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