aboutsummaryrefslogtreecommitdiff
path: root/arch/um/kernel/irq_user.c
blob: 6d6f9484b884d357240beaf65266c0d376644e55 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
/* 
 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/poll.h>
#include <sys/types.h>
#include <sys/time.h>
#include "user_util.h"
#include "kern_util.h"
#include "user.h"
#include "process.h"
#include "signal_user.h"
#include "sigio.h"
#include "irq_user.h"
#include "os.h"

struct irq_fd {
	struct irq_fd *next;
	void *id;
	int fd;
	int type;
	int irq;
	int pid;
	int events;
	int current_events;
	int freed;
};

static struct irq_fd *active_fds = NULL;
static struct irq_fd **last_irq_ptr = &active_fds;

static struct pollfd *pollfds = NULL;
static int pollfds_num = 0;
static int pollfds_size = 0;

extern int io_count, intr_count;

void sigio_handler(int sig, union uml_pt_regs *regs)
{
	struct irq_fd *irq_fd, *next;
	int i, n;

	if(smp_sigio_handler()) return;
	while(1){
		n = poll(pollfds, pollfds_num, 0);
		if(n < 0){
			if(errno == EINTR) continue;
			printk("sigio_handler : poll returned %d, "
			       "errno = %d\n", n, errno);
			break;
		}
		if(n == 0) break;

		irq_fd = active_fds;
		for(i = 0; i < pollfds_num; i++){
			if(pollfds[i].revents != 0){
				irq_fd->current_events = pollfds[i].revents;
				pollfds[i].fd = -1;
			}
			irq_fd = irq_fd->next;
		}

		for(irq_fd = active_fds; irq_fd != NULL; irq_fd = next){
			next = irq_fd->next;
			if(irq_fd->current_events != 0){
				irq_fd->current_events = 0;
				do_IRQ(irq_fd->irq, regs);

				/* This is here because the next irq may be
				 * freed in the handler.  If a console goes
				 * away, both the read and write irqs will be
				 * freed.  After do_IRQ, ->next will point to
				 * a good IRQ.
				 * Irqs can't be freed inside their handlers,
				 * so the next best thing is to have them
				 * marked as needing freeing, so that they
				 * can be freed here.
				 */
				next = irq_fd->next;
				if(irq_fd->freed){
					free_irq(irq_fd->irq, irq_fd->id);
					free_irq_by_irq_and_dev(irq_fd->irq,
								irq_fd->id);
				}
			}
		}
	}
}

int activate_ipi(int fd, int pid)
{
	return(os_set_fd_async(fd, pid));
}

static void maybe_sigio_broken(int fd, int type)
{
	if(isatty(fd)){
		if((type == IRQ_WRITE) && !pty_output_sigio){
			write_sigio_workaround();
			add_sigio_fd(fd, 0);
		}
		else if((type == IRQ_READ) && !pty_close_sigio){
			write_sigio_workaround();
			add_sigio_fd(fd, 1);			
		}
	}
}

int activate_fd(int irq, int fd, int type, void *dev_id)
{
	struct pollfd *tmp_pfd;
	struct irq_fd *new_fd, *irq_fd;
	unsigned long flags;
	int pid, events, err, n, size;

	pid = os_getpid();
	err = os_set_fd_async(fd, pid);
	if(err < 0)
		goto out;

	new_fd = um_kmalloc(sizeof(*new_fd));
	err = -ENOMEM;
	if(new_fd == NULL)
		goto out;

	if(type == IRQ_READ) events = POLLIN | POLLPRI;
	else events = POLLOUT;
	*new_fd = ((struct irq_fd) { .next  		= NULL,
				     .id 		= dev_id,
				     .fd 		= fd,
				     .type 		= type,
				     .irq 		= irq,
				     .pid  		= pid,
				     .events 		= events,
				     .current_events 	= 0,
				     .freed 		= 0  } );

	/* Critical section - locked by a spinlock because this stuff can
	 * be changed from interrupt handlers.  The stuff above is done 
	 * outside the lock because it allocates memory.
	 */

	/* Actually, it only looks like it can be called from interrupt
	 * context.  The culprit is reactivate_fd, which calls 
	 * maybe_sigio_broken, which calls write_sigio_workaround,
	 * which calls activate_fd.  However, write_sigio_workaround should
	 * only be called once, at boot time.  That would make it clear that
	 * this is called only from process context, and can be locked with
	 * a semaphore.
	 */
	flags = irq_lock();
	for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
		if((irq_fd->fd == fd) && (irq_fd->type == type)){
			printk("Registering fd %d twice\n", fd);
			printk("Irqs : %d, %d\n", irq_fd->irq, irq);
			printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
			goto out_unlock;
		}
	}

	n = pollfds_num;
	if(n == pollfds_size){
		while(1){
			/* Here we have to drop the lock in order to call 
			 * kmalloc, which might sleep.  If something else
			 * came in and changed the pollfds array, we free
			 * the buffer and try again.
			 */
			irq_unlock(flags);
			size = (pollfds_num + 1) * sizeof(pollfds[0]);
			tmp_pfd = um_kmalloc(size);
			flags = irq_lock();
			if(tmp_pfd == NULL)
				goto out_unlock;
			if(n == pollfds_size)
				break;
			kfree(tmp_pfd);
		}
		if(pollfds != NULL){
			memcpy(tmp_pfd, pollfds,
			       sizeof(pollfds[0]) * pollfds_size);
			kfree(pollfds);
		}
		pollfds = tmp_pfd;
		pollfds_size++;
	}

	if(type == IRQ_WRITE) 
		fd = -1;

	pollfds[pollfds_num] = ((struct pollfd) { .fd 	= fd,
						  .events 	= events,
						  .revents 	= 0 });
	pollfds_num++;

	*last_irq_ptr = new_fd;
	last_irq_ptr = &new_fd->next;

	irq_unlock(flags);

	/* This calls activate_fd, so it has to be outside the critical
	 * section.
	 */
	maybe_sigio_broken(fd, type);

	return(0);

 out_unlock:
	irq_unlock(flags);
	kfree(new_fd);
 out:
	return(err);
}

static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
{
	struct irq_fd **prev;
	unsigned long flags;
	int i = 0;

	flags = irq_lock();
	prev = &active_fds;
	while(*prev != NULL){
		if((*test)(*prev, arg)){
			struct irq_fd *old_fd = *prev;
			if((pollfds[i].fd != -1) && 
			   (pollfds[i].fd != (*prev)->fd)){
				printk("free_irq_by_cb - mismatch between "
				       "active_fds and pollfds, fd %d vs %d\n",
				       (*prev)->fd, pollfds[i].fd);
				goto out;
			}
			memcpy(&pollfds[i], &pollfds[i + 1],
			       (pollfds_num - i - 1) * sizeof(pollfds[0]));
			pollfds_num--;
			if(last_irq_ptr == &old_fd->next) 
				last_irq_ptr = prev;
			*prev = (*prev)->next;
			if(old_fd->type == IRQ_WRITE) 
				ignore_sigio_fd(old_fd->fd);
			kfree(old_fd);
			continue;
		}
		prev = &(*prev)->next;
		i++;
	}
 out:
	irq_unlock(flags);
}

struct irq_and_dev {
	int irq;
	void *dev;
};

static int same_irq_and_dev(struct irq_fd *irq, void *d)
{
	struct irq_and_dev *data = d;

	return((irq->irq == data->irq) && (irq->id == data->dev));
}

void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
{
	struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
							  .dev  = dev });

	free_irq_by_cb(same_irq_and_dev, &data);
}

static int same_fd(struct irq_fd *irq, void *fd)
{
	return(irq->fd == *((int *) fd));
}

void free_irq_by_fd(int fd)
{
	free_irq_by_cb(same_fd, &fd);
}

static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
{
	struct irq_fd *irq;
	int i = 0;

	for(irq=active_fds; irq != NULL; irq = irq->next){
		if((irq->fd == fd) && (irq->irq == irqnum)) break;
		i++;
	}
	if(irq == NULL){
		printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
		goto out;
	}
	if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
		printk("find_irq_by_fd - mismatch between active_fds and "
		       "pollfds, fd %d vs %d, need %d\n", irq->fd, 
		       pollfds[i].fd, fd);
		irq = NULL;
		goto out;
	}
	*index_out = i;
 out:
	return(irq);
}

void free_irq_later(int irq, void *dev_id)
{
	struct irq_fd *irq_fd;
	unsigned long flags;

	flags = irq_lock();
	for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
		if((irq_fd->irq == irq) && (irq_fd->id == dev_id))
			break;
	}
	if(irq_fd == NULL){
		printk("free_irq_later found no irq, irq = %d, "
		       "dev_id = 0x%p\n", irq, dev_id);
		goto out;
	}
	irq_fd->freed = 1;
 out:
	irq_unlock(flags);
}

void reactivate_fd(int fd, int irqnum)
{
	struct irq_fd *irq;
	unsigned long flags;
	int i;

	flags = irq_lock();
	irq = find_irq_by_fd(fd, irqnum, &i);
	if(irq == NULL){
		irq_unlock(flags);
		return;
	}

	pollfds[i].fd = irq->fd;

	irq_unlock(flags);

	/* This calls activate_fd, so it has to be outside the critical
	 * section.
	 */
	maybe_sigio_broken(fd, irq->type);
}

void deactivate_fd(int fd, int irqnum)
{
	struct irq_fd *irq;
	unsigned long flags;
	int i;

	flags = irq_lock();
	irq = find_irq_by_fd(fd, irqnum, &i);
	if(irq == NULL)
		goto out;
	pollfds[i].fd = -1;
 out:
	irq_unlock(flags);
}

int deactivate_all_fds(void)
{
	struct irq_fd *irq;
	int err;

	for(irq=active_fds;irq != NULL;irq = irq->next){
		err = os_clear_fd_async(irq->fd);
		if(err)
			return(err);
	}
	/* If there is a signal already queued, after unblocking ignore it */
	set_handler(SIGIO, SIG_IGN, 0, -1);

	return(0);
}

void forward_ipi(int fd, int pid)
{
	int err;

	err = os_set_owner(fd, pid);
	if(err < 0)
		printk("forward_ipi: set_owner failed, fd = %d, me = %d, "
		       "target = %d, err = %d\n", fd, os_getpid(), pid, -err);
}

void forward_interrupts(int pid)
{
	struct irq_fd *irq;
	unsigned long flags;
	int err;

	flags = irq_lock();
	for(irq=active_fds;irq != NULL;irq = irq->next){
		err = os_set_owner(irq->fd, pid);
		if(err < 0){
			/* XXX Just remove the irq rather than
			 * print out an infinite stream of these
			 */
			printk("Failed to forward %d to pid %d, err = %d\n",
			       irq->fd, pid, -err);
		}

		irq->pid = pid;
	}
	irq_unlock(flags);
}

void init_irq_signals(int on_sigstack)
{
	__sighandler_t h;
	int flags;

	flags = on_sigstack ? SA_ONSTACK : 0;
	if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
	else h = boot_timer_handler;

	set_handler(SIGVTALRM, h, flags | SA_RESTART, 
		    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
	set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
		    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
	signal(SIGWINCH, SIG_IGN);
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */