1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
3 *
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 #define dev_fmt pr_fmt
35
36 #define DPRINTK(fmt, args...) \
37 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
38 __func__, __LINE__, ##args)
39
40 #include <linux/kernel.h>
41 #include <linux/err.h>
42 #include <linux/string.h>
43 #include <linux/ctype.h>
44 #include <linux/fcntl.h>
45 #include <linux/mm.h>
46 #include <linux/proc_fs.h>
47 #include <linux/notifier.h>
48 #include <linux/kthread.h>
49 #include <linux/mutex.h>
50 #include <linux/io.h>
51 #include <linux/slab.h>
52 #include <linux/module.h>
53
54 #include <asm/page.h>
55 #include <asm/xen/hypervisor.h>
56
57 #include <xen/xen.h>
58 #include <xen/xenbus.h>
59 #include <xen/events.h>
60 #include <xen/xen-ops.h>
61 #include <xen/page.h>
62
63 #include <xen/hvm.h>
64
65 #include "xenbus.h"
66
67
68 int xen_store_evtchn;
69 EXPORT_SYMBOL_GPL(xen_store_evtchn);
70
71 struct xenstore_domain_interface *xen_store_interface;
72 EXPORT_SYMBOL_GPL(xen_store_interface);
73
74 enum xenstore_init xen_store_domain_type;
75 EXPORT_SYMBOL_GPL(xen_store_domain_type);
76
77 static unsigned long xen_store_gfn;
78
79 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
80
81 /* If something in array of ids matches this device, return it. */
82 static const struct xenbus_device_id *
match_device(const struct xenbus_device_id * arr,struct xenbus_device * dev)83 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
84 {
85 for (; *arr->devicetype != '\0'; arr++) {
86 if (!strcmp(arr->devicetype, dev->devicetype))
87 return arr;
88 }
89 return NULL;
90 }
91
xenbus_match(struct device * _dev,struct device_driver * _drv)92 int xenbus_match(struct device *_dev, struct device_driver *_drv)
93 {
94 struct xenbus_driver *drv = to_xenbus_driver(_drv);
95
96 if (!drv->ids)
97 return 0;
98
99 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
100 }
101 EXPORT_SYMBOL_GPL(xenbus_match);
102
103
free_otherend_details(struct xenbus_device * dev)104 static void free_otherend_details(struct xenbus_device *dev)
105 {
106 kfree(dev->otherend);
107 dev->otherend = NULL;
108 }
109
110
free_otherend_watch(struct xenbus_device * dev)111 static void free_otherend_watch(struct xenbus_device *dev)
112 {
113 if (dev->otherend_watch.node) {
114 unregister_xenbus_watch(&dev->otherend_watch);
115 kfree(dev->otherend_watch.node);
116 dev->otherend_watch.node = NULL;
117 }
118 }
119
120
talk_to_otherend(struct xenbus_device * dev)121 static int talk_to_otherend(struct xenbus_device *dev)
122 {
123 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
124
125 free_otherend_watch(dev);
126 free_otherend_details(dev);
127
128 return drv->read_otherend_details(dev);
129 }
130
131
132
watch_otherend(struct xenbus_device * dev)133 static int watch_otherend(struct xenbus_device *dev)
134 {
135 struct xen_bus_type *bus =
136 container_of(dev->dev.bus, struct xen_bus_type, bus);
137
138 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
139 bus->otherend_will_handle,
140 bus->otherend_changed,
141 "%s/%s", dev->otherend, "state");
142 }
143
144
xenbus_read_otherend_details(struct xenbus_device * xendev,char * id_node,char * path_node)145 int xenbus_read_otherend_details(struct xenbus_device *xendev,
146 char *id_node, char *path_node)
147 {
148 int err = xenbus_gather(XBT_NIL, xendev->nodename,
149 id_node, "%i", &xendev->otherend_id,
150 path_node, NULL, &xendev->otherend,
151 NULL);
152 if (err) {
153 xenbus_dev_fatal(xendev, err,
154 "reading other end details from %s",
155 xendev->nodename);
156 return err;
157 }
158 if (strlen(xendev->otherend) == 0 ||
159 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
160 xenbus_dev_fatal(xendev, -ENOENT,
161 "unable to read other end from %s. "
162 "missing or inaccessible.",
163 xendev->nodename);
164 free_otherend_details(xendev);
165 return -ENOENT;
166 }
167
168 return 0;
169 }
170 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
171
xenbus_otherend_changed(struct xenbus_watch * watch,const char * path,const char * token,int ignore_on_shutdown)172 void xenbus_otherend_changed(struct xenbus_watch *watch,
173 const char *path, const char *token,
174 int ignore_on_shutdown)
175 {
176 struct xenbus_device *dev =
177 container_of(watch, struct xenbus_device, otherend_watch);
178 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
179 enum xenbus_state state;
180
181 /* Protect us against watches firing on old details when the otherend
182 details change, say immediately after a resume. */
183 if (!dev->otherend ||
184 strncmp(dev->otherend, path, strlen(dev->otherend))) {
185 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
186 return;
187 }
188
189 state = xenbus_read_driver_state(dev->otherend);
190
191 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
192 state, xenbus_strstate(state), dev->otherend_watch.node, path);
193
194 /*
195 * Ignore xenbus transitions during shutdown. This prevents us doing
196 * work that can fail e.g., when the rootfs is gone.
197 */
198 if (system_state > SYSTEM_RUNNING) {
199 if (ignore_on_shutdown && (state == XenbusStateClosing))
200 xenbus_frontend_closed(dev);
201 return;
202 }
203
204 if (drv->otherend_changed)
205 drv->otherend_changed(dev, state);
206 }
207 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
208
209 #define XENBUS_SHOW_STAT(name) \
210 static ssize_t show_##name(struct device *_dev, \
211 struct device_attribute *attr, \
212 char *buf) \
213 { \
214 struct xenbus_device *dev = to_xenbus_device(_dev); \
215 \
216 return sprintf(buf, "%d\n", atomic_read(&dev->name)); \
217 } \
218 static DEVICE_ATTR(name, 0444, show_##name, NULL)
219
220 XENBUS_SHOW_STAT(event_channels);
221 XENBUS_SHOW_STAT(events);
222 XENBUS_SHOW_STAT(spurious_events);
223 XENBUS_SHOW_STAT(jiffies_eoi_delayed);
224
show_spurious_threshold(struct device * _dev,struct device_attribute * attr,char * buf)225 static ssize_t show_spurious_threshold(struct device *_dev,
226 struct device_attribute *attr,
227 char *buf)
228 {
229 struct xenbus_device *dev = to_xenbus_device(_dev);
230
231 return sprintf(buf, "%d\n", dev->spurious_threshold);
232 }
233
set_spurious_threshold(struct device * _dev,struct device_attribute * attr,const char * buf,size_t count)234 static ssize_t set_spurious_threshold(struct device *_dev,
235 struct device_attribute *attr,
236 const char *buf, size_t count)
237 {
238 struct xenbus_device *dev = to_xenbus_device(_dev);
239 unsigned int val;
240 ssize_t ret;
241
242 ret = kstrtouint(buf, 0, &val);
243 if (ret)
244 return ret;
245
246 dev->spurious_threshold = val;
247
248 return count;
249 }
250
251 static DEVICE_ATTR(spurious_threshold, 0644, show_spurious_threshold,
252 set_spurious_threshold);
253
254 static struct attribute *xenbus_attrs[] = {
255 &dev_attr_event_channels.attr,
256 &dev_attr_events.attr,
257 &dev_attr_spurious_events.attr,
258 &dev_attr_jiffies_eoi_delayed.attr,
259 &dev_attr_spurious_threshold.attr,
260 NULL
261 };
262
263 static const struct attribute_group xenbus_group = {
264 .name = "xenbus",
265 .attrs = xenbus_attrs,
266 };
267
xenbus_dev_probe(struct device * _dev)268 int xenbus_dev_probe(struct device *_dev)
269 {
270 struct xenbus_device *dev = to_xenbus_device(_dev);
271 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
272 const struct xenbus_device_id *id;
273 int err;
274
275 DPRINTK("%s", dev->nodename);
276
277 if (!drv->probe) {
278 err = -ENODEV;
279 goto fail;
280 }
281
282 id = match_device(drv->ids, dev);
283 if (!id) {
284 err = -ENODEV;
285 goto fail;
286 }
287
288 err = talk_to_otherend(dev);
289 if (err) {
290 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
291 dev->nodename);
292 return err;
293 }
294
295 if (!try_module_get(drv->driver.owner)) {
296 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
297 drv->driver.name);
298 err = -ESRCH;
299 goto fail;
300 }
301
302 down(&dev->reclaim_sem);
303 err = drv->probe(dev, id);
304 up(&dev->reclaim_sem);
305 if (err)
306 goto fail_put;
307
308 err = watch_otherend(dev);
309 if (err) {
310 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
311 dev->nodename);
312 return err;
313 }
314
315 dev->spurious_threshold = 1;
316 if (sysfs_create_group(&dev->dev.kobj, &xenbus_group))
317 dev_warn(&dev->dev, "sysfs_create_group on %s failed.\n",
318 dev->nodename);
319
320 return 0;
321 fail_put:
322 module_put(drv->driver.owner);
323 fail:
324 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
325 return err;
326 }
327 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
328
xenbus_dev_remove(struct device * _dev)329 int xenbus_dev_remove(struct device *_dev)
330 {
331 struct xenbus_device *dev = to_xenbus_device(_dev);
332 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
333
334 DPRINTK("%s", dev->nodename);
335
336 sysfs_remove_group(&dev->dev.kobj, &xenbus_group);
337
338 free_otherend_watch(dev);
339
340 if (drv->remove) {
341 down(&dev->reclaim_sem);
342 drv->remove(dev);
343 up(&dev->reclaim_sem);
344 }
345
346 module_put(drv->driver.owner);
347
348 free_otherend_details(dev);
349
350 /*
351 * If the toolstack has forced the device state to closing then set
352 * the state to closed now to allow it to be cleaned up.
353 * Similarly, if the driver does not support re-bind, set the
354 * closed.
355 */
356 if (!drv->allow_rebind ||
357 xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
358 xenbus_switch_state(dev, XenbusStateClosed);
359
360 return 0;
361 }
362 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
363
xenbus_register_driver_common(struct xenbus_driver * drv,struct xen_bus_type * bus,struct module * owner,const char * mod_name)364 int xenbus_register_driver_common(struct xenbus_driver *drv,
365 struct xen_bus_type *bus,
366 struct module *owner, const char *mod_name)
367 {
368 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
369 drv->driver.bus = &bus->bus;
370 drv->driver.owner = owner;
371 drv->driver.mod_name = mod_name;
372
373 return driver_register(&drv->driver);
374 }
375 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
376
xenbus_unregister_driver(struct xenbus_driver * drv)377 void xenbus_unregister_driver(struct xenbus_driver *drv)
378 {
379 driver_unregister(&drv->driver);
380 }
381 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
382
383 struct xb_find_info {
384 struct xenbus_device *dev;
385 const char *nodename;
386 };
387
cmp_dev(struct device * dev,void * data)388 static int cmp_dev(struct device *dev, void *data)
389 {
390 struct xenbus_device *xendev = to_xenbus_device(dev);
391 struct xb_find_info *info = data;
392
393 if (!strcmp(xendev->nodename, info->nodename)) {
394 info->dev = xendev;
395 get_device(dev);
396 return 1;
397 }
398 return 0;
399 }
400
xenbus_device_find(const char * nodename,struct bus_type * bus)401 static struct xenbus_device *xenbus_device_find(const char *nodename,
402 struct bus_type *bus)
403 {
404 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
405
406 bus_for_each_dev(bus, NULL, &info, cmp_dev);
407 return info.dev;
408 }
409
cleanup_dev(struct device * dev,void * data)410 static int cleanup_dev(struct device *dev, void *data)
411 {
412 struct xenbus_device *xendev = to_xenbus_device(dev);
413 struct xb_find_info *info = data;
414 int len = strlen(info->nodename);
415
416 DPRINTK("%s", info->nodename);
417
418 /* Match the info->nodename path, or any subdirectory of that path. */
419 if (strncmp(xendev->nodename, info->nodename, len))
420 return 0;
421
422 /* If the node name is longer, ensure it really is a subdirectory. */
423 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
424 return 0;
425
426 info->dev = xendev;
427 get_device(dev);
428 return 1;
429 }
430
xenbus_cleanup_devices(const char * path,struct bus_type * bus)431 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
432 {
433 struct xb_find_info info = { .nodename = path };
434
435 do {
436 info.dev = NULL;
437 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
438 if (info.dev) {
439 device_unregister(&info.dev->dev);
440 put_device(&info.dev->dev);
441 }
442 } while (info.dev);
443 }
444
xenbus_dev_release(struct device * dev)445 static void xenbus_dev_release(struct device *dev)
446 {
447 if (dev)
448 kfree(to_xenbus_device(dev));
449 }
450
nodename_show(struct device * dev,struct device_attribute * attr,char * buf)451 static ssize_t nodename_show(struct device *dev,
452 struct device_attribute *attr, char *buf)
453 {
454 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
455 }
456 static DEVICE_ATTR_RO(nodename);
457
devtype_show(struct device * dev,struct device_attribute * attr,char * buf)458 static ssize_t devtype_show(struct device *dev,
459 struct device_attribute *attr, char *buf)
460 {
461 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
462 }
463 static DEVICE_ATTR_RO(devtype);
464
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)465 static ssize_t modalias_show(struct device *dev,
466 struct device_attribute *attr, char *buf)
467 {
468 return sprintf(buf, "%s:%s\n", dev->bus->name,
469 to_xenbus_device(dev)->devicetype);
470 }
471 static DEVICE_ATTR_RO(modalias);
472
state_show(struct device * dev,struct device_attribute * attr,char * buf)473 static ssize_t state_show(struct device *dev,
474 struct device_attribute *attr, char *buf)
475 {
476 return sprintf(buf, "%s\n",
477 xenbus_strstate(to_xenbus_device(dev)->state));
478 }
479 static DEVICE_ATTR_RO(state);
480
481 static struct attribute *xenbus_dev_attrs[] = {
482 &dev_attr_nodename.attr,
483 &dev_attr_devtype.attr,
484 &dev_attr_modalias.attr,
485 &dev_attr_state.attr,
486 NULL,
487 };
488
489 static const struct attribute_group xenbus_dev_group = {
490 .attrs = xenbus_dev_attrs,
491 };
492
493 const struct attribute_group *xenbus_dev_groups[] = {
494 &xenbus_dev_group,
495 NULL,
496 };
497 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
498
xenbus_probe_node(struct xen_bus_type * bus,const char * type,const char * nodename)499 int xenbus_probe_node(struct xen_bus_type *bus,
500 const char *type,
501 const char *nodename)
502 {
503 char devname[XEN_BUS_ID_SIZE];
504 int err;
505 struct xenbus_device *xendev;
506 size_t stringlen;
507 char *tmpstring;
508
509 enum xenbus_state state = xenbus_read_driver_state(nodename);
510
511 if (state != XenbusStateInitialising) {
512 /* Device is not new, so ignore it. This can happen if a
513 device is going away after switching to Closed. */
514 return 0;
515 }
516
517 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
518 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
519 if (!xendev)
520 return -ENOMEM;
521
522 xendev->state = XenbusStateInitialising;
523
524 /* Copy the strings into the extra space. */
525
526 tmpstring = (char *)(xendev + 1);
527 strcpy(tmpstring, nodename);
528 xendev->nodename = tmpstring;
529
530 tmpstring += strlen(tmpstring) + 1;
531 strcpy(tmpstring, type);
532 xendev->devicetype = tmpstring;
533 init_completion(&xendev->down);
534
535 xendev->dev.bus = &bus->bus;
536 xendev->dev.release = xenbus_dev_release;
537
538 err = bus->get_bus_id(devname, xendev->nodename);
539 if (err)
540 goto fail;
541
542 dev_set_name(&xendev->dev, "%s", devname);
543 sema_init(&xendev->reclaim_sem, 1);
544
545 /* Register with generic device framework. */
546 err = device_register(&xendev->dev);
547 if (err) {
548 put_device(&xendev->dev);
549 xendev = NULL;
550 goto fail;
551 }
552
553 return 0;
554 fail:
555 kfree(xendev);
556 return err;
557 }
558 EXPORT_SYMBOL_GPL(xenbus_probe_node);
559
xenbus_probe_device_type(struct xen_bus_type * bus,const char * type)560 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
561 {
562 int err = 0;
563 char **dir;
564 unsigned int dir_n = 0;
565 int i;
566
567 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
568 if (IS_ERR(dir))
569 return PTR_ERR(dir);
570
571 for (i = 0; i < dir_n; i++) {
572 err = bus->probe(bus, type, dir[i]);
573 if (err)
574 break;
575 }
576
577 kfree(dir);
578 return err;
579 }
580
xenbus_probe_devices(struct xen_bus_type * bus)581 int xenbus_probe_devices(struct xen_bus_type *bus)
582 {
583 int err = 0;
584 char **dir;
585 unsigned int i, dir_n;
586
587 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
588 if (IS_ERR(dir))
589 return PTR_ERR(dir);
590
591 for (i = 0; i < dir_n; i++) {
592 err = xenbus_probe_device_type(bus, dir[i]);
593 if (err)
594 break;
595 }
596
597 kfree(dir);
598 return err;
599 }
600 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
601
char_count(const char * str,char c)602 static unsigned int char_count(const char *str, char c)
603 {
604 unsigned int i, ret = 0;
605
606 for (i = 0; str[i]; i++)
607 if (str[i] == c)
608 ret++;
609 return ret;
610 }
611
strsep_len(const char * str,char c,unsigned int len)612 static int strsep_len(const char *str, char c, unsigned int len)
613 {
614 unsigned int i;
615
616 for (i = 0; str[i]; i++)
617 if (str[i] == c) {
618 if (len == 0)
619 return i;
620 len--;
621 }
622 return (len == 0) ? i : -ERANGE;
623 }
624
xenbus_dev_changed(const char * node,struct xen_bus_type * bus)625 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
626 {
627 int exists, rootlen;
628 struct xenbus_device *dev;
629 char type[XEN_BUS_ID_SIZE];
630 const char *p, *root;
631
632 if (char_count(node, '/') < 2)
633 return;
634
635 exists = xenbus_exists(XBT_NIL, node, "");
636 if (!exists) {
637 xenbus_cleanup_devices(node, &bus->bus);
638 return;
639 }
640
641 /* backend/<type>/... or device/<type>/... */
642 p = strchr(node, '/') + 1;
643 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
644 type[XEN_BUS_ID_SIZE-1] = '\0';
645
646 rootlen = strsep_len(node, '/', bus->levels);
647 if (rootlen < 0)
648 return;
649 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
650 if (!root)
651 return;
652
653 dev = xenbus_device_find(root, &bus->bus);
654 if (!dev)
655 xenbus_probe_node(bus, type, root);
656 else
657 put_device(&dev->dev);
658
659 kfree(root);
660 }
661 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
662
xenbus_dev_suspend(struct device * dev)663 int xenbus_dev_suspend(struct device *dev)
664 {
665 int err = 0;
666 struct xenbus_driver *drv;
667 struct xenbus_device *xdev
668 = container_of(dev, struct xenbus_device, dev);
669
670 DPRINTK("%s", xdev->nodename);
671
672 if (dev->driver == NULL)
673 return 0;
674 drv = to_xenbus_driver(dev->driver);
675 if (drv->suspend)
676 err = drv->suspend(xdev);
677 if (err)
678 dev_warn(dev, "suspend failed: %i\n", err);
679 return 0;
680 }
681 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
682
xenbus_dev_resume(struct device * dev)683 int xenbus_dev_resume(struct device *dev)
684 {
685 int err;
686 struct xenbus_driver *drv;
687 struct xenbus_device *xdev
688 = container_of(dev, struct xenbus_device, dev);
689
690 DPRINTK("%s", xdev->nodename);
691
692 if (dev->driver == NULL)
693 return 0;
694 drv = to_xenbus_driver(dev->driver);
695 err = talk_to_otherend(xdev);
696 if (err) {
697 dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err);
698 return err;
699 }
700
701 xdev->state = XenbusStateInitialising;
702
703 if (drv->resume) {
704 err = drv->resume(xdev);
705 if (err) {
706 dev_warn(dev, "resume failed: %i\n", err);
707 return err;
708 }
709 }
710
711 err = watch_otherend(xdev);
712 if (err) {
713 dev_warn(dev, "resume (watch_otherend) failed: %d\n", err);
714 return err;
715 }
716
717 return 0;
718 }
719 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
720
xenbus_dev_cancel(struct device * dev)721 int xenbus_dev_cancel(struct device *dev)
722 {
723 /* Do nothing */
724 DPRINTK("cancel");
725 return 0;
726 }
727 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
728
729 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
730 int xenstored_ready;
731
732
register_xenstore_notifier(struct notifier_block * nb)733 int register_xenstore_notifier(struct notifier_block *nb)
734 {
735 int ret = 0;
736
737 if (xenstored_ready > 0)
738 ret = nb->notifier_call(nb, 0, NULL);
739 else
740 blocking_notifier_chain_register(&xenstore_chain, nb);
741
742 return ret;
743 }
744 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
745
unregister_xenstore_notifier(struct notifier_block * nb)746 void unregister_xenstore_notifier(struct notifier_block *nb)
747 {
748 blocking_notifier_chain_unregister(&xenstore_chain, nb);
749 }
750 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
751
xenbus_probe(void)752 static void xenbus_probe(void)
753 {
754 xenstored_ready = 1;
755
756 /*
757 * In the HVM case, xenbus_init() deferred its call to
758 * xs_init() in case callbacks were not operational yet.
759 * So do it now.
760 */
761 if (xen_store_domain_type == XS_HVM)
762 xs_init();
763
764 /* Notify others that xenstore is up */
765 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
766 }
767
768 /*
769 * Returns true when XenStore init must be deferred in order to
770 * allow the PCI platform device to be initialised, before we
771 * can actually have event channel interrupts working.
772 */
xs_hvm_defer_init_for_callback(void)773 static bool xs_hvm_defer_init_for_callback(void)
774 {
775 #ifdef CONFIG_XEN_PVHVM
776 return xen_store_domain_type == XS_HVM &&
777 !xen_have_vector_callback;
778 #else
779 return false;
780 #endif
781 }
782
xenbus_probe_thread(void * unused)783 static int xenbus_probe_thread(void *unused)
784 {
785 DEFINE_WAIT(w);
786
787 /*
788 * We actually just want to wait for *any* trigger of xb_waitq,
789 * and run xenbus_probe() the moment it occurs.
790 */
791 prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
792 schedule();
793 finish_wait(&xb_waitq, &w);
794
795 DPRINTK("probing");
796 xenbus_probe();
797 return 0;
798 }
799
xenbus_probe_initcall(void)800 static int __init xenbus_probe_initcall(void)
801 {
802 /*
803 * Probe XenBus here in the XS_PV case, and also XS_HVM unless we
804 * need to wait for the platform PCI device to come up.
805 */
806 if (xen_store_domain_type == XS_PV ||
807 (xen_store_domain_type == XS_HVM &&
808 !xs_hvm_defer_init_for_callback()))
809 xenbus_probe();
810
811 /*
812 * For XS_LOCAL, spawn a thread which will wait for xenstored
813 * or a xenstore-stubdom to be started, then probe. It will be
814 * triggered when communication starts happening, by waiting
815 * on xb_waitq.
816 */
817 if (xen_store_domain_type == XS_LOCAL) {
818 struct task_struct *probe_task;
819
820 probe_task = kthread_run(xenbus_probe_thread, NULL,
821 "xenbus_probe");
822 if (IS_ERR(probe_task))
823 return PTR_ERR(probe_task);
824 }
825 return 0;
826 }
827 device_initcall(xenbus_probe_initcall);
828
xen_set_callback_via(uint64_t via)829 int xen_set_callback_via(uint64_t via)
830 {
831 struct xen_hvm_param a;
832 int ret;
833
834 a.domid = DOMID_SELF;
835 a.index = HVM_PARAM_CALLBACK_IRQ;
836 a.value = via;
837
838 ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
839 if (ret)
840 return ret;
841
842 /*
843 * If xenbus_probe_initcall() deferred the xenbus_probe()
844 * due to the callback not functioning yet, we can do it now.
845 */
846 if (!xenstored_ready && xs_hvm_defer_init_for_callback())
847 xenbus_probe();
848
849 return ret;
850 }
851 EXPORT_SYMBOL_GPL(xen_set_callback_via);
852
853 /* Set up event channel for xenstored which is run as a local process
854 * (this is normally used only in dom0)
855 */
xenstored_local_init(void)856 static int __init xenstored_local_init(void)
857 {
858 int err = -ENOMEM;
859 unsigned long page = 0;
860 struct evtchn_alloc_unbound alloc_unbound;
861
862 /* Allocate Xenstore page */
863 page = get_zeroed_page(GFP_KERNEL);
864 if (!page)
865 goto out_err;
866
867 xen_store_gfn = virt_to_gfn((void *)page);
868
869 /* Next allocate a local port which xenstored can bind to */
870 alloc_unbound.dom = DOMID_SELF;
871 alloc_unbound.remote_dom = DOMID_SELF;
872
873 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
874 &alloc_unbound);
875 if (err == -ENOSYS)
876 goto out_err;
877
878 BUG_ON(err);
879 xen_store_evtchn = alloc_unbound.port;
880
881 return 0;
882
883 out_err:
884 if (page != 0)
885 free_page(page);
886 return err;
887 }
888
xenbus_resume_cb(struct notifier_block * nb,unsigned long action,void * data)889 static int xenbus_resume_cb(struct notifier_block *nb,
890 unsigned long action, void *data)
891 {
892 int err = 0;
893
894 if (xen_hvm_domain()) {
895 uint64_t v = 0;
896
897 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
898 if (!err && v)
899 xen_store_evtchn = v;
900 else
901 pr_warn("Cannot update xenstore event channel: %d\n",
902 err);
903 } else
904 xen_store_evtchn = xen_start_info->store_evtchn;
905
906 return err;
907 }
908
909 static struct notifier_block xenbus_resume_nb = {
910 .notifier_call = xenbus_resume_cb,
911 };
912
xenbus_init(void)913 static int __init xenbus_init(void)
914 {
915 int err = 0;
916 uint64_t v = 0;
917 xen_store_domain_type = XS_UNKNOWN;
918
919 if (!xen_domain())
920 return -ENODEV;
921
922 xenbus_ring_ops_init();
923
924 if (xen_pv_domain())
925 xen_store_domain_type = XS_PV;
926 if (xen_hvm_domain())
927 xen_store_domain_type = XS_HVM;
928 if (xen_hvm_domain() && xen_initial_domain())
929 xen_store_domain_type = XS_LOCAL;
930 if (xen_pv_domain() && !xen_start_info->store_evtchn)
931 xen_store_domain_type = XS_LOCAL;
932 if (xen_pv_domain() && xen_start_info->store_evtchn)
933 xenstored_ready = 1;
934
935 switch (xen_store_domain_type) {
936 case XS_LOCAL:
937 err = xenstored_local_init();
938 if (err)
939 goto out_error;
940 xen_store_interface = gfn_to_virt(xen_store_gfn);
941 break;
942 case XS_PV:
943 xen_store_evtchn = xen_start_info->store_evtchn;
944 xen_store_gfn = xen_start_info->store_mfn;
945 xen_store_interface = gfn_to_virt(xen_store_gfn);
946 break;
947 case XS_HVM:
948 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
949 if (err)
950 goto out_error;
951 xen_store_evtchn = (int)v;
952 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
953 if (err)
954 goto out_error;
955 xen_store_gfn = (unsigned long)v;
956 xen_store_interface =
957 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
958 XEN_PAGE_SIZE);
959 break;
960 default:
961 pr_warn("Xenstore state unknown\n");
962 break;
963 }
964
965 /*
966 * HVM domains may not have a functional callback yet. In that
967 * case let xs_init() be called from xenbus_probe(), which will
968 * get invoked at an appropriate time.
969 */
970 if (xen_store_domain_type != XS_HVM) {
971 err = xs_init();
972 if (err) {
973 pr_warn("Error initializing xenstore comms: %i\n", err);
974 goto out_error;
975 }
976 }
977
978 if ((xen_store_domain_type != XS_LOCAL) &&
979 (xen_store_domain_type != XS_UNKNOWN))
980 xen_resume_notifier_register(&xenbus_resume_nb);
981
982 #ifdef CONFIG_XEN_COMPAT_XENFS
983 /*
984 * Create xenfs mountpoint in /proc for compatibility with
985 * utilities that expect to find "xenbus" under "/proc/xen".
986 */
987 proc_create_mount_point("xen");
988 #endif
989
990 out_error:
991 return err;
992 }
993
994 postcore_initcall(xenbus_init);
995
996 MODULE_LICENSE("GPL");
997