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>
64 #include "xenbus_comms.h"
65 #include "xenbus_probe.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_mfn;
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 **vec, unsigned int len,
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, vec[XS_WATCH_PATH],
184 strlen(dev->otherend))) {
185 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
190 state = xenbus_read_driver_state(dev->otherend);
192 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
193 state, xenbus_strstate(state), dev->otherend_watch.node,
197 * Ignore xenbus transitions during shutdown. This prevents us doing
198 * work that can fail e.g., when the rootfs is gone.
200 if (system_state > SYSTEM_RUNNING) {
201 if (ignore_on_shutdown && (state == XenbusStateClosing))
202 xenbus_frontend_closed(dev);
206 if (drv->otherend_changed)
207 drv->otherend_changed(dev, state);
209 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
211 int xenbus_dev_probe(struct device *_dev)
213 struct xenbus_device *dev = to_xenbus_device(_dev);
214 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
215 const struct xenbus_device_id *id;
218 DPRINTK("%s", dev->nodename);
225 id = match_device(drv->ids, dev);
231 err = talk_to_otherend(dev);
233 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
238 err = drv->probe(dev, id);
242 err = watch_otherend(dev);
244 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
251 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
252 xenbus_switch_state(dev, XenbusStateClosed);
255 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
257 int xenbus_dev_remove(struct device *_dev)
259 struct xenbus_device *dev = to_xenbus_device(_dev);
260 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
262 DPRINTK("%s", dev->nodename);
264 free_otherend_watch(dev);
269 free_otherend_details(dev);
271 xenbus_switch_state(dev, XenbusStateClosed);
274 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
276 void xenbus_dev_shutdown(struct device *_dev)
278 struct xenbus_device *dev = to_xenbus_device(_dev);
279 unsigned long timeout = 5*HZ;
281 DPRINTK("%s", dev->nodename);
283 get_device(&dev->dev);
284 if (dev->state != XenbusStateConnected) {
285 pr_info("%s: %s: %s != Connected, skipping\n",
286 __func__, dev->nodename, xenbus_strstate(dev->state));
289 xenbus_switch_state(dev, XenbusStateClosing);
290 timeout = wait_for_completion_timeout(&dev->down, timeout);
292 pr_info("%s: %s timeout closing device\n",
293 __func__, dev->nodename);
295 put_device(&dev->dev);
297 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
299 int xenbus_register_driver_common(struct xenbus_driver *drv,
300 struct xen_bus_type *bus)
302 drv->driver.bus = &bus->bus;
304 return driver_register(&drv->driver);
306 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
308 void xenbus_unregister_driver(struct xenbus_driver *drv)
310 driver_unregister(&drv->driver);
312 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
314 struct xb_find_info {
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 static 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, "%s", 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);
584 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
587 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
589 int xenbus_dev_resume(struct device *dev)
592 struct xenbus_driver *drv;
593 struct xenbus_device *xdev
594 = container_of(dev, struct xenbus_device, dev);
596 DPRINTK("%s", xdev->nodename);
598 if (dev->driver == NULL)
600 drv = to_xenbus_driver(dev->driver);
601 err = talk_to_otherend(xdev);
603 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
608 xdev->state = XenbusStateInitialising;
611 err = drv->resume(xdev);
613 pr_warn("resume %s failed: %i\n", dev_name(dev), err);
618 err = watch_otherend(xdev);
620 pr_warn("resume (watch_otherend) %s failed: %d.\n",
627 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
629 int xenbus_dev_cancel(struct device *dev)
635 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
637 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
641 int register_xenstore_notifier(struct notifier_block *nb)
645 if (xenstored_ready > 0)
646 ret = nb->notifier_call(nb, 0, NULL);
648 blocking_notifier_chain_register(&xenstore_chain, nb);
652 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
654 void unregister_xenstore_notifier(struct notifier_block *nb)
656 blocking_notifier_chain_unregister(&xenstore_chain, nb);
658 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
660 void xenbus_probe(struct work_struct *unused)
664 /* Notify others that xenstore is up */
665 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
667 EXPORT_SYMBOL_GPL(xenbus_probe);
669 static int __init xenbus_probe_initcall(void)
674 if (xen_initial_domain() || xen_hvm_domain())
681 device_initcall(xenbus_probe_initcall);
683 /* Set up event channel for xenstored which is run as a local process
684 * (this is normally used only in dom0)
686 static int __init xenstored_local_init(void)
689 unsigned long page = 0;
690 struct evtchn_alloc_unbound alloc_unbound;
692 /* Allocate Xenstore page */
693 page = get_zeroed_page(GFP_KERNEL);
697 xen_store_mfn = xen_start_info->store_mfn =
698 pfn_to_mfn(virt_to_phys((void *)page) >>
701 /* Next allocate a local port which xenstored can bind to */
702 alloc_unbound.dom = DOMID_SELF;
703 alloc_unbound.remote_dom = DOMID_SELF;
705 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
711 xen_store_evtchn = xen_start_info->store_evtchn =
722 static int __init xenbus_init(void)
726 xen_store_domain_type = XS_UNKNOWN;
731 xenbus_ring_ops_init();
734 xen_store_domain_type = XS_PV;
735 if (xen_hvm_domain())
736 xen_store_domain_type = XS_HVM;
737 if (xen_hvm_domain() && xen_initial_domain())
738 xen_store_domain_type = XS_LOCAL;
739 if (xen_pv_domain() && !xen_start_info->store_evtchn)
740 xen_store_domain_type = XS_LOCAL;
741 if (xen_pv_domain() && xen_start_info->store_evtchn)
744 switch (xen_store_domain_type) {
746 err = xenstored_local_init();
749 xen_store_interface = mfn_to_virt(xen_store_mfn);
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);
757 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
760 xen_store_evtchn = (int)v;
761 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
764 xen_store_mfn = (unsigned long)v;
765 xen_store_interface =
766 xen_remap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
769 pr_warn("Xenstore state unknown\n");
773 /* Initialize the interface to xenstore. */
776 pr_warn("Error initializing xenstore comms: %i\n", err);
780 #ifdef CONFIG_XEN_COMPAT_XENFS
782 * Create xenfs mountpoint in /proc for compatibility with
783 * utilities that expect to find "xenbus" under "/proc/xen".
785 proc_mkdir("xen", NULL);
792 postcore_initcall(xenbus_init);
794 MODULE_LICENSE("GPL");