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>
65 #include "xenbus_comms.h"
66 #include "xenbus_probe.h"
70 EXPORT_SYMBOL_GPL(xen_store_evtchn);
72 struct xenstore_domain_interface *xen_store_interface;
73 EXPORT_SYMBOL_GPL(xen_store_interface);
75 enum xenstore_init xen_store_domain_type;
76 EXPORT_SYMBOL_GPL(xen_store_domain_type);
78 static unsigned long xen_store_gfn;
80 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
82 /* If something in array of ids matches this device, return it. */
83 static const struct xenbus_device_id *
84 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
86 for (; *arr->devicetype != '\0'; arr++) {
87 if (!strcmp(arr->devicetype, dev->devicetype))
93 int xenbus_match(struct device *_dev, struct device_driver *_drv)
95 struct xenbus_driver *drv = to_xenbus_driver(_drv);
100 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
102 EXPORT_SYMBOL_GPL(xenbus_match);
105 static void free_otherend_details(struct xenbus_device *dev)
107 kfree(dev->otherend);
108 dev->otherend = NULL;
112 static void free_otherend_watch(struct xenbus_device *dev)
114 if (dev->otherend_watch.node) {
115 unregister_xenbus_watch(&dev->otherend_watch);
116 kfree(dev->otherend_watch.node);
117 dev->otherend_watch.node = NULL;
122 static int talk_to_otherend(struct xenbus_device *dev)
124 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
126 free_otherend_watch(dev);
127 free_otherend_details(dev);
129 return drv->read_otherend_details(dev);
134 static int watch_otherend(struct xenbus_device *dev)
136 struct xen_bus_type *bus =
137 container_of(dev->dev.bus, struct xen_bus_type, bus);
139 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
140 bus->otherend_will_handle,
141 bus->otherend_changed,
142 "%s/%s", dev->otherend, "state");
146 int xenbus_read_otherend_details(struct xenbus_device *xendev,
147 char *id_node, char *path_node)
149 int err = xenbus_gather(XBT_NIL, xendev->nodename,
150 id_node, "%i", &xendev->otherend_id,
151 path_node, NULL, &xendev->otherend,
154 xenbus_dev_fatal(xendev, err,
155 "reading other end details from %s",
159 if (strlen(xendev->otherend) == 0 ||
160 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
161 xenbus_dev_fatal(xendev, -ENOENT,
162 "unable to read other end from %s. "
163 "missing or inaccessible.",
165 free_otherend_details(xendev);
171 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
173 void xenbus_otherend_changed(struct xenbus_watch *watch,
174 const char **vec, unsigned int len,
175 int ignore_on_shutdown)
177 struct xenbus_device *dev =
178 container_of(watch, struct xenbus_device, otherend_watch);
179 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
180 enum xenbus_state state;
182 /* Protect us against watches firing on old details when the otherend
183 details change, say immediately after a resume. */
184 if (!dev->otherend ||
185 strncmp(dev->otherend, vec[XS_WATCH_PATH],
186 strlen(dev->otherend))) {
187 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
192 state = xenbus_read_driver_state(dev->otherend);
194 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
195 state, xenbus_strstate(state), dev->otherend_watch.node,
199 * Ignore xenbus transitions during shutdown. This prevents us doing
200 * work that can fail e.g., when the rootfs is gone.
202 if (system_state > SYSTEM_RUNNING) {
203 if (ignore_on_shutdown && (state == XenbusStateClosing))
204 xenbus_frontend_closed(dev);
208 if (drv->otherend_changed)
209 drv->otherend_changed(dev, state);
211 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
213 int xenbus_dev_probe(struct device *_dev)
215 struct xenbus_device *dev = to_xenbus_device(_dev);
216 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
217 const struct xenbus_device_id *id;
220 DPRINTK("%s", dev->nodename);
227 id = match_device(drv->ids, dev);
233 err = talk_to_otherend(dev);
235 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
240 err = drv->probe(dev, id);
244 err = watch_otherend(dev);
246 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
253 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
254 xenbus_switch_state(dev, XenbusStateClosed);
257 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
259 int xenbus_dev_remove(struct device *_dev)
261 struct xenbus_device *dev = to_xenbus_device(_dev);
262 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
264 DPRINTK("%s", dev->nodename);
266 free_otherend_watch(dev);
271 free_otherend_details(dev);
273 xenbus_switch_state(dev, XenbusStateClosed);
276 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
278 void xenbus_dev_shutdown(struct device *_dev)
280 struct xenbus_device *dev = to_xenbus_device(_dev);
281 unsigned long timeout = 5*HZ;
283 DPRINTK("%s", dev->nodename);
285 get_device(&dev->dev);
286 if (dev->state != XenbusStateConnected) {
287 pr_info("%s: %s: %s != Connected, skipping\n",
288 __func__, dev->nodename, xenbus_strstate(dev->state));
291 xenbus_switch_state(dev, XenbusStateClosing);
292 timeout = wait_for_completion_timeout(&dev->down, timeout);
294 pr_info("%s: %s timeout closing device\n",
295 __func__, dev->nodename);
297 put_device(&dev->dev);
299 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
301 int xenbus_register_driver_common(struct xenbus_driver *drv,
302 struct xen_bus_type *bus,
303 struct module *owner, const char *mod_name)
305 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
306 drv->driver.bus = &bus->bus;
307 drv->driver.owner = owner;
308 drv->driver.mod_name = mod_name;
310 return driver_register(&drv->driver);
312 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
314 void xenbus_unregister_driver(struct xenbus_driver *drv)
316 driver_unregister(&drv->driver);
318 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
320 struct xb_find_info {
321 struct xenbus_device *dev;
322 const char *nodename;
325 static int cmp_dev(struct device *dev, void *data)
327 struct xenbus_device *xendev = to_xenbus_device(dev);
328 struct xb_find_info *info = data;
330 if (!strcmp(xendev->nodename, info->nodename)) {
338 static struct xenbus_device *xenbus_device_find(const char *nodename,
339 struct bus_type *bus)
341 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
343 bus_for_each_dev(bus, NULL, &info, cmp_dev);
347 static int cleanup_dev(struct device *dev, void *data)
349 struct xenbus_device *xendev = to_xenbus_device(dev);
350 struct xb_find_info *info = data;
351 int len = strlen(info->nodename);
353 DPRINTK("%s", info->nodename);
355 /* Match the info->nodename path, or any subdirectory of that path. */
356 if (strncmp(xendev->nodename, info->nodename, len))
359 /* If the node name is longer, ensure it really is a subdirectory. */
360 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
368 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
370 struct xb_find_info info = { .nodename = path };
374 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
376 device_unregister(&info.dev->dev);
377 put_device(&info.dev->dev);
382 static void xenbus_dev_release(struct device *dev)
385 kfree(to_xenbus_device(dev));
388 static ssize_t nodename_show(struct device *dev,
389 struct device_attribute *attr, char *buf)
391 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
393 static DEVICE_ATTR_RO(nodename);
395 static ssize_t devtype_show(struct device *dev,
396 struct device_attribute *attr, char *buf)
398 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
400 static DEVICE_ATTR_RO(devtype);
402 static ssize_t modalias_show(struct device *dev,
403 struct device_attribute *attr, char *buf)
405 return sprintf(buf, "%s:%s\n", dev->bus->name,
406 to_xenbus_device(dev)->devicetype);
408 static DEVICE_ATTR_RO(modalias);
410 static struct attribute *xenbus_dev_attrs[] = {
411 &dev_attr_nodename.attr,
412 &dev_attr_devtype.attr,
413 &dev_attr_modalias.attr,
417 static const struct attribute_group xenbus_dev_group = {
418 .attrs = xenbus_dev_attrs,
421 const struct attribute_group *xenbus_dev_groups[] = {
425 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
427 int xenbus_probe_node(struct xen_bus_type *bus,
429 const char *nodename)
431 char devname[XEN_BUS_ID_SIZE];
433 struct xenbus_device *xendev;
437 enum xenbus_state state = xenbus_read_driver_state(nodename);
439 if (state != XenbusStateInitialising) {
440 /* Device is not new, so ignore it. This can happen if a
441 device is going away after switching to Closed. */
445 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
446 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
450 xendev->state = XenbusStateInitialising;
452 /* Copy the strings into the extra space. */
454 tmpstring = (char *)(xendev + 1);
455 strcpy(tmpstring, nodename);
456 xendev->nodename = tmpstring;
458 tmpstring += strlen(tmpstring) + 1;
459 strcpy(tmpstring, type);
460 xendev->devicetype = tmpstring;
461 init_completion(&xendev->down);
463 xendev->dev.bus = &bus->bus;
464 xendev->dev.release = xenbus_dev_release;
466 err = bus->get_bus_id(devname, xendev->nodename);
470 dev_set_name(&xendev->dev, "%s", devname);
472 /* Register with generic device framework. */
473 err = device_register(&xendev->dev);
475 put_device(&xendev->dev);
485 EXPORT_SYMBOL_GPL(xenbus_probe_node);
487 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
491 unsigned int dir_n = 0;
494 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
498 for (i = 0; i < dir_n; i++) {
499 err = bus->probe(bus, type, dir[i]);
508 int xenbus_probe_devices(struct xen_bus_type *bus)
512 unsigned int i, dir_n;
514 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
518 for (i = 0; i < dir_n; i++) {
519 err = xenbus_probe_device_type(bus, dir[i]);
527 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
529 static unsigned int char_count(const char *str, char c)
531 unsigned int i, ret = 0;
533 for (i = 0; str[i]; i++)
539 static int strsep_len(const char *str, char c, unsigned int len)
543 for (i = 0; str[i]; i++)
549 return (len == 0) ? i : -ERANGE;
552 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
555 struct xenbus_device *dev;
556 char type[XEN_BUS_ID_SIZE];
557 const char *p, *root;
559 if (char_count(node, '/') < 2)
562 exists = xenbus_exists(XBT_NIL, node, "");
564 xenbus_cleanup_devices(node, &bus->bus);
568 /* backend/<type>/... or device/<type>/... */
569 p = strchr(node, '/') + 1;
570 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
571 type[XEN_BUS_ID_SIZE-1] = '\0';
573 rootlen = strsep_len(node, '/', bus->levels);
576 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
580 dev = xenbus_device_find(root, &bus->bus);
582 xenbus_probe_node(bus, type, root);
584 put_device(&dev->dev);
588 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
590 int xenbus_dev_suspend(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);
603 err = drv->suspend(xdev);
605 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
608 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
610 int xenbus_dev_resume(struct device *dev)
613 struct xenbus_driver *drv;
614 struct xenbus_device *xdev
615 = container_of(dev, struct xenbus_device, dev);
617 DPRINTK("%s", xdev->nodename);
619 if (dev->driver == NULL)
621 drv = to_xenbus_driver(dev->driver);
622 err = talk_to_otherend(xdev);
624 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
629 xdev->state = XenbusStateInitialising;
632 err = drv->resume(xdev);
634 pr_warn("resume %s failed: %i\n", dev_name(dev), err);
639 err = watch_otherend(xdev);
641 pr_warn("resume (watch_otherend) %s failed: %d.\n",
648 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
650 int xenbus_dev_cancel(struct device *dev)
656 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
658 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
662 int register_xenstore_notifier(struct notifier_block *nb)
666 if (xenstored_ready > 0)
667 ret = nb->notifier_call(nb, 0, NULL);
669 blocking_notifier_chain_register(&xenstore_chain, nb);
673 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
675 void unregister_xenstore_notifier(struct notifier_block *nb)
677 blocking_notifier_chain_unregister(&xenstore_chain, nb);
679 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
681 void xenbus_probe(struct work_struct *unused)
685 /* Notify others that xenstore is up */
686 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
688 EXPORT_SYMBOL_GPL(xenbus_probe);
690 static int __init xenbus_probe_initcall(void)
695 if (xen_initial_domain() || xen_hvm_domain())
702 device_initcall(xenbus_probe_initcall);
704 /* Set up event channel for xenstored which is run as a local process
705 * (this is normally used only in dom0)
707 static int __init xenstored_local_init(void)
710 unsigned long page = 0;
711 struct evtchn_alloc_unbound alloc_unbound;
713 /* Allocate Xenstore page */
714 page = get_zeroed_page(GFP_KERNEL);
718 xen_store_gfn = xen_start_info->store_mfn = virt_to_gfn((void *)page);
720 /* Next allocate a local port which xenstored can bind to */
721 alloc_unbound.dom = DOMID_SELF;
722 alloc_unbound.remote_dom = DOMID_SELF;
724 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
730 xen_store_evtchn = xen_start_info->store_evtchn =
741 static int xenbus_resume_cb(struct notifier_block *nb,
742 unsigned long action, void *data)
746 if (xen_hvm_domain()) {
749 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
751 xen_store_evtchn = v;
753 pr_warn("Cannot update xenstore event channel: %d\n",
756 xen_store_evtchn = xen_start_info->store_evtchn;
761 static struct notifier_block xenbus_resume_nb = {
762 .notifier_call = xenbus_resume_cb,
765 static int __init xenbus_init(void)
769 xen_store_domain_type = XS_UNKNOWN;
774 xenbus_ring_ops_init();
777 xen_store_domain_type = XS_PV;
778 if (xen_hvm_domain())
779 xen_store_domain_type = XS_HVM;
780 if (xen_hvm_domain() && xen_initial_domain())
781 xen_store_domain_type = XS_LOCAL;
782 if (xen_pv_domain() && !xen_start_info->store_evtchn)
783 xen_store_domain_type = XS_LOCAL;
784 if (xen_pv_domain() && xen_start_info->store_evtchn)
787 switch (xen_store_domain_type) {
789 err = xenstored_local_init();
792 xen_store_interface = gfn_to_virt(xen_store_gfn);
795 xen_store_evtchn = xen_start_info->store_evtchn;
796 xen_store_gfn = xen_start_info->store_mfn;
797 xen_store_interface = gfn_to_virt(xen_store_gfn);
800 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
803 xen_store_evtchn = (int)v;
804 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
807 xen_store_gfn = (unsigned long)v;
808 xen_store_interface =
809 xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
813 pr_warn("Xenstore state unknown\n");
817 /* Initialize the interface to xenstore. */
820 pr_warn("Error initializing xenstore comms: %i\n", err);
824 if ((xen_store_domain_type != XS_LOCAL) &&
825 (xen_store_domain_type != XS_UNKNOWN))
826 xen_resume_notifier_register(&xenbus_resume_nb);
828 #ifdef CONFIG_XEN_COMPAT_XENFS
830 * Create xenfs mountpoint in /proc for compatibility with
831 * utilities that expect to find "xenbus" under "/proc/xen".
833 proc_mkdir("xen", NULL);
840 postcore_initcall(xenbus_init);
842 MODULE_LICENSE("GPL");