drivers/xen/xen-acpi-processor.c

   1 /*
   2  * Copyright 2012 by Oracle Inc
   3  * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
   4  *
   5  * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
   6  * so many thanks go to Kevin Tian <kevin.tian@intel.com>
   7  * and Yu Ke <ke.yu@intel.com>.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms and conditions of the GNU General Public License,
  11  * version 2, as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  */
  19
  20 #include <linux/cpumask.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/freezer.h>
  23 #include <linux/kernel.h>
  24 #include <linux/kthread.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <acpi/acpi_bus.h>
  29 #include <acpi/acpi_drivers.h>
  30 #include <acpi/processor.h>
  31
  32 #include <xen/xen.h>
  33 #include <xen/interface/platform.h>
  34 #include <asm/xen/hypercall.h>
  35
  36 #define DRV_NAME "xen-acpi-processor: "
  37
  38 static int no_hypercall;
  39 MODULE_PARM_DESC(off, "Inhibit the hypercall.");
  40 module_param_named(off, no_hypercall, int, 0400);
  41
  42 /*
  43  * Note: Do not convert the acpi_id* below to cpumask_var_t or use cpumask_bit
  44  * - as those shrink to nr_cpu_bits (which is dependent on possible_cpu), which
  45  * can be less than what we want to put in. Instead use the 'nr_acpi_bits'
  46  * which is dynamically computed based on the MADT or x2APIC table.
  47  */
  48 static unsigned int nr_acpi_bits;
  49 /* Mutex to protect the acpi_ids_done - for CPU hotplug use. */
  50 static DEFINE_MUTEX(acpi_ids_mutex);
  51 /* Which ACPI ID we have processed from 'struct acpi_processor'. */
  52 static unsigned long *acpi_ids_done;
  53 /* Which ACPI ID exist in the SSDT/DSDT processor definitions. */
  54 static unsigned long __initdata *acpi_id_present;
  55 /* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
  56 static unsigned long __initdata *acpi_id_cst_present;
  57
  58 static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
  59 {
  60         struct xen_platform_op op = {
  61                 .cmd                    = XENPF_set_processor_pminfo,
  62                 .interface_version      = XENPF_INTERFACE_VERSION,
  63                 .u.set_pminfo.id        = _pr->acpi_id,
  64                 .u.set_pminfo.type      = XEN_PM_CX,
  65         };
  66         struct xen_processor_cx *dst_cx, *dst_cx_states = NULL;
  67         struct acpi_processor_cx *cx;
  68         unsigned int i, ok;
  69         int ret = 0;
  70
  71         dst_cx_states = kcalloc(_pr->power.count,
  72                                 sizeof(struct xen_processor_cx), GFP_KERNEL);
  73         if (!dst_cx_states)
  74                 return -ENOMEM;
  75
  76         for (ok = 0, i = 1; i <= _pr->power.count; i++) {
  77                 cx = &_pr->power.states[i];
  78                 if (!cx->valid)
  79                         continue;
  80
  81                 dst_cx = &(dst_cx_states[ok++]);
  82
  83                 dst_cx->reg.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
  84                 if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
  85                         dst_cx->reg.bit_width = 8;
  86                         dst_cx->reg.bit_offset = 0;
  87                         dst_cx->reg.access_size = 1;
  88                 } else {
  89                         dst_cx->reg.space_id = ACPI_ADR_SPACE_FIXED_HARDWARE;
  90                         if (cx->entry_method == ACPI_CSTATE_FFH) {
  91                                 /* NATIVE_CSTATE_BEYOND_HALT */
  92                                 dst_cx->reg.bit_offset = 2;
  93                                 dst_cx->reg.bit_width = 1; /* VENDOR_INTEL */
  94                         }
  95                         dst_cx->reg.access_size = 0;
  96                 }
  97                 dst_cx->reg.address = cx->address;
  98
  99                 dst_cx->type = cx->type;
 100                 dst_cx->latency = cx->latency;
 101
 102                 dst_cx->dpcnt = 0;
 103                 set_xen_guest_handle(dst_cx->dp, NULL);
 104         }
 105         if (!ok) {
 106                 pr_debug(DRV_NAME "No _Cx for ACPI CPU %u\n", _pr->acpi_id);
 107                 kfree(dst_cx_states);
 108                 return -EINVAL;
 109         }
 110         op.u.set_pminfo.power.count = ok;
 111         op.u.set_pminfo.power.flags.bm_control = _pr->flags.bm_control;
 112         op.u.set_pminfo.power.flags.bm_check = _pr->flags.bm_check;
 113         op.u.set_pminfo.power.flags.has_cst = _pr->flags.has_cst;
 114         op.u.set_pminfo.power.flags.power_setup_done =
 115                 _pr->flags.power_setup_done;
 116
 117         set_xen_guest_handle(op.u.set_pminfo.power.states, dst_cx_states);
 118
 119         if (!no_hypercall)
 120                 ret = HYPERVISOR_dom0_op(&op);
 121
 122         if (!ret) {
 123                 pr_debug("ACPI CPU%u - C-states uploaded.\n", _pr->acpi_id);
 124                 for (i = 1; i <= _pr->power.count; i++) {
 125                         cx = &_pr->power.states[i];
 126                         if (!cx->valid)
 127                                 continue;
 128                         pr_debug("     C%d: %s %d uS\n",
 129                                  cx->type, cx->desc, (u32)cx->latency);
 130                 }
 131         } else if (ret != -EINVAL)
 132                 /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
 133                  * table is referencing a non-existing CPU - which can happen
 134                  * with broken ACPI tables. */
 135                 pr_err(DRV_NAME "(CX): Hypervisor error (%d) for ACPI CPU%u\n",
 136                        ret, _pr->acpi_id);
 137
 138         kfree(dst_cx_states);
 139
 140         return ret;
 141 }
 142 static struct xen_processor_px *
 143 xen_copy_pss_data(struct acpi_processor *_pr,
 144                   struct xen_processor_performance *dst_perf)
 145 {
 146         struct xen_processor_px *dst_states = NULL;
 147         unsigned int i;
 148
 149         BUILD_BUG_ON(sizeof(struct xen_processor_px) !=
 150                      sizeof(struct acpi_processor_px));
 151
 152         dst_states = kcalloc(_pr->performance->state_count,
 153                              sizeof(struct xen_processor_px), GFP_KERNEL);
 154         if (!dst_states)
 155                 return ERR_PTR(-ENOMEM);
 156
 157         dst_perf->state_count = _pr->performance->state_count;
 158         for (i = 0; i < _pr->performance->state_count; i++) {
 159                 /* Fortunatly for us, they are both the same size */
 160                 memcpy(&(dst_states[i]), &(_pr->performance->states[i]),
 161                        sizeof(struct acpi_processor_px));
 162         }
 163         return dst_states;
 164 }
 165 static int xen_copy_psd_data(struct acpi_processor *_pr,
 166                              struct xen_processor_performance *dst)
 167 {
 168         struct acpi_psd_package *pdomain;
 169
 170         BUILD_BUG_ON(sizeof(struct xen_psd_package) !=
 171                      sizeof(struct acpi_psd_package));
 172
 173         /* This information is enumerated only if acpi_processor_preregister_performance
 174          * has been called.
 175          */
 176         dst->shared_type = _pr->performance->shared_type;
 177
 178         pdomain = &(_pr->performance->domain_info);
 179
 180         /* 'acpi_processor_preregister_performance' does not parse if the
 181          * num_processors <= 1, but Xen still requires it. Do it manually here.
 182          */
 183         if (pdomain->num_processors <= 1) {
 184                 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 185                         dst->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 186                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 187                         dst->shared_type = CPUFREQ_SHARED_TYPE_HW;
 188                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 189                         dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 190
 191         }
 192         memcpy(&(dst->domain_info), pdomain, sizeof(struct acpi_psd_package));
 193         return 0;
 194 }
 195 static int xen_copy_pct_data(struct acpi_pct_register *pct,
 196                              struct xen_pct_register *dst_pct)
 197 {
 198         /* It would be nice if you could just do 'memcpy(pct, dst_pct') but
 199          * sadly the Xen structure did not have the proper padding so the
 200          * descriptor field takes two (dst_pct) bytes instead of one (pct).
 201          */
 202         dst_pct->descriptor = pct->descriptor;
 203         dst_pct->length = pct->length;
 204         dst_pct->space_id = pct->space_id;
 205         dst_pct->bit_width = pct->bit_width;
 206         dst_pct->bit_offset = pct->bit_offset;
 207         dst_pct->reserved = pct->reserved;
 208         dst_pct->address = pct->address;
 209         return 0;
 210 }
 211 static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
 212 {
 213         int ret = 0;
 214         struct xen_platform_op op = {
 215                 .cmd                    = XENPF_set_processor_pminfo,
 216                 .interface_version      = XENPF_INTERFACE_VERSION,
 217                 .u.set_pminfo.id        = _pr->acpi_id,
 218                 .u.set_pminfo.type      = XEN_PM_PX,
 219         };
 220         struct xen_processor_performance *dst_perf;
 221         struct xen_processor_px *dst_states = NULL;
 222
 223         dst_perf = &op.u.set_pminfo.perf;
 224
 225         dst_perf->platform_limit = _pr->performance_platform_limit;
 226         dst_perf->flags |= XEN_PX_PPC;
 227         xen_copy_pct_data(&(_pr->performance->control_register),
 228                           &dst_perf->control_register);
 229         xen_copy_pct_data(&(_pr->performance->status_register),
 230                           &dst_perf->status_register);
 231         dst_perf->flags |= XEN_PX_PCT;
 232         dst_states = xen_copy_pss_data(_pr, dst_perf);
 233         if (!IS_ERR_OR_NULL(dst_states)) {
 234                 set_xen_guest_handle(dst_perf->states, dst_states);
 235                 dst_perf->flags |= XEN_PX_PSS;
 236         }
 237         if (!xen_copy_psd_data(_pr, dst_perf))
 238                 dst_perf->flags |= XEN_PX_PSD;
 239
 240         if (dst_perf->flags != (XEN_PX_PSD | XEN_PX_PSS | XEN_PX_PCT | XEN_PX_PPC)) {
 241                 pr_warn(DRV_NAME "ACPI CPU%u missing some P-state data (%x), skipping.\n",
 242                         _pr->acpi_id, dst_perf->flags);
 243                 ret = -ENODEV;
 244                 goto err_free;
 245         }
 246
 247         if (!no_hypercall)
 248                 ret = HYPERVISOR_dom0_op(&op);
 249
 250         if (!ret) {
 251                 struct acpi_processor_performance *perf;
 252                 unsigned int i;
 253
 254                 perf = _pr->performance;
 255                 pr_debug("ACPI CPU%u - P-states uploaded.\n", _pr->acpi_id);
 256                 for (i = 0; i < perf->state_count; i++) {
 257                         pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
 258                         (i == perf->state ? '*' : ' '), i,
 259                         (u32) perf->states[i].core_frequency,
 260                         (u32) perf->states[i].power,
 261                         (u32) perf->states[i].transition_latency);
 262                 }
 263         } else if (ret != -EINVAL)
 264                 /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
 265                  * table is referencing a non-existing CPU - which can happen
 266                  * with broken ACPI tables. */
 267                 pr_warn(DRV_NAME "(_PXX): Hypervisor error (%d) for ACPI CPU%u\n",
 268                        ret, _pr->acpi_id);
 269 err_free:
 270         if (!IS_ERR_OR_NULL(dst_states))
 271                 kfree(dst_states);
 272
 273         return ret;
 274 }
 275 static int upload_pm_data(struct acpi_processor *_pr)
 276 {
 277         int err = 0;
 278
 279         mutex_lock(&acpi_ids_mutex);
 280         if (__test_and_set_bit(_pr->acpi_id, acpi_ids_done)) {
 281                 mutex_unlock(&acpi_ids_mutex);
 282                 return -EBUSY;
 283         }
 284         if (_pr->flags.power)
 285                 err = push_cxx_to_hypervisor(_pr);
 286
 287         if (_pr->performance && _pr->performance->states)
 288                 err |= push_pxx_to_hypervisor(_pr);
 289
 290         mutex_unlock(&acpi_ids_mutex);
 291         return err;
 292 }
 293 static unsigned int __init get_max_acpi_id(void)
 294 {
 295         struct xenpf_pcpuinfo *info;
 296         struct xen_platform_op op = {
 297                 .cmd = XENPF_get_cpuinfo,
 298                 .interface_version = XENPF_INTERFACE_VERSION,
 299         };
 300         int ret = 0;
 301         unsigned int i, last_cpu, max_acpi_id = 0;
 302
 303         info = &op.u.pcpu_info;
 304         info->xen_cpuid = 0;
 305
 306         ret = HYPERVISOR_dom0_op(&op);
 307         if (ret)
 308                 return NR_CPUS;
 309
 310         /* The max_present is the same irregardless of the xen_cpuid */
 311         last_cpu = op.u.pcpu_info.max_present;
 312         for (i = 0; i <= last_cpu; i++) {
 313                 info->xen_cpuid = i;
 314                 ret = HYPERVISOR_dom0_op(&op);
 315                 if (ret)
 316                         continue;
 317                 max_acpi_id = max(info->acpi_id, max_acpi_id);
 318         }
 319         max_acpi_id *= 2; /* Slack for CPU hotplug support. */
 320         pr_debug(DRV_NAME "Max ACPI ID: %u\n", max_acpi_id);
 321         return max_acpi_id;
 322 }
 323 /*
 324  * The read_acpi_id and check_acpi_ids are there to support the Xen
 325  * oddity of virtual CPUs != physical CPUs in the initial domain.
 326  * The user can supply 'xen_max_vcpus=X' on the Xen hypervisor line
 327  * which will band the amount of CPUs the initial domain can see.
 328  * In general that is OK, except it plays havoc with any of the
 329  * for_each_[present|online]_cpu macros which are banded to the virtual
 330  * CPU amount.
 331  */
 332 static acpi_status __init
 333 read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
 334 {
 335         u32 acpi_id;
 336         acpi_status status;
 337         acpi_object_type acpi_type;
 338         unsigned long long tmp;
 339         union acpi_object object = { 0 };
 340         struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
 341         acpi_io_address pblk = 0;
 342
 343         status = acpi_get_type(handle, &acpi_type);
 344         if (ACPI_FAILURE(status))
 345                 return AE_OK;
 346
 347         switch (acpi_type) {
 348         case ACPI_TYPE_PROCESSOR:
 349                 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
 350                 if (ACPI_FAILURE(status))
 351                         return AE_OK;
 352                 acpi_id = object.processor.proc_id;
 353                 pblk = object.processor.pblk_address;
 354                 break;
 355         case ACPI_TYPE_DEVICE:
 356                 status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
 357                 if (ACPI_FAILURE(status))
 358                         return AE_OK;
 359                 acpi_id = tmp;
 360                 break;
 361         default:
 362                 return AE_OK;
 363         }
 364         /* There are more ACPI Processor objects than in x2APIC or MADT.
 365          * This can happen with incorrect ACPI SSDT declerations. */
 366         if (acpi_id > nr_acpi_bits) {
 367                 pr_debug(DRV_NAME "We only have %u, trying to set %u\n",
 368                          nr_acpi_bits, acpi_id);
 369                 return AE_OK;
 370         }
 371         /* OK, There is a ACPI Processor object */
 372         __set_bit(acpi_id, acpi_id_present);
 373
 374         pr_debug(DRV_NAME "ACPI CPU%u w/ PBLK:0x%lx\n", acpi_id,
 375                  (unsigned long)pblk);
 376
 377         status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
 378         if (ACPI_FAILURE(status)) {
 379                 if (!pblk)
 380                         return AE_OK;
 381         }
 382         /* .. and it has a C-state */
 383         __set_bit(acpi_id, acpi_id_cst_present);
 384
 385         return AE_OK;
 386 }
 387 static int __init check_acpi_ids(struct acpi_processor *pr_backup)
 388 {
 389
 390         if (!pr_backup)
 391                 return -ENODEV;
 392
 393         /* All online CPUs have been processed at this stage. Now verify
 394          * whether in fact "online CPUs" == physical CPUs.
 395          */
 396         acpi_id_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
 397         if (!acpi_id_present)
 398                 return -ENOMEM;
 399
 400         acpi_id_cst_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
 401         if (!acpi_id_cst_present) {
 402                 kfree(acpi_id_present);
 403                 return -ENOMEM;
 404         }
 405
 406         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 407                             ACPI_UINT32_MAX,
 408                             read_acpi_id, NULL, NULL, NULL);
 409         acpi_get_devices("ACPI0007", read_acpi_id, NULL, NULL);
 410
 411         if (!bitmap_equal(acpi_id_present, acpi_ids_done, nr_acpi_bits)) {
 412                 unsigned int i;
 413                 for_each_set_bit(i, acpi_id_present, nr_acpi_bits) {
 414                         pr_backup->acpi_id = i;
 415                         /* Mask out C-states if there are no _CST or PBLK */
 416                         pr_backup->flags.power = test_bit(i, acpi_id_cst_present);
 417                         (void)upload_pm_data(pr_backup);
 418                 }
 419         }
 420         kfree(acpi_id_present);
 421         acpi_id_present = NULL;
 422         kfree(acpi_id_cst_present);
 423         acpi_id_cst_present = NULL;
 424         return 0;
 425 }
 426 static int __init check_prereq(void)
 427 {
 428         struct cpuinfo_x86 *c = &cpu_data(0);
 429
 430         if (!xen_initial_domain())
 431                 return -ENODEV;
 432
 433         if (!acpi_gbl_FADT.smi_command)
 434                 return -ENODEV;
 435
 436         if (c->x86_vendor == X86_VENDOR_INTEL) {
 437                 if (!cpu_has(c, X86_FEATURE_EST))
 438                         return -ENODEV;
 439
 440                 return 0;
 441         }
 442         if (c->x86_vendor == X86_VENDOR_AMD) {
 443                 /* Copied from powernow-k8.h, can't include ../cpufreq/powernow
 444                  * as we get compile warnings for the static functions.
 445                  */
 446 #define CPUID_FREQ_VOLT_CAPABILITIES    0x80000007
 447 #define USE_HW_PSTATE                   0x00000080
 448                 u32 eax, ebx, ecx, edx;
 449                 cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
 450                 if ((edx & USE_HW_PSTATE) != USE_HW_PSTATE)
 451                         return -ENODEV;
 452                 return 0;
 453         }
 454         return -ENODEV;
 455 }
 456 /* acpi_perf_data is a pointer to percpu data. */
 457 static struct acpi_processor_performance __percpu *acpi_perf_data;
 458
 459 static void free_acpi_perf_data(void)
 460 {
 461         unsigned int i;
 462
 463         /* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
 464         for_each_possible_cpu(i)
 465                 free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
 466                                  ->shared_cpu_map);
 467         free_percpu(acpi_perf_data);
 468 }
 469
 470 static int __init xen_acpi_processor_init(void)
 471 {
 472         struct acpi_processor *pr_backup = NULL;
 473         unsigned int i;
 474         int rc = check_prereq();
 475
 476         if (rc)
 477                 return rc;
 478
 479         nr_acpi_bits = get_max_acpi_id() + 1;
 480         acpi_ids_done = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
 481         if (!acpi_ids_done)
 482                 return -ENOMEM;
 483
 484         acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
 485         if (!acpi_perf_data) {
 486                 pr_debug(DRV_NAME "Memory allocation error for acpi_perf_data.\n");
 487                 kfree(acpi_ids_done);
 488                 return -ENOMEM;
 489         }
 490         for_each_possible_cpu(i) {
 491                 if (!zalloc_cpumask_var_node(
 492                         &per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
 493                         GFP_KERNEL, cpu_to_node(i))) {
 494                         rc = -ENOMEM;
 495                         goto err_out;
 496                 }
 497         }
 498
 499         /* Do initialization in ACPI core. It is OK to fail here. */
 500         (void)acpi_processor_preregister_performance(acpi_perf_data);
 501
 502         for_each_possible_cpu(i) {
 503                 struct acpi_processor_performance *perf;
 504
 505                 perf = per_cpu_ptr(acpi_perf_data, i);
 506                 rc = acpi_processor_register_performance(perf, i);
 507                 if (rc)
 508                         goto err_out;
 509         }
 510         rc = acpi_processor_notify_smm(THIS_MODULE);
 511         if (rc)
 512                 goto err_unregister;
 513
 514         for_each_possible_cpu(i) {
 515                 struct acpi_processor *_pr;
 516                 _pr = per_cpu(processors, i /* APIC ID */);
 517                 if (!_pr)
 518                         continue;
 519
 520                 if (!pr_backup) {
 521                         pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
 522                         if (pr_backup)
 523                                 memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
 524                 }
 525                 (void)upload_pm_data(_pr);
 526         }
 527         rc = check_acpi_ids(pr_backup);
 528
 529         kfree(pr_backup);
 530         pr_backup = NULL;
 531
 532         if (rc)
 533                 goto err_unregister;
 534
 535         return 0;
 536 err_unregister:
 537         for_each_possible_cpu(i) {
 538                 struct acpi_processor_performance *perf;
 539                 perf = per_cpu_ptr(acpi_perf_data, i);
 540                 acpi_processor_unregister_performance(perf, i);
 541         }
 542 err_out:
 543         /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
 544         free_acpi_perf_data();
 545         kfree(acpi_ids_done);
 546         return rc;
 547 }
 548 static void __exit xen_acpi_processor_exit(void)
 549 {
 550         int i;
 551
 552         kfree(acpi_ids_done);
 553         for_each_possible_cpu(i) {
 554                 struct acpi_processor_performance *perf;
 555                 perf = per_cpu_ptr(acpi_perf_data, i);
 556                 acpi_processor_unregister_performance(perf, i);
 557         }
 558         free_acpi_perf_data();
 559 }
 560
 561 MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
 562 MODULE_DESCRIPTION("Xen ACPI Processor P-states (and Cx) driver which uploads PM data to Xen hypervisor");
 563 MODULE_LICENSE("GPL");
 564
 565 /* We want to be loaded before the CPU freq scaling drivers are loaded.
 566  * They are loaded in late_initcall. */
 567 device_initcall(xen_acpi_processor_init);
 568 module_exit(xen_acpi_processor_exit);