drivers/xen/xen-acpi-memhotplug.c

   1 /*
   2  * Copyright (C) 2012 Intel Corporation
   3  *    Author: Liu Jinsong <jinsong.liu@intel.com>
   4  *    Author: Jiang Yunhong <yunhong.jiang@intel.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or (at
   9  * your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  14  * NON INFRINGEMENT.  See the GNU General Public License for more
  15  * details.
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/types.h>
  24 #include <linux/acpi.h>
  25 #include <xen/acpi.h>
  26 #include <xen/interface/platform.h>
  27 #include <asm/xen/hypercall.h>
  28
  29 #define PREFIX "ACPI:xen_memory_hotplug:"
  30
  31 struct acpi_memory_info {
  32         struct list_head list;
  33         u64 start_addr;         /* Memory Range start physical addr */
  34         u64 length;             /* Memory Range length */
  35         unsigned short caching; /* memory cache attribute */
  36         unsigned short write_protect;   /* memory read/write attribute */
  37                                 /* copied from buffer getting from _CRS */
  38         unsigned int enabled:1;
  39 };
  40
  41 struct acpi_memory_device {
  42         struct acpi_device *device;
  43         struct list_head res_list;
  44 };
  45
  46 static bool acpi_hotmem_initialized __read_mostly;
  47
  48 static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
  49 {
  50         int rc;
  51         struct xen_platform_op op;
  52
  53         op.cmd = XENPF_mem_hotadd;
  54         op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
  55         op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
  56         op.u.mem_add.pxm = pxm;
  57
  58         rc = HYPERVISOR_dom0_op(&op);
  59         if (rc)
  60                 pr_err(PREFIX "Xen Hotplug Memory Add failed on "
  61                         "0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
  62                         (unsigned long)info->start_addr,
  63                         (unsigned long)(info->start_addr + info->length),
  64                         pxm, rc);
  65
  66         return rc;
  67 }
  68
  69 static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
  70 {
  71         int pxm, result;
  72         int num_enabled = 0;
  73         struct acpi_memory_info *info;
  74
  75         if (!mem_device)
  76                 return -EINVAL;
  77
  78         pxm = xen_acpi_get_pxm(mem_device->device->handle);
  79         if (pxm < 0)
  80                 return pxm;
  81
  82         list_for_each_entry(info, &mem_device->res_list, list) {
  83                 if (info->enabled) { /* just sanity check...*/
  84                         num_enabled++;
  85                         continue;
  86                 }
  87
  88                 if (!info->length)
  89                         continue;
  90
  91                 result = xen_hotadd_memory(pxm, info);
  92                 if (result)
  93                         continue;
  94                 info->enabled = 1;
  95                 num_enabled++;
  96         }
  97
  98         if (!num_enabled)
  99                 return -ENODEV;
 100
 101         return 0;
 102 }
 103
 104 static acpi_status
 105 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 106 {
 107         struct acpi_memory_device *mem_device = context;
 108         struct acpi_resource_address64 address64;
 109         struct acpi_memory_info *info, *new;
 110         acpi_status status;
 111
 112         status = acpi_resource_to_address64(resource, &address64);
 113         if (ACPI_FAILURE(status) ||
 114             (address64.resource_type != ACPI_MEMORY_RANGE))
 115                 return AE_OK;
 116
 117         list_for_each_entry(info, &mem_device->res_list, list) {
 118                 if ((info->caching == address64.info.mem.caching) &&
 119                     (info->write_protect == address64.info.mem.write_protect) &&
 120                     (info->start_addr + info->length == address64.minimum)) {
 121                         info->length += address64.address_length;
 122                         return AE_OK;
 123                 }
 124         }
 125
 126         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
 127         if (!new)
 128                 return AE_ERROR;
 129
 130         INIT_LIST_HEAD(&new->list);
 131         new->caching = address64.info.mem.caching;
 132         new->write_protect = address64.info.mem.write_protect;
 133         new->start_addr = address64.minimum;
 134         new->length = address64.address_length;
 135         list_add_tail(&new->list, &mem_device->res_list);
 136
 137         return AE_OK;
 138 }
 139
 140 static int
 141 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 142 {
 143         acpi_status status;
 144         struct acpi_memory_info *info, *n;
 145
 146         if (!list_empty(&mem_device->res_list))
 147                 return 0;
 148
 149         status = acpi_walk_resources(mem_device->device->handle,
 150                 METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
 151
 152         if (ACPI_FAILURE(status)) {
 153                 list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 154                         kfree(info);
 155                 INIT_LIST_HEAD(&mem_device->res_list);
 156                 return -EINVAL;
 157         }
 158
 159         return 0;
 160 }
 161
 162 static int acpi_memory_get_device(acpi_handle handle,
 163                                   struct acpi_memory_device **mem_device)
 164 {
 165         struct acpi_device *device = NULL;
 166         int result = 0;
 167
 168         acpi_scan_lock_acquire();
 169
 170         acpi_bus_get_device(handle, &device);
 171         if (device)
 172                 goto end;
 173
 174         /*
 175          * Now add the notified device.  This creates the acpi_device
 176          * and invokes .add function
 177          */
 178         result = acpi_bus_scan(handle);
 179         if (result) {
 180                 pr_warn(PREFIX "ACPI namespace scan failed\n");
 181                 result = -EINVAL;
 182                 goto out;
 183         }
 184         result = acpi_bus_get_device(handle, &device);
 185         if (result) {
 186                 pr_warn(PREFIX "Missing device object\n");
 187                 result = -EINVAL;
 188                 goto out;
 189         }
 190
 191 end:
 192         *mem_device = acpi_driver_data(device);
 193         if (!(*mem_device)) {
 194                 pr_err(PREFIX "driver data not found\n");
 195                 result = -ENODEV;
 196                 goto out;
 197         }
 198
 199 out:
 200         acpi_scan_lock_release();
 201         return result;
 202 }
 203
 204 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 205 {
 206         unsigned long long current_status;
 207
 208         /* Get device present/absent information from the _STA */
 209         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
 210                                 "_STA", NULL, &current_status)))
 211                 return -ENODEV;
 212         /*
 213          * Check for device status. Device should be
 214          * present/enabled/functioning.
 215          */
 216         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 217               && (current_status & ACPI_STA_DEVICE_ENABLED)
 218               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 219                 return -ENODEV;
 220
 221         return 0;
 222 }
 223
 224 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 225 {
 226         pr_debug(PREFIX "Xen does not support memory hotremove\n");
 227
 228         return -ENOSYS;
 229 }
 230
 231 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 232 {
 233         struct acpi_memory_device *mem_device;
 234         struct acpi_device *device;
 235         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 236
 237         switch (event) {
 238         case ACPI_NOTIFY_BUS_CHECK:
 239                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 240                         "\nReceived BUS CHECK notification for device\n"));
 241                 /* Fall Through */
 242         case ACPI_NOTIFY_DEVICE_CHECK:
 243                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 244                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 245                         "\nReceived DEVICE CHECK notification for device\n"));
 246
 247                 if (acpi_memory_get_device(handle, &mem_device)) {
 248                         pr_err(PREFIX "Cannot find driver data\n");
 249                         break;
 250                 }
 251
 252                 ost_code = ACPI_OST_SC_SUCCESS;
 253                 break;
 254
 255         case ACPI_NOTIFY_EJECT_REQUEST:
 256                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 257                         "\nReceived EJECT REQUEST notification for device\n"));
 258
 259                 acpi_scan_lock_acquire();
 260                 if (acpi_bus_get_device(handle, &device)) {
 261                         acpi_scan_lock_release();
 262                         pr_err(PREFIX "Device doesn't exist\n");
 263                         break;
 264                 }
 265                 mem_device = acpi_driver_data(device);
 266                 if (!mem_device) {
 267                         acpi_scan_lock_release();
 268                         pr_err(PREFIX "Driver Data is NULL\n");
 269                         break;
 270                 }
 271
 272                 /*
 273                  * TBD: implement acpi_memory_disable_device and invoke
 274                  * acpi_bus_remove if Xen support hotremove in the future
 275                  */
 276                 acpi_memory_disable_device(mem_device);
 277                 acpi_scan_lock_release();
 278                 break;
 279
 280         default:
 281                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 282                                   "Unsupported event [0x%x]\n", event));
 283                 /* non-hotplug event; possibly handled by other handler */
 284                 return;
 285         }
 286
 287         (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 288         return;
 289 }
 290
 291 static int xen_acpi_memory_device_add(struct acpi_device *device)
 292 {
 293         int result;
 294         struct acpi_memory_device *mem_device = NULL;
 295
 296
 297         if (!device)
 298                 return -EINVAL;
 299
 300         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 301         if (!mem_device)
 302                 return -ENOMEM;
 303
 304         INIT_LIST_HEAD(&mem_device->res_list);
 305         mem_device->device = device;
 306         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 307         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 308         device->driver_data = mem_device;
 309
 310         /* Get the range from the _CRS */
 311         result = acpi_memory_get_device_resources(mem_device);
 312         if (result) {
 313                 kfree(mem_device);
 314                 return result;
 315         }
 316
 317         /*
 318          * For booting existed memory devices, early boot code has recognized
 319          * memory area by EFI/E820. If DSDT shows these memory devices on boot,
 320          * hotplug is not necessary for them.
 321          * For hot-added memory devices during runtime, it need hypercall to
 322          * Xen hypervisor to add memory.
 323          */
 324         if (!acpi_hotmem_initialized)
 325                 return 0;
 326
 327         if (!acpi_memory_check_device(mem_device))
 328                 result = xen_acpi_memory_enable_device(mem_device);
 329
 330         return result;
 331 }
 332
 333 static int xen_acpi_memory_device_remove(struct acpi_device *device)
 334 {
 335         struct acpi_memory_device *mem_device = NULL;
 336
 337         if (!device || !acpi_driver_data(device))
 338                 return -EINVAL;
 339
 340         mem_device = acpi_driver_data(device);
 341         kfree(mem_device);
 342
 343         return 0;
 344 }
 345
 346 /*
 347  * Helper function to check for memory device
 348  */
 349 static acpi_status is_memory_device(acpi_handle handle)
 350 {
 351         char *hardware_id;
 352         acpi_status status;
 353         struct acpi_device_info *info;
 354
 355         status = acpi_get_object_info(handle, &info);
 356         if (ACPI_FAILURE(status))
 357                 return status;
 358
 359         if (!(info->valid & ACPI_VALID_HID)) {
 360                 kfree(info);
 361                 return AE_ERROR;
 362         }
 363
 364         hardware_id = info->hardware_id.string;
 365         if ((hardware_id == NULL) ||
 366             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 367                 status = AE_ERROR;
 368
 369         kfree(info);
 370         return status;
 371 }
 372
 373 static acpi_status
 374 acpi_memory_register_notify_handler(acpi_handle handle,
 375                                     u32 level, void *ctxt, void **retv)
 376 {
 377         acpi_status status;
 378
 379         status = is_memory_device(handle);
 380         if (ACPI_FAILURE(status))
 381                 return AE_OK;   /* continue */
 382
 383         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 384                                              acpi_memory_device_notify, NULL);
 385         /* continue */
 386         return AE_OK;
 387 }
 388
 389 static acpi_status
 390 acpi_memory_deregister_notify_handler(acpi_handle handle,
 391                                       u32 level, void *ctxt, void **retv)
 392 {
 393         acpi_status status;
 394
 395         status = is_memory_device(handle);
 396         if (ACPI_FAILURE(status))
 397                 return AE_OK;   /* continue */
 398
 399         status = acpi_remove_notify_handler(handle,
 400                                             ACPI_SYSTEM_NOTIFY,
 401                                             acpi_memory_device_notify);
 402
 403         return AE_OK;   /* continue */
 404 }
 405
 406 static const struct acpi_device_id memory_device_ids[] = {
 407         {ACPI_MEMORY_DEVICE_HID, 0},
 408         {"", 0},
 409 };
 410 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
 411
 412 static struct acpi_driver xen_acpi_memory_device_driver = {
 413         .name = "acpi_memhotplug",
 414         .class = ACPI_MEMORY_DEVICE_CLASS,
 415         .ids = memory_device_ids,
 416         .ops = {
 417                 .add = xen_acpi_memory_device_add,
 418                 .remove = xen_acpi_memory_device_remove,
 419                 },
 420 };
 421
 422 static int __init xen_acpi_memory_device_init(void)
 423 {
 424         int result;
 425         acpi_status status;
 426
 427         if (!xen_initial_domain())
 428                 return -ENODEV;
 429
 430         /* unregister the stub which only used to reserve driver space */
 431         xen_stub_memory_device_exit();
 432
 433         result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
 434         if (result < 0) {
 435                 xen_stub_memory_device_init();
 436                 return -ENODEV;
 437         }
 438
 439         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 440                                      ACPI_UINT32_MAX,
 441                                      acpi_memory_register_notify_handler,
 442                                      NULL, NULL, NULL);
 443
 444         if (ACPI_FAILURE(status)) {
 445                 pr_warn(PREFIX "walk_namespace failed\n");
 446                 acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
 447                 xen_stub_memory_device_init();
 448                 return -ENODEV;
 449         }
 450
 451         acpi_hotmem_initialized = true;
 452         return 0;
 453 }
 454
 455 static void __exit xen_acpi_memory_device_exit(void)
 456 {
 457         acpi_status status;
 458
 459         if (!xen_initial_domain())
 460                 return;
 461
 462         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 463                                      ACPI_UINT32_MAX,
 464                                      acpi_memory_deregister_notify_handler,
 465                                      NULL, NULL, NULL);
 466         if (ACPI_FAILURE(status))
 467                 pr_warn(PREFIX "walk_namespace failed\n");
 468
 469         acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
 470
 471         /*
 472          * stub reserve space again to prevent any chance of native
 473          * driver loading.
 474          */
 475         xen_stub_memory_device_init();
 476         return;
 477 }
 478
 479 module_init(xen_acpi_memory_device_init);
 480 module_exit(xen_acpi_memory_device_exit);
 481 ACPI_MODULE_NAME("xen-acpi-memhotplug");
 482 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
 483 MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
 484 MODULE_LICENSE("GPL");