blob: 1d8505b1e2908289b49961019b885908d312fed8 [file] [log] [blame]
Jeff Dike2ea5bc52007-05-10 22:22:32 -07001/*
Jeff Dikeba180fd2007-10-16 01:27:00 -07002 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * 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
Al Viro37185b32012-10-08 03:27:32 +01008#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20/*
Jeff Diked973a772007-05-06 14:51:27 -070021 * 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 */
Jeff Dikef2e62992007-02-10 01:44:23 -080028static struct irq_fd *active_fds = NULL;
Jeff Dike9b4f0182006-03-27 01:14:31 -080029static struct irq_fd **last_irq_ptr = &active_fds;
30
31extern void free_irqs(void);
32
Martin Pärteld3c1cfc2012-08-02 00:49:17 +020033void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
Jeff Dike9b4f0182006-03-27 01:14:31 -080034{
35 struct irq_fd *irq_fd;
36 int n;
37
Jesper Juhl191ef962006-05-01 12:15:57 -070038 if (smp_sigio_handler())
39 return;
40
41 while (1) {
Jeff Dike9b4f0182006-03-27 01:14:31 -080042 n = os_waiting_for_events(active_fds);
43 if (n <= 0) {
Jeff Dikeba180fd2007-10-16 01:27:00 -070044 if (n == -EINTR)
45 continue;
Jeff Dike9b4f0182006-03-27 01:14:31 -080046 else break;
47 }
48
Jeff Dikeba180fd2007-10-16 01:27:00 -070049 for (irq_fd = active_fds; irq_fd != NULL;
50 irq_fd = irq_fd->next) {
Jesper Juhl191ef962006-05-01 12:15:57 -070051 if (irq_fd->current_events != 0) {
Jeff Dike9b4f0182006-03-27 01:14:31 -080052 irq_fd->current_events = 0;
53 do_IRQ(irq_fd->irq, regs);
54 }
55 }
56 }
57
58 free_irqs();
59}
60
Jeff Dikebfaafd72006-07-10 04:45:10 -070061static DEFINE_SPINLOCK(irq_lock);
62
WANG Cong4c182ae2008-07-23 21:28:47 -070063static int activate_fd(int irq, int fd, int type, void *dev_id)
Jeff Dike9b4f0182006-03-27 01:14:31 -080064{
65 struct pollfd *tmp_pfd;
66 struct irq_fd *new_fd, *irq_fd;
67 unsigned long flags;
Jeff Dikebf8fde72008-02-04 22:31:04 -080068 int events, err, n;
Jeff Dike9b4f0182006-03-27 01:14:31 -080069
Jeff Dikebf8fde72008-02-04 22:31:04 -080070 err = os_set_fd_async(fd);
Jesper Juhl191ef962006-05-01 12:15:57 -070071 if (err < 0)
Jeff Dike9b4f0182006-03-27 01:14:31 -080072 goto out;
73
Jeff Dike9b4f0182006-03-27 01:14:31 -080074 err = -ENOMEM;
Jeff Dikef2e62992007-02-10 01:44:23 -080075 new_fd = kmalloc(sizeof(struct irq_fd), GFP_KERNEL);
Jesper Juhl191ef962006-05-01 12:15:57 -070076 if (new_fd == NULL)
Jeff Dike9b4f0182006-03-27 01:14:31 -080077 goto out;
78
Jesper Juhl191ef962006-05-01 12:15:57 -070079 if (type == IRQ_READ)
80 events = UM_POLLIN | UM_POLLPRI;
Jeff Dikeba180fd2007-10-16 01:27:00 -070081 else events = UM_POLLOUT;
Jeff Dike9b4f0182006-03-27 01:14:31 -080082 *new_fd = ((struct irq_fd) { .next = NULL,
83 .id = dev_id,
84 .fd = fd,
85 .type = type,
86 .irq = irq,
Jeff Dike9b4f0182006-03-27 01:14:31 -080087 .events = events,
88 .current_events = 0 } );
89
Paolo 'Blaisorblade' Giarrusso0f978692007-03-07 20:41:13 -080090 err = -EBUSY;
Jeff Dikebfaafd72006-07-10 04:45:10 -070091 spin_lock_irqsave(&irq_lock, flags);
Jesper Juhl191ef962006-05-01 12:15:57 -070092 for (irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next) {
93 if ((irq_fd->fd == fd) && (irq_fd->type == type)) {
Jeff Dikeba180fd2007-10-16 01:27:00 -070094 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);
Jeff Dike9b4f0182006-03-27 01:14:31 -080098 goto out_unlock;
99 }
100 }
101
Jesper Juhl191ef962006-05-01 12:15:57 -0700102 if (type == IRQ_WRITE)
Jeff Dike9b4f0182006-03-27 01:14:31 -0800103 fd = -1;
104
105 tmp_pfd = NULL;
106 n = 0;
107
Jesper Juhl191ef962006-05-01 12:15:57 -0700108 while (1) {
Jeff Dike9b4f0182006-03-27 01:14:31 -0800109 n = os_create_pollfd(fd, events, tmp_pfd, n);
110 if (n == 0)
111 break;
112
Jeff Dikeba180fd2007-10-16 01:27:00 -0700113 /*
114 * n > 0
Jeff Dike9b4f0182006-03-27 01:14:31 -0800115 * 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 */
Jeff Dikebfaafd72006-07-10 04:45:10 -0700125 spin_unlock_irqrestore(&irq_lock, flags);
Jesper Juhl191ef962006-05-01 12:15:57 -0700126 kfree(tmp_pfd);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800127
Jeff Dikef2e62992007-02-10 01:44:23 -0800128 tmp_pfd = kmalloc(n, GFP_KERNEL);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800129 if (tmp_pfd == NULL)
130 goto out_kfree;
131
Jeff Dikebfaafd72006-07-10 04:45:10 -0700132 spin_lock_irqsave(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800133 }
Jeff Dike9b4f0182006-03-27 01:14:31 -0800134
135 *last_irq_ptr = new_fd;
136 last_irq_ptr = &new_fd->next;
137
Jeff Dikebfaafd72006-07-10 04:45:10 -0700138 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800139
Jeff Dikeba180fd2007-10-16 01:27:00 -0700140 /*
141 * This calls activate_fd, so it has to be outside the critical
Jeff Dike9b4f0182006-03-27 01:14:31 -0800142 * section.
143 */
Jeff Dike8e64d96a2006-07-10 04:45:11 -0700144 maybe_sigio_broken(fd, (type == IRQ_READ));
Jeff Dike9b4f0182006-03-27 01:14:31 -0800145
Jeff Dike19bdf042006-09-25 23:33:04 -0700146 return 0;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800147
148 out_unlock:
Jeff Dikebfaafd72006-07-10 04:45:10 -0700149 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800150 out_kfree:
151 kfree(new_fd);
152 out:
Jeff Dike19bdf042006-09-25 23:33:04 -0700153 return err;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800154}
155
156static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
157{
158 unsigned long flags;
159
Jeff Dikebfaafd72006-07-10 04:45:10 -0700160 spin_lock_irqsave(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800161 os_free_irq_by_cb(test, arg, active_fds, &last_irq_ptr);
Jeff Dikebfaafd72006-07-10 04:45:10 -0700162 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800163}
164
165struct irq_and_dev {
166 int irq;
167 void *dev;
168};
169
170static int same_irq_and_dev(struct irq_fd *irq, void *d)
171{
172 struct irq_and_dev *data = d;
173
Jesper Juhl191ef962006-05-01 12:15:57 -0700174 return ((irq->irq == data->irq) && (irq->id == data->dev));
Jeff Dike9b4f0182006-03-27 01:14:31 -0800175}
176
WANG Cong4c182ae2008-07-23 21:28:47 -0700177static void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
Jeff Dike9b4f0182006-03-27 01:14:31 -0800178{
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
185static int same_fd(struct irq_fd *irq, void *fd)
186{
Jesper Juhl191ef962006-05-01 12:15:57 -0700187 return (irq->fd == *((int *)fd));
Jeff Dike9b4f0182006-03-27 01:14:31 -0800188}
189
190void free_irq_by_fd(int fd)
191{
192 free_irq_by_cb(same_fd, &fd);
193}
194
Jeff Diked973a772007-05-06 14:51:27 -0700195/* Must be called with irq_lock held */
Jeff Dike9b4f0182006-03-27 01:14:31 -0800196static 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
Jesper Juhl191ef962006-05-01 12:15:57 -0700202 for (irq = active_fds; irq != NULL; irq = irq->next) {
203 if ((irq->fd == fd) && (irq->irq == irqnum))
204 break;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800205 i++;
206 }
Jesper Juhl191ef962006-05-01 12:15:57 -0700207 if (irq == NULL) {
Jeff Dikeba180fd2007-10-16 01:27:00 -0700208 printk(KERN_ERR "find_irq_by_fd doesn't have descriptor %d\n",
209 fd);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800210 goto out;
211 }
212 fdi = os_get_pollfd(i);
Jesper Juhl191ef962006-05-01 12:15:57 -0700213 if ((fdi != -1) && (fdi != fd)) {
Jeff Dikeba180fd2007-10-16 01:27:00 -0700214 printk(KERN_ERR "find_irq_by_fd - mismatch between active_fds "
215 "and pollfds, fd %d vs %d, need %d\n", irq->fd,
Jeff Dike9b4f0182006-03-27 01:14:31 -0800216 fdi, fd);
217 irq = NULL;
218 goto out;
219 }
220 *index_out = i;
221 out:
Jesper Juhl191ef962006-05-01 12:15:57 -0700222 return irq;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800223}
224
225void reactivate_fd(int fd, int irqnum)
226{
227 struct irq_fd *irq;
228 unsigned long flags;
229 int i;
230
Jeff Dikebfaafd72006-07-10 04:45:10 -0700231 spin_lock_irqsave(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800232 irq = find_irq_by_fd(fd, irqnum, &i);
Jesper Juhl191ef962006-05-01 12:15:57 -0700233 if (irq == NULL) {
Jeff Dikebfaafd72006-07-10 04:45:10 -0700234 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800235 return;
236 }
237 os_set_pollfd(i, irq->fd);
Jeff Dikebfaafd72006-07-10 04:45:10 -0700238 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800239
Jeff Dike19bdf042006-09-25 23:33:04 -0700240 add_sigio_fd(fd);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800241}
242
243void deactivate_fd(int fd, int irqnum)
244{
245 struct irq_fd *irq;
246 unsigned long flags;
247 int i;
248
Jeff Dikebfaafd72006-07-10 04:45:10 -0700249 spin_lock_irqsave(&irq_lock, flags);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800250 irq = find_irq_by_fd(fd, irqnum, &i);
Jeff Dikeba180fd2007-10-16 01:27:00 -0700251 if (irq == NULL) {
Jeff Dike19bdf042006-09-25 23:33:04 -0700252 spin_unlock_irqrestore(&irq_lock, flags);
253 return;
254 }
255
Jeff Dike9b4f0182006-03-27 01:14:31 -0800256 os_set_pollfd(i, -1);
Jeff Dikebfaafd72006-07-10 04:45:10 -0700257 spin_unlock_irqrestore(&irq_lock, flags);
Jeff Dike19bdf042006-09-25 23:33:04 -0700258
259 ignore_sigio_fd(fd);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800260}
Al Viro73395a02011-08-18 20:14:10 +0100261EXPORT_SYMBOL(deactivate_fd);
Jeff Dike9b4f0182006-03-27 01:14:31 -0800262
Jeff Diked973a772007-05-06 14:51:27 -0700263/*
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 */
Jeff Dike9b4f0182006-03-27 01:14:31 -0800269int deactivate_all_fds(void)
270{
271 struct irq_fd *irq;
272 int err;
273
Jesper Juhl191ef962006-05-01 12:15:57 -0700274 for (irq = active_fds; irq != NULL; irq = irq->next) {
Jeff Dike9b4f0182006-03-27 01:14:31 -0800275 err = os_clear_fd_async(irq->fd);
Jesper Juhl191ef962006-05-01 12:15:57 -0700276 if (err)
277 return err;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800278 }
279 /* If there is a signal already queued, after unblocking ignore it */
280 os_set_ioignore();
281
Jesper Juhl191ef962006-05-01 12:15:57 -0700282 return 0;
Jeff Dike9b4f0182006-03-27 01:14:31 -0800283}
284
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285/*
Simon Arlottb60745b2007-10-20 01:23:03 +0200286 * do_IRQ handles all normal device IRQs (the special
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 * SMP cross-CPU interrupts have their own specific
288 * handlers).
289 */
Jeff Dike77bf4402007-10-16 01:26:58 -0700290unsigned int do_IRQ(int irq, struct uml_pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
Al Viro7bea96f2006-10-08 22:49:34 +0100292 struct pt_regs *old_regs = set_irq_regs((struct pt_regs *)regs);
293 irq_enter();
Richard Weinbergerbe76d812010-10-26 14:22:20 -0700294 generic_handle_irq(irq);
Al Viro7bea96f2006-10-08 22:49:34 +0100295 irq_exit();
296 set_irq_regs(old_regs);
297 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298}
299
Richard Weinbergerfa7a0442012-04-17 22:37:13 +0200300void um_free_irq(unsigned int irq, void *dev)
301{
302 free_irq_by_irq_and_dev(irq, dev);
303 free_irq(irq, dev);
304}
305EXPORT_SYMBOL(um_free_irq);
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307int um_request_irq(unsigned int irq, int fd, int type,
David Howells40220c12006-10-09 12:19:47 +0100308 irq_handler_t handler,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 unsigned long irqflags, const char * devname,
310 void *dev_id)
311{
312 int err;
313
Jeff Dike9ac625a2007-11-14 17:00:23 -0800314 if (fd != -1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 err = activate_fd(irq, fd, type, dev_id);
Jeff Dike9ac625a2007-11-14 17:00:23 -0800316 if (err)
317 return err;
318 }
319
320 return request_irq(irq, handler, irqflags, devname, dev_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321}
Jeff Dike9ac625a2007-11-14 17:00:23 -0800322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323EXPORT_SYMBOL(um_request_irq);
324EXPORT_SYMBOL(reactivate_fd);
325
Jeff Dikeba180fd2007-10-16 01:27:00 -0700326/*
Thomas Gleixner1d119aa2011-02-06 22:45:34 +0000327 * irq_chip must define at least enable/disable and ack when
328 * the edge handler is used.
Jeff Dikeba180fd2007-10-16 01:27:00 -0700329 */
Thomas Gleixner1d119aa2011-02-06 22:45:34 +0000330static void dummy(struct irq_data *d)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331{
332}
333
Paolo 'Blaisorblade' Giarrussodbce7062005-06-21 17:16:19 -0700334/* This is used for everything else than the timer. */
Thomas Gleixner6fa851c2009-06-16 15:33:29 -0700335static struct irq_chip normal_irq_type = {
Thomas Gleixnerd1ea13c2010-09-23 18:40:07 +0200336 .name = "SIGIO",
Thomas Gleixner1d119aa2011-02-06 22:45:34 +0000337 .irq_disable = dummy,
338 .irq_enable = dummy,
339 .irq_ack = dummy,
Richard Weinberger81bab4c2013-09-02 22:49:22 +0200340 .irq_mask = dummy,
341 .irq_unmask = dummy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342};
343
Thomas Gleixner6fa851c2009-06-16 15:33:29 -0700344static struct irq_chip SIGVTALRM_irq_type = {
Thomas Gleixnerd1ea13c2010-09-23 18:40:07 +0200345 .name = "SIGVTALRM",
Thomas Gleixner1d119aa2011-02-06 22:45:34 +0000346 .irq_disable = dummy,
347 .irq_enable = dummy,
348 .irq_ack = dummy,
Richard Weinberger81bab4c2013-09-02 22:49:22 +0200349 .irq_mask = dummy,
350 .irq_unmask = dummy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351};
352
353void __init init_IRQ(void)
354{
355 int i;
356
Thomas Gleixner0ebec352011-03-24 18:24:42 +0100357 irq_set_chip_and_handler(TIMER_IRQ, &SIGVTALRM_irq_type, handle_edge_irq);
Richard Weinbergerbe76d812010-10-26 14:22:20 -0700358
Thomas Gleixner0ebec352011-03-24 18:24:42 +0100359 for (i = 1; i < NR_IRQS; i++)
360 irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361}
362
Jeff Dikec14b8492007-05-10 22:22:34 -0700363/*
364 * IRQ stack entry and exit:
365 *
366 * Unlike i386, UML doesn't receive IRQs on the normal kernel stack
367 * and switch over to the IRQ stack after some preparation. We use
368 * sigaltstack to receive signals on a separate stack from the start.
369 * These two functions make sure the rest of the kernel won't be too
370 * upset by being on a different stack. The IRQ stack has a
371 * thread_info structure at the bottom so that current et al continue
372 * to work.
373 *
374 * to_irq_stack copies the current task's thread_info to the IRQ stack
375 * thread_info and sets the tasks's stack to point to the IRQ stack.
376 *
377 * from_irq_stack copies the thread_info struct back (flags may have
378 * been modified) and resets the task's stack pointer.
379 *
380 * Tricky bits -
381 *
382 * What happens when two signals race each other? UML doesn't block
383 * signals with sigprocmask, SA_DEFER, or sa_mask, so a second signal
384 * could arrive while a previous one is still setting up the
385 * thread_info.
386 *
387 * There are three cases -
388 * The first interrupt on the stack - sets up the thread_info and
389 * handles the interrupt
390 * A nested interrupt interrupting the copying of the thread_info -
391 * can't handle the interrupt, as the stack is in an unknown state
392 * A nested interrupt not interrupting the copying of the
393 * thread_info - doesn't do any setup, just handles the interrupt
394 *
395 * The first job is to figure out whether we interrupted stack setup.
396 * This is done by xchging the signal mask with thread_info->pending.
397 * If the value that comes back is zero, then there is no setup in
398 * progress, and the interrupt can be handled. If the value is
399 * non-zero, then there is stack setup in progress. In order to have
400 * the interrupt handled, we leave our signal in the mask, and it will
401 * be handled by the upper handler after it has set up the stack.
402 *
403 * Next is to figure out whether we are the outer handler or a nested
404 * one. As part of setting up the stack, thread_info->real_thread is
405 * set to non-NULL (and is reset to NULL on exit). This is the
406 * nesting indicator. If it is non-NULL, then the stack is already
407 * set up and the handler can run.
408 */
409
410static unsigned long pending_mask;
411
Jeff Dike508a9272007-09-18 22:46:49 -0700412unsigned long to_irq_stack(unsigned long *mask_out)
Jeff Dikec14b8492007-05-10 22:22:34 -0700413{
414 struct thread_info *ti;
415 unsigned long mask, old;
416 int nested;
417
Jeff Dike508a9272007-09-18 22:46:49 -0700418 mask = xchg(&pending_mask, *mask_out);
Jeff Dikeba180fd2007-10-16 01:27:00 -0700419 if (mask != 0) {
420 /*
421 * If any interrupts come in at this point, we want to
Jeff Dikec14b8492007-05-10 22:22:34 -0700422 * make sure that their bits aren't lost by our
423 * putting our bit in. So, this loop accumulates bits
424 * until xchg returns the same value that we put in.
425 * When that happens, there were no new interrupts,
426 * and pending_mask contains a bit for each interrupt
427 * that came in.
428 */
Jeff Dike508a9272007-09-18 22:46:49 -0700429 old = *mask_out;
Jeff Dikec14b8492007-05-10 22:22:34 -0700430 do {
431 old |= mask;
432 mask = xchg(&pending_mask, old);
Jeff Dikeba180fd2007-10-16 01:27:00 -0700433 } while (mask != old);
Jeff Dikec14b8492007-05-10 22:22:34 -0700434 return 1;
435 }
436
437 ti = current_thread_info();
438 nested = (ti->real_thread != NULL);
Jeff Dikeba180fd2007-10-16 01:27:00 -0700439 if (!nested) {
Jeff Dikec14b8492007-05-10 22:22:34 -0700440 struct task_struct *task;
441 struct thread_info *tti;
442
443 task = cpu_tasks[ti->cpu].task;
444 tti = task_thread_info(task);
Jeff Dike508a9272007-09-18 22:46:49 -0700445
Jeff Dikec14b8492007-05-10 22:22:34 -0700446 *ti = *tti;
447 ti->real_thread = tti;
448 task->stack = ti;
449 }
450
451 mask = xchg(&pending_mask, 0);
452 *mask_out |= mask | nested;
453 return 0;
454}
455
456unsigned long from_irq_stack(int nested)
457{
458 struct thread_info *ti, *to;
459 unsigned long mask;
460
461 ti = current_thread_info();
462
463 pending_mask = 1;
464
465 to = ti->real_thread;
466 current->stack = to;
467 ti->real_thread = NULL;
468 *to = *ti;
469
470 mask = xchg(&pending_mask, 0);
471 return mask & ~1;
472}
473