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                 goto fail_remove;
 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_remove:
 326         if (drv->remove) {
 327                 down(&dev->reclaim_sem);
 328                 drv->remove(dev);
 329                 up(&dev->reclaim_sem);
 330         }
 331 fail_put:
 332         module_put(drv->driver.owner);
 333 fail:
 334         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 335         return err;
 336 }
 337 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
 338
 339 void xenbus_dev_remove(struct device *_dev)
 340 {
 341         struct xenbus_device *dev = to_xenbus_device(_dev);
 342         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 343
 344         DPRINTK("%s", dev->nodename);
 345
 346         sysfs_remove_group(&dev->dev.kobj, &xenbus_group);
 347
 348         free_otherend_watch(dev);
 349
 350         if (drv->remove) {
 351                 down(&dev->reclaim_sem);
 352                 drv->remove(dev);
 353                 up(&dev->reclaim_sem);
 354         }
 355
 356         module_put(drv->driver.owner);
 357
 358         free_otherend_details(dev);
 359
 360         /*
 361          * If the toolstack has forced the device state to closing then set
 362          * the state to closed now to allow it to be cleaned up.
 363          * Similarly, if the driver does not support re-bind, set the
 364          * closed.
 365          */
 366         if (!drv->allow_rebind ||
 367             xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
 368                 xenbus_switch_state(dev, XenbusStateClosed);
 369 }
 370 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
 371
 372 int xenbus_register_driver_common(struct xenbus_driver *drv,
 373                                   struct xen_bus_type *bus,
 374                                   struct module *owner, const char *mod_name)
 375 {
 376         drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
 377         drv->driver.bus = &bus->bus;
 378         drv->driver.owner = owner;
 379         drv->driver.mod_name = mod_name;
 380
 381         return driver_register(&drv->driver);
 382 }
 383 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
 384
 385 void xenbus_unregister_driver(struct xenbus_driver *drv)
 386 {
 387         driver_unregister(&drv->driver);
 388 }
 389 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 390
 391 struct xb_find_info {
 392         struct xenbus_device *dev;
 393         const char *nodename;
 394 };
 395
 396 static int cmp_dev(struct device *dev, void *data)
 397 {
 398         struct xenbus_device *xendev = to_xenbus_device(dev);
 399         struct xb_find_info *info = data;
 400
 401         if (!strcmp(xendev->nodename, info->nodename)) {
 402                 info->dev = xendev;
 403                 get_device(dev);
 404                 return 1;
 405         }
 406         return 0;
 407 }
 408
 409 static struct xenbus_device *xenbus_device_find(const char *nodename,
 410                                                 struct bus_type *bus)
 411 {
 412         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 413
 414         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 415         return info.dev;
 416 }
 417
 418 static int cleanup_dev(struct device *dev, void *data)
 419 {
 420         struct xenbus_device *xendev = to_xenbus_device(dev);
 421         struct xb_find_info *info = data;
 422         int len = strlen(info->nodename);
 423
 424         DPRINTK("%s", info->nodename);
 425
 426         /* Match the info->nodename path, or any subdirectory of that path. */
 427         if (strncmp(xendev->nodename, info->nodename, len))
 428                 return 0;
 429
 430         /* If the node name is longer, ensure it really is a subdirectory. */
 431         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 432                 return 0;
 433
 434         info->dev = xendev;
 435         get_device(dev);
 436         return 1;
 437 }
 438
 439 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 440 {
 441         struct xb_find_info info = { .nodename = path };
 442
 443         do {
 444                 info.dev = NULL;
 445                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 446                 if (info.dev) {
 447                         device_unregister(&info.dev->dev);
 448                         put_device(&info.dev->dev);
 449                 }
 450         } while (info.dev);
 451 }
 452
 453 static void xenbus_dev_release(struct device *dev)
 454 {
 455         if (dev)
 456                 kfree(to_xenbus_device(dev));
 457 }
 458
 459 static ssize_t nodename_show(struct device *dev,
 460                              struct device_attribute *attr, char *buf)
 461 {
 462         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 463 }
 464 static DEVICE_ATTR_RO(nodename);
 465
 466 static ssize_t devtype_show(struct device *dev,
 467                             struct device_attribute *attr, char *buf)
 468 {
 469         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 470 }
 471 static DEVICE_ATTR_RO(devtype);
 472
 473 static ssize_t modalias_show(struct device *dev,
 474                              struct device_attribute *attr, char *buf)
 475 {
 476         return sprintf(buf, "%s:%s\n", dev->bus->name,
 477                        to_xenbus_device(dev)->devicetype);
 478 }
 479 static DEVICE_ATTR_RO(modalias);
 480
 481 static ssize_t state_show(struct device *dev,
 482                             struct device_attribute *attr, char *buf)
 483 {
 484         return sprintf(buf, "%s\n",
 485                         xenbus_strstate(to_xenbus_device(dev)->state));
 486 }
 487 static DEVICE_ATTR_RO(state);
 488
 489 static struct attribute *xenbus_dev_attrs[] = {
 490         &dev_attr_nodename.attr,
 491         &dev_attr_devtype.attr,
 492         &dev_attr_modalias.attr,
 493         &dev_attr_state.attr,
 494         NULL,
 495 };
 496
 497 static const struct attribute_group xenbus_dev_group = {
 498         .attrs = xenbus_dev_attrs,
 499 };
 500
 501 const struct attribute_group *xenbus_dev_groups[] = {
 502         &xenbus_dev_group,
 503         NULL,
 504 };
 505 EXPORT_SYMBOL_GPL(xenbus_dev_groups);
 506
 507 int xenbus_probe_node(struct xen_bus_type *bus,
 508                       const char *type,
 509                       const char *nodename)
 510 {
 511         char devname[XEN_BUS_ID_SIZE];
 512         int err;
 513         struct xenbus_device *xendev;
 514         size_t stringlen;
 515         char *tmpstring;
 516
 517         enum xenbus_state state = xenbus_read_driver_state(nodename);
 518
 519         if (state != XenbusStateInitialising) {
 520                 /* Device is not new, so ignore it.  This can happen if a
 521                    device is going away after switching to Closed.  */
 522                 return 0;
 523         }
 524
 525         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 526         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 527         if (!xendev)
 528                 return -ENOMEM;
 529
 530         xendev->state = XenbusStateInitialising;
 531
 532         /* Copy the strings into the extra space. */
 533
 534         tmpstring = (char *)(xendev + 1);
 535         strcpy(tmpstring, nodename);
 536         xendev->nodename = tmpstring;
 537
 538         tmpstring += strlen(tmpstring) + 1;
 539         strcpy(tmpstring, type);
 540         xendev->devicetype = tmpstring;
 541         init_completion(&xendev->down);
 542
 543         xendev->dev.bus = &bus->bus;
 544         xendev->dev.release = xenbus_dev_release;
 545
 546         err = bus->get_bus_id(devname, xendev->nodename);
 547         if (err)
 548                 goto fail;
 549
 550         dev_set_name(&xendev->dev, "%s", devname);
 551         sema_init(&xendev->reclaim_sem, 1);
 552
 553         /* Register with generic device framework. */
 554         err = device_register(&xendev->dev);
 555         if (err) {
 556                 put_device(&xendev->dev);
 557                 xendev = NULL;
 558                 goto fail;
 559         }
 560
 561         return 0;
 562 fail:
 563         kfree(xendev);
 564         return err;
 565 }
 566 EXPORT_SYMBOL_GPL(xenbus_probe_node);
 567
 568 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 569 {
 570         int err = 0;
 571         char **dir;
 572         unsigned int dir_n = 0;
 573         int i;
 574
 575         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 576         if (IS_ERR(dir))
 577                 return PTR_ERR(dir);
 578
 579         for (i = 0; i < dir_n; i++) {
 580                 err = bus->probe(bus, type, dir[i]);
 581                 if (err)
 582                         break;
 583         }
 584
 585         kfree(dir);
 586         return err;
 587 }
 588
 589 int xenbus_probe_devices(struct xen_bus_type *bus)
 590 {
 591         int err = 0;
 592         char **dir;
 593         unsigned int i, dir_n;
 594
 595         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 596         if (IS_ERR(dir))
 597                 return PTR_ERR(dir);
 598
 599         for (i = 0; i < dir_n; i++) {
 600                 err = xenbus_probe_device_type(bus, dir[i]);
 601                 if (err)
 602                         break;
 603         }
 604
 605         kfree(dir);
 606         return err;
 607 }
 608 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
 609
 610 static unsigned int char_count(const char *str, char c)
 611 {
 612         unsigned int i, ret = 0;
 613
 614         for (i = 0; str[i]; i++)
 615                 if (str[i] == c)
 616                         ret++;
 617         return ret;
 618 }
 619
 620 static int strsep_len(const char *str, char c, unsigned int len)
 621 {
 622         unsigned int i;
 623
 624         for (i = 0; str[i]; i++)
 625                 if (str[i] == c) {
 626                         if (len == 0)
 627                                 return i;
 628                         len--;
 629                 }
 630         return (len == 0) ? i : -ERANGE;
 631 }
 632
 633 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 634 {
 635         int exists, rootlen;
 636         struct xenbus_device *dev;
 637         char type[XEN_BUS_ID_SIZE];
 638         const char *p, *root;
 639
 640         if (char_count(node, '/') < 2)
 641                 return;
 642
 643         exists = xenbus_exists(XBT_NIL, node, "");
 644         if (!exists) {
 645                 xenbus_cleanup_devices(node, &bus->bus);
 646                 return;
 647         }
 648
 649         /* backend/<type>/... or device/<type>/... */
 650         p = strchr(node, '/') + 1;
 651         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 652         type[XEN_BUS_ID_SIZE-1] = '\0';
 653
 654         rootlen = strsep_len(node, '/', bus->levels);
 655         if (rootlen < 0)
 656                 return;
 657         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 658         if (!root)
 659                 return;
 660
 661         dev = xenbus_device_find(root, &bus->bus);
 662         if (!dev)
 663                 xenbus_probe_node(bus, type, root);
 664         else
 665                 put_device(&dev->dev);
 666
 667         kfree(root);
 668 }
 669 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 670
 671 int xenbus_dev_suspend(struct device *dev)
 672 {
 673         int err = 0;
 674         struct xenbus_driver *drv;
 675         struct xenbus_device *xdev
 676                 = container_of(dev, struct xenbus_device, dev);
 677
 678         DPRINTK("%s", xdev->nodename);
 679
 680         if (dev->driver == NULL)
 681                 return 0;
 682         drv = to_xenbus_driver(dev->driver);
 683         if (drv->suspend)
 684                 err = drv->suspend(xdev);
 685         if (err)
 686                 dev_warn(dev, "suspend failed: %i\n", err);
 687         return 0;
 688 }
 689 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
 690
 691 int xenbus_dev_resume(struct device *dev)
 692 {
 693         int err;
 694         struct xenbus_driver *drv;
 695         struct xenbus_device *xdev
 696                 = container_of(dev, struct xenbus_device, dev);
 697
 698         DPRINTK("%s", xdev->nodename);
 699
 700         if (dev->driver == NULL)
 701                 return 0;
 702         drv = to_xenbus_driver(dev->driver);
 703         err = talk_to_otherend(xdev);
 704         if (err) {
 705                 dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err);
 706                 return err;
 707         }
 708
 709         xdev->state = XenbusStateInitialising;
 710
 711         if (drv->resume) {
 712                 err = drv->resume(xdev);
 713                 if (err) {
 714                         dev_warn(dev, "resume failed: %i\n", err);
 715                         return err;
 716                 }
 717         }
 718
 719         err = watch_otherend(xdev);
 720         if (err) {
 721                 dev_warn(dev, "resume (watch_otherend) failed: %d\n", err);
 722                 return err;
 723         }
 724
 725         return 0;
 726 }
 727 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
 728
 729 int xenbus_dev_cancel(struct device *dev)
 730 {
 731         /* Do nothing */
 732         DPRINTK("cancel");
 733         return 0;
 734 }
 735 EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
 736
 737 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 738 int xenstored_ready;
 739
 740
 741 int register_xenstore_notifier(struct notifier_block *nb)
 742 {
 743         int ret = 0;
 744
 745         if (xenstored_ready > 0)
 746                 ret = nb->notifier_call(nb, 0, NULL);
 747         else
 748                 blocking_notifier_chain_register(&xenstore_chain, nb);
 749
 750         return ret;
 751 }
 752 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 753
 754 void unregister_xenstore_notifier(struct notifier_block *nb)
 755 {
 756         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 757 }
 758 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 759
 760 static void xenbus_probe(void)
 761 {
 762         xenstored_ready = 1;
 763
 764         if (!xen_store_interface)
 765                 xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT,
 766                                                XEN_PAGE_SIZE, MEMREMAP_WB);
 767         /*
 768          * Now it is safe to free the IRQ used for xenstore late
 769          * initialization. No need to unbind: it is about to be
 770          * bound again from xb_init_comms. Note that calling
 771          * unbind_from_irqhandler now would result in xen_evtchn_close()
 772          * being called and the event channel not being enabled again
 773          * afterwards, resulting in missed event notifications.
 774          */
 775         if (xs_init_irq >= 0)
 776                 free_irq(xs_init_irq, &xb_waitq);
 777
 778         /*
 779          * In the HVM case, xenbus_init() deferred its call to
 780          * xs_init() in case callbacks were not operational yet.
 781          * So do it now.
 782          */
 783         if (xen_store_domain_type == XS_HVM)
 784                 xs_init();
 785
 786         /* Notify others that xenstore is up */
 787         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 788 }
 789
 790 /*
 791  * Returns true when XenStore init must be deferred in order to
 792  * allow the PCI platform device to be initialised, before we
 793  * can actually have event channel interrupts working.
 794  */
 795 static bool xs_hvm_defer_init_for_callback(void)
 796 {
 797 #ifdef CONFIG_XEN_PVHVM
 798         return xen_store_domain_type == XS_HVM &&
 799                 !xen_have_vector_callback;
 800 #else
 801         return false;
 802 #endif
 803 }
 804
 805 static int xenbus_probe_thread(void *unused)
 806 {
 807         DEFINE_WAIT(w);
 808
 809         /*
 810          * We actually just want to wait for *any* trigger of xb_waitq,
 811          * and run xenbus_probe() the moment it occurs.
 812          */
 813         prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
 814         schedule();
 815         finish_wait(&xb_waitq, &w);
 816
 817         DPRINTK("probing");
 818         xenbus_probe();
 819         return 0;
 820 }
 821
 822 static int __init xenbus_probe_initcall(void)
 823 {
 824         if (!xen_domain())
 825                 return -ENODEV;
 826
 827         /*
 828          * Probe XenBus here in the XS_PV case, and also XS_HVM unless we
 829          * need to wait for the platform PCI device to come up or
 830          * xen_store_interface is not ready.
 831          */
 832         if (xen_store_domain_type == XS_PV ||
 833             (xen_store_domain_type == XS_HVM &&
 834              !xs_hvm_defer_init_for_callback() &&
 835              XS_INTERFACE_READY))
 836                 xenbus_probe();
 837
 838         /*
 839          * For XS_LOCAL or when xen_store_interface is not ready, spawn a
 840          * thread which will wait for xenstored or a xenstore-stubdom to be
 841          * started, then probe.  It will be triggered when communication
 842          * starts happening, by waiting on xb_waitq.
 843          */
 844         if (xen_store_domain_type == XS_LOCAL || !XS_INTERFACE_READY) {
 845                 struct task_struct *probe_task;
 846
 847                 probe_task = kthread_run(xenbus_probe_thread, NULL,
 848                                          "xenbus_probe");
 849                 if (IS_ERR(probe_task))
 850                         return PTR_ERR(probe_task);
 851         }
 852         return 0;
 853 }
 854 device_initcall(xenbus_probe_initcall);
 855
 856 int xen_set_callback_via(uint64_t via)
 857 {
 858         struct xen_hvm_param a;
 859         int ret;
 860
 861         a.domid = DOMID_SELF;
 862         a.index = HVM_PARAM_CALLBACK_IRQ;
 863         a.value = via;
 864
 865         ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
 866         if (ret)
 867                 return ret;
 868
 869         /*
 870          * If xenbus_probe_initcall() deferred the xenbus_probe()
 871          * due to the callback not functioning yet, we can do it now.
 872          */
 873         if (!xenstored_ready && xs_hvm_defer_init_for_callback())
 874                 xenbus_probe();
 875
 876         return ret;
 877 }
 878 EXPORT_SYMBOL_GPL(xen_set_callback_via);
 879
 880 /* Set up event channel for xenstored which is run as a local process
 881  * (this is normally used only in dom0)
 882  */
 883 static int __init xenstored_local_init(void)
 884 {
 885         int err = -ENOMEM;
 886         unsigned long page = 0;
 887         struct evtchn_alloc_unbound alloc_unbound;
 888
 889         /* Allocate Xenstore page */
 890         page = get_zeroed_page(GFP_KERNEL);
 891         if (!page)
 892                 goto out_err;
 893
 894         xen_store_gfn = virt_to_gfn((void *)page);
 895
 896         /* Next allocate a local port which xenstored can bind to */
 897         alloc_unbound.dom        = DOMID_SELF;
 898         alloc_unbound.remote_dom = DOMID_SELF;
 899
 900         err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
 901                                           &alloc_unbound);
 902         if (err == -ENOSYS)
 903                 goto out_err;
 904
 905         BUG_ON(err);
 906         xen_store_evtchn = alloc_unbound.port;
 907
 908         return 0;
 909
 910  out_err:
 911         if (page != 0)
 912                 free_page(page);
 913         return err;
 914 }
 915
 916 static int xenbus_resume_cb(struct notifier_block *nb,
 917                             unsigned long action, void *data)
 918 {
 919         int err = 0;
 920
 921         if (xen_hvm_domain()) {
 922                 uint64_t v = 0;
 923
 924                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 925                 if (!err && v)
 926                         xen_store_evtchn = v;
 927                 else
 928                         pr_warn("Cannot update xenstore event channel: %d\n",
 929                                 err);
 930         } else
 931                 xen_store_evtchn = xen_start_info->store_evtchn;
 932
 933         return err;
 934 }
 935
 936 static struct notifier_block xenbus_resume_nb = {
 937         .notifier_call = xenbus_resume_cb,
 938 };
 939
 940 static irqreturn_t xenbus_late_init(int irq, void *unused)
 941 {
 942         int err;
 943         uint64_t v = 0;
 944
 945         err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 946         if (err || !v || !~v)
 947                 return IRQ_HANDLED;
 948         xen_store_gfn = (unsigned long)v;
 949
 950         wake_up(&xb_waitq);
 951         return IRQ_HANDLED;
 952 }
 953
 954 static int __init xenbus_init(void)
 955 {
 956         int err;
 957         uint64_t v = 0;
 958         bool wait = false;
 959         xen_store_domain_type = XS_UNKNOWN;
 960
 961         if (!xen_domain())
 962                 return -ENODEV;
 963
 964         xenbus_ring_ops_init();
 965
 966         if (xen_pv_domain())
 967                 xen_store_domain_type = XS_PV;
 968         if (xen_hvm_domain())
 969                 xen_store_domain_type = XS_HVM;
 970         if (xen_hvm_domain() && xen_initial_domain())
 971                 xen_store_domain_type = XS_LOCAL;
 972         if (xen_pv_domain() && !xen_start_info->store_evtchn)
 973                 xen_store_domain_type = XS_LOCAL;
 974         if (xen_pv_domain() && xen_start_info->store_evtchn)
 975                 xenstored_ready = 1;
 976
 977         switch (xen_store_domain_type) {
 978         case XS_LOCAL:
 979                 err = xenstored_local_init();
 980                 if (err)
 981                         goto out_error;
 982                 xen_store_interface = gfn_to_virt(xen_store_gfn);
 983                 break;
 984         case XS_PV:
 985                 xen_store_evtchn = xen_start_info->store_evtchn;
 986                 xen_store_gfn = xen_start_info->store_mfn;
 987                 xen_store_interface = gfn_to_virt(xen_store_gfn);
 988                 break;
 989         case XS_HVM:
 990                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 991                 if (err)
 992                         goto out_error;
 993                 xen_store_evtchn = (int)v;
 994                 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 995                 if (err)
 996                         goto out_error;
 997                 /*
 998                  * Uninitialized hvm_params are zero and return no error.
 999                  * Although it is theoretically possible to have
1000                  * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is
1001                  * not zero when valid. If zero, it means that Xenstore hasn't
1002                  * been properly initialized. Instead of attempting to map a
1003                  * wrong guest physical address return error.
1004                  *
1005                  * Also recognize all bits set as an invalid/uninitialized value.
1006                  */
1007                 if (!v) {
1008                         err = -ENOENT;
1009                         goto out_error;
1010                 }
1011                 if (v == ~0ULL) {
1012                         wait = true;
1013                 } else {
1014                         /* Avoid truncation on 32-bit. */
1015 #if BITS_PER_LONG == 32
1016                         if (v > ULONG_MAX) {
1017                                 pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
1018                                        __func__, v);
1019                                 err = -EINVAL;
1020                                 goto out_error;
1021                         }
1022 #endif
1023                         xen_store_gfn = (unsigned long)v;
1024                         xen_store_interface =
1025                                 memremap(xen_store_gfn << XEN_PAGE_SHIFT,
1026                                          XEN_PAGE_SIZE, MEMREMAP_WB);
1027                         if (!xen_store_interface) {
1028                                 pr_err("%s: cannot map HVM_PARAM_STORE_PFN=%llx\n",
1029                                        __func__, v);
1030                                 err = -EINVAL;
1031                                 goto out_error;
1032                         }
1033                         if (xen_store_interface->connection != XENSTORE_CONNECTED)
1034                                 wait = true;
1035                 }
1036                 if (wait) {
1037                         err = bind_evtchn_to_irqhandler(xen_store_evtchn,
1038                                                         xenbus_late_init,
1039                                                         0, "xenstore_late_init",
1040                                                         &xb_waitq);
1041                         if (err < 0) {
1042                                 pr_err("xenstore_late_init couldn't bind irq err=%d\n",
1043                                        err);
1044                                 goto out_error;
1045                         }
1046
1047                         xs_init_irq = err;
1048                 }
1049                 break;
1050         default:
1051                 pr_warn("Xenstore state unknown\n");
1052                 break;
1053         }
1054
1055         /*
1056          * HVM domains may not have a functional callback yet. In that
1057          * case let xs_init() be called from xenbus_probe(), which will
1058          * get invoked at an appropriate time.
1059          */
1060         if (xen_store_domain_type != XS_HVM) {
1061                 err = xs_init();
1062                 if (err) {
1063                         pr_warn("Error initializing xenstore comms: %i\n", err);
1064                         goto out_error;
1065                 }
1066         }
1067
1068         if ((xen_store_domain_type != XS_LOCAL) &&
1069             (xen_store_domain_type != XS_UNKNOWN))
1070                 xen_resume_notifier_register(&xenbus_resume_nb);
1071
1072 #ifdef CONFIG_XEN_COMPAT_XENFS
1073         /*
1074          * Create xenfs mountpoint in /proc for compatibility with
1075          * utilities that expect to find "xenbus" under "/proc/xen".
1076          */
1077         proc_create_mount_point("xen");
1078 #endif
1079         return 0;
1080
1081 out_error:
1082         xen_store_domain_type = XS_UNKNOWN;
1083         return err;
1084 }
1085
1086 postcore_initcall(xenbus_init);
1087
1088 MODULE_LICENSE("GPL");