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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  34
  35 #define DPRINTK(fmt, args...)                           \
  36         pr_debug("xenbus_probe (%s:%d) " fmt ".\n",     \
  37                  __func__, __LINE__, ##args)
  38
  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>
  44 #include <linux/mm.h>
  45 #include <linux/proc_fs.h>
  46 #include <linux/notifier.h>
  47 #include <linux/kthread.h>
  48 #include <linux/mutex.h>
  49 #include <linux/io.h>
  50 #include <linux/slab.h>
  51 #include <linux/module.h>
  52
  53 #include <asm/page.h>
  54 #include <asm/pgtable.h>
  55 #include <asm/xen/hypervisor.h>
  56
  57 #include <xen/xen.h>
  58 #include <xen/xenbus.h>
  59 #include <xen/events.h>
  60 #include <xen/page.h>
  61
  62 #include <xen/hvm.h>
  63
  64 #include "xenbus_comms.h"
  65 #include "xenbus_probe.h"
  66
  67
  68 int xen_store_evtchn;
  69 EXPORT_SYMBOL_GPL(xen_store_evtchn);
  70
  71 struct xenstore_domain_interface *xen_store_interface;
  72 EXPORT_SYMBOL_GPL(xen_store_interface);
  73
  74 enum xenstore_init xen_store_domain_type;
  75 EXPORT_SYMBOL_GPL(xen_store_domain_type);
  76
  77 static unsigned long xen_store_mfn;
  78
  79 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  80
  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)
  84 {
  85         for (; *arr->devicetype != '\0'; arr++) {
  86                 if (!strcmp(arr->devicetype, dev->devicetype))
  87                         return arr;
  88         }
  89         return NULL;
  90 }
  91
  92 int xenbus_match(struct device *_dev, struct device_driver *_drv)
  93 {
  94         struct xenbus_driver *drv = to_xenbus_driver(_drv);
  95
  96         if (!drv->ids)
  97                 return 0;
  98
  99         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
 100 }
 101 EXPORT_SYMBOL_GPL(xenbus_match);
 102
 103
 104 static void free_otherend_details(struct xenbus_device *dev)
 105 {
 106         kfree(dev->otherend);
 107         dev->otherend = NULL;
 108 }
 109
 110
 111 static void free_otherend_watch(struct xenbus_device *dev)
 112 {
 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;
 117         }
 118 }
 119
 120
 121 static int talk_to_otherend(struct xenbus_device *dev)
 122 {
 123         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 124
 125         free_otherend_watch(dev);
 126         free_otherend_details(dev);
 127
 128         return drv->read_otherend_details(dev);
 129 }
 130
 131
 132
 133 static int watch_otherend(struct xenbus_device *dev)
 134 {
 135         struct xen_bus_type *bus =
 136                 container_of(dev->dev.bus, struct xen_bus_type, bus);
 137
 138         return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
 139                                     bus->otherend_changed,
 140                                     "%s/%s", dev->otherend, "state");
 141 }
 142
 143
 144 int xenbus_read_otherend_details(struct xenbus_device *xendev,
 145                                  char *id_node, char *path_node)
 146 {
 147         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 148                                 id_node, "%i", &xendev->otherend_id,
 149                                 path_node, NULL, &xendev->otherend,
 150                                 NULL);
 151         if (err) {
 152                 xenbus_dev_fatal(xendev, err,
 153                                  "reading other end details from %s",
 154                                  xendev->nodename);
 155                 return err;
 156         }
 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.",
 162                                  xendev->nodename);
 163                 free_otherend_details(xendev);
 164                 return -ENOENT;
 165         }
 166
 167         return 0;
 168 }
 169 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
 170
 171 void xenbus_otherend_changed(struct xenbus_watch *watch,
 172                              const char **vec, unsigned int len,
 173                              int ignore_on_shutdown)
 174 {
 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;
 179
 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",
 186                         vec[XS_WATCH_PATH]);
 187                 return;
 188         }
 189
 190         state = xenbus_read_driver_state(dev->otherend);
 191
 192         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 193                 state, xenbus_strstate(state), dev->otherend_watch.node,
 194                 vec[XS_WATCH_PATH]);
 195
 196         /*
 197          * Ignore xenbus transitions during shutdown. This prevents us doing
 198          * work that can fail e.g., when the rootfs is gone.
 199          */
 200         if (system_state > SYSTEM_RUNNING) {
 201                 if (ignore_on_shutdown && (state == XenbusStateClosing))
 202                         xenbus_frontend_closed(dev);
 203                 return;
 204         }
 205
 206         if (drv->otherend_changed)
 207                 drv->otherend_changed(dev, state);
 208 }
 209 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
 210
 211 int xenbus_dev_probe(struct device *_dev)
 212 {
 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;
 216         int err;
 217
 218         DPRINTK("%s", dev->nodename);
 219
 220         if (!drv->probe) {
 221                 err = -ENODEV;
 222                 goto fail;
 223         }
 224
 225         id = match_device(drv->ids, dev);
 226         if (!id) {
 227                 err = -ENODEV;
 228                 goto fail;
 229         }
 230
 231         err = talk_to_otherend(dev);
 232         if (err) {
 233                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 234                          dev->nodename);
 235                 return err;
 236         }
 237
 238         err = drv->probe(dev, id);
 239         if (err)
 240                 goto fail;
 241
 242         err = watch_otherend(dev);
 243         if (err) {
 244                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 245                        dev->nodename);
 246                 return err;
 247         }
 248
 249         return 0;
 250 fail:
 251         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 252         xenbus_switch_state(dev, XenbusStateClosed);
 253         return err;
 254 }
 255 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
 256
 257 int xenbus_dev_remove(struct device *_dev)
 258 {
 259         struct xenbus_device *dev = to_xenbus_device(_dev);
 260         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 261
 262         DPRINTK("%s", dev->nodename);
 263
 264         free_otherend_watch(dev);
 265
 266         if (drv->remove)
 267                 drv->remove(dev);
 268
 269         free_otherend_details(dev);
 270
 271         xenbus_switch_state(dev, XenbusStateClosed);
 272         return 0;
 273 }
 274 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
 275
 276 void xenbus_dev_shutdown(struct device *_dev)
 277 {
 278         struct xenbus_device *dev = to_xenbus_device(_dev);
 279         unsigned long timeout = 5*HZ;
 280
 281         DPRINTK("%s", dev->nodename);
 282
 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));
 287                 goto out;
 288         }
 289         xenbus_switch_state(dev, XenbusStateClosing);
 290         timeout = wait_for_completion_timeout(&dev->down, timeout);
 291         if (!timeout)
 292                 pr_info("%s: %s timeout closing device\n",
 293                         __func__, dev->nodename);
 294  out:
 295         put_device(&dev->dev);
 296 }
 297 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
 298
 299 int xenbus_register_driver_common(struct xenbus_driver *drv,
 300                                   struct xen_bus_type *bus)
 301 {
 302         drv->driver.bus = &bus->bus;
 303
 304         return driver_register(&drv->driver);
 305 }
 306 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
 307
 308 void xenbus_unregister_driver(struct xenbus_driver *drv)
 309 {
 310         driver_unregister(&drv->driver);
 311 }
 312 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 313
 314 struct xb_find_info {
 315         struct xenbus_device *dev;
 316         const char *nodename;
 317 };
 318
 319 static int cmp_dev(struct device *dev, void *data)
 320 {
 321         struct xenbus_device *xendev = to_xenbus_device(dev);
 322         struct xb_find_info *info = data;
 323
 324         if (!strcmp(xendev->nodename, info->nodename)) {
 325                 info->dev = xendev;
 326                 get_device(dev);
 327                 return 1;
 328         }
 329         return 0;
 330 }
 331
 332 static struct xenbus_device *xenbus_device_find(const char *nodename,
 333                                                 struct bus_type *bus)
 334 {
 335         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 336
 337         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 338         return info.dev;
 339 }
 340
 341 static int cleanup_dev(struct device *dev, void *data)
 342 {
 343         struct xenbus_device *xendev = to_xenbus_device(dev);
 344         struct xb_find_info *info = data;
 345         int len = strlen(info->nodename);
 346
 347         DPRINTK("%s", info->nodename);
 348
 349         /* Match the info->nodename path, or any subdirectory of that path. */
 350         if (strncmp(xendev->nodename, info->nodename, len))
 351                 return 0;
 352
 353         /* If the node name is longer, ensure it really is a subdirectory. */
 354         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 355                 return 0;
 356
 357         info->dev = xendev;
 358         get_device(dev);
 359         return 1;
 360 }
 361
 362 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 363 {
 364         struct xb_find_info info = { .nodename = path };
 365
 366         do {
 367                 info.dev = NULL;
 368                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 369                 if (info.dev) {
 370                         device_unregister(&info.dev->dev);
 371                         put_device(&info.dev->dev);
 372                 }
 373         } while (info.dev);
 374 }
 375
 376 static void xenbus_dev_release(struct device *dev)
 377 {
 378         if (dev)
 379                 kfree(to_xenbus_device(dev));
 380 }
 381
 382 static ssize_t nodename_show(struct device *dev,
 383                              struct device_attribute *attr, char *buf)
 384 {
 385         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 386 }
 387 static DEVICE_ATTR_RO(nodename);
 388
 389 static ssize_t devtype_show(struct device *dev,
 390                             struct device_attribute *attr, char *buf)
 391 {
 392         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 393 }
 394 static DEVICE_ATTR_RO(devtype);
 395
 396 static ssize_t modalias_show(struct device *dev,
 397                              struct device_attribute *attr, char *buf)
 398 {
 399         return sprintf(buf, "%s:%s\n", dev->bus->name,
 400                        to_xenbus_device(dev)->devicetype);
 401 }
 402 static DEVICE_ATTR_RO(modalias);
 403
 404 static struct attribute *xenbus_dev_attrs[] = {
 405         &dev_attr_nodename.attr,
 406         &dev_attr_devtype.attr,
 407         &dev_attr_modalias.attr,
 408         NULL,
 409 };
 410
 411 static const struct attribute_group xenbus_dev_group = {
 412         .attrs = xenbus_dev_attrs,
 413 };
 414
 415 const struct attribute_group *xenbus_dev_groups[] = {
 416         &xenbus_dev_group,
 417         NULL,
 418 };
 419 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
 420
 421 int xenbus_probe_node(struct xen_bus_type *bus,
 422                       const char *type,
 423                       const char *nodename)
 424 {
 425         char devname[XEN_BUS_ID_SIZE];
 426         int err;
 427         struct xenbus_device *xendev;
 428         size_t stringlen;
 429         char *tmpstring;
 430
 431         enum xenbus_state state = xenbus_read_driver_state(nodename);
 432
 433         if (state != XenbusStateInitialising) {
 434                 /* Device is not new, so ignore it.  This can happen if a
 435                    device is going away after switching to Closed.  */
 436                 return 0;
 437         }
 438
 439         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 440         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 441         if (!xendev)
 442                 return -ENOMEM;
 443
 444         xendev->state = XenbusStateInitialising;
 445
 446         /* Copy the strings into the extra space. */
 447
 448         tmpstring = (char *)(xendev + 1);
 449         strcpy(tmpstring, nodename);
 450         xendev->nodename = tmpstring;
 451
 452         tmpstring += strlen(tmpstring) + 1;
 453         strcpy(tmpstring, type);
 454         xendev->devicetype = tmpstring;
 455         init_completion(&xendev->down);
 456
 457         xendev->dev.bus = &bus->bus;
 458         xendev->dev.release = xenbus_dev_release;
 459
 460         err = bus->get_bus_id(devname, xendev->nodename);
 461         if (err)
 462                 goto fail;
 463
 464         dev_set_name(&xendev->dev, "%s", devname);
 465
 466         /* Register with generic device framework. */
 467         err = device_register(&xendev->dev);
 468         if (err)
 469                 goto fail;
 470
 471         return 0;
 472 fail:
 473         kfree(xendev);
 474         return err;
 475 }
 476 EXPORT_SYMBOL_GPL(xenbus_probe_node);
 477
 478 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 479 {
 480         int err = 0;
 481         char **dir;
 482         unsigned int dir_n = 0;
 483         int i;
 484
 485         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 486         if (IS_ERR(dir))
 487                 return PTR_ERR(dir);
 488
 489         for (i = 0; i < dir_n; i++) {
 490                 err = bus->probe(bus, type, dir[i]);
 491                 if (err)
 492                         break;
 493         }
 494
 495         kfree(dir);
 496         return err;
 497 }
 498
 499 int xenbus_probe_devices(struct xen_bus_type *bus)
 500 {
 501         int err = 0;
 502         char **dir;
 503         unsigned int i, dir_n;
 504
 505         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 506         if (IS_ERR(dir))
 507                 return PTR_ERR(dir);
 508
 509         for (i = 0; i < dir_n; i++) {
 510                 err = xenbus_probe_device_type(bus, dir[i]);
 511                 if (err)
 512                         break;
 513         }
 514
 515         kfree(dir);
 516         return err;
 517 }
 518 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
 519
 520 static unsigned int char_count(const char *str, char c)
 521 {
 522         unsigned int i, ret = 0;
 523
 524         for (i = 0; str[i]; i++)
 525                 if (str[i] == c)
 526                         ret++;
 527         return ret;
 528 }
 529
 530 static int strsep_len(const char *str, char c, unsigned int len)
 531 {
 532         unsigned int i;
 533
 534         for (i = 0; str[i]; i++)
 535                 if (str[i] == c) {
 536                         if (len == 0)
 537                                 return i;
 538                         len--;
 539                 }
 540         return (len == 0) ? i : -ERANGE;
 541 }
 542
 543 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 544 {
 545         int exists, rootlen;
 546         struct xenbus_device *dev;
 547         char type[XEN_BUS_ID_SIZE];
 548         const char *p, *root;
 549
 550         if (char_count(node, '/') < 2)
 551                 return;
 552
 553         exists = xenbus_exists(XBT_NIL, node, "");
 554         if (!exists) {
 555                 xenbus_cleanup_devices(node, &bus->bus);
 556                 return;
 557         }
 558
 559         /* backend/<type>/... or device/<type>/... */
 560         p = strchr(node, '/') + 1;
 561         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 562         type[XEN_BUS_ID_SIZE-1] = '\0';
 563
 564         rootlen = strsep_len(node, '/', bus->levels);
 565         if (rootlen < 0)
 566                 return;
 567         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 568         if (!root)
 569                 return;
 570
 571         dev = xenbus_device_find(root, &bus->bus);
 572         if (!dev)
 573                 xenbus_probe_node(bus, type, root);
 574         else
 575                 put_device(&dev->dev);
 576
 577         kfree(root);
 578 }
 579 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 580
 581 int xenbus_dev_suspend(struct device *dev)
 582 {
 583         int err = 0;
 584         struct xenbus_driver *drv;
 585         struct xenbus_device *xdev
 586                 = container_of(dev, struct xenbus_device, dev);
 587
 588         DPRINTK("%s", xdev->nodename);
 589
 590         if (dev->driver == NULL)
 591                 return 0;
 592         drv = to_xenbus_driver(dev->driver);
 593         if (drv->suspend)
 594                 err = drv->suspend(xdev);
 595         if (err)
 596                 pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
 597         return 0;
 598 }
 599 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
 600
 601 int xenbus_dev_resume(struct device *dev)
 602 {
 603         int err;
 604         struct xenbus_driver *drv;
 605         struct xenbus_device *xdev
 606                 = container_of(dev, struct xenbus_device, dev);
 607
 608         DPRINTK("%s", xdev->nodename);
 609
 610         if (dev->driver == NULL)
 611                 return 0;
 612         drv = to_xenbus_driver(dev->driver);
 613         err = talk_to_otherend(xdev);
 614         if (err) {
 615                 pr_warn("resume (talk_to_otherend) %s failed: %i\n",
 616                         dev_name(dev), err);
 617                 return err;
 618         }
 619
 620         xdev->state = XenbusStateInitialising;
 621
 622         if (drv->resume) {
 623                 err = drv->resume(xdev);
 624                 if (err) {
 625                         pr_warn("resume %s failed: %i\n", dev_name(dev), err);
 626                         return err;
 627                 }
 628         }
 629
 630         err = watch_otherend(xdev);
 631         if (err) {
 632                 pr_warn("resume (watch_otherend) %s failed: %d.\n",
 633                         dev_name(dev), err);
 634                 return err;
 635         }
 636
 637         return 0;
 638 }
 639 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
 640
 641 int xenbus_dev_cancel(struct device *dev)
 642 {
 643         /* Do nothing */
 644         DPRINTK("cancel");
 645         return 0;
 646 }
 647 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
 648
 649 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 650 int xenstored_ready;
 651
 652
 653 int register_xenstore_notifier(struct notifier_block *nb)
 654 {
 655         int ret = 0;
 656
 657         if (xenstored_ready > 0)
 658                 ret = nb->notifier_call(nb, 0, NULL);
 659         else
 660                 blocking_notifier_chain_register(&xenstore_chain, nb);
 661
 662         return ret;
 663 }
 664 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 665
 666 void unregister_xenstore_notifier(struct notifier_block *nb)
 667 {
 668         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 669 }
 670 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 671
 672 void xenbus_probe(struct work_struct *unused)
 673 {
 674         xenstored_ready = 1;
 675
 676         /* Notify others that xenstore is up */
 677         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 678 }
 679 EXPORT_SYMBOL_GPL(xenbus_probe);
 680
 681 static int __init xenbus_probe_initcall(void)
 682 {
 683         if (!xen_domain())
 684                 return -ENODEV;
 685
 686         if (xen_initial_domain() || xen_hvm_domain())
 687                 return 0;
 688
 689         xenbus_probe(NULL);
 690         return 0;
 691 }
 692
 693 device_initcall(xenbus_probe_initcall);
 694
 695 /* Set up event channel for xenstored which is run as a local process
 696  * (this is normally used only in dom0)
 697  */
 698 static int __init xenstored_local_init(void)
 699 {
 700         int err = 0;
 701         unsigned long page = 0;
 702         struct evtchn_alloc_unbound alloc_unbound;
 703
 704         /* Allocate Xenstore page */
 705         page = get_zeroed_page(GFP_KERNEL);
 706         if (!page)
 707                 goto out_err;
 708
 709         xen_store_mfn = xen_start_info->store_mfn =
 710                 pfn_to_mfn(virt_to_phys((void *)page) >>
 711                            PAGE_SHIFT);
 712
 713         /* Next allocate a local port which xenstored can bind to */
 714         alloc_unbound.dom        = DOMID_SELF;
 715         alloc_unbound.remote_dom = DOMID_SELF;
 716
 717         err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
 718                                           &alloc_unbound);
 719         if (err == -ENOSYS)
 720                 goto out_err;
 721
 722         BUG_ON(err);
 723         xen_store_evtchn = xen_start_info->store_evtchn =
 724                 alloc_unbound.port;
 725
 726         return 0;
 727
 728  out_err:
 729         if (page != 0)
 730                 free_page(page);
 731         return err;
 732 }
 733
 734 static int __init xenbus_init(void)
 735 {
 736         int err = 0;
 737         uint64_t v = 0;
 738         xen_store_domain_type = XS_UNKNOWN;
 739
 740         if (!xen_domain())
 741                 return -ENODEV;
 742
 743         xenbus_ring_ops_init();
 744
 745         if (xen_pv_domain())
 746                 xen_store_domain_type = XS_PV;
 747         if (xen_hvm_domain())
 748                 xen_store_domain_type = XS_HVM;
 749         if (xen_hvm_domain() && xen_initial_domain())
 750                 xen_store_domain_type = XS_LOCAL;
 751         if (xen_pv_domain() && !xen_start_info->store_evtchn)
 752                 xen_store_domain_type = XS_LOCAL;
 753         if (xen_pv_domain() && xen_start_info->store_evtchn)
 754                 xenstored_ready = 1;
 755
 756         switch (xen_store_domain_type) {
 757         case XS_LOCAL:
 758                 err = xenstored_local_init();
 759                 if (err)
 760                         goto out_error;
 761                 xen_store_interface = mfn_to_virt(xen_store_mfn);
 762                 break;
 763         case XS_PV:
 764                 xen_store_evtchn = xen_start_info->store_evtchn;
 765                 xen_store_mfn = xen_start_info->store_mfn;
 766                 xen_store_interface = mfn_to_virt(xen_store_mfn);
 767                 break;
 768         case XS_HVM:
 769                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 770                 if (err)
 771                         goto out_error;
 772                 xen_store_evtchn = (int)v;
 773                 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 774                 if (err)
 775                         goto out_error;
 776                 xen_store_mfn = (unsigned long)v;
 777                 xen_store_interface =
 778                         xen_remap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
 779                 break;
 780         default:
 781                 pr_warn("Xenstore state unknown\n");
 782                 break;
 783         }
 784
 785         /* Initialize the interface to xenstore. */
 786         err = xs_init();
 787         if (err) {
 788                 pr_warn("Error initializing xenstore comms: %i\n", err);
 789                 goto out_error;
 790         }
 791
 792 #ifdef CONFIG_XEN_COMPAT_XENFS
 793         /*
 794          * Create xenfs mountpoint in /proc for compatibility with
 795          * utilities that expect to find "xenbus" under "/proc/xen".
 796          */
 797         proc_mkdir("xen", NULL);
 798 #endif
 799
 800 out_error:
 801         return err;
 802 }
 803
 804 postcore_initcall(xenbus_init);
 805
 806 MODULE_LICENSE("GPL");