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/xen/hypervisor.h>
57 #include <xen/xenbus.h>
58 #include <xen/events.h>
59 #include <xen/xen-ops.h>
68 EXPORT_SYMBOL_GPL(xen_store_evtchn);
70 struct xenstore_domain_interface *xen_store_interface;
71 EXPORT_SYMBOL_GPL(xen_store_interface);
73 enum xenstore_init xen_store_domain_type;
74 EXPORT_SYMBOL_GPL(xen_store_domain_type);
76 static unsigned long xen_store_gfn;
78 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
80 /* If something in array of ids matches this device, return it. */
81 static const struct xenbus_device_id *
82 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
84 for (; *arr->devicetype != '\0'; arr++) {
85 if (!strcmp(arr->devicetype, dev->devicetype))
91 int xenbus_match(struct device *_dev, struct device_driver *_drv)
93 struct xenbus_driver *drv = to_xenbus_driver(_drv);
98 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
100 EXPORT_SYMBOL_GPL(xenbus_match);
103 static void free_otherend_details(struct xenbus_device *dev)
105 kfree(dev->otherend);
106 dev->otherend = NULL;
110 static void free_otherend_watch(struct xenbus_device *dev)
112 if (dev->otherend_watch.node) {
113 unregister_xenbus_watch(&dev->otherend_watch);
114 kfree(dev->otherend_watch.node);
115 dev->otherend_watch.node = NULL;
120 static int talk_to_otherend(struct xenbus_device *dev)
122 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
124 free_otherend_watch(dev);
125 free_otherend_details(dev);
127 return drv->read_otherend_details(dev);
132 static int watch_otherend(struct xenbus_device *dev)
134 struct xen_bus_type *bus =
135 container_of(dev->dev.bus, struct xen_bus_type, bus);
137 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
138 bus->otherend_changed,
139 "%s/%s", dev->otherend, "state");
143 int xenbus_read_otherend_details(struct xenbus_device *xendev,
144 char *id_node, char *path_node)
146 int err = xenbus_gather(XBT_NIL, xendev->nodename,
147 id_node, "%i", &xendev->otherend_id,
148 path_node, NULL, &xendev->otherend,
151 xenbus_dev_fatal(xendev, err,
152 "reading other end details from %s",
156 if (strlen(xendev->otherend) == 0 ||
157 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
158 xenbus_dev_fatal(xendev, -ENOENT,
159 "unable to read other end from %s. "
160 "missing or inaccessible.",
162 free_otherend_details(xendev);
168 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
170 void xenbus_otherend_changed(struct xenbus_watch *watch,
171 const char *path, const char *token,
172 int ignore_on_shutdown)
174 struct xenbus_device *dev =
175 container_of(watch, struct xenbus_device, otherend_watch);
176 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
177 enum xenbus_state state;
179 /* Protect us against watches firing on old details when the otherend
180 details change, say immediately after a resume. */
181 if (!dev->otherend ||
182 strncmp(dev->otherend, path, strlen(dev->otherend))) {
183 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
187 state = xenbus_read_driver_state(dev->otherend);
189 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
190 state, xenbus_strstate(state), dev->otherend_watch.node, path);
193 * Ignore xenbus transitions during shutdown. This prevents us doing
194 * work that can fail e.g., when the rootfs is gone.
196 if (system_state > SYSTEM_RUNNING) {
197 if (ignore_on_shutdown && (state == XenbusStateClosing))
198 xenbus_frontend_closed(dev);
202 if (drv->otherend_changed)
203 drv->otherend_changed(dev, state);
205 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
207 int xenbus_dev_probe(struct device *_dev)
209 struct xenbus_device *dev = to_xenbus_device(_dev);
210 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
211 const struct xenbus_device_id *id;
214 DPRINTK("%s", dev->nodename);
221 id = match_device(drv->ids, dev);
227 err = talk_to_otherend(dev);
229 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
234 if (!try_module_get(drv->driver.owner)) {
235 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
241 down(&dev->reclaim_sem);
242 err = drv->probe(dev, id);
243 up(&dev->reclaim_sem);
247 err = watch_otherend(dev);
249 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
256 module_put(drv->driver.owner);
258 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
261 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
263 int xenbus_dev_remove(struct device *_dev)
265 struct xenbus_device *dev = to_xenbus_device(_dev);
266 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
268 DPRINTK("%s", dev->nodename);
270 free_otherend_watch(dev);
273 down(&dev->reclaim_sem);
275 up(&dev->reclaim_sem);
278 module_put(drv->driver.owner);
280 free_otherend_details(dev);
283 * If the toolstack has forced the device state to closing then set
284 * the state to closed now to allow it to be cleaned up.
285 * Similarly, if the driver does not support re-bind, set the
288 if (!drv->allow_rebind ||
289 xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
290 xenbus_switch_state(dev, XenbusStateClosed);
294 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
296 int xenbus_register_driver_common(struct xenbus_driver *drv,
297 struct xen_bus_type *bus,
298 struct module *owner, const char *mod_name)
300 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
301 drv->driver.bus = &bus->bus;
302 drv->driver.owner = owner;
303 drv->driver.mod_name = mod_name;
305 return driver_register(&drv->driver);
307 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
309 void xenbus_unregister_driver(struct xenbus_driver *drv)
311 driver_unregister(&drv->driver);
313 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
315 struct xb_find_info {
316 struct xenbus_device *dev;
317 const char *nodename;
320 static int cmp_dev(struct device *dev, void *data)
322 struct xenbus_device *xendev = to_xenbus_device(dev);
323 struct xb_find_info *info = data;
325 if (!strcmp(xendev->nodename, info->nodename)) {
333 static struct xenbus_device *xenbus_device_find(const char *nodename,
334 struct bus_type *bus)
336 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
338 bus_for_each_dev(bus, NULL, &info, cmp_dev);
342 static int cleanup_dev(struct device *dev, void *data)
344 struct xenbus_device *xendev = to_xenbus_device(dev);
345 struct xb_find_info *info = data;
346 int len = strlen(info->nodename);
348 DPRINTK("%s", info->nodename);
350 /* Match the info->nodename path, or any subdirectory of that path. */
351 if (strncmp(xendev->nodename, info->nodename, len))
354 /* If the node name is longer, ensure it really is a subdirectory. */
355 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
363 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
365 struct xb_find_info info = { .nodename = path };
369 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
371 device_unregister(&info.dev->dev);
372 put_device(&info.dev->dev);
377 static void xenbus_dev_release(struct device *dev)
380 kfree(to_xenbus_device(dev));
383 static ssize_t nodename_show(struct device *dev,
384 struct device_attribute *attr, char *buf)
386 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
388 static DEVICE_ATTR_RO(nodename);
390 static ssize_t devtype_show(struct device *dev,
391 struct device_attribute *attr, char *buf)
393 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
395 static DEVICE_ATTR_RO(devtype);
397 static ssize_t modalias_show(struct device *dev,
398 struct device_attribute *attr, char *buf)
400 return sprintf(buf, "%s:%s\n", dev->bus->name,
401 to_xenbus_device(dev)->devicetype);
403 static DEVICE_ATTR_RO(modalias);
405 static ssize_t state_show(struct device *dev,
406 struct device_attribute *attr, char *buf)
408 return sprintf(buf, "%s\n",
409 xenbus_strstate(to_xenbus_device(dev)->state));
411 static DEVICE_ATTR_RO(state);
413 static struct attribute *xenbus_dev_attrs[] = {
414 &dev_attr_nodename.attr,
415 &dev_attr_devtype.attr,
416 &dev_attr_modalias.attr,
417 &dev_attr_state.attr,
421 static const struct attribute_group xenbus_dev_group = {
422 .attrs = xenbus_dev_attrs,
425 const struct attribute_group *xenbus_dev_groups[] = {
429 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
431 int xenbus_probe_node(struct xen_bus_type *bus,
433 const char *nodename)
435 char devname[XEN_BUS_ID_SIZE];
437 struct xenbus_device *xendev;
441 enum xenbus_state state = xenbus_read_driver_state(nodename);
443 if (state != XenbusStateInitialising) {
444 /* Device is not new, so ignore it. This can happen if a
445 device is going away after switching to Closed. */
449 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
450 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
454 xendev->state = XenbusStateInitialising;
456 /* Copy the strings into the extra space. */
458 tmpstring = (char *)(xendev + 1);
459 strcpy(tmpstring, nodename);
460 xendev->nodename = tmpstring;
462 tmpstring += strlen(tmpstring) + 1;
463 strcpy(tmpstring, type);
464 xendev->devicetype = tmpstring;
465 init_completion(&xendev->down);
467 xendev->dev.bus = &bus->bus;
468 xendev->dev.release = xenbus_dev_release;
470 err = bus->get_bus_id(devname, xendev->nodename);
474 dev_set_name(&xendev->dev, "%s", devname);
475 sema_init(&xendev->reclaim_sem, 1);
477 /* Register with generic device framework. */
478 err = device_register(&xendev->dev);
480 put_device(&xendev->dev);
490 EXPORT_SYMBOL_GPL(xenbus_probe_node);
492 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
496 unsigned int dir_n = 0;
499 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
503 for (i = 0; i < dir_n; i++) {
504 err = bus->probe(bus, type, dir[i]);
513 int xenbus_probe_devices(struct xen_bus_type *bus)
517 unsigned int i, dir_n;
519 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
523 for (i = 0; i < dir_n; i++) {
524 err = xenbus_probe_device_type(bus, dir[i]);
532 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
534 static unsigned int char_count(const char *str, char c)
536 unsigned int i, ret = 0;
538 for (i = 0; str[i]; i++)
544 static int strsep_len(const char *str, char c, unsigned int len)
548 for (i = 0; str[i]; i++)
554 return (len == 0) ? i : -ERANGE;
557 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
560 struct xenbus_device *dev;
561 char type[XEN_BUS_ID_SIZE];
562 const char *p, *root;
564 if (char_count(node, '/') < 2)
567 exists = xenbus_exists(XBT_NIL, node, "");
569 xenbus_cleanup_devices(node, &bus->bus);
573 /* backend/<type>/... or device/<type>/... */
574 p = strchr(node, '/') + 1;
575 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
576 type[XEN_BUS_ID_SIZE-1] = '\0';
578 rootlen = strsep_len(node, '/', bus->levels);
581 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
585 dev = xenbus_device_find(root, &bus->bus);
587 xenbus_probe_node(bus, type, root);
589 put_device(&dev->dev);
593 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
595 int xenbus_dev_suspend(struct device *dev)
598 struct xenbus_driver *drv;
599 struct xenbus_device *xdev
600 = container_of(dev, struct xenbus_device, dev);
602 DPRINTK("%s", xdev->nodename);
604 if (dev->driver == NULL)
606 drv = to_xenbus_driver(dev->driver);
608 err = drv->suspend(xdev);
610 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
613 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
615 int xenbus_dev_resume(struct device *dev)
618 struct xenbus_driver *drv;
619 struct xenbus_device *xdev
620 = container_of(dev, struct xenbus_device, dev);
622 DPRINTK("%s", xdev->nodename);
624 if (dev->driver == NULL)
626 drv = to_xenbus_driver(dev->driver);
627 err = talk_to_otherend(xdev);
629 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
634 xdev->state = XenbusStateInitialising;
637 err = drv->resume(xdev);
639 pr_warn("resume %s failed: %i\n", dev_name(dev), err);
644 err = watch_otherend(xdev);
646 pr_warn("resume (watch_otherend) %s failed: %d.\n",
653 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
655 int xenbus_dev_cancel(struct device *dev)
661 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
663 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
667 int register_xenstore_notifier(struct notifier_block *nb)
671 if (xenstored_ready > 0)
672 ret = nb->notifier_call(nb, 0, NULL);
674 blocking_notifier_chain_register(&xenstore_chain, nb);
678 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
680 void unregister_xenstore_notifier(struct notifier_block *nb)
682 blocking_notifier_chain_unregister(&xenstore_chain, nb);
684 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
686 void xenbus_probe(struct work_struct *unused)
690 /* Notify others that xenstore is up */
691 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
693 EXPORT_SYMBOL_GPL(xenbus_probe);
695 static int __init xenbus_probe_initcall(void)
700 if (xen_initial_domain() || xen_hvm_domain())
707 device_initcall(xenbus_probe_initcall);
709 /* Set up event channel for xenstored which is run as a local process
710 * (this is normally used only in dom0)
712 static int __init xenstored_local_init(void)
715 unsigned long page = 0;
716 struct evtchn_alloc_unbound alloc_unbound;
718 /* Allocate Xenstore page */
719 page = get_zeroed_page(GFP_KERNEL);
723 xen_store_gfn = virt_to_gfn((void *)page);
725 /* Next allocate a local port which xenstored can bind to */
726 alloc_unbound.dom = DOMID_SELF;
727 alloc_unbound.remote_dom = DOMID_SELF;
729 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
735 xen_store_evtchn = alloc_unbound.port;
745 static int xenbus_resume_cb(struct notifier_block *nb,
746 unsigned long action, void *data)
750 if (xen_hvm_domain()) {
753 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
755 xen_store_evtchn = v;
757 pr_warn("Cannot update xenstore event channel: %d\n",
760 xen_store_evtchn = xen_start_info->store_evtchn;
765 static struct notifier_block xenbus_resume_nb = {
766 .notifier_call = xenbus_resume_cb,
769 static int __init xenbus_init(void)
773 xen_store_domain_type = XS_UNKNOWN;
778 xenbus_ring_ops_init();
781 xen_store_domain_type = XS_PV;
782 if (xen_hvm_domain())
783 xen_store_domain_type = XS_HVM;
784 if (xen_hvm_domain() && xen_initial_domain())
785 xen_store_domain_type = XS_LOCAL;
786 if (xen_pv_domain() && !xen_start_info->store_evtchn)
787 xen_store_domain_type = XS_LOCAL;
788 if (xen_pv_domain() && xen_start_info->store_evtchn)
791 switch (xen_store_domain_type) {
793 err = xenstored_local_init();
796 xen_store_interface = gfn_to_virt(xen_store_gfn);
799 xen_store_evtchn = xen_start_info->store_evtchn;
800 xen_store_gfn = xen_start_info->store_mfn;
801 xen_store_interface = gfn_to_virt(xen_store_gfn);
804 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
807 xen_store_evtchn = (int)v;
808 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
811 xen_store_gfn = (unsigned long)v;
812 xen_store_interface =
813 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
817 pr_warn("Xenstore state unknown\n");
821 /* Initialize the interface to xenstore. */
824 pr_warn("Error initializing xenstore comms: %i\n", err);
828 if ((xen_store_domain_type != XS_LOCAL) &&
829 (xen_store_domain_type != XS_UNKNOWN))
830 xen_resume_notifier_register(&xenbus_resume_nb);
832 #ifdef CONFIG_XEN_COMPAT_XENFS
834 * Create xenfs mountpoint in /proc for compatibility with
835 * utilities that expect to find "xenbus" under "/proc/xen".
837 proc_create_mount_point("xen");
844 postcore_initcall(xenbus_init);
846 MODULE_LICENSE("GPL");