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 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/types.h>
  22 #include <linux/cpu.h>
  23 #include <linux/acpi.h>
  24 #include <linux/uaccess.h>
  25 #include <acpi/acpi_bus.h>
  26 #include <acpi/acpi_drivers.h>
  27 #include <acpi/processor.h>
  28
  29 #include <xen/acpi.h>
  30 #include <xen/interface/platform.h>
  31 #include <asm/xen/hypercall.h>
  32
  33 #define PREFIX "ACPI:xen_cpu_hotplug:"
  34
  35 #define INSTALL_NOTIFY_HANDLER          0
  36 #define UNINSTALL_NOTIFY_HANDLER        1
  37
  38 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
  39
  40 /* --------------------------------------------------------------------------
  41                                 Driver Interface
  42 -------------------------------------------------------------------------- */
  43
  44 static int xen_acpi_processor_enable(struct acpi_device *device)
  45 {
  46         acpi_status status = 0;
  47         unsigned long long value;
  48         union acpi_object object = { 0 };
  49         struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
  50         struct acpi_processor *pr;
  51
  52         pr = acpi_driver_data(device);
  53         if (!pr) {
  54                 pr_err(PREFIX "Cannot find driver data\n");
  55                 return -EINVAL;
  56         }
  57
  58         if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
  59                 /* Declared with "Processor" statement; match ProcessorID */
  60                 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
  61                 if (ACPI_FAILURE(status)) {
  62                         pr_err(PREFIX "Evaluating processor object\n");
  63                         return -ENODEV;
  64                 }
  65
  66                 pr->acpi_id = object.processor.proc_id;
  67         } else {
  68                 /* Declared with "Device" statement; match _UID */
  69                 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
  70                                                 NULL, &value);
  71                 if (ACPI_FAILURE(status)) {
  72                         pr_err(PREFIX "Evaluating processor _UID\n");
  73                         return -ENODEV;
  74                 }
  75
  76                 pr->acpi_id = value;
  77         }
  78
  79         pr->id = xen_pcpu_id(pr->acpi_id);
  80
  81         if ((int)pr->id < 0)
  82                 /* This cpu is not presented at hypervisor, try to hotadd it */
  83                 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
  84                         pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
  85                                         pr->acpi_id);
  86                         return -ENODEV;
  87                 }
  88
  89         return 0;
  90 }
  91
  92 static int __cpuinit xen_acpi_processor_add(struct acpi_device *device)
  93 {
  94         int ret;
  95         struct acpi_processor *pr;
  96
  97         if (!device)
  98                 return -EINVAL;
  99
 100         pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
 101         if (!pr)
 102                 return -ENOMEM;
 103
 104         pr->handle = device->handle;
 105         strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
 106         strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
 107         device->driver_data = pr;
 108
 109         ret = xen_acpi_processor_enable(device);
 110         if (ret)
 111                 pr_err(PREFIX "Error when enabling Xen processor\n");
 112
 113         return ret;
 114 }
 115
 116 static int xen_acpi_processor_remove(struct acpi_device *device)
 117 {
 118         struct acpi_processor *pr;
 119
 120         if (!device)
 121                 return -EINVAL;
 122
 123         pr = acpi_driver_data(device);
 124         if (!pr)
 125                 return -EINVAL;
 126
 127         kfree(pr);
 128         return 0;
 129 }
 130
 131 /*--------------------------------------------------------------
 132                 Acpi processor hotplug support
 133 --------------------------------------------------------------*/
 134
 135 static int is_processor_present(acpi_handle handle)
 136 {
 137         acpi_status status;
 138         unsigned long long sta = 0;
 139
 140
 141         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 142
 143         if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
 144                 return 1;
 145
 146         /*
 147          * _STA is mandatory for a processor that supports hot plug
 148          */
 149         if (status == AE_NOT_FOUND)
 150                 pr_info(PREFIX "Processor does not support hot plug\n");
 151         else
 152                 pr_info(PREFIX "Processor Device is not present");
 153         return 0;
 154 }
 155
 156 static int xen_apic_id(acpi_handle handle)
 157 {
 158         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 159         union acpi_object *obj;
 160         struct acpi_madt_local_apic *lapic;
 161         int apic_id;
 162
 163         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
 164                 return -EINVAL;
 165
 166         if (!buffer.length || !buffer.pointer)
 167                 return -EINVAL;
 168
 169         obj = buffer.pointer;
 170         if (obj->type != ACPI_TYPE_BUFFER ||
 171             obj->buffer.length < sizeof(*lapic)) {
 172                 kfree(buffer.pointer);
 173                 return -EINVAL;
 174         }
 175
 176         lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
 177
 178         if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
 179             !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
 180                 kfree(buffer.pointer);
 181                 return -EINVAL;
 182         }
 183
 184         apic_id = (uint32_t)lapic->id;
 185         kfree(buffer.pointer);
 186         buffer.length = ACPI_ALLOCATE_BUFFER;
 187         buffer.pointer = NULL;
 188
 189         return apic_id;
 190 }
 191
 192 static int xen_hotadd_cpu(struct acpi_processor *pr)
 193 {
 194         int cpu_id, apic_id, pxm;
 195         struct xen_platform_op op;
 196
 197         apic_id = xen_apic_id(pr->handle);
 198         if (apic_id < 0) {
 199                 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
 200                                 pr->acpi_id);
 201                 return -ENODEV;
 202         }
 203
 204         pxm = xen_acpi_get_pxm(pr->handle);
 205         if (pxm < 0) {
 206                 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
 207                                 pr->acpi_id);
 208                 return pxm;
 209         }
 210
 211         op.cmd = XENPF_cpu_hotadd;
 212         op.u.cpu_add.apic_id = apic_id;
 213         op.u.cpu_add.acpi_id = pr->acpi_id;
 214         op.u.cpu_add.pxm = pxm;
 215
 216         cpu_id = HYPERVISOR_dom0_op(&op);
 217         if (cpu_id < 0)
 218                 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
 219                                 pr->acpi_id);
 220
 221         return cpu_id;
 222 }
 223
 224 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
 225 {
 226         if (!is_processor_present(pr->handle))
 227                 return AE_ERROR;
 228
 229         pr->id = xen_hotadd_cpu(pr);
 230         if ((int)pr->id < 0)
 231                 return AE_ERROR;
 232
 233         /*
 234          * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
 235          * interface after cpu hotadded.
 236          */
 237         xen_pcpu_hotplug_sync();
 238
 239         return AE_OK;
 240 }
 241
 242 static int acpi_processor_device_remove(struct acpi_device *device)
 243 {
 244         pr_debug(PREFIX "Xen does not support CPU hotremove\n");
 245
 246         return -ENOSYS;
 247 }
 248
 249 static void acpi_processor_hotplug_notify(acpi_handle handle,
 250                                           u32 event, void *data)
 251 {
 252         struct acpi_processor *pr;
 253         struct acpi_device *device = NULL;
 254         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 255         int result;
 256
 257         acpi_scan_lock_acquire();
 258
 259         switch (event) {
 260         case ACPI_NOTIFY_BUS_CHECK:
 261         case ACPI_NOTIFY_DEVICE_CHECK:
 262                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 263                         "Processor driver received %s event\n",
 264                         (event == ACPI_NOTIFY_BUS_CHECK) ?
 265                         "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
 266
 267                 if (!is_processor_present(handle))
 268                         break;
 269
 270                 if (!acpi_bus_get_device(handle, &device))
 271                         break;
 272
 273                 result = acpi_bus_scan(handle);
 274                 if (result) {
 275                         pr_err(PREFIX "Unable to add the device\n");
 276                         break;
 277                 }
 278                 result = acpi_bus_get_device(handle, &device);
 279                 if (result) {
 280                         pr_err(PREFIX "Missing device object\n");
 281                         break;
 282                 }
 283                 ost_code = ACPI_OST_SC_SUCCESS;
 284                 break;
 285
 286         case ACPI_NOTIFY_EJECT_REQUEST:
 287                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 288                                   "received ACPI_NOTIFY_EJECT_REQUEST\n"));
 289
 290                 if (acpi_bus_get_device(handle, &device)) {
 291                         pr_err(PREFIX "Device don't exist, dropping EJECT\n");
 292                         break;
 293                 }
 294                 pr = acpi_driver_data(device);
 295                 if (!pr) {
 296                         pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
 297                         break;
 298                 }
 299
 300                 /*
 301                  * TBD: implement acpi_processor_device_remove if Xen support
 302                  * CPU hotremove in the future.
 303                  */
 304                 acpi_processor_device_remove(device);
 305                 break;
 306
 307         default:
 308                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 309                                   "Unsupported event [0x%x]\n", event));
 310
 311                 /* non-hotplug event; possibly handled by other handler */
 312                 goto out;
 313         }
 314
 315         (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 316
 317 out:
 318         acpi_scan_lock_release();
 319 }
 320
 321 static acpi_status is_processor_device(acpi_handle handle)
 322 {
 323         struct acpi_device_info *info;
 324         char *hid;
 325         acpi_status status;
 326
 327         status = acpi_get_object_info(handle, &info);
 328         if (ACPI_FAILURE(status))
 329                 return status;
 330
 331         if (info->type == ACPI_TYPE_PROCESSOR) {
 332                 kfree(info);
 333                 return AE_OK;   /* found a processor object */
 334         }
 335
 336         if (!(info->valid & ACPI_VALID_HID)) {
 337                 kfree(info);
 338                 return AE_ERROR;
 339         }
 340
 341         hid = info->hardware_id.string;
 342         if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
 343                 kfree(info);
 344                 return AE_ERROR;
 345         }
 346
 347         kfree(info);
 348         return AE_OK;   /* found a processor device object */
 349 }
 350
 351 static acpi_status
 352 processor_walk_namespace_cb(acpi_handle handle,
 353                             u32 lvl, void *context, void **rv)
 354 {
 355         acpi_status status;
 356         int *action = context;
 357
 358         status = is_processor_device(handle);
 359         if (ACPI_FAILURE(status))
 360                 return AE_OK;   /* not a processor; continue to walk */
 361
 362         switch (*action) {
 363         case INSTALL_NOTIFY_HANDLER:
 364                 acpi_install_notify_handler(handle,
 365                                             ACPI_SYSTEM_NOTIFY,
 366                                             acpi_processor_hotplug_notify,
 367                                             NULL);
 368                 break;
 369         case UNINSTALL_NOTIFY_HANDLER:
 370                 acpi_remove_notify_handler(handle,
 371                                            ACPI_SYSTEM_NOTIFY,
 372                                            acpi_processor_hotplug_notify);
 373                 break;
 374         default:
 375                 break;
 376         }
 377
 378         /* found a processor; skip walking underneath */
 379         return AE_CTRL_DEPTH;
 380 }
 381
 382 static
 383 void acpi_processor_install_hotplug_notify(void)
 384 {
 385         int action = INSTALL_NOTIFY_HANDLER;
 386         acpi_walk_namespace(ACPI_TYPE_ANY,
 387                             ACPI_ROOT_OBJECT,
 388                             ACPI_UINT32_MAX,
 389                             processor_walk_namespace_cb, NULL, &action, NULL);
 390 }
 391
 392 static
 393 void acpi_processor_uninstall_hotplug_notify(void)
 394 {
 395         int action = UNINSTALL_NOTIFY_HANDLER;
 396         acpi_walk_namespace(ACPI_TYPE_ANY,
 397                             ACPI_ROOT_OBJECT,
 398                             ACPI_UINT32_MAX,
 399                             processor_walk_namespace_cb, NULL, &action, NULL);
 400 }
 401
 402 static const struct acpi_device_id processor_device_ids[] = {
 403         {ACPI_PROCESSOR_OBJECT_HID, 0},
 404         {ACPI_PROCESSOR_DEVICE_HID, 0},
 405         {"", 0},
 406 };
 407 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
 408
 409 static struct acpi_driver xen_acpi_processor_driver = {
 410         .name = "processor",
 411         .class = ACPI_PROCESSOR_CLASS,
 412         .ids = processor_device_ids,
 413         .ops = {
 414                 .add = xen_acpi_processor_add,
 415                 .remove = xen_acpi_processor_remove,
 416                 },
 417 };
 418
 419 static int __init xen_acpi_processor_init(void)
 420 {
 421         int result = 0;
 422
 423         if (!xen_initial_domain())
 424                 return -ENODEV;
 425
 426         /* unregister the stub which only used to reserve driver space */
 427         xen_stub_processor_exit();
 428
 429         result = acpi_bus_register_driver(&xen_acpi_processor_driver);
 430         if (result < 0) {
 431                 xen_stub_processor_init();
 432                 return result;
 433         }
 434
 435         acpi_processor_install_hotplug_notify();
 436         return 0;
 437 }
 438
 439 static void __exit xen_acpi_processor_exit(void)
 440 {
 441         if (!xen_initial_domain())
 442                 return;
 443
 444         acpi_processor_uninstall_hotplug_notify();
 445
 446         acpi_bus_unregister_driver(&xen_acpi_processor_driver);
 447
 448         /*
 449          * stub reserve space again to prevent any chance of native
 450          * driver loading.
 451          */
 452         xen_stub_processor_init();
 453         return;
 454 }
 455
 456 module_init(xen_acpi_processor_init);
 457 module_exit(xen_acpi_processor_exit);
 458 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
 459 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
 460 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
 461 MODULE_LICENSE("GPL");