drivers/idle/intel_idle.c

   1 /*
   2  * intel_idle.c - native hardware idle loop for modern Intel processors
   3  *
   4  * Copyright (c) 2010, Intel Corporation.
   5  * Len Brown <len.brown@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 /*
  22  * intel_idle is a cpuidle driver that loads on specific Intel processors
  23  * in lieu of the legacy ACPI processor_idle driver.  The intent is to
  24  * make Linux more efficient on these processors, as intel_idle knows
  25  * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
  26  */
  27
  28 /*
  29  * Design Assumptions
  30  *
  31  * All CPUs have same idle states as boot CPU
  32  *
  33  * Chipset BM_STS (bus master status) bit is a NOP
  34  *      for preventing entry into deep C-stats
  35  */
  36
  37 /*
  38  * Known limitations
  39  *
  40  * The driver currently initializes for_each_online_cpu() upon modprobe.
  41  * It it unaware of subsequent processors hot-added to the system.
  42  * This means that if you boot with maxcpus=n and later online
  43  * processors above n, those processors will use C1 only.
  44  *
  45  * ACPI has a .suspend hack to turn off deep c-statees during suspend
  46  * to avoid complications with the lapic timer workaround.
  47  * Have not seen issues with suspend, but may need same workaround here.
  48  *
  49  * There is currently no kernel-based automatic probing/loading mechanism
  50  * if the driver is built as a module.
  51  */
  52
  53 /* un-comment DEBUG to enable pr_debug() statements */
  54 #define DEBUG
  55
  56 #include <linux/kernel.h>
  57 #include <linux/cpuidle.h>
  58 #include <linux/clockchips.h>
  59 #include <trace/events/power.h>
  60 #include <linux/sched.h>
  61 #include <linux/notifier.h>
  62 #include <linux/cpu.h>
  63 #include <linux/module.h>
  64 #include <asm/cpu_device_id.h>
  65 #include <asm/mwait.h>
  66 #include <asm/msr.h>
  67
  68 #define INTEL_IDLE_VERSION "0.4"
  69 #define PREFIX "intel_idle: "
  70
  71 static struct cpuidle_driver intel_idle_driver = {
  72         .name = "intel_idle",
  73         .owner = THIS_MODULE,
  74         .en_core_tk_irqen = 1,
  75 };
  76 /* intel_idle.max_cstate=0 disables driver */
  77 static int max_cstate = CPUIDLE_STATE_MAX - 1;
  78
  79 static unsigned int mwait_substates;
  80
  81 #define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
  82 /* Reliable LAPIC Timer States, bit 1 for C1 etc.  */
  83 static unsigned int lapic_timer_reliable_states = (1 << 1);      /* Default to only C1 */
  84
  85 struct idle_cpu {
  86         struct cpuidle_state *state_table;
  87
  88         /*
  89          * Hardware C-state auto-demotion may not always be optimal.
  90          * Indicate which enable bits to clear here.
  91          */
  92         unsigned long auto_demotion_disable_flags;
  93         bool disable_promotion_to_c1e;
  94 };
  95
  96 static const struct idle_cpu *icpu;
  97 static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
  98 static int intel_idle(struct cpuidle_device *dev,
  99                         struct cpuidle_driver *drv, int index);
 100 static int intel_idle_cpu_init(int cpu);
 101
 102 static struct cpuidle_state *cpuidle_state_table;
 103
 104 /*
 105  * Set this flag for states where the HW flushes the TLB for us
 106  * and so we don't need cross-calls to keep it consistent.
 107  * If this flag is set, SW flushes the TLB, so even if the
 108  * HW doesn't do the flushing, this flag is safe to use.
 109  */
 110 #define CPUIDLE_FLAG_TLB_FLUSHED        0x10000
 111
 112 /*
 113  * MWAIT takes an 8-bit "hint" in EAX "suggesting"
 114  * the C-state (top nibble) and sub-state (bottom nibble)
 115  * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
 116  *
 117  * We store the hint at the top of our "flags" for each state.
 118  */
 119 #define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)
 120 #define MWAIT2flg(eax) ((eax & 0xFF) << 24)
 121
 122 /*
 123  * States are indexed by the cstate number,
 124  * which is also the index into the MWAIT hint array.
 125  * Thus C0 is a dummy.
 126  */
 127 static struct cpuidle_state nehalem_cstates[CPUIDLE_STATE_MAX] = {
 128         {
 129                 .name = "C1-NHM",
 130                 .desc = "MWAIT 0x00",
 131                 .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TIME_VALID,
 132                 .exit_latency = 3,
 133                 .target_residency = 6,
 134                 .enter = &intel_idle },
 135         {
 136                 .name = "C1E-NHM",
 137                 .desc = "MWAIT 0x01",
 138                 .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_TIME_VALID,
 139                 .exit_latency = 10,
 140                 .target_residency = 20,
 141                 .enter = &intel_idle },
 142         {
 143                 .name = "C3-NHM",
 144                 .desc = "MWAIT 0x10",
 145                 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 146                 .exit_latency = 20,
 147                 .target_residency = 80,
 148                 .enter = &intel_idle },
 149         {
 150                 .name = "C6-NHM",
 151                 .desc = "MWAIT 0x20",
 152                 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 153                 .exit_latency = 200,
 154                 .target_residency = 800,
 155                 .enter = &intel_idle },
 156         {
 157                 .enter = NULL }
 158 };
 159
 160 static struct cpuidle_state snb_cstates[CPUIDLE_STATE_MAX] = {
 161         {
 162                 .name = "C1-SNB",
 163                 .desc = "MWAIT 0x00",
 164                 .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TIME_VALID,
 165                 .exit_latency = 2,
 166                 .target_residency = 2,
 167                 .enter = &intel_idle },
 168         {
 169                 .name = "C1E-SNB",
 170                 .desc = "MWAIT 0x01",
 171                 .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_TIME_VALID,
 172                 .exit_latency = 10,
 173                 .target_residency = 20,
 174                 .enter = &intel_idle },
 175         {
 176                 .name = "C3-SNB",
 177                 .desc = "MWAIT 0x10",
 178                 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 179                 .exit_latency = 80,
 180                 .target_residency = 211,
 181                 .enter = &intel_idle },
 182         {
 183                 .name = "C6-SNB",
 184                 .desc = "MWAIT 0x20",
 185                 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 186                 .exit_latency = 104,
 187                 .target_residency = 345,
 188                 .enter = &intel_idle },
 189         {
 190                 .name = "C7-SNB",
 191                 .desc = "MWAIT 0x30",
 192                 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 193                 .exit_latency = 109,
 194                 .target_residency = 345,
 195                 .enter = &intel_idle },
 196         {
 197                 .enter = NULL }
 198 };
 199
 200 static struct cpuidle_state ivb_cstates[CPUIDLE_STATE_MAX] = {
 201         {
 202                 .name = "C1-IVB",
 203                 .desc = "MWAIT 0x00",
 204                 .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TIME_VALID,
 205                 .exit_latency = 1,
 206                 .target_residency = 1,
 207                 .enter = &intel_idle },
 208         {
 209                 .name = "C1E-IVB",
 210                 .desc = "MWAIT 0x01",
 211                 .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_TIME_VALID,
 212                 .exit_latency = 10,
 213                 .target_residency = 20,
 214                 .enter = &intel_idle },
 215         {
 216                 .name = "C3-IVB",
 217                 .desc = "MWAIT 0x10",
 218                 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 219                 .exit_latency = 59,
 220                 .target_residency = 156,
 221                 .enter = &intel_idle },
 222         {
 223                 .name = "C6-IVB",
 224                 .desc = "MWAIT 0x20",
 225                 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 226                 .exit_latency = 80,
 227                 .target_residency = 300,
 228                 .enter = &intel_idle },
 229         {
 230                 .name = "C7-IVB",
 231                 .desc = "MWAIT 0x30",
 232                 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 233                 .exit_latency = 87,
 234                 .target_residency = 300,
 235                 .enter = &intel_idle },
 236         {
 237                 .enter = NULL }
 238 };
 239
 240 static struct cpuidle_state hsw_cstates[CPUIDLE_STATE_MAX] = {
 241         {
 242                 .name = "C1-HSW",
 243                 .desc = "MWAIT 0x00",
 244                 .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TIME_VALID,
 245                 .exit_latency = 2,
 246                 .target_residency = 2,
 247                 .enter = &intel_idle },
 248         {
 249                 .name = "C1E-HSW",
 250                 .desc = "MWAIT 0x01",
 251                 .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_TIME_VALID,
 252                 .exit_latency = 10,
 253                 .target_residency = 20,
 254                 .enter = &intel_idle },
 255         {
 256                 .name = "C3-HSW",
 257                 .desc = "MWAIT 0x10",
 258                 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 259                 .exit_latency = 33,
 260                 .target_residency = 100,
 261                 .enter = &intel_idle },
 262         {
 263                 .name = "C6-HSW",
 264                 .desc = "MWAIT 0x20",
 265                 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 266                 .exit_latency = 133,
 267                 .target_residency = 400,
 268                 .enter = &intel_idle },
 269         {
 270                 .name = "C7s-HSW",
 271                 .desc = "MWAIT 0x32",
 272                 .flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 273                 .exit_latency = 166,
 274                 .target_residency = 500,
 275                 .enter = &intel_idle },
 276         {
 277                 .enter = NULL }
 278 };
 279
 280 static struct cpuidle_state atom_cstates[CPUIDLE_STATE_MAX] = {
 281         {
 282                 .name = "C1E-ATM",
 283                 .desc = "MWAIT 0x00",
 284                 .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TIME_VALID,
 285                 .exit_latency = 10,
 286                 .target_residency = 20,
 287                 .enter = &intel_idle },
 288         {
 289                 .name = "C2-ATM",
 290                 .desc = "MWAIT 0x10",
 291                 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TIME_VALID,
 292                 .exit_latency = 20,
 293                 .target_residency = 80,
 294                 .enter = &intel_idle },
 295         {
 296                 .name = "C4-ATM",
 297                 .desc = "MWAIT 0x30",
 298                 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 299                 .exit_latency = 100,
 300                 .target_residency = 400,
 301                 .enter = &intel_idle },
 302         {
 303                 .name = "C6-ATM",
 304                 .desc = "MWAIT 0x52",
 305                 .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
 306                 .exit_latency = 140,
 307                 .target_residency = 560,
 308                 .enter = &intel_idle },
 309         {
 310                 .enter = NULL }
 311 };
 312
 313 /**
 314  * intel_idle
 315  * @dev: cpuidle_device
 316  * @drv: cpuidle driver
 317  * @index: index of cpuidle state
 318  *
 319  * Must be called under local_irq_disable().
 320  */
 321 static int intel_idle(struct cpuidle_device *dev,
 322                 struct cpuidle_driver *drv, int index)
 323 {
 324         unsigned long ecx = 1; /* break on interrupt flag */
 325         struct cpuidle_state *state = &drv->states[index];
 326         unsigned long eax = flg2MWAIT(state->flags);
 327         unsigned int cstate;
 328         int cpu = smp_processor_id();
 329
 330         cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
 331
 332         /*
 333          * leave_mm() to avoid costly and often unnecessary wakeups
 334          * for flushing the user TLB's associated with the active mm.
 335          */
 336         if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
 337                 leave_mm(cpu);
 338
 339         if (!(lapic_timer_reliable_states & (1 << (cstate))))
 340                 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
 341
 342         stop_critical_timings();
 343         if (!need_resched()) {
 344
 345                 __monitor((void *)&current_thread_info()->flags, 0, 0);
 346                 smp_mb();
 347                 if (!need_resched())
 348                         __mwait(eax, ecx);
 349         }
 350
 351         start_critical_timings();
 352
 353         if (!(lapic_timer_reliable_states & (1 << (cstate))))
 354                 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
 355
 356         return index;
 357 }
 358
 359 static void __setup_broadcast_timer(void *arg)
 360 {
 361         unsigned long reason = (unsigned long)arg;
 362         int cpu = smp_processor_id();
 363
 364         reason = reason ?
 365                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
 366
 367         clockevents_notify(reason, &cpu);
 368 }
 369
 370 static int cpu_hotplug_notify(struct notifier_block *n,
 371                               unsigned long action, void *hcpu)
 372 {
 373         int hotcpu = (unsigned long)hcpu;
 374         struct cpuidle_device *dev;
 375
 376         switch (action & 0xf) {
 377         case CPU_ONLINE:
 378
 379                 if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
 380                         smp_call_function_single(hotcpu, __setup_broadcast_timer,
 381                                                  (void *)true, 1);
 382
 383                 /*
 384                  * Some systems can hotplug a cpu at runtime after
 385                  * the kernel has booted, we have to initialize the
 386                  * driver in this case
 387                  */
 388                 dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);
 389                 if (!dev->registered)
 390                         intel_idle_cpu_init(hotcpu);
 391
 392                 break;
 393         }
 394         return NOTIFY_OK;
 395 }
 396
 397 static struct notifier_block cpu_hotplug_notifier = {
 398         .notifier_call = cpu_hotplug_notify,
 399 };
 400
 401 static void auto_demotion_disable(void *dummy)
 402 {
 403         unsigned long long msr_bits;
 404
 405         rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
 406         msr_bits &= ~(icpu->auto_demotion_disable_flags);
 407         wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
 408 }
 409 static void c1e_promotion_disable(void *dummy)
 410 {
 411         unsigned long long msr_bits;
 412
 413         rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
 414         msr_bits &= ~0x2;
 415         wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
 416 }
 417
 418 static const struct idle_cpu idle_cpu_nehalem = {
 419         .state_table = nehalem_cstates,
 420         .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
 421         .disable_promotion_to_c1e = true,
 422 };
 423
 424 static const struct idle_cpu idle_cpu_atom = {
 425         .state_table = atom_cstates,
 426 };
 427
 428 static const struct idle_cpu idle_cpu_lincroft = {
 429         .state_table = atom_cstates,
 430         .auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE,
 431 };
 432
 433 static const struct idle_cpu idle_cpu_snb = {
 434         .state_table = snb_cstates,
 435         .disable_promotion_to_c1e = true,
 436 };
 437
 438 static const struct idle_cpu idle_cpu_ivb = {
 439         .state_table = ivb_cstates,
 440         .disable_promotion_to_c1e = true,
 441 };
 442
 443 static const struct idle_cpu idle_cpu_hsw = {
 444         .state_table = hsw_cstates,
 445         .disable_promotion_to_c1e = true,
 446 };
 447
 448 #define ICPU(model, cpu) \
 449         { X86_VENDOR_INTEL, 6, model, X86_FEATURE_MWAIT, (unsigned long)&cpu }
 450
 451 static const struct x86_cpu_id intel_idle_ids[] = {
 452         ICPU(0x1a, idle_cpu_nehalem),
 453         ICPU(0x1e, idle_cpu_nehalem),
 454         ICPU(0x1f, idle_cpu_nehalem),
 455         ICPU(0x25, idle_cpu_nehalem),
 456         ICPU(0x2c, idle_cpu_nehalem),
 457         ICPU(0x2e, idle_cpu_nehalem),
 458         ICPU(0x1c, idle_cpu_atom),
 459         ICPU(0x26, idle_cpu_lincroft),
 460         ICPU(0x2f, idle_cpu_nehalem),
 461         ICPU(0x2a, idle_cpu_snb),
 462         ICPU(0x2d, idle_cpu_snb),
 463         ICPU(0x3a, idle_cpu_ivb),
 464         ICPU(0x3e, idle_cpu_ivb),
 465         ICPU(0x3c, idle_cpu_hsw),
 466         ICPU(0x3f, idle_cpu_hsw),
 467         ICPU(0x45, idle_cpu_hsw),
 468         ICPU(0x46, idle_cpu_hsw),
 469         {}
 470 };
 471 MODULE_DEVICE_TABLE(x86cpu, intel_idle_ids);
 472
 473 /*
 474  * intel_idle_probe()
 475  */
 476 static int intel_idle_probe(void)
 477 {
 478         unsigned int eax, ebx, ecx;
 479         const struct x86_cpu_id *id;
 480
 481         if (max_cstate == 0) {
 482                 pr_debug(PREFIX "disabled\n");
 483                 return -EPERM;
 484         }
 485
 486         id = x86_match_cpu(intel_idle_ids);
 487         if (!id) {
 488                 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
 489                     boot_cpu_data.x86 == 6)
 490                         pr_debug(PREFIX "does not run on family %d model %d\n",
 491                                 boot_cpu_data.x86, boot_cpu_data.x86_model);
 492                 return -ENODEV;
 493         }
 494
 495         if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
 496                 return -ENODEV;
 497
 498         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
 499
 500         if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
 501             !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
 502             !mwait_substates)
 503                         return -ENODEV;
 504
 505         pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);
 506
 507         icpu = (const struct idle_cpu *)id->driver_data;
 508         cpuidle_state_table = icpu->state_table;
 509
 510         if (boot_cpu_has(X86_FEATURE_ARAT))     /* Always Reliable APIC Timer */
 511                 lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
 512         else
 513                 on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
 514
 515         pr_debug(PREFIX "v" INTEL_IDLE_VERSION
 516                 " model 0x%X\n", boot_cpu_data.x86_model);
 517
 518         pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
 519                 lapic_timer_reliable_states);
 520         return 0;
 521 }
 522
 523 /*
 524  * intel_idle_cpuidle_devices_uninit()
 525  * unregister, free cpuidle_devices
 526  */
 527 static void intel_idle_cpuidle_devices_uninit(void)
 528 {
 529         int i;
 530         struct cpuidle_device *dev;
 531
 532         for_each_online_cpu(i) {
 533                 dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
 534                 cpuidle_unregister_device(dev);
 535         }
 536
 537         free_percpu(intel_idle_cpuidle_devices);
 538         return;
 539 }
 540 /*
 541  * intel_idle_cpuidle_driver_init()
 542  * allocate, initialize cpuidle_states
 543  */
 544 static int intel_idle_cpuidle_driver_init(void)
 545 {
 546         int cstate;
 547         struct cpuidle_driver *drv = &intel_idle_driver;
 548
 549         drv->state_count = 1;
 550
 551         for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
 552                 int num_substates, mwait_hint, mwait_cstate, mwait_substate;
 553
 554                 if (cpuidle_state_table[cstate].enter == NULL)
 555                         break;
 556
 557                 if (cstate + 1 > max_cstate) {
 558                         printk(PREFIX "max_cstate %d reached\n",
 559                                 max_cstate);
 560                         break;
 561                 }
 562
 563                 mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
 564                 mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);
 565                 mwait_substate = MWAIT_HINT2SUBSTATE(mwait_hint);
 566
 567                 /* does the state exist in CPUID.MWAIT? */
 568                 num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
 569                                         & MWAIT_SUBSTATE_MASK;
 570
 571                 /* if sub-state in table is not enumerated by CPUID */
 572                 if ((mwait_substate + 1) > num_substates)
 573                         continue;
 574
 575                 if (((mwait_cstate + 1) > 2) &&
 576                         !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 577                         mark_tsc_unstable("TSC halts in idle"
 578                                         " states deeper than C2");
 579
 580                 drv->states[drv->state_count] = /* structure copy */
 581                         cpuidle_state_table[cstate];
 582
 583                 drv->state_count += 1;
 584         }
 585
 586         if (icpu->auto_demotion_disable_flags)
 587                 on_each_cpu(auto_demotion_disable, NULL, 1);
 588
 589         if (icpu->disable_promotion_to_c1e)     /* each-cpu is redundant */
 590                 on_each_cpu(c1e_promotion_disable, NULL, 1);
 591
 592         return 0;
 593 }
 594
 595
 596 /*
 597  * intel_idle_cpu_init()
 598  * allocate, initialize, register cpuidle_devices
 599  * @cpu: cpu/core to initialize
 600  */
 601 static int intel_idle_cpu_init(int cpu)
 602 {
 603         int cstate;
 604         struct cpuidle_device *dev;
 605
 606         dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
 607
 608         dev->state_count = 1;
 609
 610         for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
 611                 int num_substates, mwait_hint, mwait_cstate, mwait_substate;
 612
 613                 if (cpuidle_state_table[cstate].enter == NULL)
 614                         continue;
 615
 616                 if (cstate + 1 > max_cstate) {
 617                         printk(PREFIX "max_cstate %d reached\n", max_cstate);
 618                         break;
 619                 }
 620
 621                 mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
 622                 mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);
 623                 mwait_substate = MWAIT_HINT2SUBSTATE(mwait_hint);
 624
 625                 /* does the state exist in CPUID.MWAIT? */
 626                 num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
 627                                         & MWAIT_SUBSTATE_MASK;
 628
 629                 /* if sub-state in table is not enumerated by CPUID */
 630                 if ((mwait_substate + 1) > num_substates)
 631                         continue;
 632
 633                 dev->state_count += 1;
 634         }
 635
 636         dev->cpu = cpu;
 637
 638         if (cpuidle_register_device(dev)) {
 639                 pr_debug(PREFIX "cpuidle_register_device %d failed!\n", cpu);
 640                 intel_idle_cpuidle_devices_uninit();
 641                 return -EIO;
 642         }
 643
 644         if (icpu->auto_demotion_disable_flags)
 645                 smp_call_function_single(cpu, auto_demotion_disable, NULL, 1);
 646
 647         return 0;
 648 }
 649
 650 static int __init intel_idle_init(void)
 651 {
 652         int retval, i;
 653
 654         /* Do not load intel_idle at all for now if idle= is passed */
 655         if (boot_option_idle_override != IDLE_NO_OVERRIDE)
 656                 return -ENODEV;
 657
 658         retval = intel_idle_probe();
 659         if (retval)
 660                 return retval;
 661
 662         intel_idle_cpuidle_driver_init();
 663         retval = cpuidle_register_driver(&intel_idle_driver);
 664         if (retval) {
 665                 struct cpuidle_driver *drv = cpuidle_get_driver();
 666                 printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
 667                         drv ? drv->name : "none");
 668                 return retval;
 669         }
 670
 671         intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
 672         if (intel_idle_cpuidle_devices == NULL)
 673                 return -ENOMEM;
 674
 675         for_each_online_cpu(i) {
 676                 retval = intel_idle_cpu_init(i);
 677                 if (retval) {
 678                         cpuidle_unregister_driver(&intel_idle_driver);
 679                         return retval;
 680                 }
 681         }
 682         register_cpu_notifier(&cpu_hotplug_notifier);
 683
 684         return 0;
 685 }
 686
 687 static void __exit intel_idle_exit(void)
 688 {
 689         intel_idle_cpuidle_devices_uninit();
 690         cpuidle_unregister_driver(&intel_idle_driver);
 691
 692
 693         if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
 694                 on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
 695         unregister_cpu_notifier(&cpu_hotplug_notifier);
 696
 697         return;
 698 }
 699
 700 module_init(intel_idle_init);
 701 module_exit(intel_idle_exit);
 702
 703 module_param(max_cstate, int, 0444);
 704
 705 MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
 706 MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
 707 MODULE_LICENSE("GPL");