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