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