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