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 err = drv->probe(dev, id);
239 err = watch_otherend(dev);
241 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
248 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
249 xenbus_switch_state(dev, XenbusStateClosed);
252 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
254 int xenbus_dev_remove(struct device *_dev)
256 struct xenbus_device *dev = to_xenbus_device(_dev);
257 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
259 DPRINTK("%s", dev->nodename);
261 free_otherend_watch(dev);
266 free_otherend_details(dev);
268 xenbus_switch_state(dev, XenbusStateClosed);
271 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
273 void xenbus_dev_shutdown(struct device *_dev)
275 struct xenbus_device *dev = to_xenbus_device(_dev);
276 unsigned long timeout = 5*HZ;
278 DPRINTK("%s", dev->nodename);
280 get_device(&dev->dev);
281 if (dev->state != XenbusStateConnected) {
282 pr_info("%s: %s: %s != Connected, skipping\n",
283 __func__, dev->nodename, xenbus_strstate(dev->state));
286 xenbus_switch_state(dev, XenbusStateClosing);
287 timeout = wait_for_completion_timeout(&dev->down, timeout);
289 pr_info("%s: %s timeout closing device\n",
290 __func__, dev->nodename);
292 put_device(&dev->dev);
294 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
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);
476 /* Register with generic device framework. */
477 err = device_register(&xendev->dev);
479 put_device(&xendev->dev);
489 EXPORT_SYMBOL_GPL(xenbus_probe_node);
491 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
495 unsigned int dir_n = 0;
498 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
502 for (i = 0; i < dir_n; i++) {
503 err = bus->probe(bus, type, dir[i]);
512 int xenbus_probe_devices(struct xen_bus_type *bus)
516 unsigned int i, dir_n;
518 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
522 for (i = 0; i < dir_n; i++) {
523 err = xenbus_probe_device_type(bus, dir[i]);
531 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
533 static unsigned int char_count(const char *str, char c)
535 unsigned int i, ret = 0;
537 for (i = 0; str[i]; i++)
543 static int strsep_len(const char *str, char c, unsigned int len)
547 for (i = 0; str[i]; i++)
553 return (len == 0) ? i : -ERANGE;
556 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
559 struct xenbus_device *dev;
560 char type[XEN_BUS_ID_SIZE];
561 const char *p, *root;
563 if (char_count(node, '/') < 2)
566 exists = xenbus_exists(XBT_NIL, node, "");
568 xenbus_cleanup_devices(node, &bus->bus);
572 /* backend/<type>/... or device/<type>/... */
573 p = strchr(node, '/') + 1;
574 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
575 type[XEN_BUS_ID_SIZE-1] = '\0';
577 rootlen = strsep_len(node, '/', bus->levels);
580 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
584 dev = xenbus_device_find(root, &bus->bus);
586 xenbus_probe_node(bus, type, root);
588 put_device(&dev->dev);
592 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
594 int xenbus_dev_suspend(struct device *dev)
597 struct xenbus_driver *drv;
598 struct xenbus_device *xdev
599 = container_of(dev, struct xenbus_device, dev);
601 DPRINTK("%s", xdev->nodename);
603 if (dev->driver == NULL)
605 drv = to_xenbus_driver(dev->driver);
607 err = drv->suspend(xdev);
609 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
612 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
614 int xenbus_dev_resume(struct device *dev)
617 struct xenbus_driver *drv;
618 struct xenbus_device *xdev
619 = container_of(dev, struct xenbus_device, dev);
621 DPRINTK("%s", xdev->nodename);
623 if (dev->driver == NULL)
625 drv = to_xenbus_driver(dev->driver);
626 err = talk_to_otherend(xdev);
628 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
633 xdev->state = XenbusStateInitialising;
636 err = drv->resume(xdev);
638 pr_warn("resume %s failed: %i\n", dev_name(dev), err);
643 err = watch_otherend(xdev);
645 pr_warn("resume (watch_otherend) %s failed: %d.\n",
652 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
654 int xenbus_dev_cancel(struct device *dev)
660 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
662 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
666 int register_xenstore_notifier(struct notifier_block *nb)
670 if (xenstored_ready > 0)
671 ret = nb->notifier_call(nb, 0, NULL);
673 blocking_notifier_chain_register(&xenstore_chain, nb);
677 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
679 void unregister_xenstore_notifier(struct notifier_block *nb)
681 blocking_notifier_chain_unregister(&xenstore_chain, nb);
683 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
685 void xenbus_probe(struct work_struct *unused)
689 /* Notify others that xenstore is up */
690 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
692 EXPORT_SYMBOL_GPL(xenbus_probe);
694 static int __init xenbus_probe_initcall(void)
699 if (xen_initial_domain() || xen_hvm_domain())
706 device_initcall(xenbus_probe_initcall);
708 /* Set up event channel for xenstored which is run as a local process
709 * (this is normally used only in dom0)
711 static int __init xenstored_local_init(void)
714 unsigned long page = 0;
715 struct evtchn_alloc_unbound alloc_unbound;
717 /* Allocate Xenstore page */
718 page = get_zeroed_page(GFP_KERNEL);
722 xen_store_gfn = virt_to_gfn((void *)page);
724 /* Next allocate a local port which xenstored can bind to */
725 alloc_unbound.dom = DOMID_SELF;
726 alloc_unbound.remote_dom = DOMID_SELF;
728 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
734 xen_store_evtchn = alloc_unbound.port;
744 static int xenbus_resume_cb(struct notifier_block *nb,
745 unsigned long action, void *data)
749 if (xen_hvm_domain()) {
752 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
754 xen_store_evtchn = v;
756 pr_warn("Cannot update xenstore event channel: %d\n",
759 xen_store_evtchn = xen_start_info->store_evtchn;
764 static struct notifier_block xenbus_resume_nb = {
765 .notifier_call = xenbus_resume_cb,
768 static int __init xenbus_init(void)
772 xen_store_domain_type = XS_UNKNOWN;
777 xenbus_ring_ops_init();
780 xen_store_domain_type = XS_PV;
781 if (xen_hvm_domain())
782 xen_store_domain_type = XS_HVM;
783 if (xen_hvm_domain() && xen_initial_domain())
784 xen_store_domain_type = XS_LOCAL;
785 if (xen_pv_domain() && !xen_start_info->store_evtchn)
786 xen_store_domain_type = XS_LOCAL;
787 if (xen_pv_domain() && xen_start_info->store_evtchn)
790 switch (xen_store_domain_type) {
792 err = xenstored_local_init();
795 xen_store_interface = gfn_to_virt(xen_store_gfn);
798 xen_store_evtchn = xen_start_info->store_evtchn;
799 xen_store_gfn = xen_start_info->store_mfn;
800 xen_store_interface = gfn_to_virt(xen_store_gfn);
803 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
806 xen_store_evtchn = (int)v;
807 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
810 xen_store_gfn = (unsigned long)v;
811 xen_store_interface =
812 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
816 pr_warn("Xenstore state unknown\n");
820 /* Initialize the interface to xenstore. */
823 pr_warn("Error initializing xenstore comms: %i\n", err);
827 if ((xen_store_domain_type != XS_LOCAL) &&
828 (xen_store_domain_type != XS_UNKNOWN))
829 xen_resume_notifier_register(&xenbus_resume_nb);
831 #ifdef CONFIG_XEN_COMPAT_XENFS
833 * Create xenfs mountpoint in /proc for compatibility with
834 * utilities that expect to find "xenbus" under "/proc/xen".
836 proc_create_mount_point("xen");
843 postcore_initcall(xenbus_init);
845 MODULE_LICENSE("GPL");