| 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"); |