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