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