drivers/xen/xen-acpi-cpuhotplug.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/cpu.h>
  25 #include <linux/acpi.h>
  26 #include <linux/uaccess.h>
  27 #include <acpi/processor.h>
  28 #include <xen/acpi.h>
  29 #include <xen/interface/platform.h>
  30 #include <asm/xen/hypercall.h>
  31
  32 #define PREFIX "ACPI:xen_cpu_hotplug:"
  33
  34 #define INSTALL_NOTIFY_HANDLER          0
  35 #define UNINSTALL_NOTIFY_HANDLER        1
  36
  37 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
  38
  39 /* --------------------------------------------------------------------------
  40                                 Driver Interface
  41 -------------------------------------------------------------------------- */
  42
  43 static int xen_acpi_processor_enable(struct acpi_device *device)
  44 {
  45         acpi_status status = 0;
  46         unsigned long long value;
  47         union acpi_object object = { 0 };
  48         struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
  49         struct acpi_processor *pr = acpi_driver_data(device);
  50
  51         if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
  52                 /* Declared with "Processor" statement; match ProcessorID */
  53                 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
  54                 if (ACPI_FAILURE(status)) {
  55                         pr_err(PREFIX "Evaluating processor object\n");
  56                         return -ENODEV;
  57                 }
  58
  59                 pr->acpi_id = object.processor.proc_id;
  60         } else {
  61                 /* Declared with "Device" statement; match _UID */
  62                 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
  63                                                 NULL, &value);
  64                 if (ACPI_FAILURE(status)) {
  65                         pr_err(PREFIX "Evaluating processor _UID\n");
  66                         return -ENODEV;
  67                 }
  68
  69                 pr->acpi_id = value;
  70         }
  71
  72         pr->id = xen_pcpu_id(pr->acpi_id);
  73
  74         if (invalid_logical_cpuid(pr->id))
  75                 /* This cpu is not presented at hypervisor, try to hotadd it */
  76                 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
  77                         pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
  78                                         pr->acpi_id);
  79                         return -ENODEV;
  80                 }
  81
  82         return 0;
  83 }
  84
  85 static int xen_acpi_processor_add(struct acpi_device *device)
  86 {
  87         int ret;
  88         struct acpi_processor *pr;
  89
  90         if (!device)
  91                 return -EINVAL;
  92
  93         pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
  94         if (!pr)
  95                 return -ENOMEM;
  96
  97         pr->handle = device->handle;
  98         strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
  99         strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
 100         device->driver_data = pr;
 101
 102         ret = xen_acpi_processor_enable(device);
 103         if (ret)
 104                 pr_err(PREFIX "Error when enabling Xen processor\n");
 105
 106         return ret;
 107 }
 108
 109 static int xen_acpi_processor_remove(struct acpi_device *device)
 110 {
 111         struct acpi_processor *pr;
 112
 113         if (!device)
 114                 return -EINVAL;
 115
 116         pr = acpi_driver_data(device);
 117         if (!pr)
 118                 return -EINVAL;
 119
 120         kfree(pr);
 121         return 0;
 122 }
 123
 124 /*--------------------------------------------------------------
 125                 Acpi processor hotplug support
 126 --------------------------------------------------------------*/
 127
 128 static int is_processor_present(acpi_handle handle)
 129 {
 130         acpi_status status;
 131         unsigned long long sta = 0;
 132
 133
 134         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 135
 136         if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
 137                 return 1;
 138
 139         /*
 140          * _STA is mandatory for a processor that supports hot plug
 141          */
 142         if (status == AE_NOT_FOUND)
 143                 pr_info(PREFIX "Processor does not support hot plug\n");
 144         else
 145                 pr_info(PREFIX "Processor Device is not present");
 146         return 0;
 147 }
 148
 149 static int xen_apic_id(acpi_handle handle)
 150 {
 151         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 152         union acpi_object *obj;
 153         struct acpi_madt_local_apic *lapic;
 154         int apic_id;
 155
 156         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
 157                 return -EINVAL;
 158
 159         if (!buffer.length || !buffer.pointer)
 160                 return -EINVAL;
 161
 162         obj = buffer.pointer;
 163         if (obj->type != ACPI_TYPE_BUFFER ||
 164             obj->buffer.length < sizeof(*lapic)) {
 165                 kfree(buffer.pointer);
 166                 return -EINVAL;
 167         }
 168
 169         lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
 170
 171         if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
 172             !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
 173                 kfree(buffer.pointer);
 174                 return -EINVAL;
 175         }
 176
 177         apic_id = (uint32_t)lapic->id;
 178         kfree(buffer.pointer);
 179         buffer.length = ACPI_ALLOCATE_BUFFER;
 180         buffer.pointer = NULL;
 181
 182         return apic_id;
 183 }
 184
 185 static int xen_hotadd_cpu(struct acpi_processor *pr)
 186 {
 187         int cpu_id, apic_id, pxm;
 188         struct xen_platform_op op;
 189
 190         apic_id = xen_apic_id(pr->handle);
 191         if (apic_id < 0) {
 192                 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
 193                                 pr->acpi_id);
 194                 return -ENODEV;
 195         }
 196
 197         pxm = xen_acpi_get_pxm(pr->handle);
 198         if (pxm < 0) {
 199                 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
 200                                 pr->acpi_id);
 201                 return pxm;
 202         }
 203
 204         op.cmd = XENPF_cpu_hotadd;
 205         op.u.cpu_add.apic_id = apic_id;
 206         op.u.cpu_add.acpi_id = pr->acpi_id;
 207         op.u.cpu_add.pxm = pxm;
 208
 209         cpu_id = HYPERVISOR_platform_op(&op);
 210         if (cpu_id < 0)
 211                 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
 212                                 pr->acpi_id);
 213
 214         return cpu_id;
 215 }
 216
 217 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
 218 {
 219         if (!is_processor_present(pr->handle))
 220                 return AE_ERROR;
 221
 222         pr->id = xen_hotadd_cpu(pr);
 223         if (invalid_logical_cpuid(pr->id))
 224                 return AE_ERROR;
 225
 226         /*
 227          * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
 228          * interface after cpu hotadded.
 229          */
 230         xen_pcpu_hotplug_sync();
 231
 232         return AE_OK;
 233 }
 234
 235 static int acpi_processor_device_remove(struct acpi_device *device)
 236 {
 237         pr_debug(PREFIX "Xen does not support CPU hotremove\n");
 238
 239         return -ENOSYS;
 240 }
 241
 242 static void acpi_processor_hotplug_notify(acpi_handle handle,
 243                                           u32 event, void *data)
 244 {
 245         struct acpi_processor *pr;
 246         struct acpi_device *device = NULL;
 247         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 248         int result;
 249
 250         acpi_scan_lock_acquire();
 251
 252         switch (event) {
 253         case ACPI_NOTIFY_BUS_CHECK:
 254         case ACPI_NOTIFY_DEVICE_CHECK:
 255                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 256                         "Processor driver received %s event\n",
 257                         (event == ACPI_NOTIFY_BUS_CHECK) ?
 258                         "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
 259
 260                 if (!is_processor_present(handle))
 261                         break;
 262
 263                 acpi_bus_get_device(handle, &device);
 264                 if (acpi_device_enumerated(device))
 265                         break;
 266
 267                 result = acpi_bus_scan(handle);
 268                 if (result) {
 269                         pr_err(PREFIX "Unable to add the device\n");
 270                         break;
 271                 }
 272                 device = NULL;
 273                 acpi_bus_get_device(handle, &device);
 274                 if (!acpi_device_enumerated(device)) {
 275                         pr_err(PREFIX "Missing device object\n");
 276                         break;
 277                 }
 278                 ost_code = ACPI_OST_SC_SUCCESS;
 279                 break;
 280
 281         case ACPI_NOTIFY_EJECT_REQUEST:
 282                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 283                                   "received ACPI_NOTIFY_EJECT_REQUEST\n"));
 284
 285                 if (acpi_bus_get_device(handle, &device)) {
 286                         pr_err(PREFIX "Device don't exist, dropping EJECT\n");
 287                         break;
 288                 }
 289                 pr = acpi_driver_data(device);
 290                 if (!pr) {
 291                         pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
 292                         break;
 293                 }
 294
 295                 /*
 296                  * TBD: implement acpi_processor_device_remove if Xen support
 297                  * CPU hotremove in the future.
 298                  */
 299                 acpi_processor_device_remove(device);
 300                 break;
 301
 302         default:
 303                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 304                                   "Unsupported event [0x%x]\n", event));
 305
 306                 /* non-hotplug event; possibly handled by other handler */
 307                 goto out;
 308         }
 309
 310         (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
 311
 312 out:
 313         acpi_scan_lock_release();
 314 }
 315
 316 static acpi_status is_processor_device(acpi_handle handle)
 317 {
 318         struct acpi_device_info *info;
 319         char *hid;
 320         acpi_status status;
 321
 322         status = acpi_get_object_info(handle, &info);
 323         if (ACPI_FAILURE(status))
 324                 return status;
 325
 326         if (info->type == ACPI_TYPE_PROCESSOR) {
 327                 kfree(info);
 328                 return AE_OK;   /* found a processor object */
 329         }
 330
 331         if (!(info->valid & ACPI_VALID_HID)) {
 332                 kfree(info);
 333                 return AE_ERROR;
 334         }
 335
 336         hid = info->hardware_id.string;
 337         if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
 338                 kfree(info);
 339                 return AE_ERROR;
 340         }
 341
 342         kfree(info);
 343         return AE_OK;   /* found a processor device object */
 344 }
 345
 346 static acpi_status
 347 processor_walk_namespace_cb(acpi_handle handle,
 348                             u32 lvl, void *context, void **rv)
 349 {
 350         acpi_status status;
 351         int *action = context;
 352
 353         status = is_processor_device(handle);
 354         if (ACPI_FAILURE(status))
 355                 return AE_OK;   /* not a processor; continue to walk */
 356
 357         switch (*action) {
 358         case INSTALL_NOTIFY_HANDLER:
 359                 acpi_install_notify_handler(handle,
 360                                             ACPI_SYSTEM_NOTIFY,
 361                                             acpi_processor_hotplug_notify,
 362                                             NULL);
 363                 break;
 364         case UNINSTALL_NOTIFY_HANDLER:
 365                 acpi_remove_notify_handler(handle,
 366                                            ACPI_SYSTEM_NOTIFY,
 367                                            acpi_processor_hotplug_notify);
 368                 break;
 369         default:
 370                 break;
 371         }
 372
 373         /* found a processor; skip walking underneath */
 374         return AE_CTRL_DEPTH;
 375 }
 376
 377 static
 378 void acpi_processor_install_hotplug_notify(void)
 379 {
 380         int action = INSTALL_NOTIFY_HANDLER;
 381         acpi_walk_namespace(ACPI_TYPE_ANY,
 382                             ACPI_ROOT_OBJECT,
 383                             ACPI_UINT32_MAX,
 384                             processor_walk_namespace_cb, NULL, &action, NULL);
 385 }
 386
 387 static
 388 void acpi_processor_uninstall_hotplug_notify(void)
 389 {
 390         int action = UNINSTALL_NOTIFY_HANDLER;
 391         acpi_walk_namespace(ACPI_TYPE_ANY,
 392                             ACPI_ROOT_OBJECT,
 393                             ACPI_UINT32_MAX,
 394                             processor_walk_namespace_cb, NULL, &action, NULL);
 395 }
 396
 397 static const struct acpi_device_id processor_device_ids[] = {
 398         {ACPI_PROCESSOR_OBJECT_HID, 0},
 399         {ACPI_PROCESSOR_DEVICE_HID, 0},
 400         {"", 0},
 401 };
 402 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
 403
 404 static struct acpi_driver xen_acpi_processor_driver = {
 405         .name = "processor",
 406         .class = ACPI_PROCESSOR_CLASS,
 407         .ids = processor_device_ids,
 408         .ops = {
 409                 .add = xen_acpi_processor_add,
 410                 .remove = xen_acpi_processor_remove,
 411                 },
 412 };
 413
 414 static int __init xen_acpi_processor_init(void)
 415 {
 416         int result = 0;
 417
 418         if (!xen_initial_domain())
 419                 return -ENODEV;
 420
 421         /* unregister the stub which only used to reserve driver space */
 422         xen_stub_processor_exit();
 423
 424         result = acpi_bus_register_driver(&xen_acpi_processor_driver);
 425         if (result < 0) {
 426                 xen_stub_processor_init();
 427                 return result;
 428         }
 429
 430         acpi_processor_install_hotplug_notify();
 431         return 0;
 432 }
 433
 434 static void __exit xen_acpi_processor_exit(void)
 435 {
 436         if (!xen_initial_domain())
 437                 return;
 438
 439         acpi_processor_uninstall_hotplug_notify();
 440
 441         acpi_bus_unregister_driver(&xen_acpi_processor_driver);
 442
 443         /*
 444          * stub reserve space again to prevent any chance of native
 445          * driver loading.
 446          */
 447         xen_stub_processor_init();
 448         return;
 449 }
 450
 451 module_init(xen_acpi_processor_init);
 452 module_exit(xen_acpi_processor_exit);
 453 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
 454 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
 455 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
 456 MODULE_LICENSE("GPL");