uml: tidy IRQ code
[linux-2.6] / 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 }