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 #define dev_fmt pr_fmt
  35
  36 #define DPRINTK(fmt, args...)                           \
  37         pr_debug("xenbus_probe (%s:%d) " fmt ".\n",     \
  38                  __func__, __LINE__, ##args)
  39
  40 #include <linux/kernel.h>
  41 #include <linux/err.h>
  42 #include <linux/string.h>
  43 #include <linux/ctype.h>
  44 #include <linux/fcntl.h>
  45 #include <linux/mm.h>
  46 #include <linux/proc_fs.h>
  47 #include <linux/notifier.h>
  48 #include <linux/kthread.h>
  49 #include <linux/mutex.h>
  50 #include <linux/io.h>
  51 #include <linux/slab.h>
  52 #include <linux/module.h>
  53
  54 #include <asm/page.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/xen-ops.h>
  61 #include <xen/page.h>
  62
  63 #include <xen/hvm.h>
  64
  65 #include "xenbus.h"
  66
  67
  68 static int xs_init_irq = -1;
  69 int xen_store_evtchn;
  70 EXPORT_SYMBOL_GPL(xen_store_evtchn);
  71
  72 struct xenstore_domain_interface *xen_store_interface;
  73 EXPORT_SYMBOL_GPL(xen_store_interface);
  74
  75 #define XS_INTERFACE_READY \
  76         ((xen_store_interface != NULL) && \
  77          (xen_store_interface->connection == XENSTORE_CONNECTED))
  78
  79 enum xenstore_init xen_store_domain_type;
  80 EXPORT_SYMBOL_GPL(xen_store_domain_type);
  81
  82 static unsigned long xen_store_gfn;
  83
  84 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  85
  86 /* If something in array of ids matches this device, return it. */
  87 static const struct xenbus_device_id *
  88 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
  89 {
  90         for (; *arr->devicetype != '\0'; arr++) {
  91                 if (!strcmp(arr->devicetype, dev->devicetype))
  92                         return arr;
  93         }
  94         return NULL;
  95 }
  96
  97 int xenbus_match(struct device *_dev, const struct device_driver *_drv)
  98 {
  99         const struct xenbus_driver *drv = to_xenbus_driver(_drv);
 100
 101         if (!drv->ids)
 102                 return 0;
 103
 104         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
 105 }
 106 EXPORT_SYMBOL_GPL(xenbus_match);
 107
 108
 109 static void free_otherend_details(struct xenbus_device *dev)
 110 {
 111         kfree(dev->otherend);
 112         dev->otherend = NULL;
 113 }
 114
 115
 116 static void free_otherend_watch(struct xenbus_device *dev)
 117 {
 118         if (dev->otherend_watch.node) {
 119                 unregister_xenbus_watch(&dev->otherend_watch);
 120                 kfree(dev->otherend_watch.node);
 121                 dev->otherend_watch.node = NULL;
 122         }
 123 }
 124
 125
 126 static int talk_to_otherend(struct xenbus_device *dev)
 127 {
 128         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 129
 130         free_otherend_watch(dev);
 131         free_otherend_details(dev);
 132
 133         return drv->read_otherend_details(dev);
 134 }
 135
 136
 137
 138 static int watch_otherend(struct xenbus_device *dev)
 139 {
 140         struct xen_bus_type *bus =
 141                 container_of(dev->dev.bus, struct xen_bus_type, bus);
 142
 143         return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
 144                                     bus->otherend_will_handle,
 145                                     bus->otherend_changed,
 146                                     "%s/%s", dev->otherend, "state");
 147 }
 148
 149
 150 int xenbus_read_otherend_details(struct xenbus_device *xendev,
 151                                  char *id_node, char *path_node)
 152 {
 153         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 154                                 id_node, "%i", &xendev->otherend_id,
 155                                 path_node, NULL, &xendev->otherend,
 156                                 NULL);
 157         if (err) {
 158                 xenbus_dev_fatal(xendev, err,
 159                                  "reading other end details from %s",
 160                                  xendev->nodename);
 161                 return err;
 162         }
 163         if (strlen(xendev->otherend) == 0 ||
 164             !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
 165                 xenbus_dev_fatal(xendev, -ENOENT,
 166                                  "unable to read other end from %s.  "
 167                                  "missing or inaccessible.",
 168                                  xendev->nodename);
 169                 free_otherend_details(xendev);
 170                 return -ENOENT;
 171         }
 172
 173         return 0;
 174 }
 175 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
 176
 177 void xenbus_otherend_changed(struct xenbus_watch *watch,
 178                              const char *path, const char *token,
 179                              int ignore_on_shutdown)
 180 {
 181         struct xenbus_device *dev =
 182                 container_of(watch, struct xenbus_device, otherend_watch);
 183         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 184         enum xenbus_state state;
 185
 186         /* Protect us against watches firing on old details when the otherend
 187            details change, say immediately after a resume. */
 188         if (!dev->otherend ||
 189             strncmp(dev->otherend, path, strlen(dev->otherend))) {
 190                 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
 191                 return;
 192         }
 193
 194         state = xenbus_read_driver_state(dev->otherend);
 195
 196         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 197                 state, xenbus_strstate(state), dev->otherend_watch.node, path);
 198
 199         /*
 200          * Ignore xenbus transitions during shutdown. This prevents us doing
 201          * work that can fail e.g., when the rootfs is gone.
 202          */
 203         if (system_state > SYSTEM_RUNNING) {
 204                 if (ignore_on_shutdown && (state == XenbusStateClosing))
 205                         xenbus_frontend_closed(dev);
 206                 return;
 207         }
 208
 209         if (drv->otherend_changed)
 210                 drv->otherend_changed(dev, state);
 211 }
 212 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
 213
 214 #define XENBUS_SHOW_STAT(name)                                          \
 215 static ssize_t name##_show(struct device *_dev,                         \
 216                            struct device_attribute *attr,               \
 217                            char *buf)                                   \
 218 {                                                                       \
 219         struct xenbus_device *dev = to_xenbus_device(_dev);             \
 220                                                                         \
 221         return sprintf(buf, "%d\n", atomic_read(&dev->name));           \
 222 }                                                                       \
 223 static DEVICE_ATTR_RO(name)
 224
 225 XENBUS_SHOW_STAT(event_channels);
 226 XENBUS_SHOW_STAT(events);
 227 XENBUS_SHOW_STAT(spurious_events);
 228 XENBUS_SHOW_STAT(jiffies_eoi_delayed);
 229
 230 static ssize_t spurious_threshold_show(struct device *_dev,
 231                                        struct device_attribute *attr,
 232                                        char *buf)
 233 {
 234         struct xenbus_device *dev = to_xenbus_device(_dev);
 235
 236         return sprintf(buf, "%d\n", dev->spurious_threshold);
 237 }
 238
 239 static ssize_t spurious_threshold_store(struct device *_dev,
 240                                         struct device_attribute *attr,
 241                                         const char *buf, size_t count)
 242 {
 243         struct xenbus_device *dev = to_xenbus_device(_dev);
 244         unsigned int val;
 245         ssize_t ret;
 246
 247         ret = kstrtouint(buf, 0, &val);
 248         if (ret)
 249                 return ret;
 250
 251         dev->spurious_threshold = val;
 252
 253         return count;
 254 }
 255
 256 static DEVICE_ATTR_RW(spurious_threshold);
 257
 258 static struct attribute *xenbus_attrs[] = {
 259         &dev_attr_event_channels.attr,
 260         &dev_attr_events.attr,
 261         &dev_attr_spurious_events.attr,
 262         &dev_attr_jiffies_eoi_delayed.attr,
 263         &dev_attr_spurious_threshold.attr,
 264         NULL
 265 };
 266
 267 static const struct attribute_group xenbus_group = {
 268         .name = "xenbus",
 269         .attrs = xenbus_attrs,
 270 };
 271
 272 int xenbus_dev_probe(struct device *_dev)
 273 {
 274         struct xenbus_device *dev = to_xenbus_device(_dev);
 275         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 276         const struct xenbus_device_id *id;
 277         int err;
 278
 279         DPRINTK("%s", dev->nodename);
 280
 281         if (!drv->probe) {
 282                 err = -ENODEV;
 283                 goto fail;
 284         }
 285
 286         id = match_device(drv->ids, dev);
 287         if (!id) {
 288                 err = -ENODEV;
 289                 goto fail;
 290         }
 291
 292         err = talk_to_otherend(dev);
 293         if (err) {
 294                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 295                          dev->nodename);
 296                 return err;
 297         }
 298
 299         if (!try_module_get(drv->driver.owner)) {
 300                 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
 301                          drv->driver.name);
 302                 err = -ESRCH;
 303                 goto fail;
 304         }
 305
 306         down(&dev->reclaim_sem);
 307         err = drv->probe(dev, id);
 308         up(&dev->reclaim_sem);
 309         if (err)
 310                 goto fail_put;
 311
 312         err = watch_otherend(dev);
 313         if (err) {
 314                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 315                        dev->nodename);
 316                 return err;
 317         }
 318
 319         dev->spurious_threshold = 1;
 320         if (sysfs_create_group(&dev->dev.kobj, &xenbus_group))
 321                 dev_warn(&dev->dev, "sysfs_create_group on %s failed.\n",
 322                          dev->nodename);
 323
 324         return 0;
 325 fail_put:
 326         module_put(drv->driver.owner);
 327 fail:
 328         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 329         return err;
 330 }
 331 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
 332
 333 void xenbus_dev_remove(struct device *_dev)
 334 {
 335         struct xenbus_device *dev = to_xenbus_device(_dev);
 336         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 337
 338         DPRINTK("%s", dev->nodename);
 339
 340         sysfs_remove_group(&dev->dev.kobj, &xenbus_group);
 341
 342         free_otherend_watch(dev);
 343
 344         if (drv->remove) {
 345                 down(&dev->reclaim_sem);
 346                 drv->remove(dev);
 347                 up(&dev->reclaim_sem);
 348         }
 349
 350         module_put(drv->driver.owner);
 351
 352         free_otherend_details(dev);
 353
 354         /*
 355          * If the toolstack has forced the device state to closing then set
 356          * the state to closed now to allow it to be cleaned up.
 357          * Similarly, if the driver does not support re-bind, set the
 358          * closed.
 359          */
 360         if (!drv->allow_rebind ||
 361             xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
 362                 xenbus_switch_state(dev, XenbusStateClosed);
 363 }
 364 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
 365
 366 int xenbus_register_driver_common(struct xenbus_driver *drv,
 367                                   struct xen_bus_type *bus,
 368                                   struct module *owner, const char *mod_name)
 369 {
 370         drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
 371         drv->driver.bus = &bus->bus;
 372         drv->driver.owner = owner;
 373         drv->driver.mod_name = mod_name;
 374
 375         return driver_register(&drv->driver);
 376 }
 377 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
 378
 379 void xenbus_unregister_driver(struct xenbus_driver *drv)
 380 {
 381         driver_unregister(&drv->driver);
 382 }
 383 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 384
 385 struct xb_find_info {
 386         struct xenbus_device *dev;
 387         const char *nodename;
 388 };
 389
 390 static int cmp_dev(struct device *dev, void *data)
 391 {
 392         struct xenbus_device *xendev = to_xenbus_device(dev);
 393         struct xb_find_info *info = data;
 394
 395         if (!strcmp(xendev->nodename, info->nodename)) {
 396                 info->dev = xendev;
 397                 get_device(dev);
 398                 return 1;
 399         }
 400         return 0;
 401 }
 402
 403 static struct xenbus_device *xenbus_device_find(const char *nodename,
 404                                                 struct bus_type *bus)
 405 {
 406         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 407
 408         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 409         return info.dev;
 410 }
 411
 412 static int cleanup_dev(struct device *dev, void *data)
 413 {
 414         struct xenbus_device *xendev = to_xenbus_device(dev);
 415         struct xb_find_info *info = data;
 416         int len = strlen(info->nodename);
 417
 418         DPRINTK("%s", info->nodename);
 419
 420         /* Match the info->nodename path, or any subdirectory of that path. */
 421         if (strncmp(xendev->nodename, info->nodename, len))
 422                 return 0;
 423
 424         /* If the node name is longer, ensure it really is a subdirectory. */
 425         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 426                 return 0;
 427
 428         info->dev = xendev;
 429         get_device(dev);
 430         return 1;
 431 }
 432
 433 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 434 {
 435         struct xb_find_info info = { .nodename = path };
 436
 437         do {
 438                 info.dev = NULL;
 439                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 440                 if (info.dev) {
 441                         device_unregister(&info.dev->dev);
 442                         put_device(&info.dev->dev);
 443                 }
 444         } while (info.dev);
 445 }
 446
 447 static void xenbus_dev_release(struct device *dev)
 448 {
 449         if (dev)
 450                 kfree(to_xenbus_device(dev));
 451 }
 452
 453 static ssize_t nodename_show(struct device *dev,
 454                              struct device_attribute *attr, char *buf)
 455 {
 456         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 457 }
 458 static DEVICE_ATTR_RO(nodename);
 459
 460 static ssize_t devtype_show(struct device *dev,
 461                             struct device_attribute *attr, char *buf)
 462 {
 463         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 464 }
 465 static DEVICE_ATTR_RO(devtype);
 466
 467 static ssize_t modalias_show(struct device *dev,
 468                              struct device_attribute *attr, char *buf)
 469 {
 470         return sprintf(buf, "%s:%s\n", dev->bus->name,
 471                        to_xenbus_device(dev)->devicetype);
 472 }
 473 static DEVICE_ATTR_RO(modalias);
 474
 475 static ssize_t state_show(struct device *dev,
 476                             struct device_attribute *attr, char *buf)
 477 {
 478         return sprintf(buf, "%s\n",
 479                         xenbus_strstate(to_xenbus_device(dev)->state));
 480 }
 481 static DEVICE_ATTR_RO(state);
 482
 483 static struct attribute *xenbus_dev_attrs[] = {
 484         &dev_attr_nodename.attr,
 485         &dev_attr_devtype.attr,
 486         &dev_attr_modalias.attr,
 487         &dev_attr_state.attr,
 488         NULL,
 489 };
 490
 491 static const struct attribute_group xenbus_dev_group = {
 492         .attrs = xenbus_dev_attrs,
 493 };
 494
 495 const struct attribute_group *xenbus_dev_groups[] = {
 496         &xenbus_dev_group,
 497         NULL,
 498 };
 499 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
 500
 501 int xenbus_probe_node(struct xen_bus_type *bus,
 502                       const char *type,
 503                       const char *nodename)
 504 {
 505         char devname[XEN_BUS_ID_SIZE];
 506         int err;
 507         struct xenbus_device *xendev;
 508         size_t stringlen;
 509         char *tmpstring;
 510
 511         enum xenbus_state state = xenbus_read_driver_state(nodename);
 512
 513         if (state != XenbusStateInitialising) {
 514                 /* Device is not new, so ignore it.  This can happen if a
 515                    device is going away after switching to Closed.  */
 516                 return 0;
 517         }
 518
 519         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 520         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 521         if (!xendev)
 522                 return -ENOMEM;
 523
 524         xendev->state = XenbusStateInitialising;
 525
 526         /* Copy the strings into the extra space. */
 527
 528         tmpstring = (char *)(xendev + 1);
 529         strcpy(tmpstring, nodename);
 530         xendev->nodename = tmpstring;
 531
 532         tmpstring += strlen(tmpstring) + 1;
 533         strcpy(tmpstring, type);
 534         xendev->devicetype = tmpstring;
 535         init_completion(&xendev->down);
 536
 537         xendev->dev.bus = &bus->bus;
 538         xendev->dev.release = xenbus_dev_release;
 539
 540         err = bus->get_bus_id(devname, xendev->nodename);
 541         if (err)
 542                 goto fail;
 543
 544         dev_set_name(&xendev->dev, "%s", devname);
 545         sema_init(&xendev->reclaim_sem, 1);
 546
 547         /* Register with generic device framework. */
 548         err = device_register(&xendev->dev);
 549         if (err) {
 550                 put_device(&xendev->dev);
 551                 xendev = NULL;
 552                 goto fail;
 553         }
 554
 555         return 0;
 556 fail:
 557         kfree(xendev);
 558         return err;
 559 }
 560 EXPORT_SYMBOL_GPL(xenbus_probe_node);
 561
 562 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 563 {
 564         int err = 0;
 565         char **dir;
 566         unsigned int dir_n = 0;
 567         int i;
 568
 569         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 570         if (IS_ERR(dir))
 571                 return PTR_ERR(dir);
 572
 573         for (i = 0; i < dir_n; i++) {
 574                 err = bus->probe(bus, type, dir[i]);
 575                 if (err)
 576                         break;
 577         }
 578
 579         kfree(dir);
 580         return err;
 581 }
 582
 583 int xenbus_probe_devices(struct xen_bus_type *bus)
 584 {
 585         int err = 0;
 586         char **dir;
 587         unsigned int i, dir_n;
 588
 589         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 590         if (IS_ERR(dir))
 591                 return PTR_ERR(dir);
 592
 593         for (i = 0; i < dir_n; i++) {
 594                 err = xenbus_probe_device_type(bus, dir[i]);
 595                 if (err)
 596                         break;
 597         }
 598
 599         kfree(dir);
 600         return err;
 601 }
 602 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
 603
 604 static unsigned int char_count(const char *str, char c)
 605 {
 606         unsigned int i, ret = 0;
 607
 608         for (i = 0; str[i]; i++)
 609                 if (str[i] == c)
 610                         ret++;
 611         return ret;
 612 }
 613
 614 static int strsep_len(const char *str, char c, unsigned int len)
 615 {
 616         unsigned int i;
 617
 618         for (i = 0; str[i]; i++)
 619                 if (str[i] == c) {
 620                         if (len == 0)
 621                                 return i;
 622                         len--;
 623                 }
 624         return (len == 0) ? i : -ERANGE;
 625 }
 626
 627 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 628 {
 629         int exists, rootlen;
 630         struct xenbus_device *dev;
 631         char type[XEN_BUS_ID_SIZE];
 632         const char *p, *root;
 633
 634         if (char_count(node, '/') < 2)
 635                 return;
 636
 637         exists = xenbus_exists(XBT_NIL, node, "");
 638         if (!exists) {
 639                 xenbus_cleanup_devices(node, &bus->bus);
 640                 return;
 641         }
 642
 643         /* backend/<type>/... or device/<type>/... */
 644         p = strchr(node, '/') + 1;
 645         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 646         type[XEN_BUS_ID_SIZE-1] = '\0';
 647
 648         rootlen = strsep_len(node, '/', bus->levels);
 649         if (rootlen < 0)
 650                 return;
 651         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 652         if (!root)
 653                 return;
 654
 655         dev = xenbus_device_find(root, &bus->bus);
 656         if (!dev)
 657                 xenbus_probe_node(bus, type, root);
 658         else
 659                 put_device(&dev->dev);
 660
 661         kfree(root);
 662 }
 663 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 664
 665 int xenbus_dev_suspend(struct device *dev)
 666 {
 667         int err = 0;
 668         struct xenbus_driver *drv;
 669         struct xenbus_device *xdev
 670                 = container_of(dev, struct xenbus_device, dev);
 671
 672         DPRINTK("%s", xdev->nodename);
 673
 674         if (dev->driver == NULL)
 675                 return 0;
 676         drv = to_xenbus_driver(dev->driver);
 677         if (drv->suspend)
 678                 err = drv->suspend(xdev);
 679         if (err)
 680                 dev_warn(dev, "suspend failed: %i\n", err);
 681         return 0;
 682 }
 683 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
 684
 685 int xenbus_dev_resume(struct device *dev)
 686 {
 687         int err;
 688         struct xenbus_driver *drv;
 689         struct xenbus_device *xdev
 690                 = container_of(dev, struct xenbus_device, dev);
 691
 692         DPRINTK("%s", xdev->nodename);
 693
 694         if (dev->driver == NULL)
 695                 return 0;
 696         drv = to_xenbus_driver(dev->driver);
 697         err = talk_to_otherend(xdev);
 698         if (err) {
 699                 dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err);
 700                 return err;
 701         }
 702
 703         xdev->state = XenbusStateInitialising;
 704
 705         if (drv->resume) {
 706                 err = drv->resume(xdev);
 707                 if (err) {
 708                         dev_warn(dev, "resume failed: %i\n", err);
 709                         return err;
 710                 }
 711         }
 712
 713         err = watch_otherend(xdev);
 714         if (err) {
 715                 dev_warn(dev, "resume (watch_otherend) failed: %d\n", err);
 716                 return err;
 717         }
 718
 719         return 0;
 720 }
 721 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
 722
 723 int xenbus_dev_cancel(struct device *dev)
 724 {
 725         /* Do nothing */
 726         DPRINTK("cancel");
 727         return 0;
 728 }
 729 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
 730
 731 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 732 int xenstored_ready;
 733
 734
 735 int register_xenstore_notifier(struct notifier_block *nb)
 736 {
 737         int ret = 0;
 738
 739         if (xenstored_ready > 0)
 740                 ret = nb->notifier_call(nb, 0, NULL);
 741         else
 742                 blocking_notifier_chain_register(&xenstore_chain, nb);
 743
 744         return ret;
 745 }
 746 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 747
 748 void unregister_xenstore_notifier(struct notifier_block *nb)
 749 {
 750         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 751 }
 752 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 753
 754 static void xenbus_probe(void)
 755 {
 756         xenstored_ready = 1;
 757
 758         if (!xen_store_interface)
 759                 xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT,
 760                                                XEN_PAGE_SIZE, MEMREMAP_WB);
 761         /*
 762          * Now it is safe to free the IRQ used for xenstore late
 763          * initialization. No need to unbind: it is about to be
 764          * bound again from xb_init_comms. Note that calling
 765          * unbind_from_irqhandler now would result in xen_evtchn_close()
 766          * being called and the event channel not being enabled again
 767          * afterwards, resulting in missed event notifications.
 768          */
 769         if (xs_init_irq >= 0)
 770                 free_irq(xs_init_irq, &xb_waitq);
 771
 772         /*
 773          * In the HVM case, xenbus_init() deferred its call to
 774          * xs_init() in case callbacks were not operational yet.
 775          * So do it now.
 776          */
 777         if (xen_store_domain_type == XS_HVM)
 778                 xs_init();
 779
 780         /* Notify others that xenstore is up */
 781         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 782 }
 783
 784 /*
 785  * Returns true when XenStore init must be deferred in order to
 786  * allow the PCI platform device to be initialised, before we
 787  * can actually have event channel interrupts working.
 788  */
 789 static bool xs_hvm_defer_init_for_callback(void)
 790 {
 791 #ifdef CONFIG_XEN_PVHVM
 792         return xen_store_domain_type == XS_HVM &&
 793                 !xen_have_vector_callback;
 794 #else
 795         return false;
 796 #endif
 797 }
 798
 799 static int xenbus_probe_thread(void *unused)
 800 {
 801         DEFINE_WAIT(w);
 802
 803         /*
 804          * We actually just want to wait for *any* trigger of xb_waitq,
 805          * and run xenbus_probe() the moment it occurs.
 806          */
 807         prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
 808         schedule();
 809         finish_wait(&xb_waitq, &w);
 810
 811         DPRINTK("probing");
 812         xenbus_probe();
 813         return 0;
 814 }
 815
 816 static int __init xenbus_probe_initcall(void)
 817 {
 818         if (!xen_domain())
 819                 return -ENODEV;
 820
 821         /*
 822          * Probe XenBus here in the XS_PV case, and also XS_HVM unless we
 823          * need to wait for the platform PCI device to come up or
 824          * xen_store_interface is not ready.
 825          */
 826         if (xen_store_domain_type == XS_PV ||
 827             (xen_store_domain_type == XS_HVM &&
 828              !xs_hvm_defer_init_for_callback() &&
 829              XS_INTERFACE_READY))
 830                 xenbus_probe();
 831
 832         /*
 833          * For XS_LOCAL or when xen_store_interface is not ready, spawn a
 834          * thread which will wait for xenstored or a xenstore-stubdom to be
 835          * started, then probe.  It will be triggered when communication
 836          * starts happening, by waiting on xb_waitq.
 837          */
 838         if (xen_store_domain_type == XS_LOCAL || !XS_INTERFACE_READY) {
 839                 struct task_struct *probe_task;
 840
 841                 probe_task = kthread_run(xenbus_probe_thread, NULL,
 842                                          "xenbus_probe");
 843                 if (IS_ERR(probe_task))
 844                         return PTR_ERR(probe_task);
 845         }
 846         return 0;
 847 }
 848 device_initcall(xenbus_probe_initcall);
 849
 850 int xen_set_callback_via(uint64_t via)
 851 {
 852         struct xen_hvm_param a;
 853         int ret;
 854
 855         a.domid = DOMID_SELF;
 856         a.index = HVM_PARAM_CALLBACK_IRQ;
 857         a.value = via;
 858
 859         ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
 860         if (ret)
 861                 return ret;
 862
 863         /*
 864          * If xenbus_probe_initcall() deferred the xenbus_probe()
 865          * due to the callback not functioning yet, we can do it now.
 866          */
 867         if (!xenstored_ready && xs_hvm_defer_init_for_callback())
 868                 xenbus_probe();
 869
 870         return ret;
 871 }
 872 EXPORT_SYMBOL_GPL(xen_set_callback_via);
 873
 874 /* Set up event channel for xenstored which is run as a local process
 875  * (this is normally used only in dom0)
 876  */
 877 static int __init xenstored_local_init(void)
 878 {
 879         int err = -ENOMEM;
 880         unsigned long page = 0;
 881         struct evtchn_alloc_unbound alloc_unbound;
 882
 883         /* Allocate Xenstore page */
 884         page = get_zeroed_page(GFP_KERNEL);
 885         if (!page)
 886                 goto out_err;
 887
 888         xen_store_gfn = virt_to_gfn((void *)page);
 889
 890         /* Next allocate a local port which xenstored can bind to */
 891         alloc_unbound.dom        = DOMID_SELF;
 892         alloc_unbound.remote_dom = DOMID_SELF;
 893
 894         err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
 895                                           &alloc_unbound);
 896         if (err == -ENOSYS)
 897                 goto out_err;
 898
 899         BUG_ON(err);
 900         xen_store_evtchn = alloc_unbound.port;
 901
 902         return 0;
 903
 904  out_err:
 905         if (page != 0)
 906                 free_page(page);
 907         return err;
 908 }
 909
 910 static int xenbus_resume_cb(struct notifier_block *nb,
 911                             unsigned long action, void *data)
 912 {
 913         int err = 0;
 914
 915         if (xen_hvm_domain()) {
 916                 uint64_t v = 0;
 917
 918                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 919                 if (!err && v)
 920                         xen_store_evtchn = v;
 921                 else
 922                         pr_warn("Cannot update xenstore event channel: %d\n",
 923                                 err);
 924         } else
 925                 xen_store_evtchn = xen_start_info->store_evtchn;
 926
 927         return err;
 928 }
 929
 930 static struct notifier_block xenbus_resume_nb = {
 931         .notifier_call = xenbus_resume_cb,
 932 };
 933
 934 static irqreturn_t xenbus_late_init(int irq, void *unused)
 935 {
 936         int err;
 937         uint64_t v = 0;
 938
 939         err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 940         if (err || !v || !~v)
 941                 return IRQ_HANDLED;
 942         xen_store_gfn = (unsigned long)v;
 943
 944         wake_up(&xb_waitq);
 945         return IRQ_HANDLED;
 946 }
 947
 948 static int __init xenbus_init(void)
 949 {
 950         int err;
 951         uint64_t v = 0;
 952         bool wait = false;
 953         xen_store_domain_type = XS_UNKNOWN;
 954
 955         if (!xen_domain())
 956                 return -ENODEV;
 957
 958         xenbus_ring_ops_init();
 959
 960         if (xen_pv_domain())
 961                 xen_store_domain_type = XS_PV;
 962         if (xen_hvm_domain())
 963                 xen_store_domain_type = XS_HVM;
 964         if (xen_hvm_domain() && xen_initial_domain())
 965                 xen_store_domain_type = XS_LOCAL;
 966         if (xen_pv_domain() && !xen_start_info->store_evtchn)
 967                 xen_store_domain_type = XS_LOCAL;
 968         if (xen_pv_domain() && xen_start_info->store_evtchn)
 969                 xenstored_ready = 1;
 970
 971         switch (xen_store_domain_type) {
 972         case XS_LOCAL:
 973                 err = xenstored_local_init();
 974                 if (err)
 975                         goto out_error;
 976                 xen_store_interface = gfn_to_virt(xen_store_gfn);
 977                 break;
 978         case XS_PV:
 979                 xen_store_evtchn = xen_start_info->store_evtchn;
 980                 xen_store_gfn = xen_start_info->store_mfn;
 981                 xen_store_interface = gfn_to_virt(xen_store_gfn);
 982                 break;
 983         case XS_HVM:
 984                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 985                 if (err)
 986                         goto out_error;
 987                 xen_store_evtchn = (int)v;
 988                 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 989                 if (err)
 990                         goto out_error;
 991                 /*
 992                  * Uninitialized hvm_params are zero and return no error.
 993                  * Although it is theoretically possible to have
 994                  * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is
 995                  * not zero when valid. If zero, it means that Xenstore hasn't
 996                  * been properly initialized. Instead of attempting to map a
 997                  * wrong guest physical address return error.
 998                  *
 999                  * Also recognize all bits set as an invalid/uninitialized value.
1000                  */
1001                 if (!v) {
1002                         err = -ENOENT;
1003                         goto out_error;
1004                 }
1005                 if (v == ~0ULL) {
1006                         wait = true;
1007                 } else {
1008                         /* Avoid truncation on 32-bit. */
1009 #if BITS_PER_LONG == 32
1010                         if (v > ULONG_MAX) {
1011                                 pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
1012                                        __func__, v);
1013                                 err = -EINVAL;
1014                                 goto out_error;
1015                         }
1016 #endif
1017                         xen_store_gfn = (unsigned long)v;
1018                         xen_store_interface =
1019                                 memremap(xen_store_gfn << XEN_PAGE_SHIFT,
1020                                          XEN_PAGE_SIZE, MEMREMAP_WB);
1021                         if (!xen_store_interface) {
1022                                 pr_err("%s: cannot map HVM_PARAM_STORE_PFN=%llx\n",
1023                                        __func__, v);
1024                                 err = -EINVAL;
1025                                 goto out_error;
1026                         }
1027                         if (xen_store_interface->connection != XENSTORE_CONNECTED)
1028                                 wait = true;
1029                 }
1030                 if (wait) {
1031                         err = bind_evtchn_to_irqhandler(xen_store_evtchn,
1032                                                         xenbus_late_init,
1033                                                         0, "xenstore_late_init",
1034                                                         &xb_waitq);
1035                         if (err < 0) {
1036                                 pr_err("xenstore_late_init couldn't bind irq err=%d\n",
1037                                        err);
1038                                 goto out_error;
1039                         }
1040
1041                         xs_init_irq = err;
1042                 }
1043                 break;
1044         default:
1045                 pr_warn("Xenstore state unknown\n");
1046                 break;
1047         }
1048
1049         /*
1050          * HVM domains may not have a functional callback yet. In that
1051          * case let xs_init() be called from xenbus_probe(), which will
1052          * get invoked at an appropriate time.
1053          */
1054         if (xen_store_domain_type != XS_HVM) {
1055                 err = xs_init();
1056                 if (err) {
1057                         pr_warn("Error initializing xenstore comms: %i\n", err);
1058                         goto out_error;
1059                 }
1060         }
1061
1062         if ((xen_store_domain_type != XS_LOCAL) &&
1063             (xen_store_domain_type != XS_UNKNOWN))
1064                 xen_resume_notifier_register(&xenbus_resume_nb);
1065
1066 #ifdef CONFIG_XEN_COMPAT_XENFS
1067         /*
1068          * Create xenfs mountpoint in /proc for compatibility with
1069          * utilities that expect to find "xenbus" under "/proc/xen".
1070          */
1071         proc_create_mount_point("xen");
1072 #endif
1073         return 0;
1074
1075 out_error:
1076         xen_store_domain_type = XS_UNKNOWN;
1077         return err;
1078 }
1079
1080 postcore_initcall(xenbus_init);
1081
1082 MODULE_LICENSE("GPL");