1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
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:
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:
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
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
33 #define DPRINTK(fmt, args...) \
34 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
35 __func__, __LINE__, ##args)
37 #include <linux/kernel.h>
38 #include <linux/err.h>
39 #include <linux/string.h>
40 #include <linux/ctype.h>
41 #include <linux/fcntl.h>
43 #include <linux/proc_fs.h>
44 #include <linux/notifier.h>
45 #include <linux/kthread.h>
46 #include <linux/mutex.h>
48 #include <linux/slab.h>
51 #include <asm/pgtable.h>
52 #include <asm/xen/hypervisor.h>
55 #include <xen/xenbus.h>
56 #include <xen/events.h>
61 #include "xenbus_comms.h"
62 #include "xenbus_probe.h"
66 EXPORT_SYMBOL_GPL(xen_store_evtchn);
68 struct xenstore_domain_interface *xen_store_interface;
69 EXPORT_SYMBOL_GPL(xen_store_interface);
71 static unsigned long xen_store_mfn;
73 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
75 /* If something in array of ids matches this device, return it. */
76 static const struct xenbus_device_id *
77 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
79 for (; *arr->devicetype != '\0'; arr++) {
80 if (!strcmp(arr->devicetype, dev->devicetype))
86 int xenbus_match(struct device *_dev, struct device_driver *_drv)
88 struct xenbus_driver *drv = to_xenbus_driver(_drv);
93 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
95 EXPORT_SYMBOL_GPL(xenbus_match);
98 static void free_otherend_details(struct xenbus_device *dev)
100 kfree(dev->otherend);
101 dev->otherend = NULL;
105 static void free_otherend_watch(struct xenbus_device *dev)
107 if (dev->otherend_watch.node) {
108 unregister_xenbus_watch(&dev->otherend_watch);
109 kfree(dev->otherend_watch.node);
110 dev->otherend_watch.node = NULL;
115 static int talk_to_otherend(struct xenbus_device *dev)
117 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
119 free_otherend_watch(dev);
120 free_otherend_details(dev);
122 return drv->read_otherend_details(dev);
127 static int watch_otherend(struct xenbus_device *dev)
129 struct xen_bus_type *bus =
130 container_of(dev->dev.bus, struct xen_bus_type, bus);
132 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
133 bus->otherend_changed,
134 "%s/%s", dev->otherend, "state");
138 int xenbus_read_otherend_details(struct xenbus_device *xendev,
139 char *id_node, char *path_node)
141 int err = xenbus_gather(XBT_NIL, xendev->nodename,
142 id_node, "%i", &xendev->otherend_id,
143 path_node, NULL, &xendev->otherend,
146 xenbus_dev_fatal(xendev, err,
147 "reading other end details from %s",
151 if (strlen(xendev->otherend) == 0 ||
152 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
153 xenbus_dev_fatal(xendev, -ENOENT,
154 "unable to read other end from %s. "
155 "missing or inaccessible.",
157 free_otherend_details(xendev);
163 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
165 void xenbus_otherend_changed(struct xenbus_watch *watch,
166 const char **vec, unsigned int len,
167 int ignore_on_shutdown)
169 struct xenbus_device *dev =
170 container_of(watch, struct xenbus_device, otherend_watch);
171 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
172 enum xenbus_state state;
174 /* Protect us against watches firing on old details when the otherend
175 details change, say immediately after a resume. */
176 if (!dev->otherend ||
177 strncmp(dev->otherend, vec[XS_WATCH_PATH],
178 strlen(dev->otherend))) {
179 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
184 state = xenbus_read_driver_state(dev->otherend);
186 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
187 state, xenbus_strstate(state), dev->otherend_watch.node,
191 * Ignore xenbus transitions during shutdown. This prevents us doing
192 * work that can fail e.g., when the rootfs is gone.
194 if (system_state > SYSTEM_RUNNING) {
195 if (ignore_on_shutdown && (state == XenbusStateClosing))
196 xenbus_frontend_closed(dev);
200 if (drv->otherend_changed)
201 drv->otherend_changed(dev, state);
203 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
205 int xenbus_dev_probe(struct device *_dev)
207 struct xenbus_device *dev = to_xenbus_device(_dev);
208 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
209 const struct xenbus_device_id *id;
212 DPRINTK("%s", dev->nodename);
219 id = match_device(drv->ids, dev);
225 err = talk_to_otherend(dev);
227 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
232 err = drv->probe(dev, id);
236 err = watch_otherend(dev);
238 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
245 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
246 xenbus_switch_state(dev, XenbusStateClosed);
249 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
251 int xenbus_dev_remove(struct device *_dev)
253 struct xenbus_device *dev = to_xenbus_device(_dev);
254 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
256 DPRINTK("%s", dev->nodename);
258 free_otherend_watch(dev);
259 free_otherend_details(dev);
264 xenbus_switch_state(dev, XenbusStateClosed);
267 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
269 void xenbus_dev_shutdown(struct device *_dev)
271 struct xenbus_device *dev = to_xenbus_device(_dev);
272 unsigned long timeout = 5*HZ;
274 DPRINTK("%s", dev->nodename);
276 get_device(&dev->dev);
277 if (dev->state != XenbusStateConnected) {
278 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
279 dev->nodename, xenbus_strstate(dev->state));
282 xenbus_switch_state(dev, XenbusStateClosing);
283 timeout = wait_for_completion_timeout(&dev->down, timeout);
285 printk(KERN_INFO "%s: %s timeout closing device\n",
286 __func__, dev->nodename);
288 put_device(&dev->dev);
290 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
292 int xenbus_register_driver_common(struct xenbus_driver *drv,
293 struct xen_bus_type *bus,
294 struct module *owner,
295 const char *mod_name)
297 drv->driver.name = drv->name;
298 drv->driver.bus = &bus->bus;
299 drv->driver.owner = owner;
300 drv->driver.mod_name = mod_name;
302 return driver_register(&drv->driver);
304 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
306 void xenbus_unregister_driver(struct xenbus_driver *drv)
308 driver_unregister(&drv->driver);
310 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
314 struct xenbus_device *dev;
315 const char *nodename;
318 static int cmp_dev(struct device *dev, void *data)
320 struct xenbus_device *xendev = to_xenbus_device(dev);
321 struct xb_find_info *info = data;
323 if (!strcmp(xendev->nodename, info->nodename)) {
331 struct xenbus_device *xenbus_device_find(const char *nodename,
332 struct bus_type *bus)
334 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
336 bus_for_each_dev(bus, NULL, &info, cmp_dev);
340 static int cleanup_dev(struct device *dev, void *data)
342 struct xenbus_device *xendev = to_xenbus_device(dev);
343 struct xb_find_info *info = data;
344 int len = strlen(info->nodename);
346 DPRINTK("%s", info->nodename);
348 /* Match the info->nodename path, or any subdirectory of that path. */
349 if (strncmp(xendev->nodename, info->nodename, len))
352 /* If the node name is longer, ensure it really is a subdirectory. */
353 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
361 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
363 struct xb_find_info info = { .nodename = path };
367 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
369 device_unregister(&info.dev->dev);
370 put_device(&info.dev->dev);
375 static void xenbus_dev_release(struct device *dev)
378 kfree(to_xenbus_device(dev));
381 static ssize_t xendev_show_nodename(struct device *dev,
382 struct device_attribute *attr, char *buf)
384 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
386 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
388 static ssize_t xendev_show_devtype(struct device *dev,
389 struct device_attribute *attr, char *buf)
391 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
393 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
395 static ssize_t xendev_show_modalias(struct device *dev,
396 struct device_attribute *attr, char *buf)
398 return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
400 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
402 int xenbus_probe_node(struct xen_bus_type *bus,
404 const char *nodename)
406 char devname[XEN_BUS_ID_SIZE];
408 struct xenbus_device *xendev;
412 enum xenbus_state state = xenbus_read_driver_state(nodename);
414 if (state != XenbusStateInitialising) {
415 /* Device is not new, so ignore it. This can happen if a
416 device is going away after switching to Closed. */
420 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
421 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
425 xendev->state = XenbusStateInitialising;
427 /* Copy the strings into the extra space. */
429 tmpstring = (char *)(xendev + 1);
430 strcpy(tmpstring, nodename);
431 xendev->nodename = tmpstring;
433 tmpstring += strlen(tmpstring) + 1;
434 strcpy(tmpstring, type);
435 xendev->devicetype = tmpstring;
436 init_completion(&xendev->down);
438 xendev->dev.bus = &bus->bus;
439 xendev->dev.release = xenbus_dev_release;
441 err = bus->get_bus_id(devname, xendev->nodename);
445 dev_set_name(&xendev->dev, devname);
447 /* Register with generic device framework. */
448 err = device_register(&xendev->dev);
452 err = device_create_file(&xendev->dev, &dev_attr_nodename);
454 goto fail_unregister;
456 err = device_create_file(&xendev->dev, &dev_attr_devtype);
458 goto fail_remove_nodename;
460 err = device_create_file(&xendev->dev, &dev_attr_modalias);
462 goto fail_remove_devtype;
466 device_remove_file(&xendev->dev, &dev_attr_devtype);
467 fail_remove_nodename:
468 device_remove_file(&xendev->dev, &dev_attr_nodename);
470 device_unregister(&xendev->dev);
475 EXPORT_SYMBOL_GPL(xenbus_probe_node);
477 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
481 unsigned int dir_n = 0;
484 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
488 for (i = 0; i < dir_n; i++) {
489 err = bus->probe(bus, type, dir[i]);
498 int xenbus_probe_devices(struct xen_bus_type *bus)
502 unsigned int i, dir_n;
504 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
508 for (i = 0; i < dir_n; i++) {
509 err = xenbus_probe_device_type(bus, dir[i]);
517 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
519 static unsigned int char_count(const char *str, char c)
521 unsigned int i, ret = 0;
523 for (i = 0; str[i]; i++)
529 static int strsep_len(const char *str, char c, unsigned int len)
533 for (i = 0; str[i]; i++)
539 return (len == 0) ? i : -ERANGE;
542 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
545 struct xenbus_device *dev;
546 char type[XEN_BUS_ID_SIZE];
547 const char *p, *root;
549 if (char_count(node, '/') < 2)
552 exists = xenbus_exists(XBT_NIL, node, "");
554 xenbus_cleanup_devices(node, &bus->bus);
558 /* backend/<type>/... or device/<type>/... */
559 p = strchr(node, '/') + 1;
560 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
561 type[XEN_BUS_ID_SIZE-1] = '\0';
563 rootlen = strsep_len(node, '/', bus->levels);
566 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
570 dev = xenbus_device_find(root, &bus->bus);
572 xenbus_probe_node(bus, type, root);
574 put_device(&dev->dev);
578 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
580 int xenbus_dev_suspend(struct device *dev)
583 struct xenbus_driver *drv;
584 struct xenbus_device *xdev
585 = container_of(dev, struct xenbus_device, dev);
587 DPRINTK("%s", xdev->nodename);
589 if (dev->driver == NULL)
591 drv = to_xenbus_driver(dev->driver);
593 err = drv->suspend(xdev);
596 "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
599 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
601 int xenbus_dev_resume(struct device *dev)
604 struct xenbus_driver *drv;
605 struct xenbus_device *xdev
606 = container_of(dev, struct xenbus_device, dev);
608 DPRINTK("%s", xdev->nodename);
610 if (dev->driver == NULL)
612 drv = to_xenbus_driver(dev->driver);
613 err = talk_to_otherend(xdev);
616 "xenbus: resume (talk_to_otherend) %s failed: %i\n",
621 xdev->state = XenbusStateInitialising;
624 err = drv->resume(xdev);
627 "xenbus: resume %s failed: %i\n",
633 err = watch_otherend(xdev);
636 "xenbus_probe: resume (watch_otherend) %s failed: "
637 "%d.\n", dev_name(dev), err);
643 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
645 int xenbus_dev_cancel(struct device *dev)
651 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
653 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
654 int xenstored_ready = 0;
657 int register_xenstore_notifier(struct notifier_block *nb)
661 if (xenstored_ready > 0)
662 ret = nb->notifier_call(nb, 0, NULL);
664 blocking_notifier_chain_register(&xenstore_chain, nb);
668 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
670 void unregister_xenstore_notifier(struct notifier_block *nb)
672 blocking_notifier_chain_unregister(&xenstore_chain, nb);
674 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
676 void xenbus_probe(struct work_struct *unused)
680 /* Notify others that xenstore is up */
681 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
683 EXPORT_SYMBOL_GPL(xenbus_probe);
685 static int __init xenbus_probe_initcall(void)
690 if (xen_initial_domain() || xen_hvm_domain())
697 device_initcall(xenbus_probe_initcall);
699 static int __init xenbus_init(void)
702 unsigned long page = 0;
711 * Domain0 doesn't have a store_evtchn or store_mfn yet.
713 if (xen_initial_domain()) {
714 struct evtchn_alloc_unbound alloc_unbound;
716 /* Allocate Xenstore page */
717 page = get_zeroed_page(GFP_KERNEL);
721 xen_store_mfn = xen_start_info->store_mfn =
722 pfn_to_mfn(virt_to_phys((void *)page) >>
725 /* Next allocate a local port which xenstored can bind to */
726 alloc_unbound.dom = DOMID_SELF;
727 alloc_unbound.remote_dom = 0;
729 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
735 xen_store_evtchn = xen_start_info->store_evtchn =
738 xen_store_interface = mfn_to_virt(xen_store_mfn);
740 if (xen_hvm_domain()) {
742 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
745 xen_store_evtchn = (int)v;
746 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
749 xen_store_mfn = (unsigned long)v;
750 xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
752 xen_store_evtchn = xen_start_info->store_evtchn;
753 xen_store_mfn = xen_start_info->store_mfn;
754 xen_store_interface = mfn_to_virt(xen_store_mfn);
759 /* Initialize the interface to xenstore. */
763 "XENBUS: Error initializing xenstore comms: %i\n", err);
767 #ifdef CONFIG_XEN_COMPAT_XENFS
769 * Create xenfs mountpoint in /proc for compatibility with
770 * utilities that expect to find "xenbus" under "/proc/xen".
772 proc_mkdir("xen", NULL);
784 postcore_initcall(xenbus_init);
786 MODULE_LICENSE("GPL");