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>
49 #include <linux/module.h>
52 #include <asm/pgtable.h>
53 #include <asm/xen/hypervisor.h>
56 #include <xen/xenbus.h>
57 #include <xen/events.h>
62 #include "xenbus_comms.h"
63 #include "xenbus_probe.h"
67 EXPORT_SYMBOL_GPL(xen_store_evtchn);
69 struct xenstore_domain_interface *xen_store_interface;
70 EXPORT_SYMBOL_GPL(xen_store_interface);
72 static unsigned long xen_store_mfn;
74 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
76 /* If something in array of ids matches this device, return it. */
77 static const struct xenbus_device_id *
78 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
80 for (; *arr->devicetype != '\0'; arr++) {
81 if (!strcmp(arr->devicetype, dev->devicetype))
87 int xenbus_match(struct device *_dev, struct device_driver *_drv)
89 struct xenbus_driver *drv = to_xenbus_driver(_drv);
94 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
96 EXPORT_SYMBOL_GPL(xenbus_match);
99 static void free_otherend_details(struct xenbus_device *dev)
101 kfree(dev->otherend);
102 dev->otherend = NULL;
106 static void free_otherend_watch(struct xenbus_device *dev)
108 if (dev->otherend_watch.node) {
109 unregister_xenbus_watch(&dev->otherend_watch);
110 kfree(dev->otherend_watch.node);
111 dev->otherend_watch.node = NULL;
116 static int talk_to_otherend(struct xenbus_device *dev)
118 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
120 free_otherend_watch(dev);
121 free_otherend_details(dev);
123 return drv->read_otherend_details(dev);
128 static int watch_otherend(struct xenbus_device *dev)
130 struct xen_bus_type *bus =
131 container_of(dev->dev.bus, struct xen_bus_type, bus);
133 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
134 bus->otherend_changed,
135 "%s/%s", dev->otherend, "state");
139 int xenbus_read_otherend_details(struct xenbus_device *xendev,
140 char *id_node, char *path_node)
142 int err = xenbus_gather(XBT_NIL, xendev->nodename,
143 id_node, "%i", &xendev->otherend_id,
144 path_node, NULL, &xendev->otherend,
147 xenbus_dev_fatal(xendev, err,
148 "reading other end details from %s",
152 if (strlen(xendev->otherend) == 0 ||
153 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
154 xenbus_dev_fatal(xendev, -ENOENT,
155 "unable to read other end from %s. "
156 "missing or inaccessible.",
158 free_otherend_details(xendev);
164 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
166 void xenbus_otherend_changed(struct xenbus_watch *watch,
167 const char **vec, unsigned int len,
168 int ignore_on_shutdown)
170 struct xenbus_device *dev =
171 container_of(watch, struct xenbus_device, otherend_watch);
172 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
173 enum xenbus_state state;
175 /* Protect us against watches firing on old details when the otherend
176 details change, say immediately after a resume. */
177 if (!dev->otherend ||
178 strncmp(dev->otherend, vec[XS_WATCH_PATH],
179 strlen(dev->otherend))) {
180 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
185 state = xenbus_read_driver_state(dev->otherend);
187 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
188 state, xenbus_strstate(state), dev->otherend_watch.node,
192 * Ignore xenbus transitions during shutdown. This prevents us doing
193 * work that can fail e.g., when the rootfs is gone.
195 if (system_state > SYSTEM_RUNNING) {
196 if (ignore_on_shutdown && (state == XenbusStateClosing))
197 xenbus_frontend_closed(dev);
201 if (drv->otherend_changed)
202 drv->otherend_changed(dev, state);
204 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
206 int xenbus_dev_probe(struct device *_dev)
208 struct xenbus_device *dev = to_xenbus_device(_dev);
209 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
210 const struct xenbus_device_id *id;
213 DPRINTK("%s", dev->nodename);
220 id = match_device(drv->ids, dev);
226 err = talk_to_otherend(dev);
228 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
233 err = drv->probe(dev, id);
237 err = watch_otherend(dev);
239 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
246 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
247 xenbus_switch_state(dev, XenbusStateClosed);
250 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
252 int xenbus_dev_remove(struct device *_dev)
254 struct xenbus_device *dev = to_xenbus_device(_dev);
255 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
257 DPRINTK("%s", dev->nodename);
259 free_otherend_watch(dev);
260 free_otherend_details(dev);
265 xenbus_switch_state(dev, XenbusStateClosed);
268 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
270 void xenbus_dev_shutdown(struct device *_dev)
272 struct xenbus_device *dev = to_xenbus_device(_dev);
273 unsigned long timeout = 5*HZ;
275 DPRINTK("%s", dev->nodename);
277 get_device(&dev->dev);
278 if (dev->state != XenbusStateConnected) {
279 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
280 dev->nodename, xenbus_strstate(dev->state));
283 xenbus_switch_state(dev, XenbusStateClosing);
284 timeout = wait_for_completion_timeout(&dev->down, timeout);
286 printk(KERN_INFO "%s: %s timeout closing device\n",
287 __func__, dev->nodename);
289 put_device(&dev->dev);
291 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
293 int xenbus_register_driver_common(struct xenbus_driver *drv,
294 struct xen_bus_type *bus,
295 struct module *owner,
296 const char *mod_name)
298 drv->driver.name = drv->name;
299 drv->driver.bus = &bus->bus;
300 drv->driver.owner = owner;
301 drv->driver.mod_name = mod_name;
303 return driver_register(&drv->driver);
305 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
307 void xenbus_unregister_driver(struct xenbus_driver *drv)
309 driver_unregister(&drv->driver);
311 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
315 struct xenbus_device *dev;
316 const char *nodename;
319 static int cmp_dev(struct device *dev, void *data)
321 struct xenbus_device *xendev = to_xenbus_device(dev);
322 struct xb_find_info *info = data;
324 if (!strcmp(xendev->nodename, info->nodename)) {
332 struct xenbus_device *xenbus_device_find(const char *nodename,
333 struct bus_type *bus)
335 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
337 bus_for_each_dev(bus, NULL, &info, cmp_dev);
341 static int cleanup_dev(struct device *dev, void *data)
343 struct xenbus_device *xendev = to_xenbus_device(dev);
344 struct xb_find_info *info = data;
345 int len = strlen(info->nodename);
347 DPRINTK("%s", info->nodename);
349 /* Match the info->nodename path, or any subdirectory of that path. */
350 if (strncmp(xendev->nodename, info->nodename, len))
353 /* If the node name is longer, ensure it really is a subdirectory. */
354 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
362 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
364 struct xb_find_info info = { .nodename = path };
368 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
370 device_unregister(&info.dev->dev);
371 put_device(&info.dev->dev);
376 static void xenbus_dev_release(struct device *dev)
379 kfree(to_xenbus_device(dev));
382 static ssize_t nodename_show(struct device *dev,
383 struct device_attribute *attr, char *buf)
385 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
388 static ssize_t devtype_show(struct device *dev,
389 struct device_attribute *attr, char *buf)
391 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
394 static ssize_t modalias_show(struct device *dev,
395 struct device_attribute *attr, char *buf)
397 return sprintf(buf, "%s:%s\n", dev->bus->name,
398 to_xenbus_device(dev)->devicetype);
401 struct device_attribute xenbus_dev_attrs[] = {
407 EXPORT_SYMBOL_GPL(xenbus_dev_attrs);
409 int xenbus_probe_node(struct xen_bus_type *bus,
411 const char *nodename)
413 char devname[XEN_BUS_ID_SIZE];
415 struct xenbus_device *xendev;
419 enum xenbus_state state = xenbus_read_driver_state(nodename);
421 if (state != XenbusStateInitialising) {
422 /* Device is not new, so ignore it. This can happen if a
423 device is going away after switching to Closed. */
427 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
428 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
432 xendev->state = XenbusStateInitialising;
434 /* Copy the strings into the extra space. */
436 tmpstring = (char *)(xendev + 1);
437 strcpy(tmpstring, nodename);
438 xendev->nodename = tmpstring;
440 tmpstring += strlen(tmpstring) + 1;
441 strcpy(tmpstring, type);
442 xendev->devicetype = tmpstring;
443 init_completion(&xendev->down);
445 xendev->dev.bus = &bus->bus;
446 xendev->dev.release = xenbus_dev_release;
448 err = bus->get_bus_id(devname, xendev->nodename);
452 dev_set_name(&xendev->dev, devname);
454 /* Register with generic device framework. */
455 err = device_register(&xendev->dev);
464 EXPORT_SYMBOL_GPL(xenbus_probe_node);
466 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
470 unsigned int dir_n = 0;
473 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
477 for (i = 0; i < dir_n; i++) {
478 err = bus->probe(bus, type, dir[i]);
487 int xenbus_probe_devices(struct xen_bus_type *bus)
491 unsigned int i, dir_n;
493 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
497 for (i = 0; i < dir_n; i++) {
498 err = xenbus_probe_device_type(bus, dir[i]);
506 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
508 static unsigned int char_count(const char *str, char c)
510 unsigned int i, ret = 0;
512 for (i = 0; str[i]; i++)
518 static int strsep_len(const char *str, char c, unsigned int len)
522 for (i = 0; str[i]; i++)
528 return (len == 0) ? i : -ERANGE;
531 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
534 struct xenbus_device *dev;
535 char type[XEN_BUS_ID_SIZE];
536 const char *p, *root;
538 if (char_count(node, '/') < 2)
541 exists = xenbus_exists(XBT_NIL, node, "");
543 xenbus_cleanup_devices(node, &bus->bus);
547 /* backend/<type>/... or device/<type>/... */
548 p = strchr(node, '/') + 1;
549 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
550 type[XEN_BUS_ID_SIZE-1] = '\0';
552 rootlen = strsep_len(node, '/', bus->levels);
555 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
559 dev = xenbus_device_find(root, &bus->bus);
561 xenbus_probe_node(bus, type, root);
563 put_device(&dev->dev);
567 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
569 int xenbus_dev_suspend(struct device *dev)
572 struct xenbus_driver *drv;
573 struct xenbus_device *xdev
574 = container_of(dev, struct xenbus_device, dev);
576 DPRINTK("%s", xdev->nodename);
578 if (dev->driver == NULL)
580 drv = to_xenbus_driver(dev->driver);
582 err = drv->suspend(xdev);
585 "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
588 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
590 int xenbus_dev_resume(struct device *dev)
593 struct xenbus_driver *drv;
594 struct xenbus_device *xdev
595 = container_of(dev, struct xenbus_device, dev);
597 DPRINTK("%s", xdev->nodename);
599 if (dev->driver == NULL)
601 drv = to_xenbus_driver(dev->driver);
602 err = talk_to_otherend(xdev);
605 "xenbus: resume (talk_to_otherend) %s failed: %i\n",
610 xdev->state = XenbusStateInitialising;
613 err = drv->resume(xdev);
616 "xenbus: resume %s failed: %i\n",
622 err = watch_otherend(xdev);
625 "xenbus_probe: resume (watch_otherend) %s failed: "
626 "%d.\n", dev_name(dev), err);
632 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
634 int xenbus_dev_cancel(struct device *dev)
640 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
642 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
643 int xenstored_ready = 0;
646 int register_xenstore_notifier(struct notifier_block *nb)
650 if (xenstored_ready > 0)
651 ret = nb->notifier_call(nb, 0, NULL);
653 blocking_notifier_chain_register(&xenstore_chain, nb);
657 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
659 void unregister_xenstore_notifier(struct notifier_block *nb)
661 blocking_notifier_chain_unregister(&xenstore_chain, nb);
663 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
665 void xenbus_probe(struct work_struct *unused)
669 /* Notify others that xenstore is up */
670 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
672 EXPORT_SYMBOL_GPL(xenbus_probe);
674 static int __init xenbus_probe_initcall(void)
679 if (xen_initial_domain() || xen_hvm_domain())
686 device_initcall(xenbus_probe_initcall);
688 /* Set up event channel for xenstored which is run as a local process
689 * (this is normally used only in dom0)
691 static int __init xenstored_local_init(void)
694 unsigned long page = 0;
695 struct evtchn_alloc_unbound alloc_unbound;
697 /* Allocate Xenstore page */
698 page = get_zeroed_page(GFP_KERNEL);
702 xen_store_mfn = xen_start_info->store_mfn =
703 pfn_to_mfn(virt_to_phys((void *)page) >>
706 /* Next allocate a local port which xenstored can bind to */
707 alloc_unbound.dom = DOMID_SELF;
708 alloc_unbound.remote_dom = DOMID_SELF;
710 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
716 xen_store_evtchn = xen_start_info->store_evtchn =
727 static int __init xenbus_init(void)
734 if (xen_hvm_domain()) {
736 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
739 xen_store_evtchn = (int)v;
740 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
743 xen_store_mfn = (unsigned long)v;
744 xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
746 xen_store_evtchn = xen_start_info->store_evtchn;
747 xen_store_mfn = xen_start_info->store_mfn;
748 if (xen_store_evtchn)
751 err = xenstored_local_init();
755 xen_store_interface = mfn_to_virt(xen_store_mfn);
758 /* Initialize the interface to xenstore. */
762 "XENBUS: Error initializing xenstore comms: %i\n", err);
766 #ifdef CONFIG_XEN_COMPAT_XENFS
768 * Create xenfs mountpoint in /proc for compatibility with
769 * utilities that expect to find "xenbus" under "/proc/xen".
771 proc_mkdir("xen", NULL);
778 postcore_initcall(xenbus_init);
780 MODULE_LICENSE("GPL");