)
 416 {
 417         spin_unlock_irqrestore(&irq_spinlock, flags);
 418 }
 419
 420 /* hw_interrupt_type must define (startup || enable) &&
 421  * (shutdown || disable) && end */
 422 static void dummy(unsigned int irq)
 423 {
 424 }
 425
 426 /* This is used for everything else than the timer. */
 427 static struct hw_interrupt_type normal_irq_type = {
 428         .typename = "SIGIO",
 429         .release = free_irq_by_irq_and_dev,
 430         .disable = dummy,
 431         .enable = dummy,
 432         .ack = dummy,
 433         .end = dummy
 434 };
 435
 436 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 437         .typename = "SIGVTALRM",
 438         .release = free_irq_by_irq_and_dev,
 439         .shutdown = dummy, /* never called */
 440         .disable = dummy,
 441         .enable = dummy,
 442         .ack = dummy,
 443         .end = dummy
 444 };
 445
 446 void __init init_IRQ(void)
 447 {
 448         int i;
 449
 450         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 451         irq_desc[TIMER_IRQ].action = NULL;
 452         irq_desc[TIMER_IRQ].depth = 1;
 453         irq_desc[TIMER_IRQ].handler = &SIGVTALRM_irq_type;
 454         enable_irq(TIMER_IRQ);
 455         for(i=1;i<NR_IRQS;i++){
 456                 irq_desc[i].status = IRQ_DISABLED;
 457                 irq_desc[i].action = NULL;
 458                 irq_desc[i].depth = 1;
 459                 irq_desc[i].handler = &normal_irq_type;
 460                 enable_irq(i);
 461         }
 462 }
 463
 464 int init_aio_irq(int irq, char *name, irqreturn_t (*handler)(int, void *,
 465                                                              struct pt_regs *))
 466 {
 467         int fds[2], err;
 468
 469         err = os_pipe(fds, 1, 1);
 470         if(err){
 471                 printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
 472                 goto out;
 473         }
 474
 475         err = um_request_irq(irq, fds[0], IRQ_READ, handler,
 476                              SA_INTERRUPT | SA_SAMPLE_RANDOM, name,
 477                              (void *) (long) fds[0]);
 478         if(err){
 479                 printk("init_aio_irq - : um_request_irq failed, err = %d\n",
 480                        err);
 481                 goto out_close;
 482         }
 483
 484         err = fds[1];
 485         goto out;
 486
 487  out_close:
 488         os_close_file(fds[0]);
 489         os_close_file(fds[1]);
 490  out:
 491         return(err);
 492 }