processor_idle.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * processor_idle - idle state submodule to the ACPI processor driver
   4 *
   5 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7 *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
   8 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   9 *  			- Added processor hotplug support
  10 *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  11 *  			- Added support for C3 on SMP
  12 */
  13#define pr_fmt(fmt) "ACPI: " fmt
  14
  15#include <linux/module.h>
  16#include <linux/acpi.h>
  17#include <linux/dmi.h>
  18#include <linux/sched.h>       /* need_resched() */
  19#include <linux/tick.h>
  20#include <linux/cpuidle.h>
  21#include <linux/cpu.h>
  22#include <linux/minmax.h>
  23#include <linux/perf_event.h>
  24#include <acpi/processor.h>
  25#include <linux/context_tracking.h>
  26
  27#include "internal.h"
  28
  29/*
  30 * Include the apic definitions for x86 to have the APIC timer related defines
  31 * available also for UP (on SMP it gets magically included via linux/smp.h).
  32 * asm/acpi.h is not an option, as it would require more include magic. Also
  33 * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  34 */
  35#ifdef CONFIG_X86
  36#include <asm/apic.h>
  37#include <asm/cpu.h>
  38#endif
  39
  40#define ACPI_IDLE_STATE_START	(IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  41
  42static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  43module_param(max_cstate, uint, 0400);
  44static bool nocst __read_mostly;
  45module_param(nocst, bool, 0400);
  46static bool bm_check_disable __read_mostly;
  47module_param(bm_check_disable, bool, 0400);
  48
  49static unsigned int latency_factor __read_mostly = 2;
  50module_param(latency_factor, uint, 0644);
  51
  52static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  53
  54struct cpuidle_driver acpi_idle_driver = {
  55	.name =		"acpi_idle",
  56	.owner =	THIS_MODULE,
  57};
  58
  59#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  60void acpi_idle_rescan_dead_smt_siblings(void)
  61{
  62	if (cpuidle_get_driver() == &acpi_idle_driver)
  63		arch_cpu_rescan_dead_smt_siblings();
  64}
  65
  66static
  67DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  68
  69static int disabled_by_idle_boot_param(void)
  70{
  71	return boot_option_idle_override == IDLE_POLL ||
  72		boot_option_idle_override == IDLE_HALT;
  73}
  74
  75/*
  76 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  77 * For now disable this. Probably a bug somewhere else.
  78 *
  79 * To skip this limit, boot/load with a large max_cstate limit.
  80 */
  81static int set_max_cstate(const struct dmi_system_id *id)
  82{
  83	if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  84		return 0;
  85
  86	pr_notice("%s detected - limiting to C%ld max_cstate."
  87		  " Override with \"processor.max_cstate=%d\"\n", id->ident,
  88		  (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  89
  90	max_cstate = (long)id->driver_data;
  91
  92	return 0;
  93}
  94
  95static const struct dmi_system_id processor_power_dmi_table[] = {
  96	{ set_max_cstate, "Clevo 5600D", {
  97	  DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  98	  DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  99	 (void *)2},
 100	{ set_max_cstate, "Pavilion zv5000", {
 101	  DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 102	  DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
 103	 (void *)1},
 104	{ set_max_cstate, "Asus L8400B", {
 105	  DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 106	  DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
 107	 (void *)1},
 108	{},
 109};
 110
 111
 112/*
 113 * Callers should disable interrupts before the call and enable
 114 * interrupts after return.
 115 */
 116static void __cpuidle acpi_safe_halt(void)
 117{
 118	if (!tif_need_resched()) {
 119		raw_safe_halt();
 120		raw_local_irq_disable();
 121	}
 122}
 123
 124#ifdef ARCH_APICTIMER_STOPS_ON_C3
 125
 126/*
 127 * Some BIOS implementations switch to C3 in the published C2 state.
 128 * This seems to be a common problem on AMD boxen, but other vendors
 129 * are affected too. We pick the most conservative approach: we assume
 130 * that the local APIC stops in both C2 and C3.
 131 */
 132static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 133				   struct acpi_processor_cx *cx)
 134{
 135	struct acpi_processor_power *pwr = &pr->power;
 136	u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 137
 138	if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 139		return;
 140
 141	if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 142		type = ACPI_STATE_C1;
 143
 144	/*
 145	 * Check, if one of the previous states already marked the lapic
 146	 * unstable
 147	 */
 148	if (pwr->timer_broadcast_on_state < state)
 149		return;
 150
 151	if (cx->type >= type)
 152		pr->power.timer_broadcast_on_state = state;
 153}
 154
 155static void __lapic_timer_propagate_broadcast(void *arg)
 156{
 157	struct acpi_processor *pr = arg;
 158
 159	if (pr->power.timer_broadcast_on_state < INT_MAX)
 160		tick_broadcast_enable();
 161	else
 162		tick_broadcast_disable();
 163}
 164
 165static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 166{
 167	smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 168				 (void *)pr, 1);
 169}
 170
 171/* Power(C) State timer broadcast control */
 172static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 173					struct acpi_processor_cx *cx)
 174{
 175	return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 176}
 177
 178#else
 179
 180static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 181				   struct acpi_processor_cx *cstate) { }
 182static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 183
 184static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 185					struct acpi_processor_cx *cx)
 186{
 187	return false;
 188}
 189
 190#endif
 191
 192#if defined(CONFIG_X86)
 193static void tsc_check_state(int state)
 194{
 195	switch (boot_cpu_data.x86_vendor) {
 196	case X86_VENDOR_HYGON:
 197	case X86_VENDOR_AMD:
 198	case X86_VENDOR_INTEL:
 199	case X86_VENDOR_CENTAUR:
 200	case X86_VENDOR_ZHAOXIN:
 201		/*
 202		 * AMD Fam10h TSC will tick in all
 203		 * C/P/S0/S1 states when this bit is set.
 204		 */
 205		if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 206			return;
 207		fallthrough;
 208	default:
 209		/* TSC could halt in idle, so notify users */
 210		if (state > ACPI_STATE_C1)
 211			mark_tsc_unstable("TSC halts in idle");
 212	}
 213}
 214#else
 215static void tsc_check_state(int state) { return; }
 216#endif
 217
 218static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 219{
 220
 221	if (!pr->pblk)
 222		return -ENODEV;
 223
 224	/* if info is obtained from pblk/fadt, type equals state */
 225	pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 226	pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 227
 228#ifndef CONFIG_HOTPLUG_CPU
 229	/*
 230	 * Check for P_LVL2_UP flag before entering C2 and above on
 231	 * an SMP system.
 232	 */
 233	if ((num_online_cpus() > 1) &&
 234	    !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 235		return -ENODEV;
 236#endif
 237
 238	/* determine C2 and C3 address from pblk */
 239	pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 240	pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 241
 242	/* determine latencies from FADT */
 243	pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 244	pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 245
 246	/*
 247	 * FADT specified C2 latency must be less than or equal to
 248	 * 100 microseconds.
 249	 */
 250	if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 251		acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 252				  acpi_gbl_FADT.c2_latency);
 253		/* invalidate C2 */
 254		pr->power.states[ACPI_STATE_C2].address = 0;
 255	}
 256
 257	/*
 258	 * FADT supplied C3 latency must be less than or equal to
 259	 * 1000 microseconds.
 260	 */
 261	if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 262		acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 263				  acpi_gbl_FADT.c3_latency);
 264		/* invalidate C3 */
 265		pr->power.states[ACPI_STATE_C3].address = 0;
 266	}
 267
 268	acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 269			  pr->power.states[ACPI_STATE_C2].address,
 270			  pr->power.states[ACPI_STATE_C3].address);
 271
 272	snprintf(pr->power.states[ACPI_STATE_C2].desc,
 273			 ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 274			 pr->power.states[ACPI_STATE_C2].address);
 275	snprintf(pr->power.states[ACPI_STATE_C3].desc,
 276			 ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 277			 pr->power.states[ACPI_STATE_C3].address);
 278
 279	if (!pr->power.states[ACPI_STATE_C2].address &&
 280	    !pr->power.states[ACPI_STATE_C3].address)
 281		return -ENODEV;
 282
 283	return 0;
 284}
 285
 286static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 287{
 288	if (!pr->power.states[ACPI_STATE_C1].valid) {
 289		/* set the first C-State to C1 */
 290		/* all processors need to support C1 */
 291		pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 292		pr->power.states[ACPI_STATE_C1].valid = 1;
 293		pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 294
 295		snprintf(pr->power.states[ACPI_STATE_C1].desc,
 296			 ACPI_CX_DESC_LEN, "ACPI HLT");
 297	}
 298	/* the C0 state only exists as a filler in our array */
 299	pr->power.states[ACPI_STATE_C0].valid = 1;
 300	return 0;
 301}
 302
 303static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 304{
 305	int ret;
 306
 307	if (nocst)
 308		return -ENODEV;
 309
 310	ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 311	if (ret)
 312		return ret;
 313
 314	if (!pr->power.count)
 315		return -EFAULT;
 316
 317	pr->flags.has_cst = 1;
 318	return 0;
 319}
 320
 321static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 322					   struct acpi_processor_cx *cx)
 323{
 324	static int bm_check_flag = -1;
 325	static int bm_control_flag = -1;
 326
 327
 328	if (!cx->address)
 329		return;
 330
 331	/*
 332	 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 333	 * DMA transfers are used by any ISA device to avoid livelock.
 334	 * Note that we could disable Type-F DMA (as recommended by
 335	 * the erratum), but this is known to disrupt certain ISA
 336	 * devices thus we take the conservative approach.
 337	 */
 338	if (errata.piix4.fdma) {
 339		acpi_handle_debug(pr->handle,
 340				  "C3 not supported on PIIX4 with Type-F DMA\n");
 341		return;
 342	}
 343
 344	/* All the logic here assumes flags.bm_check is same across all CPUs */
 345	if (bm_check_flag == -1) {
 346		/* Determine whether bm_check is needed based on CPU  */
 347		acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 348		bm_check_flag = pr->flags.bm_check;
 349		bm_control_flag = pr->flags.bm_control;
 350	} else {
 351		pr->flags.bm_check = bm_check_flag;
 352		pr->flags.bm_control = bm_control_flag;
 353	}
 354
 355	if (pr->flags.bm_check) {
 356		if (!pr->flags.bm_control) {
 357			if (pr->flags.has_cst != 1) {
 358				/* bus mastering control is necessary */
 359				acpi_handle_debug(pr->handle,
 360						  "C3 support requires BM control\n");
 361				return;
 362			} else {
 363				/* Here we enter C3 without bus mastering */
 364				acpi_handle_debug(pr->handle,
 365						  "C3 support without BM control\n");
 366			}
 367		}
 368	} else {
 369		/*
 370		 * WBINVD should be set in fadt, for C3 state to be
 371		 * supported on when bm_check is not required.
 372		 */
 373		if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 374			acpi_handle_debug(pr->handle,
 375					  "Cache invalidation should work properly"
 376					  " for C3 to be enabled on SMP systems\n");
 377			return;
 378		}
 379	}
 380
 381	/*
 382	 * Otherwise we've met all of our C3 requirements.
 383	 * Normalize the C3 latency to expidite policy.  Enable
 384	 * checking of bus mastering status (bm_check) so we can
 385	 * use this in our C3 policy
 386	 */
 387	cx->valid = 1;
 388
 389	/*
 390	 * On older chipsets, BM_RLD needs to be set
 391	 * in order for Bus Master activity to wake the
 392	 * system from C3.  Newer chipsets handle DMA
 393	 * during C3 automatically and BM_RLD is a NOP.
 394	 * In either case, the proper way to
 395	 * handle BM_RLD is to set it and leave it set.
 396	 */
 397	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 398}
 399
 400static void acpi_cst_latency_sort(struct acpi_processor_cx *states, size_t length)
 401{
 402	int i, j, k;
 403
 404	for (i = 1; i < length; i++) {
 405		if (!states[i].valid)
 406			continue;
 407
 408		for (j = i - 1, k = i; j >= 0; j--) {
 409			if (!states[j].valid)
 410				continue;
 411
 412			if (states[j].latency > states[k].latency)
 413				swap(states[j].latency, states[k].latency);
 414
 415			k = j;
 416		}
 417	}
 418}
 419
 420static int acpi_processor_power_verify(struct acpi_processor *pr)
 421{
 422	unsigned int i;
 423	unsigned int working = 0;
 424	unsigned int last_latency = 0;
 425	unsigned int last_type = 0;
 426	bool buggy_latency = false;
 427
 428	pr->power.timer_broadcast_on_state = INT_MAX;
 429
 430	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 431		struct acpi_processor_cx *cx = &pr->power.states[i];
 432
 433		switch (cx->type) {
 434		case ACPI_STATE_C1:
 435			cx->valid = 1;
 436			break;
 437
 438		case ACPI_STATE_C2:
 439			if (!cx->address)
 440				break;
 441			cx->valid = 1;
 442			break;
 443
 444		case ACPI_STATE_C3:
 445			acpi_processor_power_verify_c3(pr, cx);
 446			break;
 447		}
 448		if (!cx->valid)
 449			continue;
 450		if (cx->type >= last_type && cx->latency < last_latency)
 451			buggy_latency = true;
 452		last_latency = cx->latency;
 453		last_type = cx->type;
 454
 455		lapic_timer_check_state(i, pr, cx);
 456		tsc_check_state(cx->type);
 457		working++;
 458	}
 459
 460	if (buggy_latency) {
 461		pr_notice("FW issue: working around C-state latencies out of order\n");
 462		acpi_cst_latency_sort(&pr->power.states[1], max_cstate);
 463	}
 464
 465	lapic_timer_propagate_broadcast(pr);
 466
 467	return working;
 468}
 469
 470static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 471{
 472	int result;
 473
 474	/* NOTE: the idle thread may not be running while calling
 475	 * this function */
 476
 477	/* Zero initialize all the C-states info. */
 478	memset(pr->power.states, 0, sizeof(pr->power.states));
 479
 480	result = acpi_processor_get_power_info_cst(pr);
 481	if (result == -ENODEV)
 482		result = acpi_processor_get_power_info_fadt(pr);
 483
 484	if (result)
 485		return result;
 486
 487	acpi_processor_get_power_info_default(pr);
 488
 489	pr->power.count = acpi_processor_power_verify(pr);
 490	pr->flags.power = 1;
 491
 492	return 0;
 493}
 494
 495/**
 496 * acpi_idle_bm_check - checks if bus master activity was detected
 497 */
 498static int acpi_idle_bm_check(void)
 499{
 500	u32 bm_status = 0;
 501
 502	if (bm_check_disable)
 503		return 0;
 504
 505	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 506	if (bm_status)
 507		acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 508	/*
 509	 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 510	 * the true state of bus mastering activity; forcing us to
 511	 * manually check the BMIDEA bit of each IDE channel.
 512	 */
 513	else if (errata.piix4.bmisx) {
 514		if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 515		    || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 516			bm_status = 1;
 517	}
 518	return bm_status;
 519}
 520
 521static __cpuidle void io_idle(unsigned long addr)
 522{
 523	/* IO port based C-state */
 524	inb(addr);
 525
 526#ifdef	CONFIG_X86
 527	/* No delay is needed if we are in guest */
 528	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 529		return;
 530	/*
 531	 * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
 532	 * not this code.  Assume that any Intel systems using this
 533	 * are ancient and may need the dummy wait.  This also assumes
 534	 * that the motivating chipset issue was Intel-only.
 535	 */
 536	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 537		return;
 538#endif
 539	/*
 540	 * Dummy wait op - must do something useless after P_LVL2 read
 541	 * because chipsets cannot guarantee that STPCLK# signal gets
 542	 * asserted in time to freeze execution properly
 543	 *
 544	 * This workaround has been in place since the original ACPI
 545	 * implementation was merged, circa 2002.
 546	 *
 547	 * If a profile is pointing to this instruction, please first
 548	 * consider moving your system to a more modern idle
 549	 * mechanism.
 550	 */
 551	inl(acpi_gbl_FADT.xpm_timer_block.address);
 552}
 553
 554/**
 555 * acpi_idle_do_entry - enter idle state using the appropriate method
 556 * @cx: cstate data
 557 *
 558 * Caller disables interrupt before call and enables interrupt after return.
 559 */
 560static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 561{
 562	perf_lopwr_cb(true);
 563
 564	if (cx->entry_method == ACPI_CSTATE_FFH) {
 565		/* Call into architectural FFH based C-state */
 566		acpi_processor_ffh_cstate_enter(cx);
 567	} else if (cx->entry_method == ACPI_CSTATE_HALT) {
 568		acpi_safe_halt();
 569	} else {
 570		io_idle(cx->address);
 571	}
 572
 573	perf_lopwr_cb(false);
 574}
 575
 576/**
 577 * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 578 * @dev: the target CPU
 579 * @index: the index of suggested state
 580 */
 581static void acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 582{
 583	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 584
 585	ACPI_FLUSH_CPU_CACHE();
 586
 587	while (1) {
 588
 589		if (cx->entry_method == ACPI_CSTATE_HALT)
 590			raw_safe_halt();
 591		else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 592			io_idle(cx->address);
 593		} else if (cx->entry_method == ACPI_CSTATE_FFH) {
 594			acpi_processor_ffh_play_dead(cx);
 595		} else
 596			return;
 597	}
 598}
 599
 600static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 601{
 602	return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 603		!(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 604}
 605
 606static int c3_cpu_count;
 607static DEFINE_RAW_SPINLOCK(c3_lock);
 608
 609/**
 610 * acpi_idle_enter_bm - enters C3 with proper BM handling
 611 * @drv: cpuidle driver
 612 * @pr: Target processor
 613 * @cx: Target state context
 614 * @index: index of target state
 615 */
 616static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
 617			       struct acpi_processor *pr,
 618			       struct acpi_processor_cx *cx,
 619			       int index)
 620{
 621	static struct acpi_processor_cx safe_cx = {
 622		.entry_method = ACPI_CSTATE_HALT,
 623	};
 624
 625	/*
 626	 * disable bus master
 627	 * bm_check implies we need ARB_DIS
 628	 * bm_control implies whether we can do ARB_DIS
 629	 *
 630	 * That leaves a case where bm_check is set and bm_control is not set.
 631	 * In that case we cannot do much, we enter C3 without doing anything.
 632	 */
 633	bool dis_bm = pr->flags.bm_control;
 634
 635	instrumentation_begin();
 636
 637	/* If we can skip BM, demote to a safe state. */
 638	if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 639		dis_bm = false;
 640		index = drv->safe_state_index;
 641		if (index >= 0) {
 642			cx = this_cpu_read(acpi_cstate[index]);
 643		} else {
 644			cx = &safe_cx;
 645			index = -EBUSY;
 646		}
 647	}
 648
 649	if (dis_bm) {
 650		raw_spin_lock(&c3_lock);
 651		c3_cpu_count++;
 652		/* Disable bus master arbitration when all CPUs are in C3 */
 653		if (c3_cpu_count == num_online_cpus())
 654			acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 655		raw_spin_unlock(&c3_lock);
 656	}
 657
 658	ct_cpuidle_enter();
 659
 660	acpi_idle_do_entry(cx);
 661
 662	ct_cpuidle_exit();
 663
 664	/* Re-enable bus master arbitration */
 665	if (dis_bm) {
 666		raw_spin_lock(&c3_lock);
 667		acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 668		c3_cpu_count--;
 669		raw_spin_unlock(&c3_lock);
 670	}
 671
 672	instrumentation_end();
 673
 674	return index;
 675}
 676
 677static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
 678			   struct cpuidle_driver *drv, int index)
 679{
 680	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 681	struct acpi_processor *pr;
 682
 683	pr = __this_cpu_read(processors);
 684	if (unlikely(!pr))
 685		return -EINVAL;
 686
 687	if (cx->type != ACPI_STATE_C1) {
 688		if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 689			return acpi_idle_enter_bm(drv, pr, cx, index);
 690
 691		/* C2 to C1 demotion. */
 692		if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 693			index = ACPI_IDLE_STATE_START;
 694			cx = per_cpu(acpi_cstate[index], dev->cpu);
 695		}
 696	}
 697
 698	if (cx->type == ACPI_STATE_C3)
 699		ACPI_FLUSH_CPU_CACHE();
 700
 701	acpi_idle_do_entry(cx);
 702
 703	return index;
 704}
 705
 706static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 707				  struct cpuidle_driver *drv, int index)
 708{
 709	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 710
 711	if (cx->type == ACPI_STATE_C3) {
 712		struct acpi_processor *pr = __this_cpu_read(processors);
 713
 714		if (unlikely(!pr))
 715			return 0;
 716
 717		if (pr->flags.bm_check) {
 718			u8 bm_sts_skip = cx->bm_sts_skip;
 719
 720			/* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 721			cx->bm_sts_skip = 1;
 722			acpi_idle_enter_bm(drv, pr, cx, index);
 723			cx->bm_sts_skip = bm_sts_skip;
 724
 725			return 0;
 726		} else {
 727			ACPI_FLUSH_CPU_CACHE();
 728		}
 729	}
 730	acpi_idle_do_entry(cx);
 731
 732	return 0;
 733}
 734
 735static void acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 736					    struct cpuidle_device *dev)
 737{
 738	int i, count = ACPI_IDLE_STATE_START;
 739	struct acpi_processor_cx *cx;
 740
 741	if (max_cstate == 0)
 742		max_cstate = 1;
 743
 744	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 745		cx = &pr->power.states[i];
 746
 747		if (!cx->valid)
 748			continue;
 749
 750		per_cpu(acpi_cstate[count], dev->cpu) = cx;
 751
 752		count++;
 753		if (count == CPUIDLE_STATE_MAX)
 754			break;
 755	}
 756}
 757
 758static void acpi_processor_setup_cstates(struct acpi_processor *pr)
 759{
 760	int i, count;
 761	struct acpi_processor_cx *cx;
 762	struct cpuidle_state *state;
 763	struct cpuidle_driver *drv = &acpi_idle_driver;
 764
 765	if (max_cstate == 0)
 766		max_cstate = 1;
 767
 768	if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 769		cpuidle_poll_state_init(drv);
 770		count = 1;
 771	} else {
 772		count = 0;
 773	}
 774
 775	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 776		cx = &pr->power.states[i];
 777
 778		if (!cx->valid)
 779			continue;
 780
 781		state = &drv->states[count];
 782		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 783		strscpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 784		state->exit_latency = cx->latency;
 785		state->target_residency = cx->latency * latency_factor;
 786		state->enter = acpi_idle_enter;
 787
 788		state->flags = 0;
 789
 790		state->enter_dead = acpi_idle_play_dead;
 791
 792		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2)
 793			drv->safe_state_index = count;
 794
 795		/*
 796		 * Halt-induced C1 is not good for ->enter_s2idle, because it
 797		 * re-enables interrupts on exit.  Moreover, C1 is generally not
 798		 * particularly interesting from the suspend-to-idle angle, so
 799		 * avoid C1 and the situations in which we may need to fall back
 800		 * to it altogether.
 801		 */
 802		if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
 803			state->enter_s2idle = acpi_idle_enter_s2idle;
 804
 805		if (lapic_timer_needs_broadcast(pr, cx))
 806			state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 807
 808		if (cx->type == ACPI_STATE_C3) {
 809			state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 810			if (pr->flags.bm_check)
 811				state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 812		}
 813
 814		count++;
 815		if (count == CPUIDLE_STATE_MAX)
 816			break;
 817	}
 818
 819	drv->state_count = count;
 820}
 821
 822static inline void acpi_processor_cstate_first_run_checks(void)
 823{
 824	static int first_run;
 825
 826	if (first_run)
 827		return;
 828	dmi_check_system(processor_power_dmi_table);
 829	max_cstate = acpi_processor_cstate_check(max_cstate);
 830	if (max_cstate < ACPI_C_STATES_MAX)
 831		pr_notice("processor limited to max C-state %d\n", max_cstate);
 832
 833	first_run++;
 834
 835	if (nocst)
 836		return;
 837
 838	acpi_processor_claim_cst_control();
 839}
 840#else
 841
 842static inline int disabled_by_idle_boot_param(void) { return 0; }
 843static inline void acpi_processor_cstate_first_run_checks(void) { }
 844static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 845{
 846	return -ENODEV;
 847}
 848
 849static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 850					   struct cpuidle_device *dev)
 851{
 852	return -EINVAL;
 853}
 854
 855static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 856{
 857	return -EINVAL;
 858}
 859
 860#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 861
 862struct acpi_lpi_states_array {
 863	unsigned int size;
 864	unsigned int composite_states_size;
 865	struct acpi_lpi_state *entries;
 866	struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
 867};
 868
 869static int obj_get_integer(union acpi_object *obj, u32 *value)
 870{
 871	if (obj->type != ACPI_TYPE_INTEGER)
 872		return -EINVAL;
 873
 874	*value = obj->integer.value;
 875	return 0;
 876}
 877
 878static int acpi_processor_evaluate_lpi(acpi_handle handle,
 879				       struct acpi_lpi_states_array *info)
 880{
 881	acpi_status status;
 882	int ret = 0;
 883	int pkg_count, state_idx = 1, loop;
 884	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 885	union acpi_object *lpi_data;
 886	struct acpi_lpi_state *lpi_state;
 887
 888	status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
 889	if (ACPI_FAILURE(status)) {
 890		acpi_handle_debug(handle, "No _LPI, giving up\n");
 891		return -ENODEV;
 892	}
 893
 894	lpi_data = buffer.pointer;
 895
 896	/* There must be at least 4 elements = 3 elements + 1 package */
 897	if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
 898	    lpi_data->package.count < 4) {
 899		pr_debug("not enough elements in _LPI\n");
 900		ret = -ENODATA;
 901		goto end;
 902	}
 903
 904	pkg_count = lpi_data->package.elements[2].integer.value;
 905
 906	/* Validate number of power states. */
 907	if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
 908		pr_debug("count given by _LPI is not valid\n");
 909		ret = -ENODATA;
 910		goto end;
 911	}
 912
 913	lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
 914	if (!lpi_state) {
 915		ret = -ENOMEM;
 916		goto end;
 917	}
 918
 919	info->size = pkg_count;
 920	info->entries = lpi_state;
 921
 922	/* LPI States start at index 3 */
 923	for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
 924		union acpi_object *element, *pkg_elem, *obj;
 925
 926		element = &lpi_data->package.elements[loop];
 927		if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
 928			continue;
 929
 930		pkg_elem = element->package.elements;
 931
 932		obj = pkg_elem + 6;
 933		if (obj->type == ACPI_TYPE_BUFFER) {
 934			struct acpi_power_register *reg;
 935
 936			reg = (struct acpi_power_register *)obj->buffer.pointer;
 937			if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 938			    reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
 939				continue;
 940
 941			lpi_state->address = reg->address;
 942			lpi_state->entry_method =
 943				reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
 944				ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
 945		} else if (obj->type == ACPI_TYPE_INTEGER) {
 946			lpi_state->entry_method = ACPI_CSTATE_INTEGER;
 947			lpi_state->address = obj->integer.value;
 948		} else {
 949			continue;
 950		}
 951
 952		/* elements[7,8] skipped for now i.e. Residency/Usage counter*/
 953
 954		obj = pkg_elem + 9;
 955		if (obj->type == ACPI_TYPE_STRING)
 956			strscpy(lpi_state->desc, obj->string.pointer,
 957				ACPI_CX_DESC_LEN);
 958
 959		lpi_state->index = state_idx;
 960		if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
 961			pr_debug("No min. residency found, assuming 10 us\n");
 962			lpi_state->min_residency = 10;
 963		}
 964
 965		if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
 966			pr_debug("No wakeup residency found, assuming 10 us\n");
 967			lpi_state->wake_latency = 10;
 968		}
 969
 970		if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
 971			lpi_state->flags = 0;
 972
 973		if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
 974			lpi_state->arch_flags = 0;
 975
 976		if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
 977			lpi_state->res_cnt_freq = 1;
 978
 979		if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
 980			lpi_state->enable_parent_state = 0;
 981	}
 982
 983	acpi_handle_debug(handle, "Found %d power states\n", state_idx);
 984end:
 985	kfree(buffer.pointer);
 986	return ret;
 987}
 988
 989/**
 990 * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
 991 *
 992 * @local: local LPI state
 993 * @parent: parent LPI state
 994 * @result: composite LPI state
 995 */
 996static bool combine_lpi_states(struct acpi_lpi_state *local,
 997			       struct acpi_lpi_state *parent,
 998			       struct acpi_lpi_state *result)
 999{
1000	if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1001		if (!parent->address) /* 0 means autopromotable */
1002			return false;
1003		result->address = local->address + parent->address;
1004	} else {
1005		result->address = parent->address;
1006	}
1007
1008	result->min_residency = max(local->min_residency, parent->min_residency);
1009	result->wake_latency = local->wake_latency + parent->wake_latency;
1010	result->enable_parent_state = parent->enable_parent_state;
1011	result->entry_method = local->entry_method;
1012
1013	result->flags = parent->flags;
1014	result->arch_flags = parent->arch_flags;
1015	result->index = parent->index;
1016
1017	strscpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
1018	strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
1019	strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
1020	return true;
1021}
1022
1023#define ACPI_LPI_STATE_FLAGS_ENABLED			BIT(0)
1024
1025static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1026				  struct acpi_lpi_state *t)
1027{
1028	curr_level->composite_states[curr_level->composite_states_size++] = t;
1029}
1030
1031static unsigned int flatten_lpi_states(struct acpi_processor *pr,
1032				       unsigned int flat_state_cnt,
1033				       struct acpi_lpi_states_array *curr_level,
1034				       struct acpi_lpi_states_array *prev_level)
1035{
1036	int i, j, state_count = curr_level->size;
1037	struct acpi_lpi_state *p, *t = curr_level->entries;
1038
1039	curr_level->composite_states_size = 0;
1040	for (j = 0; j < state_count; j++, t++) {
1041		struct acpi_lpi_state *flpi;
1042
1043		if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1044			continue;
1045
1046		if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1047			pr_warn("Limiting number of LPI states to max (%d)\n",
1048				ACPI_PROCESSOR_MAX_POWER);
1049			pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1050			break;
1051		}
1052
1053		flpi = &pr->power.lpi_states[flat_state_cnt];
1054
1055		if (!prev_level) { /* leaf/processor node */
1056			memcpy(flpi, t, sizeof(*t));
1057			stash_composite_state(curr_level, flpi);
1058			flat_state_cnt++;
1059			continue;
1060		}
1061
1062		for (i = 0; i < prev_level->composite_states_size; i++) {
1063			p = prev_level->composite_states[i];
1064			if (t->index <= p->enable_parent_state &&
1065			    combine_lpi_states(p, t, flpi)) {
1066				stash_composite_state(curr_level, flpi);
1067				flat_state_cnt++;
1068				flpi++;
1069			}
1070		}
1071	}
1072
1073	kfree(curr_level->entries);
1074	return flat_state_cnt;
1075}
1076
1077int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1078{
1079	return -EOPNOTSUPP;
1080}
1081
1082static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1083{
1084	int ret, i;
1085	acpi_status status;
1086	acpi_handle handle = pr->handle, pr_ahandle;
1087	struct acpi_device *d = NULL;
1088	struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1089	unsigned int state_count;
1090
1091	/* make sure our architecture has support */
1092	ret = acpi_processor_ffh_lpi_probe(pr->id);
1093	if (ret == -EOPNOTSUPP)
1094		return ret;
1095
1096	if (!osc_pc_lpi_support_confirmed)
1097		return -EOPNOTSUPP;
1098
1099	if (!acpi_has_method(handle, "_LPI"))
1100		return -EINVAL;
1101
1102	prev = &info[0];
1103	curr = &info[1];
1104	handle = pr->handle;
1105	ret = acpi_processor_evaluate_lpi(handle, prev);
1106	if (ret)
1107		return ret;
1108	state_count = flatten_lpi_states(pr, 0, prev, NULL);
1109
1110	status = acpi_get_parent(handle, &pr_ahandle);
1111	while (ACPI_SUCCESS(status)) {
1112		d = acpi_fetch_acpi_dev(pr_ahandle);
1113		if (!d)
1114			break;
1115
1116		handle = pr_ahandle;
1117
1118		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
1119			break;
1120
1121		/* can be optional ? */
1122		if (!acpi_has_method(handle, "_LPI"))
1123			break;
1124
1125		ret = acpi_processor_evaluate_lpi(handle, curr);
1126		if (ret)
1127			break;
1128
1129		/* flatten all the LPI states in this level of hierarchy */
1130		state_count = flatten_lpi_states(pr, state_count, curr, prev);
1131
1132		tmp = prev, prev = curr, curr = tmp;
1133
1134		status = acpi_get_parent(handle, &pr_ahandle);
1135	}
1136
1137	/* reset the index after flattening */
1138	for (i = 0; i < state_count; i++)
1139		pr->power.lpi_states[i].index = i;
1140
1141	pr->power.count = state_count;
1142
1143	/* Tell driver that _LPI is supported. */
1144	pr->flags.has_lpi = 1;
1145	pr->flags.power = 1;
1146
1147	return 0;
1148}
1149
1150int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1151{
1152	return -ENODEV;
1153}
1154
1155/**
1156 * acpi_idle_lpi_enter - enters an ACPI any LPI state
1157 * @dev: the target CPU
1158 * @drv: cpuidle driver containing cpuidle state info
1159 * @index: index of target state
1160 *
1161 * Return: 0 for success or negative value for error
1162 */
1163static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1164			       struct cpuidle_driver *drv, int index)
1165{
1166	struct acpi_processor *pr;
1167	struct acpi_lpi_state *lpi;
1168
1169	pr = __this_cpu_read(processors);
1170
1171	if (unlikely(!pr))
1172		return -EINVAL;
1173
1174	lpi = &pr->power.lpi_states[index];
1175	if (lpi->entry_method == ACPI_CSTATE_FFH)
1176		return acpi_processor_ffh_lpi_enter(lpi);
1177
1178	return -EINVAL;
1179}
1180
1181static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1182{
1183	int i;
1184	struct acpi_lpi_state *lpi;
1185	struct cpuidle_state *state;
1186	struct cpuidle_driver *drv = &acpi_idle_driver;
1187
1188	if (!pr->flags.has_lpi)
1189		return -EOPNOTSUPP;
1190
1191	for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1192		lpi = &pr->power.lpi_states[i];
1193
1194		state = &drv->states[i];
1195		snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
1196		strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
1197		state->exit_latency = lpi->wake_latency;
1198		state->target_residency = lpi->min_residency;
1199		state->flags |= arch_get_idle_state_flags(lpi->arch_flags);
1200		if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
1201			state->flags |= CPUIDLE_FLAG_RCU_IDLE;
1202		state->enter = acpi_idle_lpi_enter;
1203		drv->safe_state_index = i;
1204	}
1205
1206	drv->state_count = i;
1207
1208	return 0;
1209}
1210
1211/**
1212 * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1213 * global state data i.e. idle routines
1214 *
1215 * @pr: the ACPI processor
1216 */
1217static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1218{
1219	int i;
1220	struct cpuidle_driver *drv = &acpi_idle_driver;
1221
1222	if (!pr->flags.power_setup_done || !pr->flags.power)
1223		return -EINVAL;
1224
1225	drv->safe_state_index = -1;
1226	for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1227		drv->states[i].name[0] = '\0';
1228		drv->states[i].desc[0] = '\0';
1229	}
1230
1231	if (pr->flags.has_lpi)
1232		return acpi_processor_setup_lpi_states(pr);
1233
1234	acpi_processor_setup_cstates(pr);
1235	return 0;
1236}
1237
1238/**
1239 * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1240 * device i.e. per-cpu data
1241 *
1242 * @pr: the ACPI processor
1243 * @dev : the cpuidle device
1244 */
1245static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1246					    struct cpuidle_device *dev)
1247{
1248	if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1249		return -EINVAL;
1250
1251	dev->cpu = pr->id;
1252	if (pr->flags.has_lpi)
1253		return acpi_processor_ffh_lpi_probe(pr->id);
1254
1255	acpi_processor_setup_cpuidle_cx(pr, dev);
1256	return 0;
1257}
1258
1259static int acpi_processor_get_power_info(struct acpi_processor *pr)
1260{
1261	int ret;
1262
1263	ret = acpi_processor_get_lpi_info(pr);
1264	if (ret)
1265		ret = acpi_processor_get_cstate_info(pr);
1266
1267	return ret;
1268}
1269
1270int acpi_processor_hotplug(struct acpi_processor *pr)
1271{
1272	int ret = 0;
1273	struct cpuidle_device *dev;
1274
1275	if (disabled_by_idle_boot_param())
1276		return 0;
1277
1278	if (!pr->flags.power_setup_done)
1279		return -ENODEV;
1280
1281	dev = per_cpu(acpi_cpuidle_device, pr->id);
1282	cpuidle_pause_and_lock();
1283	cpuidle_disable_device(dev);
1284	ret = acpi_processor_get_power_info(pr);
1285	if (!ret && pr->flags.power) {
1286		acpi_processor_setup_cpuidle_dev(pr, dev);
1287		ret = cpuidle_enable_device(dev);
1288	}
1289	cpuidle_resume_and_unlock();
1290
1291	return ret;
1292}
1293
1294int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1295{
1296	int cpu;
1297	struct acpi_processor *_pr;
1298	struct cpuidle_device *dev;
1299
1300	if (disabled_by_idle_boot_param())
1301		return 0;
1302
1303	if (!pr->flags.power_setup_done)
1304		return -ENODEV;
1305
1306	/*
1307	 * FIXME:  Design the ACPI notification to make it once per
1308	 * system instead of once per-cpu.  This condition is a hack
1309	 * to make the code that updates C-States be called once.
1310	 */
1311
1312	if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1313
1314		/* Protect against cpu-hotplug */
1315		cpus_read_lock();
1316		cpuidle_pause_and_lock();
1317
1318		/* Disable all cpuidle devices */
1319		for_each_online_cpu(cpu) {
1320			_pr = per_cpu(processors, cpu);
1321			if (!_pr || !_pr->flags.power_setup_done)
1322				continue;
1323			dev = per_cpu(acpi_cpuidle_device, cpu);
1324			cpuidle_disable_device(dev);
1325		}
1326
1327		/* Populate Updated C-state information */
1328		acpi_processor_get_power_info(pr);
1329		acpi_processor_setup_cpuidle_states(pr);
1330
1331		/* Enable all cpuidle devices */
1332		for_each_online_cpu(cpu) {
1333			_pr = per_cpu(processors, cpu);
1334			if (!_pr || !_pr->flags.power_setup_done)
1335				continue;
1336			acpi_processor_get_power_info(_pr);
1337			if (_pr->flags.power) {
1338				dev = per_cpu(acpi_cpuidle_device, cpu);
1339				acpi_processor_setup_cpuidle_dev(_pr, dev);
1340				cpuidle_enable_device(dev);
1341			}
1342		}
1343		cpuidle_resume_and_unlock();
1344		cpus_read_unlock();
1345	}
1346
1347	return 0;
1348}
1349
1350static int acpi_processor_registered;
1351
1352int acpi_processor_power_init(struct acpi_processor *pr)
1353{
1354	int retval;
1355	struct cpuidle_device *dev;
1356
1357	if (disabled_by_idle_boot_param())
1358		return 0;
1359
1360	acpi_processor_cstate_first_run_checks();
1361
1362	if (!acpi_processor_get_power_info(pr))
1363		pr->flags.power_setup_done = 1;
1364
1365	/*
1366	 * Install the idle handler if processor power management is supported.
1367	 * Note that we use previously set idle handler will be used on
1368	 * platforms that only support C1.
1369	 */
1370	if (pr->flags.power) {
1371		/* Register acpi_idle_driver if not already registered */
1372		if (!acpi_processor_registered) {
1373			acpi_processor_setup_cpuidle_states(pr);
1374			retval = cpuidle_register_driver(&acpi_idle_driver);
1375			if (retval)
1376				return retval;
1377			pr_debug("%s registered with cpuidle\n",
1378				 acpi_idle_driver.name);
1379		}
1380
1381		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1382		if (!dev)
1383			return -ENOMEM;
1384		per_cpu(acpi_cpuidle_device, pr->id) = dev;
1385
1386		acpi_processor_setup_cpuidle_dev(pr, dev);
1387
1388		/* Register per-cpu cpuidle_device. Cpuidle driver
1389		 * must already be registered before registering device
1390		 */
1391		retval = cpuidle_register_device(dev);
1392		if (retval) {
1393			if (acpi_processor_registered == 0)
1394				cpuidle_unregister_driver(&acpi_idle_driver);
1395
1396			per_cpu(acpi_cpuidle_device, pr->id) = NULL;
1397			kfree(dev);
1398			return retval;
1399		}
1400		acpi_processor_registered++;
1401	}
1402	return 0;
1403}
1404
1405int acpi_processor_power_exit(struct acpi_processor *pr)
1406{
1407	struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1408
1409	if (disabled_by_idle_boot_param())
1410		return 0;
1411
1412	if (pr->flags.power) {
1413		cpuidle_unregister_device(dev);
1414		acpi_processor_registered--;
1415		if (acpi_processor_registered == 0)
1416			cpuidle_unregister_driver(&acpi_idle_driver);
1417
1418		kfree(dev);
1419	}
1420
1421	pr->flags.power_setup_done = 0;
1422	return 0;
1423}
1424
1425MODULE_IMPORT_NS("ACPI_PROCESSOR_IDLE");