Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
/*
 * intel_idle.c - native hardware idle loop for modern Intel processors
 *
 * Copyright (c) 2013, Intel Corporation.
 * Len Brown <len.brown@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * intel_idle is a cpuidle driver that loads on specific Intel processors
 * in lieu of the legacy ACPI processor_idle driver.  The intent is to
 * make Linux more efficient on these processors, as intel_idle knows
 * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
 */

/*
 * Design Assumptions
 *
 * All CPUs have same idle states as boot CPU
 *
 * Chipset BM_STS (bus master status) bit is a NOP
 *	for preventing entry into deep C-stats
 */

/*
 * Known limitations
 *
 * The driver currently initializes for_each_online_cpu() upon modprobe.
 * It it unaware of subsequent processors hot-added to the system.
 * This means that if you boot with maxcpus=n and later online
 * processors above n, those processors will use C1 only.
 *
 * ACPI has a .suspend hack to turn off deep c-statees during suspend
 * to avoid complications with the lapic timer workaround.
 * Have not seen issues with suspend, but may need same workaround here.
 *
 * There is currently no kernel-based automatic probing/loading mechanism
 * if the driver is built as a module.
 */

/* un-comment DEBUG to enable pr_debug() statements */
#define DEBUG

#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/clockchips.h>
#include <trace/events/power.h>
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <asm/cpu_device_id.h>
#include <asm/mwait.h>
#include <asm/msr.h>

#define INTEL_IDLE_VERSION "0.4"
#define PREFIX "intel_idle: "

static struct cpuidle_driver intel_idle_driver = {
	.name = "intel_idle",
	.owner = THIS_MODULE,
};
/* intel_idle.max_cstate=0 disables driver */
static int max_cstate = CPUIDLE_STATE_MAX - 1;

static unsigned int mwait_substates;

#define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
/* Reliable LAPIC Timer States, bit 1 for C1 etc.  */
static unsigned int lapic_timer_reliable_states = (1 << 1);	 /* Default to only C1 */

struct idle_cpu {
	struct cpuidle_state *state_table;

	/*
	 * Hardware C-state auto-demotion may not always be optimal.
	 * Indicate which enable bits to clear here.
	 */
	unsigned long auto_demotion_disable_flags;
	bool byt_auto_demotion_disable_flag;
	bool disable_promotion_to_c1e;
};

static const struct idle_cpu *icpu;
static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
static int intel_idle(struct cpuidle_device *dev,
			struct cpuidle_driver *drv, int index);
static int intel_idle_cpu_init(int cpu);

static struct cpuidle_state *cpuidle_state_table;

/*
 * Set this flag for states where the HW flushes the TLB for us
 * and so we don't need cross-calls to keep it consistent.
 * If this flag is set, SW flushes the TLB, so even if the
 * HW doesn't do the flushing, this flag is safe to use.
 */
#define CPUIDLE_FLAG_TLB_FLUSHED	0x10000

/*
 * MWAIT takes an 8-bit "hint" in EAX "suggesting"
 * the C-state (top nibble) and sub-state (bottom nibble)
 * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
 *
 * We store the hint at the top of our "flags" for each state.
 */
#define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)
#define MWAIT2flg(eax) ((eax & 0xFF) << 24)

/*
 * States are indexed by the cstate number,
 * which is also the index into the MWAIT hint array.
 * Thus C0 is a dummy.
 */
static struct cpuidle_state nehalem_cstates[] = {
	{
		.name = "C1-NHM",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 3,
		.target_residency = 6,
		.enter = &intel_idle },
	{
		.name = "C1E-NHM",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C3-NHM",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 20,
		.target_residency = 80,
		.enter = &intel_idle },
	{
		.name = "C6-NHM",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 200,
		.target_residency = 800,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state snb_cstates[] = {
	{
		.name = "C1-SNB",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 2,
		.target_residency = 2,
		.enter = &intel_idle },
	{
		.name = "C1E-SNB",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C3-SNB",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 80,
		.target_residency = 211,
		.enter = &intel_idle },
	{
		.name = "C6-SNB",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 104,
		.target_residency = 345,
		.enter = &intel_idle },
	{
		.name = "C7-SNB",
		.desc = "MWAIT 0x30",
		.flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 109,
		.target_residency = 345,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state byt_cstates[] = {
	{
		.name = "C1-BYT",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 1,
		.target_residency = 1,
		.enter = &intel_idle },
	{
		.name = "C1E-BYT",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 15,
		.target_residency = 30,
		.enter = &intel_idle },
	{
		.name = "C6N-BYT",
		.desc = "MWAIT 0x58",
		.flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 40,
		.target_residency = 275,
		.enter = &intel_idle },
	{
		.name = "C6S-BYT",
		.desc = "MWAIT 0x52",
		.flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 140,
		.target_residency = 560,
		.enter = &intel_idle },
	{
		.name = "C7-BYT",
		.desc = "MWAIT 0x60",
		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 1200,
		.target_residency = 1500,
		.enter = &intel_idle },
	{
		.name = "C7S-BYT",
		.desc = "MWAIT 0x64",
		.flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 10000,
		.target_residency = 20000,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state ivb_cstates[] = {
	{
		.name = "C1-IVB",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 1,
		.target_residency = 1,
		.enter = &intel_idle },
	{
		.name = "C1E-IVB",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C3-IVB",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 59,
		.target_residency = 156,
		.enter = &intel_idle },
	{
		.name = "C6-IVB",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 80,
		.target_residency = 300,
		.enter = &intel_idle },
	{
		.name = "C7-IVB",
		.desc = "MWAIT 0x30",
		.flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 87,
		.target_residency = 300,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state ivt_cstates[] = {
	{
		.name = "C1-IVT",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 1,
		.target_residency = 1,
		.enter = &intel_idle },
	{
		.name = "C1E-IVT",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 80,
		.enter = &intel_idle },
	{
		.name = "C3-IVT",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 59,
		.target_residency = 156,
		.enter = &intel_idle },
	{
		.name = "C6-IVT",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 82,
		.target_residency = 300,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state ivt_cstates_4s[] = {
	{
		.name = "C1-IVT-4S",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 1,
		.target_residency = 1,
		.enter = &intel_idle },
	{
		.name = "C1E-IVT-4S",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 250,
		.enter = &intel_idle },
	{
		.name = "C3-IVT-4S",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 59,
		.target_residency = 300,
		.enter = &intel_idle },
	{
		.name = "C6-IVT-4S",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 84,
		.target_residency = 400,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state ivt_cstates_8s[] = {
	{
		.name = "C1-IVT-8S",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 1,
		.target_residency = 1,
		.enter = &intel_idle },
	{
		.name = "C1E-IVT-8S",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 500,
		.enter = &intel_idle },
	{
		.name = "C3-IVT-8S",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 59,
		.target_residency = 600,
		.enter = &intel_idle },
	{
		.name = "C6-IVT-8S",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 88,
		.target_residency = 700,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state hsw_cstates[] = {
	{
		.name = "C1-HSW",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 2,
		.target_residency = 2,
		.enter = &intel_idle },
	{
		.name = "C1E-HSW",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C3-HSW",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 33,
		.target_residency = 100,
		.enter = &intel_idle },
	{
		.name = "C6-HSW",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 133,
		.target_residency = 400,
		.enter = &intel_idle },
	{
		.name = "C7s-HSW",
		.desc = "MWAIT 0x32",
		.flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 166,
		.target_residency = 500,
		.enter = &intel_idle },
	{
		.name = "C8-HSW",
		.desc = "MWAIT 0x40",
		.flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 300,
		.target_residency = 900,
		.enter = &intel_idle },
	{
		.name = "C9-HSW",
		.desc = "MWAIT 0x50",
		.flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 600,
		.target_residency = 1800,
		.enter = &intel_idle },
	{
		.name = "C10-HSW",
		.desc = "MWAIT 0x60",
		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 2600,
		.target_residency = 7700,
		.enter = &intel_idle },
	{
		.enter = NULL }
};
static struct cpuidle_state bdw_cstates[] = {
	{
		.name = "C1-BDW",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 2,
		.target_residency = 2,
		.enter = &intel_idle },
	{
		.name = "C1E-BDW",
		.desc = "MWAIT 0x01",
		.flags = MWAIT2flg(0x01),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C3-BDW",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 40,
		.target_residency = 100,
		.enter = &intel_idle },
	{
		.name = "C6-BDW",
		.desc = "MWAIT 0x20",
		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 133,
		.target_residency = 400,
		.enter = &intel_idle },
	{
		.name = "C7s-BDW",
		.desc = "MWAIT 0x32",
		.flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 166,
		.target_residency = 500,
		.enter = &intel_idle },
	{
		.name = "C8-BDW",
		.desc = "MWAIT 0x40",
		.flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 300,
		.target_residency = 900,
		.enter = &intel_idle },
	{
		.name = "C9-BDW",
		.desc = "MWAIT 0x50",
		.flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 600,
		.target_residency = 1800,
		.enter = &intel_idle },
	{
		.name = "C10-BDW",
		.desc = "MWAIT 0x60",
		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 2600,
		.target_residency = 7700,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

static struct cpuidle_state atom_cstates[] = {
	{
		.name = "C1E-ATM",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 10,
		.target_residency = 20,
		.enter = &intel_idle },
	{
		.name = "C2-ATM",
		.desc = "MWAIT 0x10",
		.flags = MWAIT2flg(0x10),
		.exit_latency = 20,
		.target_residency = 80,
		.enter = &intel_idle },
	{
		.name = "C4-ATM",
		.desc = "MWAIT 0x30",
		.flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 100,
		.target_residency = 400,
		.enter = &intel_idle },
	{
		.name = "C6-ATM",
		.desc = "MWAIT 0x52",
		.flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 140,
		.target_residency = 560,
		.enter = &intel_idle },
	{
		.enter = NULL }
};
static struct cpuidle_state avn_cstates[] = {
	{
		.name = "C1-AVN",
		.desc = "MWAIT 0x00",
		.flags = MWAIT2flg(0x00),
		.exit_latency = 2,
		.target_residency = 2,
		.enter = &intel_idle },
	{
		.name = "C6-AVN",
		.desc = "MWAIT 0x51",
		.flags = MWAIT2flg(0x51) | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 15,
		.target_residency = 45,
		.enter = &intel_idle },
	{
		.enter = NULL }
};

/**
 * intel_idle
 * @dev: cpuidle_device
 * @drv: cpuidle driver
 * @index: index of cpuidle state
 *
 * Must be called under local_irq_disable().
 */
static int intel_idle(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int index)
{
	unsigned long ecx = 1; /* break on interrupt flag */
	struct cpuidle_state *state = &drv->states[index];
	unsigned long eax = flg2MWAIT(state->flags);
	unsigned int cstate;
	int cpu = smp_processor_id();

	cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;

	/*
	 * leave_mm() to avoid costly and often unnecessary wakeups
	 * for flushing the user TLB's associated with the active mm.
	 */
	if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
		leave_mm(cpu);

	if (!(lapic_timer_reliable_states & (1 << (cstate))))
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);

	mwait_idle_with_hints(eax, ecx);

	if (!(lapic_timer_reliable_states & (1 << (cstate))))
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);

	return index;
}

static void __setup_broadcast_timer(void *arg)
{
	unsigned long reason = (unsigned long)arg;
	int cpu = smp_processor_id();

	reason = reason ?
		CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;

	clockevents_notify(reason, &cpu);
}

static int cpu_hotplug_notify(struct notifier_block *n,
			      unsigned long action, void *hcpu)
{
	int hotcpu = (unsigned long)hcpu;
	struct cpuidle_device *dev;

	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_ONLINE:

		if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
			smp_call_function_single(hotcpu, __setup_broadcast_timer,
						 (void *)true, 1);

		/*
		 * Some systems can hotplug a cpu at runtime after
		 * the kernel has booted, we have to initialize the
		 * driver in this case
		 */
		dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);
		if (!dev->registered)
			intel_idle_cpu_init(hotcpu);

		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block cpu_hotplug_notifier = {
	.notifier_call = cpu_hotplug_notify,
};

static void auto_demotion_disable(void *dummy)
{
	unsigned long long msr_bits;

	rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
	msr_bits &= ~(icpu->auto_demotion_disable_flags);
	wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
}
static void c1e_promotion_disable(void *dummy)
{
	unsigned long long msr_bits;

	rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
	msr_bits &= ~0x2;
	wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
}

static const struct idle_cpu idle_cpu_nehalem = {
	.state_table = nehalem_cstates,
	.auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_atom = {
	.state_table = atom_cstates,
};

static const struct idle_cpu idle_cpu_lincroft = {
	.state_table = atom_cstates,
	.auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE,
};

static const struct idle_cpu idle_cpu_snb = {
	.state_table = snb_cstates,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_byt = {
	.state_table = byt_cstates,
	.disable_promotion_to_c1e = true,
	.byt_auto_demotion_disable_flag = true,
};

static const struct idle_cpu idle_cpu_ivb = {
	.state_table = ivb_cstates,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_ivt = {
	.state_table = ivt_cstates,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_hsw = {
	.state_table = hsw_cstates,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_bdw = {
	.state_table = bdw_cstates,
	.disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_avn = {
	.state_table = avn_cstates,
	.disable_promotion_to_c1e = true,
};

#define ICPU(model, cpu) \
	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_MWAIT, (unsigned long)&cpu }

static const struct x86_cpu_id intel_idle_ids[] = {
	ICPU(0x1a, idle_cpu_nehalem),
	ICPU(0x1e, idle_cpu_nehalem),
	ICPU(0x1f, idle_cpu_nehalem),
	ICPU(0x25, idle_cpu_nehalem),
	ICPU(0x2c, idle_cpu_nehalem),
	ICPU(0x2e, idle_cpu_nehalem),
	ICPU(0x1c, idle_cpu_atom),
	ICPU(0x26, idle_cpu_lincroft),
	ICPU(0x2f, idle_cpu_nehalem),
	ICPU(0x2a, idle_cpu_snb),
	ICPU(0x2d, idle_cpu_snb),
	ICPU(0x36, idle_cpu_atom),
	ICPU(0x37, idle_cpu_byt),
	ICPU(0x3a, idle_cpu_ivb),
	ICPU(0x3e, idle_cpu_ivt),
	ICPU(0x3c, idle_cpu_hsw),
	ICPU(0x3f, idle_cpu_hsw),
	ICPU(0x45, idle_cpu_hsw),
	ICPU(0x46, idle_cpu_hsw),
	ICPU(0x4d, idle_cpu_avn),
	ICPU(0x3d, idle_cpu_bdw),
	ICPU(0x4f, idle_cpu_bdw),
	ICPU(0x56, idle_cpu_bdw),
	{}
};
MODULE_DEVICE_TABLE(x86cpu, intel_idle_ids);

/*
 * intel_idle_probe()
 */
static int __init intel_idle_probe(void)
{
	unsigned int eax, ebx, ecx;
	const struct x86_cpu_id *id;

	if (max_cstate == 0) {
		pr_debug(PREFIX "disabled\n");
		return -EPERM;
	}

	id = x86_match_cpu(intel_idle_ids);
	if (!id) {
		if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
		    boot_cpu_data.x86 == 6)
			pr_debug(PREFIX "does not run on family %d model %d\n",
				boot_cpu_data.x86, boot_cpu_data.x86_model);
		return -ENODEV;
	}

	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
		return -ENODEV;

	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);

	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
	    !mwait_substates)
			return -ENODEV;

	pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);

	icpu = (const struct idle_cpu *)id->driver_data;
	cpuidle_state_table = icpu->state_table;

	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */
		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
	else
		on_each_cpu(__setup_broadcast_timer, (void *)true, 1);

	pr_debug(PREFIX "v" INTEL_IDLE_VERSION
		" model 0x%X\n", boot_cpu_data.x86_model);

	pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
		lapic_timer_reliable_states);
	return 0;
}

/*
 * intel_idle_cpuidle_devices_uninit()
 * unregister, free cpuidle_devices
 */
static void intel_idle_cpuidle_devices_uninit(void)
{
	int i;
	struct cpuidle_device *dev;

	for_each_online_cpu(i) {
		dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
		cpuidle_unregister_device(dev);
	}

	free_percpu(intel_idle_cpuidle_devices);
	return;
}

/*
 * intel_idle_state_table_update()
 *
 * Update the default state_table for this CPU-id
 *
 * Currently used to access tuned IVT multi-socket targets
 * Assumption: num_sockets == (max_package_num + 1)
 */
void intel_idle_state_table_update(void)
{
	/* IVT uses a different table for 1-2, 3-4, and > 4 sockets */
	if (boot_cpu_data.x86_model == 0x3e) { /* IVT */
		int cpu, package_num, num_sockets = 1;

		for_each_online_cpu(cpu) {
			package_num = topology_physical_package_id(cpu);
			if (package_num + 1 > num_sockets) {
				num_sockets = package_num + 1;

				if (num_sockets > 4) {
					cpuidle_state_table = ivt_cstates_8s;
					return;
				}
			}
		}

		if (num_sockets > 2)
			cpuidle_state_table = ivt_cstates_4s;
		/* else, 1 and 2 socket systems use default ivt_cstates */
	}
	return;
}

/*
 * intel_idle_cpuidle_driver_init()
 * allocate, initialize cpuidle_states
 */
static int __init intel_idle_cpuidle_driver_init(void)
{
	int cstate;
	struct cpuidle_driver *drv = &intel_idle_driver;

	intel_idle_state_table_update();

	drv->state_count = 1;

	for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
		int num_substates, mwait_hint, mwait_cstate;

		if (cpuidle_state_table[cstate].enter == NULL)
			break;

		if (cstate + 1 > max_cstate) {
			printk(PREFIX "max_cstate %d reached\n",
				max_cstate);
			break;
		}

		mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
		mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);

		/* number of sub-states for this state in CPUID.MWAIT */
		num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
					& MWAIT_SUBSTATE_MASK;

		/* if NO sub-states for this state in CPUID, skip it */
		if (num_substates == 0)
			continue;

		if (((mwait_cstate + 1) > 2) &&
			!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
			mark_tsc_unstable("TSC halts in idle"
					" states deeper than C2");

		drv->states[drv->state_count] =	/* structure copy */
			cpuidle_state_table[cstate];

		drv->state_count += 1;
	}

	if (icpu->auto_demotion_disable_flags)
		on_each_cpu(auto_demotion_disable, NULL, 1);

	if (icpu->byt_auto_demotion_disable_flag) {
		wrmsrl(MSR_CC6_DEMOTION_POLICY_CONFIG, 0);
		wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0);
	}

	if (icpu->disable_promotion_to_c1e)	/* each-cpu is redundant */
		on_each_cpu(c1e_promotion_disable, NULL, 1);

	return 0;
}


/*
 * intel_idle_cpu_init()
 * allocate, initialize, register cpuidle_devices
 * @cpu: cpu/core to initialize
 */
static int intel_idle_cpu_init(int cpu)
{
	struct cpuidle_device *dev;

	dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);

	dev->cpu = cpu;

	if (cpuidle_register_device(dev)) {
		pr_debug(PREFIX "cpuidle_register_device %d failed!\n", cpu);
		intel_idle_cpuidle_devices_uninit();
		return -EIO;
	}

	if (icpu->auto_demotion_disable_flags)
		smp_call_function_single(cpu, auto_demotion_disable, NULL, 1);

	if (icpu->disable_promotion_to_c1e)
		smp_call_function_single(cpu, c1e_promotion_disable, NULL, 1);

	return 0;
}

static int __init intel_idle_init(void)
{
	int retval, i;

	/* Do not load intel_idle at all for now if idle= is passed */
	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
		return -ENODEV;

	retval = intel_idle_probe();
	if (retval)
		return retval;

	intel_idle_cpuidle_driver_init();
	retval = cpuidle_register_driver(&intel_idle_driver);
	if (retval) {
		struct cpuidle_driver *drv = cpuidle_get_driver();
		printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
			drv ? drv->name : "none");
		return retval;
	}

	intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	if (intel_idle_cpuidle_devices == NULL)
		return -ENOMEM;

	cpu_notifier_register_begin();

	for_each_online_cpu(i) {
		retval = intel_idle_cpu_init(i);
		if (retval) {
			cpu_notifier_register_done();
			cpuidle_unregister_driver(&intel_idle_driver);
			return retval;
		}
	}
	__register_cpu_notifier(&cpu_hotplug_notifier);

	cpu_notifier_register_done();

	return 0;
}

static void __exit intel_idle_exit(void)
{
	intel_idle_cpuidle_devices_uninit();
	cpuidle_unregister_driver(&intel_idle_driver);

	cpu_notifier_register_begin();

	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
		on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
	__unregister_cpu_notifier(&cpu_hotplug_notifier);

	cpu_notifier_register_done();

	return;
}

module_init(intel_idle_init);
module_exit(intel_idle_exit);

module_param(max_cstate, int, 0444);

MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
MODULE_LICENSE("GPL");