Commit | Line | Data |
---|---|---|
2ea5bc5e | 1 | /* |
ba180fd4 | 2 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
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 | ||
37185b33 AV |
8 | #include <linux/cpumask.h> |
9 | #include <linux/hardirq.h> | |
10 | #include <linux/interrupt.h> | |
11 | #include <linux/kernel_stat.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/seq_file.h> | |
15 | #include <linux/slab.h> | |
16 | #include <as-layout.h> | |
17 | #include <kern_util.h> | |
18 | #include <os.h> | |
1da177e4 | 19 | |
d973a77b JD |
20 | /* |
21 | * This list is accessed under irq_lock, except in sigio_handler, | |
22 | * where it is safe from being modified. IRQ handlers won't change it - | |
23 | * if an IRQ source has vanished, it will be freed by free_irqs just | |
24 | * before returning from sigio_handler. That will process a separate | |
25 | * list of irqs to free, with its own locking, coming back here to | |
26 | * remove list elements, taking the irq_lock to do so. | |
27 | */ | |
f2e62992 | 28 | static struct irq_fd *active_fds = NULL; |
9b4f018d JD |
29 | static struct irq_fd **last_irq_ptr = &active_fds; |
30 | ||
31 | extern void free_irqs(void); | |
32 | ||
d3c1cfcd | 33 | void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) |
9b4f018d JD |
34 | { |
35 | struct irq_fd *irq_fd; | |
36 | int n; | |
37 | ||
191ef966 | 38 | while (1) { |
9b4f018d JD |
39 | n = os_waiting_for_events(active_fds); |
40 | if (n <= 0) { | |
ba180fd4 JD |
41 | if (n == -EINTR) |
42 | continue; | |
9b4f018d JD |
43 | else break; |
44 | } | |
45 | ||
ba180fd4 JD |
46 | for (irq_fd = active_fds; irq_fd != NULL; |
47 | irq_fd = irq_fd->next) { | |
191ef966 | 48 | if (irq_fd->current_events != 0) { |
9b4f018d JD |
49 | irq_fd->current_events = 0; |
50 | do_IRQ(irq_fd->irq, regs); | |
51 | } | |
52 | } | |
53 | } | |
54 | ||
55 | free_irqs(); | |
56 | } | |
57 | ||
bfaafd71 JD |
58 | static DEFINE_SPINLOCK(irq_lock); |
59 | ||
4c182ae7 | 60 | static int activate_fd(int irq, int fd, int type, void *dev_id) |
9b4f018d JD |
61 | { |
62 | struct pollfd *tmp_pfd; | |
63 | struct irq_fd *new_fd, *irq_fd; | |
64 | unsigned long flags; | |
bf8fde78 | 65 | int events, err, n; |
9b4f018d | 66 | |
bf8fde78 | 67 | err = os_set_fd_async(fd); |
191ef966 | 68 | if (err < 0) |
9b4f018d JD |
69 | goto out; |
70 | ||
9b4f018d | 71 | err = -ENOMEM; |
f2e62992 | 72 | new_fd = kmalloc(sizeof(struct irq_fd), GFP_KERNEL); |
191ef966 | 73 | if (new_fd == NULL) |
9b4f018d JD |
74 | goto out; |
75 | ||
191ef966 JJ |
76 | if (type == IRQ_READ) |
77 | events = UM_POLLIN | UM_POLLPRI; | |
ba180fd4 | 78 | else events = UM_POLLOUT; |
9b4f018d JD |
79 | *new_fd = ((struct irq_fd) { .next = NULL, |
80 | .id = dev_id, | |
81 | .fd = fd, | |
82 | .type = type, | |
83 | .irq = irq, | |
9b4f018d JD |
84 | .events = events, |
85 | .current_events = 0 } ); | |
86 | ||
0f97869d | 87 | err = -EBUSY; |
bfaafd71 | 88 | spin_lock_irqsave(&irq_lock, flags); |
191ef966 JJ |
89 | for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) { |
90 | if ((irq_fd->fd == fd) && (irq_fd->type == type)) { | |
ba180fd4 JD |
91 | printk(KERN_ERR "Registering fd %d twice\n", fd); |
92 | printk(KERN_ERR "Irqs : %d, %d\n", irq_fd->irq, irq); | |
93 | printk(KERN_ERR "Ids : 0x%p, 0x%p\n", irq_fd->id, | |
94 | dev_id); | |
9b4f018d JD |
95 | goto out_unlock; |
96 | } | |
97 | } | |
98 | ||
191ef966 | 99 | if (type == IRQ_WRITE) |
9b4f018d JD |
100 | fd = -1; |
101 | ||
102 | tmp_pfd = NULL; | |
103 | n = 0; | |
104 | ||
191ef966 | 105 | while (1) { |
9b4f018d JD |
106 | n = os_create_pollfd(fd, events, tmp_pfd, n); |
107 | if (n == 0) | |
108 | break; | |
109 | ||
ba180fd4 JD |
110 | /* |
111 | * n > 0 | |
9b4f018d JD |
112 | * It means we couldn't put new pollfd to current pollfds |
113 | * and tmp_fds is NULL or too small for new pollfds array. | |
114 | * Needed size is equal to n as minimum. | |
115 | * | |
116 | * Here we have to drop the lock in order to call | |
117 | * kmalloc, which might sleep. | |
118 | * If something else came in and changed the pollfds array | |
119 | * so we will not be able to put new pollfd struct to pollfds | |
120 | * then we free the buffer tmp_fds and try again. | |
121 | */ | |
bfaafd71 | 122 | spin_unlock_irqrestore(&irq_lock, flags); |
191ef966 | 123 | kfree(tmp_pfd); |
9b4f018d | 124 | |
f2e62992 | 125 | tmp_pfd = kmalloc(n, GFP_KERNEL); |
9b4f018d JD |
126 | if (tmp_pfd == NULL) |
127 | goto out_kfree; | |
128 | ||
bfaafd71 | 129 | spin_lock_irqsave(&irq_lock, flags); |
9b4f018d | 130 | } |
9b4f018d JD |
131 | |
132 | *last_irq_ptr = new_fd; | |
133 | last_irq_ptr = &new_fd->next; | |
134 | ||
bfaafd71 | 135 | spin_unlock_irqrestore(&irq_lock, flags); |
9b4f018d | 136 | |
ba180fd4 JD |
137 | /* |
138 | * This calls activate_fd, so it has to be outside the critical | |
9b4f018d JD |
139 | * section. |
140 | */ | |
8e64d96a | 141 | maybe_sigio_broken(fd, (type == IRQ_READ)); |
9b4f018d | 142 | |
19bdf040 | 143 | return 0; |
9b4f018d JD |
144 | |
145 | out_unlock: | |
bfaafd71 | 146 | spin_unlock_irqrestore(&irq_lock, flags); |
9b4f018d JD |
147 | out_kfree: |
148 | kfree(new_fd); | |
149 | out: | |
19bdf040 | 150 | return err; |
9b4f018d JD |
151 | } |
152 | ||
153 | static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg) | |
154 | { | |
155 | unsigned long flags; | |
156 | ||
bfaafd71 | 157 | spin_lock_irqsave(&irq_lock, flags); |
9b4f018d | 158 | os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr); |
bfaafd71 | 159 | spin_unlock_irqrestore(&irq_lock, flags); |
9b4f018d JD |
160 | } |
161 | ||
162 | struct irq_and_dev { | |
163 | int irq; | |
164 | void *dev; | |
165 | }; | |
166 | ||
167 | static int same_irq_and_dev(struct irq_fd *irq, void *d) | |
168 | { | |
169 | struct irq_and_dev *data = d; | |
170 | ||
191ef966 | 171 | return ((irq->irq == data->irq) && (irq->id == data->dev)); |
9b4f018d JD |
172 | } |
173 | ||
4c182ae7 | 174 | static void free_irq_by_irq_and_dev(unsigned int irq, void *dev) |
9b4f018d JD |
175 | { |
176 | struct irq_and_dev data = ((struct irq_and_dev) { .irq = irq, | |
177 | .dev = dev }); | |
178 | ||
179 | free_irq_by_cb(same_irq_and_dev, &data); | |
180 | } | |
181 | ||
182 | static int same_fd(struct irq_fd *irq, void *fd) | |
183 | { | |
191ef966 | 184 | return (irq->fd == *((int *)fd)); |
9b4f018d JD |
185 | } |
186 | ||
187 | void free_irq_by_fd(int fd) | |
188 | { | |
189 | free_irq_by_cb(same_fd, &fd); | |
190 | } | |
191 | ||
d973a77b | 192 | /* Must be called with irq_lock held */ |
9b4f018d JD |
193 | static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out) |
194 | { | |
195 | struct irq_fd *irq; | |
196 | int i = 0; | |
197 | int fdi; | |
198 | ||
191ef966 JJ |
199 | for (irq = active_fds; irq != NULL; irq = irq->next) { |
200 | if ((irq->fd == fd) && (irq->irq == irqnum)) | |
201 | break; | |
9b4f018d JD |
202 | i++; |
203 | } | |
191ef966 | 204 | if (irq == NULL) { |
ba180fd4 JD |
205 | printk(KERN_ERR "find_irq_by_fd doesn't have descriptor %d\n", |
206 | fd); | |
9b4f018d JD |
207 | goto out; |
208 | } | |
209 | fdi = os_get_pollfd(i); | |
191ef966 | 210 | if ((fdi != -1) && (fdi != fd)) { |
ba180fd4 JD |
211 | printk(KERN_ERR "find_irq_by_fd - mismatch between active_fds " |
212 | "and pollfds, fd %d vs %d, need %d\n", irq->fd, | |
9b4f018d JD |
213 | fdi, fd); |
214 | irq = NULL; | |
215 | goto out; | |
216 | } | |
217 | *index_out = i; | |
218 | out: | |
191ef966 | 219 | return irq; |
9b4f018d JD |
220 | } |
221 | ||
222 | void reactivate_fd(int fd, int irqnum) | |
223 | { | |
224 | struct irq_fd *irq; | |
225 | unsigned long flags; | |
226 | int i; | |
227 | ||
bfaafd71 | 228 | spin_lock_irqsave(&irq_lock, flags); |
9b4f018d | 229 | irq = find_irq_by_fd(fd, irqnum, &i); |
191ef966 | 230 | if (irq == NULL) { |
bfaafd71 | 231 | spin_unlock_irqrestore(&irq_lock, flags); |
9b4f018d JD |
232 | return; |
233 | } | |
234 | os_set_pollfd(i, irq->fd); | |
bfaafd71 | 235 | spin_unlock_irqrestore(&irq_lock, flags); |
9b4f018d | 236 | |
19bdf040 | 237 | add_sigio_fd(fd); |
9b4f018d JD |
238 | } |
239 | ||
240 | void deactivate_fd(int fd, int irqnum) | |
241 | { | |
242 | struct irq_fd *irq; | |
243 | unsigned long flags; | |
244 | int i; | |
245 | ||
bfaafd71 | 246 | spin_lock_irqsave(&irq_lock, flags); |
9b4f018d | 247 | irq = find_irq_by_fd(fd, irqnum, &i); |
ba180fd4 | 248 | if (irq == NULL) { |
19bdf040 JD |
249 | spin_unlock_irqrestore(&irq_lock, flags); |
250 | return; | |
251 | } | |
252 | ||
9b4f018d | 253 | os_set_pollfd(i, -1); |
bfaafd71 | 254 | spin_unlock_irqrestore(&irq_lock, flags); |
19bdf040 JD |
255 | |
256 | ignore_sigio_fd(fd); | |
9b4f018d | 257 | } |
73395a00 | 258 | EXPORT_SYMBOL(deactivate_fd); |
9b4f018d | 259 | |
d973a77b JD |
260 | /* |
261 | * Called just before shutdown in order to provide a clean exec | |
262 | * environment in case the system is rebooting. No locking because | |
263 | * that would cause a pointless shutdown hang if something hadn't | |
264 | * released the lock. | |
265 | */ | |
9b4f018d JD |
266 | int deactivate_all_fds(void) |
267 | { | |
268 | struct irq_fd *irq; | |
269 | int err; | |
270 | ||
191ef966 | 271 | for (irq = active_fds; irq != NULL; irq = irq->next) { |
9b4f018d | 272 | err = os_clear_fd_async(irq->fd); |
191ef966 JJ |
273 | if (err) |
274 | return err; | |
9b4f018d JD |
275 | } |
276 | /* If there is a signal already queued, after unblocking ignore it */ | |
277 | os_set_ioignore(); | |
278 | ||
191ef966 | 279 | return 0; |
9b4f018d JD |
280 | } |
281 | ||
1da177e4 | 282 | /* |
b60745b9 | 283 | * do_IRQ handles all normal device IRQs (the special |
1da177e4 LT |
284 | * SMP cross-CPU interrupts have their own specific |
285 | * handlers). | |
286 | */ | |
77bf4400 | 287 | unsigned int do_IRQ(int irq, struct uml_pt_regs *regs) |
1da177e4 | 288 | { |
7bea96fd AV |
289 | struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)regs); |
290 | irq_enter(); | |
be76d81f | 291 | generic_handle_irq(irq); |
7bea96fd AV |
292 | irq_exit(); |
293 | set_irq_regs(old_regs); | |
294 | return 1; | |
1da177e4 LT |
295 | } |
296 | ||
fa7a0449 RW |
297 | void um_free_irq(unsigned int irq, void *dev) |
298 | { | |
299 | free_irq_by_irq_and_dev(irq, dev); | |
300 | free_irq(irq, dev); | |
301 | } | |
302 | EXPORT_SYMBOL(um_free_irq); | |
303 | ||
1da177e4 | 304 | int um_request_irq(unsigned int irq, int fd, int type, |
40220c1a | 305 | irq_handler_t handler, |
1da177e4 LT |
306 | unsigned long irqflags, const char * devname, |
307 | void *dev_id) | |
308 | { | |
309 | int err; | |
310 | ||
9ac625a3 | 311 | if (fd != -1) { |
1da177e4 | 312 | err = activate_fd(irq, fd, type, dev_id); |
9ac625a3 JD |
313 | if (err) |
314 | return err; | |
315 | } | |
316 | ||
317 | return request_irq(irq, handler, irqflags, devname, dev_id); | |
1da177e4 | 318 | } |
9ac625a3 | 319 | |
1da177e4 LT |
320 | EXPORT_SYMBOL(um_request_irq); |
321 | EXPORT_SYMBOL(reactivate_fd); | |
322 | ||
ba180fd4 | 323 | /* |
1d119aa0 TG |
324 | * irq_chip must define at least enable/disable and ack when |
325 | * the edge handler is used. | |
ba180fd4 | 326 | */ |
1d119aa0 | 327 | static void dummy(struct irq_data *d) |
1da177e4 LT |
328 | { |
329 | } | |
330 | ||
dbce706e | 331 | /* This is used for everything else than the timer. */ |
6fa851c3 | 332 | static struct irq_chip normal_irq_type = { |
d1ea13c6 | 333 | .name = "SIGIO", |
1d119aa0 TG |
334 | .irq_disable = dummy, |
335 | .irq_enable = dummy, | |
336 | .irq_ack = dummy, | |
81bab4c3 RW |
337 | .irq_mask = dummy, |
338 | .irq_unmask = dummy, | |
1da177e4 LT |
339 | }; |
340 | ||
6fa851c3 | 341 | static struct irq_chip SIGVTALRM_irq_type = { |
d1ea13c6 | 342 | .name = "SIGVTALRM", |
1d119aa0 TG |
343 | .irq_disable = dummy, |
344 | .irq_enable = dummy, | |
345 | .irq_ack = dummy, | |
81bab4c3 RW |
346 | .irq_mask = dummy, |
347 | .irq_unmask = dummy, | |
1da177e4 LT |
348 | }; |
349 | ||
350 | void __init init_IRQ(void) | |
351 | { | |
352 | int i; | |
353 | ||
0ebec35f | 354 | irq_set_chip_and_handler(TIMER_IRQ, &SIGVTALRM_irq_type, handle_edge_irq); |
be76d81f | 355 | |
0ebec35f TG |
356 | for (i = 1; i < NR_IRQS; i++) |
357 | irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq); | |
1da177e4 LT |
358 | } |
359 | ||
c14b8494 JD |
360 | /* |
361 | * IRQ stack entry and exit: | |
362 | * | |
363 | * Unlike i386, UML doesn't receive IRQs on the normal kernel stack | |
364 | * and switch over to the IRQ stack after some preparation. We use | |
365 | * sigaltstack to receive signals on a separate stack from the start. | |
366 | * These two functions make sure the rest of the kernel won't be too | |
367 | * upset by being on a different stack. The IRQ stack has a | |
368 | * thread_info structure at the bottom so that current et al continue | |
369 | * to work. | |
370 | * | |
371 | * to_irq_stack copies the current task's thread_info to the IRQ stack | |
372 | * thread_info and sets the tasks's stack to point to the IRQ stack. | |
373 | * | |
374 | * from_irq_stack copies the thread_info struct back (flags may have | |
375 | * been modified) and resets the task's stack pointer. | |
376 | * | |
377 | * Tricky bits - | |
378 | * | |
379 | * What happens when two signals race each other? UML doesn't block | |
380 | * signals with sigprocmask, SA_DEFER, or sa_mask, so a second signal | |
381 | * could arrive while a previous one is still setting up the | |
382 | * thread_info. | |
383 | * | |
384 | * There are three cases - | |
385 | * The first interrupt on the stack - sets up the thread_info and | |
386 | * handles the interrupt | |
387 | * A nested interrupt interrupting the copying of the thread_info - | |
388 | * can't handle the interrupt, as the stack is in an unknown state | |
389 | * A nested interrupt not interrupting the copying of the | |
390 | * thread_info - doesn't do any setup, just handles the interrupt | |
391 | * | |
392 | * The first job is to figure out whether we interrupted stack setup. | |
393 | * This is done by xchging the signal mask with thread_info->pending. | |
394 | * If the value that comes back is zero, then there is no setup in | |
395 | * progress, and the interrupt can be handled. If the value is | |
396 | * non-zero, then there is stack setup in progress. In order to have | |
397 | * the interrupt handled, we leave our signal in the mask, and it will | |
398 | * be handled by the upper handler after it has set up the stack. | |
399 | * | |
400 | * Next is to figure out whether we are the outer handler or a nested | |
401 | * one. As part of setting up the stack, thread_info->real_thread is | |
402 | * set to non-NULL (and is reset to NULL on exit). This is the | |
403 | * nesting indicator. If it is non-NULL, then the stack is already | |
404 | * set up and the handler can run. | |
405 | */ | |
406 | ||
407 | static unsigned long pending_mask; | |
408 | ||
508a9274 | 409 | unsigned long to_irq_stack(unsigned long *mask_out) |
c14b8494 JD |
410 | { |
411 | struct thread_info *ti; | |
412 | unsigned long mask, old; | |
413 | int nested; | |
414 | ||
508a9274 | 415 | mask = xchg(&pending_mask, *mask_out); |
ba180fd4 JD |
416 | if (mask != 0) { |
417 | /* | |
418 | * If any interrupts come in at this point, we want to | |
c14b8494 JD |
419 | * make sure that their bits aren't lost by our |
420 | * putting our bit in. So, this loop accumulates bits | |
421 | * until xchg returns the same value that we put in. | |
422 | * When that happens, there were no new interrupts, | |
423 | * and pending_mask contains a bit for each interrupt | |
424 | * that came in. | |
425 | */ | |
508a9274 | 426 | old = *mask_out; |
c14b8494 JD |
427 | do { |
428 | old |= mask; | |
429 | mask = xchg(&pending_mask, old); | |
ba180fd4 | 430 | } while (mask != old); |
c14b8494 JD |
431 | return 1; |
432 | } | |
433 | ||
434 | ti = current_thread_info(); | |
435 | nested = (ti->real_thread != NULL); | |
ba180fd4 | 436 | if (!nested) { |
c14b8494 JD |
437 | struct task_struct *task; |
438 | struct thread_info *tti; | |
439 | ||
440 | task = cpu_tasks[ti->cpu].task; | |
441 | tti = task_thread_info(task); | |
508a9274 | 442 | |
c14b8494 JD |
443 | *ti = *tti; |
444 | ti->real_thread = tti; | |
445 | task->stack = ti; | |
446 | } | |
447 | ||
448 | mask = xchg(&pending_mask, 0); | |
449 | *mask_out |= mask | nested; | |
450 | return 0; | |
451 | } | |
452 | ||
453 | unsigned long from_irq_stack(int nested) | |
454 | { | |
455 | struct thread_info *ti, *to; | |
456 | unsigned long mask; | |
457 | ||
458 | ti = current_thread_info(); | |
459 | ||
460 | pending_mask = 1; | |
461 | ||
462 | to = ti->real_thread; | |
463 | current->stack = to; | |
464 | ti->real_thread = NULL; | |
465 | *to = *ti; | |
466 | ||
467 | mask = xchg(&pending_mask, 0); | |
468 | return mask & ~1; | |
469 | } | |
470 |