drivers/xen/xenbus/xenbus_probe.c

   1 /******************************************************************************
   2  * Talks to Xen Store to figure out what devices we have.
   3  *
   4  * Copyright (C) 2005 Rusty Russell, IBM Corporation
   5  * Copyright (C) 2005 Mike Wray, Hewlett-Packard
   6  * Copyright (C) 2005, 2006 XenSource Ltd
   7  *
   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:
  13  *
  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:
  20  *
  21  * The above copyright notice and this permission notice shall be included in
  22  * all copies or substantial portions of the Software.
  23  *
  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
  30  * IN THE SOFTWARE.
  31  */
  32
  33 #define DPRINTK(fmt, args...)                           \
  34         pr_debug("xenbus_probe (%s:%d) " fmt ".\n",     \
  35                  __func__, __LINE__, ##args)
  36
  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>
  42 #include <linux/mm.h>
  43 #include <linux/proc_fs.h>
  44 #include <linux/notifier.h>
  45 #include <linux/kthread.h>
  46 #include <linux/mutex.h>
  47 #include <linux/io.h>
  48 #include <linux/slab.h>
  49
  50 #include <asm/page.h>
  51 #include <asm/pgtable.h>
  52 #include <asm/xen/hypervisor.h>
  53
  54 #include <xen/xen.h>
  55 #include <xen/xenbus.h>
  56 #include <xen/events.h>
  57 #include <xen/page.h>
  58
  59 #include <xen/hvm.h>
  60
  61 #include "xenbus_comms.h"
  62 #include "xenbus_probe.h"
  63
  64
  65 int xen_store_evtchn;
  66 EXPORT_SYMBOL_GPL(xen_store_evtchn);
  67
  68 struct xenstore_domain_interface *xen_store_interface;
  69 EXPORT_SYMBOL_GPL(xen_store_interface);
  70
  71 static unsigned long xen_store_mfn;
  72
  73 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  74
  75 /* If something in array of ids matches this device, return it. */
  76 static const struct xenbus_device_id *
  77 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
  78 {
  79         for (; *arr->devicetype != '\0'; arr++) {
  80                 if (!strcmp(arr->devicetype, dev->devicetype))
  81                         return arr;
  82         }
  83         return NULL;
  84 }
  85
  86 int xenbus_match(struct device *_dev, struct device_driver *_drv)
  87 {
  88         struct xenbus_driver *drv = to_xenbus_driver(_drv);
  89
  90         if (!drv->ids)
  91                 return 0;
  92
  93         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
  94 }
  95 EXPORT_SYMBOL_GPL(xenbus_match);
  96
  97
  98 static void free_otherend_details(struct xenbus_device *dev)
  99 {
 100         kfree(dev->otherend);
 101         dev->otherend = NULL;
 102 }
 103
 104
 105 static void free_otherend_watch(struct xenbus_device *dev)
 106 {
 107         if (dev->otherend_watch.node) {
 108                 unregister_xenbus_watch(&dev->otherend_watch);
 109                 kfree(dev->otherend_watch.node);
 110                 dev->otherend_watch.node = NULL;
 111         }
 112 }
 113
 114
 115 static int talk_to_otherend(struct xenbus_device *dev)
 116 {
 117         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 118
 119         free_otherend_watch(dev);
 120         free_otherend_details(dev);
 121
 122         return drv->read_otherend_details(dev);
 123 }
 124
 125
 126
 127 static int watch_otherend(struct xenbus_device *dev)
 128 {
 129         struct xen_bus_type *bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
 130
 131         return xenbus_watch_pathfmt(dev, &dev->otherend_watch, bus->otherend_changed,
 132                                     "%s/%s", dev->otherend, "state");
 133 }
 134
 135
 136 int xenbus_read_otherend_details(struct xenbus_device *xendev,
 137                                  char *id_node, char *path_node)
 138 {
 139         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 140                                 id_node, "%i", &xendev->otherend_id,
 141                                 path_node, NULL, &xendev->otherend,
 142                                 NULL);
 143         if (err) {
 144                 xenbus_dev_fatal(xendev, err,
 145                                  "reading other end details from %s",
 146                                  xendev->nodename);
 147                 return err;
 148         }
 149         if (strlen(xendev->otherend) == 0 ||
 150             !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
 151                 xenbus_dev_fatal(xendev, -ENOENT,
 152                                  "unable to read other end from %s.  "
 153                                  "missing or inaccessible.",
 154                                  xendev->nodename);
 155                 free_otherend_details(xendev);
 156                 return -ENOENT;
 157         }
 158
 159         return 0;
 160 }
 161 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
 162
 163 void xenbus_otherend_changed(struct xenbus_watch *watch,
 164                              const char **vec, unsigned int len,
 165                              int ignore_on_shutdown)
 166 {
 167         struct xenbus_device *dev =
 168                 container_of(watch, struct xenbus_device, otherend_watch);
 169         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 170         enum xenbus_state state;
 171
 172         /* Protect us against watches firing on old details when the otherend
 173            details change, say immediately after a resume. */
 174         if (!dev->otherend ||
 175             strncmp(dev->otherend, vec[XS_WATCH_PATH],
 176                     strlen(dev->otherend))) {
 177                 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
 178                         vec[XS_WATCH_PATH]);
 179                 return;
 180         }
 181
 182         state = xenbus_read_driver_state(dev->otherend);
 183
 184         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 185                 state, xenbus_strstate(state), dev->otherend_watch.node,
 186                 vec[XS_WATCH_PATH]);
 187
 188         /*
 189          * Ignore xenbus transitions during shutdown. This prevents us doing
 190          * work that can fail e.g., when the rootfs is gone.
 191          */
 192         if (system_state > SYSTEM_RUNNING) {
 193                 if (ignore_on_shutdown && (state == XenbusStateClosing))
 194                         xenbus_frontend_closed(dev);
 195                 return;
 196         }
 197
 198         if (drv->otherend_changed)
 199                 drv->otherend_changed(dev, state);
 200 }
 201 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
 202
 203 int xenbus_dev_probe(struct device *_dev)
 204 {
 205         struct xenbus_device *dev = to_xenbus_device(_dev);
 206         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 207         const struct xenbus_device_id *id;
 208         int err;
 209
 210         DPRINTK("%s", dev->nodename);
 211
 212         if (!drv->probe) {
 213                 err = -ENODEV;
 214                 goto fail;
 215         }
 216
 217         id = match_device(drv->ids, dev);
 218         if (!id) {
 219                 err = -ENODEV;
 220                 goto fail;
 221         }
 222
 223         err = talk_to_otherend(dev);
 224         if (err) {
 225                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 226                          dev->nodename);
 227                 return err;
 228         }
 229
 230         err = drv->probe(dev, id);
 231         if (err)
 232                 goto fail;
 233
 234         err = watch_otherend(dev);
 235         if (err) {
 236                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 237                        dev->nodename);
 238                 return err;
 239         }
 240
 241         return 0;
 242 fail:
 243         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 244         xenbus_switch_state(dev, XenbusStateClosed);
 245         return err;
 246 }
 247 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
 248
 249 int xenbus_dev_remove(struct device *_dev)
 250 {
 251         struct xenbus_device *dev = to_xenbus_device(_dev);
 252         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 253
 254         DPRINTK("%s", dev->nodename);
 255
 256         free_otherend_watch(dev);
 257         free_otherend_details(dev);
 258
 259         if (drv->remove)
 260                 drv->remove(dev);
 261
 262         xenbus_switch_state(dev, XenbusStateClosed);
 263         return 0;
 264 }
 265 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
 266
 267 void xenbus_dev_shutdown(struct device *_dev)
 268 {
 269         struct xenbus_device *dev = to_xenbus_device(_dev);
 270         unsigned long timeout = 5*HZ;
 271
 272         DPRINTK("%s", dev->nodename);
 273
 274         get_device(&dev->dev);
 275         if (dev->state != XenbusStateConnected) {
 276                 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
 277                        dev->nodename, xenbus_strstate(dev->state));
 278                 goto out;
 279         }
 280         xenbus_switch_state(dev, XenbusStateClosing);
 281         timeout = wait_for_completion_timeout(&dev->down, timeout);
 282         if (!timeout)
 283                 printk(KERN_INFO "%s: %s timeout closing device\n",
 284                        __func__, dev->nodename);
 285  out:
 286         put_device(&dev->dev);
 287 }
 288 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
 289
 290 int xenbus_register_driver_common(struct xenbus_driver *drv,
 291                                   struct xen_bus_type *bus,
 292                                   struct module *owner,
 293                                   const char *mod_name)
 294 {
 295         drv->driver.name = drv->name;
 296         drv->driver.bus = &bus->bus;
 297         drv->driver.owner = owner;
 298         drv->driver.mod_name = mod_name;
 299
 300         return driver_register(&drv->driver);
 301 }
 302 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
 303
 304 void xenbus_unregister_driver(struct xenbus_driver *drv)
 305 {
 306         driver_unregister(&drv->driver);
 307 }
 308 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 309
 310 struct xb_find_info
 311 {
 312         struct xenbus_device *dev;
 313         const char *nodename;
 314 };
 315
 316 static int cmp_dev(struct device *dev, void *data)
 317 {
 318         struct xenbus_device *xendev = to_xenbus_device(dev);
 319         struct xb_find_info *info = data;
 320
 321         if (!strcmp(xendev->nodename, info->nodename)) {
 322                 info->dev = xendev;
 323                 get_device(dev);
 324                 return 1;
 325         }
 326         return 0;
 327 }
 328
 329 struct xenbus_device *xenbus_device_find(const char *nodename,
 330                                          struct bus_type *bus)
 331 {
 332         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 333
 334         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 335         return info.dev;
 336 }
 337
 338 static int cleanup_dev(struct device *dev, void *data)
 339 {
 340         struct xenbus_device *xendev = to_xenbus_device(dev);
 341         struct xb_find_info *info = data;
 342         int len = strlen(info->nodename);
 343
 344         DPRINTK("%s", info->nodename);
 345
 346         /* Match the info->nodename path, or any subdirectory of that path. */
 347         if (strncmp(xendev->nodename, info->nodename, len))
 348                 return 0;
 349
 350         /* If the node name is longer, ensure it really is a subdirectory. */
 351         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 352                 return 0;
 353
 354         info->dev = xendev;
 355         get_device(dev);
 356         return 1;
 357 }
 358
 359 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 360 {
 361         struct xb_find_info info = { .nodename = path };
 362
 363         do {
 364                 info.dev = NULL;
 365                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 366                 if (info.dev) {
 367                         device_unregister(&info.dev->dev);
 368                         put_device(&info.dev->dev);
 369                 }
 370         } while (info.dev);
 371 }
 372
 373 static void xenbus_dev_release(struct device *dev)
 374 {
 375         if (dev)
 376                 kfree(to_xenbus_device(dev));
 377 }
 378
 379 static ssize_t xendev_show_nodename(struct device *dev,
 380                                     struct device_attribute *attr, char *buf)
 381 {
 382         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 383 }
 384 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
 385
 386 static ssize_t xendev_show_devtype(struct device *dev,
 387                                    struct device_attribute *attr, char *buf)
 388 {
 389         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 390 }
 391 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
 392
 393 static ssize_t xendev_show_modalias(struct device *dev,
 394                                     struct device_attribute *attr, char *buf)
 395 {
 396         return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
 397 }
 398 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
 399
 400 int xenbus_probe_node(struct xen_bus_type *bus,
 401                       const char *type,
 402                       const char *nodename)
 403 {
 404         char devname[XEN_BUS_ID_SIZE];
 405         int err;
 406         struct xenbus_device *xendev;
 407         size_t stringlen;
 408         char *tmpstring;
 409
 410         enum xenbus_state state = xenbus_read_driver_state(nodename);
 411
 412         if (state != XenbusStateInitialising) {
 413                 /* Device is not new, so ignore it.  This can happen if a
 414                    device is going away after switching to Closed.  */
 415                 return 0;
 416         }
 417
 418         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 419         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 420         if (!xendev)
 421                 return -ENOMEM;
 422
 423         xendev->state = XenbusStateInitialising;
 424
 425         /* Copy the strings into the extra space. */
 426
 427         tmpstring = (char *)(xendev + 1);
 428         strcpy(tmpstring, nodename);
 429         xendev->nodename = tmpstring;
 430
 431         tmpstring += strlen(tmpstring) + 1;
 432         strcpy(tmpstring, type);
 433         xendev->devicetype = tmpstring;
 434         init_completion(&xendev->down);
 435
 436         xendev->dev.bus = &bus->bus;
 437         xendev->dev.release = xenbus_dev_release;
 438
 439         err = bus->get_bus_id(devname, xendev->nodename);
 440         if (err)
 441                 goto fail;
 442
 443         dev_set_name(&xendev->dev, devname);
 444
 445         /* Register with generic device framework. */
 446         err = device_register(&xendev->dev);
 447         if (err)
 448                 goto fail;
 449
 450         err = device_create_file(&xendev->dev, &dev_attr_nodename);
 451         if (err)
 452                 goto fail_unregister;
 453
 454         err = device_create_file(&xendev->dev, &dev_attr_devtype);
 455         if (err)
 456                 goto fail_remove_nodename;
 457
 458         err = device_create_file(&xendev->dev, &dev_attr_modalias);
 459         if (err)
 460                 goto fail_remove_devtype;
 461
 462         return 0;
 463 fail_remove_devtype:
 464         device_remove_file(&xendev->dev, &dev_attr_devtype);
 465 fail_remove_nodename:
 466         device_remove_file(&xendev->dev, &dev_attr_nodename);
 467 fail_unregister:
 468         device_unregister(&xendev->dev);
 469 fail:
 470         kfree(xendev);
 471         return err;
 472 }
 473 EXPORT_SYMBOL_GPL(xenbus_probe_node);
 474
 475 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 476 {
 477         int err = 0;
 478         char **dir;
 479         unsigned int dir_n = 0;
 480         int i;
 481
 482         printk(KERN_CRIT "%s type %s\n", __func__, type);
 483
 484         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 485         if (IS_ERR(dir)) {
 486                 printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
 487                 return PTR_ERR(dir);
 488         }
 489
 490         for (i = 0; i < dir_n; i++) {
 491                 printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
 492                 err = bus->probe(bus, type, dir[i]);
 493                 if (err) {
 494                         printk(KERN_CRIT "%s failed\n", __func__);
 495                         break;
 496                 }
 497         }
 498         printk("%s done\n", __func__);
 499         kfree(dir);
 500         return err;
 501 }
 502
 503 int xenbus_probe_devices(struct xen_bus_type *bus)
 504 {
 505         int err = 0;
 506         char **dir;
 507         unsigned int i, dir_n;
 508
 509         printk(KERN_CRIT "%s %s\n", __func__, bus->root);
 510
 511         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 512         if (IS_ERR(dir)) {
 513                 printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
 514                 return PTR_ERR(dir);
 515         }
 516
 517         for (i = 0; i < dir_n; i++) {
 518                 printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
 519                 err = xenbus_probe_device_type(bus, dir[i]);
 520                 if (err) {
 521                         printk(KERN_CRIT "%s failed\n", __func__);
 522                         break;
 523                 }
 524         }
 525         printk("%s done\n", __func__);
 526         kfree(dir);
 527         return err;
 528 }
 529 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
 530
 531 static unsigned int char_count(const char *str, char c)
 532 {
 533         unsigned int i, ret = 0;
 534
 535         for (i = 0; str[i]; i++)
 536                 if (str[i] == c)
 537                         ret++;
 538         return ret;
 539 }
 540
 541 static int strsep_len(const char *str, char c, unsigned int len)
 542 {
 543         unsigned int i;
 544
 545         for (i = 0; str[i]; i++)
 546                 if (str[i] == c) {
 547                         if (len == 0)
 548                                 return i;
 549                         len--;
 550                 }
 551         return (len == 0) ? i : -ERANGE;
 552 }
 553
 554 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 555 {
 556         int exists, rootlen;
 557         struct xenbus_device *dev;
 558         char type[XEN_BUS_ID_SIZE];
 559         const char *p, *root;
 560
 561         if (char_count(node, '/') < 2)
 562                 return;
 563
 564         exists = xenbus_exists(XBT_NIL, node, "");
 565         if (!exists) {
 566                 xenbus_cleanup_devices(node, &bus->bus);
 567                 return;
 568         }
 569
 570         /* backend/<type>/... or device/<type>/... */
 571         p = strchr(node, '/') + 1;
 572         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 573         type[XEN_BUS_ID_SIZE-1] = '\0';
 574
 575         rootlen = strsep_len(node, '/', bus->levels);
 576         if (rootlen < 0)
 577                 return;
 578         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 579         if (!root)
 580                 return;
 581
 582         dev = xenbus_device_find(root, &bus->bus);
 583         if (!dev)
 584                 xenbus_probe_node(bus, type, root);
 585         else
 586                 put_device(&dev->dev);
 587
 588         kfree(root);
 589 }
 590 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 591
 592 int xenbus_dev_suspend(struct device *dev, pm_message_t state)
 593 {
 594         int err = 0;
 595         struct xenbus_driver *drv;
 596         struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
 597
 598         DPRINTK("%s", xdev->nodename);
 599
 600         if (dev->driver == NULL)
 601                 return 0;
 602         drv = to_xenbus_driver(dev->driver);
 603         if (drv->suspend)
 604                 err = drv->suspend(xdev, state);
 605         if (err)
 606                 printk(KERN_WARNING
 607                        "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
 608         return 0;
 609 }
 610 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
 611
 612 int xenbus_dev_resume(struct device *dev)
 613 {
 614         int err;
 615         struct xenbus_driver *drv;
 616         struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
 617
 618         DPRINTK("%s", xdev->nodename);
 619
 620         if (dev->driver == NULL)
 621                 return 0;
 622         drv = to_xenbus_driver(dev->driver);
 623         err = talk_to_otherend(xdev);
 624         if (err) {
 625                 printk(KERN_WARNING
 626                        "xenbus: resume (talk_to_otherend) %s failed: %i\n",
 627                        dev_name(dev), err);
 628                 return err;
 629         }
 630
 631         xdev->state = XenbusStateInitialising;
 632
 633         if (drv->resume) {
 634                 err = drv->resume(xdev);
 635                 if (err) {
 636                         printk(KERN_WARNING
 637                                "xenbus: resume %s failed: %i\n",
 638                                dev_name(dev), err);
 639                         return err;
 640                 }
 641         }
 642
 643         err = watch_otherend(xdev);
 644         if (err) {
 645                 printk(KERN_WARNING
 646                        "xenbus_probe: resume (watch_otherend) %s failed: "
 647                        "%d.\n", dev_name(dev), err);
 648                 return err;
 649         }
 650
 651         return 0;
 652 }
 653 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
 654
 655 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 656 int xenstored_ready = 0;
 657
 658
 659 int register_xenstore_notifier(struct notifier_block *nb)
 660 {
 661         int ret = 0;
 662
 663         if (xenstored_ready > 0)
 664                 ret = nb->notifier_call(nb, 0, NULL);
 665         else
 666                 blocking_notifier_chain_register(&xenstore_chain, nb);
 667
 668         return ret;
 669 }
 670 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 671
 672 void unregister_xenstore_notifier(struct notifier_block *nb)
 673 {
 674         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 675 }
 676 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 677
 678 void xenbus_probe(struct work_struct *unused)
 679 {
 680         xenstored_ready = 1;
 681
 682         printk(KERN_CRIT "xenbus_probe wake_waiting\n");
 683
 684         /* Notify others that xenstore is up */
 685         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 686 }
 687 EXPORT_SYMBOL_GPL(xenbus_probe);
 688
 689 static int __init xenbus_probe_initcall(void)
 690 {
 691         if (!xen_domain())
 692                 return -ENODEV;
 693
 694         if (xen_initial_domain() || xen_hvm_domain())
 695                 return 0;
 696
 697         xenbus_probe(NULL);
 698         return 0;
 699 }
 700
 701 device_initcall(xenbus_probe_initcall);
 702
 703 static int __init xenbus_init(void)
 704 {
 705         int err = 0;
 706         unsigned long page = 0;
 707
 708         DPRINTK("");
 709
 710         err = -ENODEV;
 711         if (!xen_domain())
 712                 return err;
 713
 714         /*
 715          * Domain0 doesn't have a store_evtchn or store_mfn yet.
 716          */
 717         if (xen_initial_domain()) {
 718                 struct evtchn_alloc_unbound alloc_unbound;
 719
 720                 /* Allocate Xenstore page */
 721                 page = get_zeroed_page(GFP_KERNEL);
 722                 if (!page)
 723                         goto out_error;
 724
 725                 xen_store_mfn = xen_start_info->store_mfn =
 726                         pfn_to_mfn(virt_to_phys((void *)page) >>
 727                                    PAGE_SHIFT);
 728
 729                 /* Next allocate a local port which xenstored can bind to */
 730                 alloc_unbound.dom        = DOMID_SELF;
 731                 alloc_unbound.remote_dom = 0;
 732
 733                 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
 734                                                   &alloc_unbound);
 735                 if (err == -ENOSYS)
 736                         goto out_error;
 737
 738                 BUG_ON(err);
 739                 xen_store_evtchn = xen_start_info->store_evtchn =
 740                         alloc_unbound.port;
 741
 742                 xen_store_interface = mfn_to_virt(xen_store_mfn);
 743         } else {
 744                 if (xen_hvm_domain()) {
 745                         uint64_t v = 0;
 746                         err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 747                         if (err)
 748                                 goto out_error;
 749                         xen_store_evtchn = (int)v;
 750                         err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 751                         if (err)
 752                                 goto out_error;
 753                         xen_store_mfn = (unsigned long)v;
 754                         xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
 755                 } else {
 756                         xen_store_evtchn = xen_start_info->store_evtchn;
 757                         xen_store_mfn = xen_start_info->store_mfn;
 758                         xen_store_interface = mfn_to_virt(xen_store_mfn);
 759                         xenstored_ready = 1;
 760                 }
 761         }
 762
 763         /* Initialize the interface to xenstore. */
 764         err = xs_init();
 765         if (err) {
 766                 printk(KERN_WARNING
 767                        "XENBUS: Error initializing xenstore comms: %i\n", err);
 768                 goto out_error;
 769         }
 770
 771 #ifdef CONFIG_XEN_COMPAT_XENFS
 772         /*
 773          * Create xenfs mountpoint in /proc for compatibility with
 774          * utilities that expect to find "xenbus" under "/proc/xen".
 775          */
 776         proc_mkdir("xen", NULL);
 777 #endif
 778
 779         printk(KERN_CRIT "%s ok\n", __func__);
 780         return 0;
 781
 782   out_error:
 783         if (page != 0)
 784                 free_page(page);
 785
 786         return err;
 787 }
 788
 789 postcore_initcall(xenbus_init);
 790
 791 MODULE_LICENSE("GPL");