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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35 #define DPRINTK(fmt, args...) \
36 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
37 __func__, __LINE__, ##args)
39 #include <linux/kernel.h>
40 #include <linux/err.h>
41 #include <linux/string.h>
42 #include <linux/ctype.h>
43 #include <linux/fcntl.h>
45 #include <linux/proc_fs.h>
46 #include <linux/notifier.h>
47 #include <linux/kthread.h>
48 #include <linux/mutex.h>
50 #include <linux/slab.h>
51 #include <linux/module.h>
54 #include <asm/pgtable.h>
55 #include <asm/xen/hypervisor.h>
58 #include <xen/xenbus.h>
59 #include <xen/events.h>
60 #include <xen/xen-ops.h>
69 EXPORT_SYMBOL_GPL(xen_store_evtchn);
71 struct xenstore_domain_interface *xen_store_interface;
72 EXPORT_SYMBOL_GPL(xen_store_interface);
74 enum xenstore_init xen_store_domain_type;
75 EXPORT_SYMBOL_GPL(xen_store_domain_type);
77 static unsigned long xen_store_gfn;
79 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
81 /* If something in array of ids matches this device, return it. */
82 static const struct xenbus_device_id *
83 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
85 for (; *arr->devicetype != '\0'; arr++) {
86 if (!strcmp(arr->devicetype, dev->devicetype))
92 int xenbus_match(struct device *_dev, struct device_driver *_drv)
94 struct xenbus_driver *drv = to_xenbus_driver(_drv);
99 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
101 EXPORT_SYMBOL_GPL(xenbus_match);
104 static void free_otherend_details(struct xenbus_device *dev)
106 kfree(dev->otherend);
107 dev->otherend = NULL;
111 static void free_otherend_watch(struct xenbus_device *dev)
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;
121 static int talk_to_otherend(struct xenbus_device *dev)
123 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
125 free_otherend_watch(dev);
126 free_otherend_details(dev);
128 return drv->read_otherend_details(dev);
133 static int watch_otherend(struct xenbus_device *dev)
135 struct xen_bus_type *bus =
136 container_of(dev->dev.bus, struct xen_bus_type, bus);
138 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
139 bus->otherend_changed,
140 "%s/%s", dev->otherend, "state");
144 int xenbus_read_otherend_details(struct xenbus_device *xendev,
145 char *id_node, char *path_node)
147 int err = xenbus_gather(XBT_NIL, xendev->nodename,
148 id_node, "%i", &xendev->otherend_id,
149 path_node, NULL, &xendev->otherend,
152 xenbus_dev_fatal(xendev, err,
153 "reading other end details from %s",
157 if (strlen(xendev->otherend) == 0 ||
158 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
159 xenbus_dev_fatal(xendev, -ENOENT,
160 "unable to read other end from %s. "
161 "missing or inaccessible.",
163 free_otherend_details(xendev);
169 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
171 void xenbus_otherend_changed(struct xenbus_watch *watch,
172 const char *path, const char *token,
173 int ignore_on_shutdown)
175 struct xenbus_device *dev =
176 container_of(watch, struct xenbus_device, otherend_watch);
177 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
178 enum xenbus_state state;
180 /* Protect us against watches firing on old details when the otherend
181 details change, say immediately after a resume. */
182 if (!dev->otherend ||
183 strncmp(dev->otherend, path, strlen(dev->otherend))) {
184 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
188 state = xenbus_read_driver_state(dev->otherend);
190 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
191 state, xenbus_strstate(state), dev->otherend_watch.node, path);
194 * Ignore xenbus transitions during shutdown. This prevents us doing
195 * work that can fail e.g., when the rootfs is gone.
197 if (system_state > SYSTEM_RUNNING) {
198 if (ignore_on_shutdown && (state == XenbusStateClosing))
199 xenbus_frontend_closed(dev);
203 if (drv->otherend_changed)
204 drv->otherend_changed(dev, state);
206 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
208 int xenbus_dev_probe(struct device *_dev)
210 struct xenbus_device *dev = to_xenbus_device(_dev);
211 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
212 const struct xenbus_device_id *id;
215 DPRINTK("%s", dev->nodename);
222 id = match_device(drv->ids, dev);
228 err = talk_to_otherend(dev);
230 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
235 if (!try_module_get(drv->driver.owner)) {
236 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
242 spin_lock(&dev->reclaim_lock);
243 err = drv->probe(dev, id);
244 spin_unlock(&dev->reclaim_lock);
248 err = watch_otherend(dev);
250 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
257 module_put(drv->driver.owner);
259 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
262 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
264 int xenbus_dev_remove(struct device *_dev)
266 struct xenbus_device *dev = to_xenbus_device(_dev);
267 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
269 DPRINTK("%s", dev->nodename);
271 free_otherend_watch(dev);
274 spin_lock(&dev->reclaim_lock);
276 spin_unlock(&dev->reclaim_lock);
279 module_put(drv->driver.owner);
281 free_otherend_details(dev);
284 * If the toolstack has forced the device state to closing then set
285 * the state to closed now to allow it to be cleaned up.
286 * Similarly, if the driver does not support re-bind, set the
289 if (!drv->allow_rebind ||
290 xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
291 xenbus_switch_state(dev, XenbusStateClosed);
295 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
297 int xenbus_register_driver_common(struct xenbus_driver *drv,
298 struct xen_bus_type *bus,
299 struct module *owner, const char *mod_name)
301 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
302 drv->driver.bus = &bus->bus;
303 drv->driver.owner = owner;
304 drv->driver.mod_name = mod_name;
306 return driver_register(&drv->driver);
308 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
310 void xenbus_unregister_driver(struct xenbus_driver *drv)
312 driver_unregister(&drv->driver);
314 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
316 struct xb_find_info {
317 struct xenbus_device *dev;
318 const char *nodename;
321 static int cmp_dev(struct device *dev, void *data)
323 struct xenbus_device *xendev = to_xenbus_device(dev);
324 struct xb_find_info *info = data;
326 if (!strcmp(xendev->nodename, info->nodename)) {
334 static struct xenbus_device *xenbus_device_find(const char *nodename,
335 struct bus_type *bus)
337 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
339 bus_for_each_dev(bus, NULL, &info, cmp_dev);
343 static int cleanup_dev(struct device *dev, void *data)
345 struct xenbus_device *xendev = to_xenbus_device(dev);
346 struct xb_find_info *info = data;
347 int len = strlen(info->nodename);
349 DPRINTK("%s", info->nodename);
351 /* Match the info->nodename path, or any subdirectory of that path. */
352 if (strncmp(xendev->nodename, info->nodename, len))
355 /* If the node name is longer, ensure it really is a subdirectory. */
356 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
364 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
366 struct xb_find_info info = { .nodename = path };
370 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
372 device_unregister(&info.dev->dev);
373 put_device(&info.dev->dev);
378 static void xenbus_dev_release(struct device *dev)
381 kfree(to_xenbus_device(dev));
384 static ssize_t nodename_show(struct device *dev,
385 struct device_attribute *attr, char *buf)
387 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
389 static DEVICE_ATTR_RO(nodename);
391 static ssize_t devtype_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
394 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
396 static DEVICE_ATTR_RO(devtype);
398 static ssize_t modalias_show(struct device *dev,
399 struct device_attribute *attr, char *buf)
401 return sprintf(buf, "%s:%s\n", dev->bus->name,
402 to_xenbus_device(dev)->devicetype);
404 static DEVICE_ATTR_RO(modalias);
406 static ssize_t state_show(struct device *dev,
407 struct device_attribute *attr, char *buf)
409 return sprintf(buf, "%s\n",
410 xenbus_strstate(to_xenbus_device(dev)->state));
412 static DEVICE_ATTR_RO(state);
414 static struct attribute *xenbus_dev_attrs[] = {
415 &dev_attr_nodename.attr,
416 &dev_attr_devtype.attr,
417 &dev_attr_modalias.attr,
418 &dev_attr_state.attr,
422 static const struct attribute_group xenbus_dev_group = {
423 .attrs = xenbus_dev_attrs,
426 const struct attribute_group *xenbus_dev_groups[] = {
430 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
432 int xenbus_probe_node(struct xen_bus_type *bus,
434 const char *nodename)
436 char devname[XEN_BUS_ID_SIZE];
438 struct xenbus_device *xendev;
442 enum xenbus_state state = xenbus_read_driver_state(nodename);
444 if (state != XenbusStateInitialising) {
445 /* Device is not new, so ignore it. This can happen if a
446 device is going away after switching to Closed. */
450 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
451 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
455 xendev->state = XenbusStateInitialising;
457 /* Copy the strings into the extra space. */
459 tmpstring = (char *)(xendev + 1);
460 strcpy(tmpstring, nodename);
461 xendev->nodename = tmpstring;
463 tmpstring += strlen(tmpstring) + 1;
464 strcpy(tmpstring, type);
465 xendev->devicetype = tmpstring;
466 init_completion(&xendev->down);
468 xendev->dev.bus = &bus->bus;
469 xendev->dev.release = xenbus_dev_release;
471 err = bus->get_bus_id(devname, xendev->nodename);
475 dev_set_name(&xendev->dev, "%s", devname);
476 spin_lock_init(&xendev->reclaim_lock);
478 /* Register with generic device framework. */
479 err = device_register(&xendev->dev);
481 put_device(&xendev->dev);
491 EXPORT_SYMBOL_GPL(xenbus_probe_node);
493 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
497 unsigned int dir_n = 0;
500 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
504 for (i = 0; i < dir_n; i++) {
505 err = bus->probe(bus, type, dir[i]);
514 int xenbus_probe_devices(struct xen_bus_type *bus)
518 unsigned int i, dir_n;
520 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
524 for (i = 0; i < dir_n; i++) {
525 err = xenbus_probe_device_type(bus, dir[i]);
533 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
535 static unsigned int char_count(const char *str, char c)
537 unsigned int i, ret = 0;
539 for (i = 0; str[i]; i++)
545 static int strsep_len(const char *str, char c, unsigned int len)
549 for (i = 0; str[i]; i++)
555 return (len == 0) ? i : -ERANGE;
558 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
561 struct xenbus_device *dev;
562 char type[XEN_BUS_ID_SIZE];
563 const char *p, *root;
565 if (char_count(node, '/') < 2)
568 exists = xenbus_exists(XBT_NIL, node, "");
570 xenbus_cleanup_devices(node, &bus->bus);
574 /* backend/<type>/... or device/<type>/... */
575 p = strchr(node, '/') + 1;
576 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
577 type[XEN_BUS_ID_SIZE-1] = '\0';
579 rootlen = strsep_len(node, '/', bus->levels);
582 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
586 dev = xenbus_device_find(root, &bus->bus);
588 xenbus_probe_node(bus, type, root);
590 put_device(&dev->dev);
594 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
596 int xenbus_dev_suspend(struct device *dev)
599 struct xenbus_driver *drv;
600 struct xenbus_device *xdev
601 = container_of(dev, struct xenbus_device, dev);
603 DPRINTK("%s", xdev->nodename);
605 if (dev->driver == NULL)
607 drv = to_xenbus_driver(dev->driver);
609 err = drv->suspend(xdev);
611 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
614 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
616 int xenbus_dev_resume(struct device *dev)
619 struct xenbus_driver *drv;
620 struct xenbus_device *xdev
621 = container_of(dev, struct xenbus_device, dev);
623 DPRINTK("%s", xdev->nodename);
625 if (dev->driver == NULL)
627 drv = to_xenbus_driver(dev->driver);
628 err = talk_to_otherend(xdev);
630 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
635 xdev->state = XenbusStateInitialising;
638 err = drv->resume(xdev);
640 pr_warn("resume %s failed: %i\n", dev_name(dev), err);
645 err = watch_otherend(xdev);
647 pr_warn("resume (watch_otherend) %s failed: %d.\n",
654 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
656 int xenbus_dev_cancel(struct device *dev)
662 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
664 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
668 int register_xenstore_notifier(struct notifier_block *nb)
672 if (xenstored_ready > 0)
673 ret = nb->notifier_call(nb, 0, NULL);
675 blocking_notifier_chain_register(&xenstore_chain, nb);
679 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
681 void unregister_xenstore_notifier(struct notifier_block *nb)
683 blocking_notifier_chain_unregister(&xenstore_chain, nb);
685 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
687 void xenbus_probe(struct work_struct *unused)
691 /* Notify others that xenstore is up */
692 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
694 EXPORT_SYMBOL_GPL(xenbus_probe);
696 static int __init xenbus_probe_initcall(void)
701 if (xen_initial_domain() || xen_hvm_domain())
708 device_initcall(xenbus_probe_initcall);
710 /* Set up event channel for xenstored which is run as a local process
711 * (this is normally used only in dom0)
713 static int __init xenstored_local_init(void)
716 unsigned long page = 0;
717 struct evtchn_alloc_unbound alloc_unbound;
719 /* Allocate Xenstore page */
720 page = get_zeroed_page(GFP_KERNEL);
724 xen_store_gfn = virt_to_gfn((void *)page);
726 /* Next allocate a local port which xenstored can bind to */
727 alloc_unbound.dom = DOMID_SELF;
728 alloc_unbound.remote_dom = DOMID_SELF;
730 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
736 xen_store_evtchn = alloc_unbound.port;
746 static int xenbus_resume_cb(struct notifier_block *nb,
747 unsigned long action, void *data)
751 if (xen_hvm_domain()) {
754 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
756 xen_store_evtchn = v;
758 pr_warn("Cannot update xenstore event channel: %d\n",
761 xen_store_evtchn = xen_start_info->store_evtchn;
766 static struct notifier_block xenbus_resume_nb = {
767 .notifier_call = xenbus_resume_cb,
770 static int __init xenbus_init(void)
774 xen_store_domain_type = XS_UNKNOWN;
779 xenbus_ring_ops_init();
782 xen_store_domain_type = XS_PV;
783 if (xen_hvm_domain())
784 xen_store_domain_type = XS_HVM;
785 if (xen_hvm_domain() && xen_initial_domain())
786 xen_store_domain_type = XS_LOCAL;
787 if (xen_pv_domain() && !xen_start_info->store_evtchn)
788 xen_store_domain_type = XS_LOCAL;
789 if (xen_pv_domain() && xen_start_info->store_evtchn)
792 switch (xen_store_domain_type) {
794 err = xenstored_local_init();
797 xen_store_interface = gfn_to_virt(xen_store_gfn);
800 xen_store_evtchn = xen_start_info->store_evtchn;
801 xen_store_gfn = xen_start_info->store_mfn;
802 xen_store_interface = gfn_to_virt(xen_store_gfn);
805 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
808 xen_store_evtchn = (int)v;
809 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
812 xen_store_gfn = (unsigned long)v;
813 xen_store_interface =
814 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
818 pr_warn("Xenstore state unknown\n");
822 /* Initialize the interface to xenstore. */
825 pr_warn("Error initializing xenstore comms: %i\n", err);
829 if ((xen_store_domain_type != XS_LOCAL) &&
830 (xen_store_domain_type != XS_UNKNOWN))
831 xen_resume_notifier_register(&xenbus_resume_nb);
833 #ifdef CONFIG_XEN_COMPAT_XENFS
835 * Create xenfs mountpoint in /proc for compatibility with
836 * utilities that expect to find "xenbus" under "/proc/xen".
838 proc_create_mount_point("xen");
845 postcore_initcall(xenbus_init);
847 MODULE_LICENSE("GPL");