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1/*
2 * intel_idle.c - native hardware idle loop for modern Intel processors
3 *
4 * Copyright (c) 2013, 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/tick.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 "0.4.1"
69#define PREFIX "intel_idle: "
70
71static struct cpuidle_driver intel_idle_driver = {
72 .name = "intel_idle",
73 .owner = THIS_MODULE,
74};
75/* intel_idle.max_cstate=0 disables driver */
76static int max_cstate = CPUIDLE_STATE_MAX - 1;
77
78static unsigned int mwait_substates;
79
80#define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
81/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
82static unsigned int lapic_timer_reliable_states = (1 << 1); /* Default to only C1 */
83
84struct idle_cpu {
85 struct cpuidle_state *state_table;
86
87 /*
88 * Hardware C-state auto-demotion may not always be optimal.
89 * Indicate which enable bits to clear here.
90 */
91 unsigned long auto_demotion_disable_flags;
92 bool byt_auto_demotion_disable_flag;
93 bool disable_promotion_to_c1e;
94};
95
96static const struct idle_cpu *icpu;
97static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
98static int intel_idle(struct cpuidle_device *dev,
99 struct cpuidle_driver *drv, int index);
100static void intel_idle_freeze(struct cpuidle_device *dev,
101 struct cpuidle_driver *drv, int index);
102static int intel_idle_cpu_init(int cpu);
103
104static struct cpuidle_state *cpuidle_state_table;
105
106/*
107 * Set this flag for states where the HW flushes the TLB for us
108 * and so we don't need cross-calls to keep it consistent.
109 * If this flag is set, SW flushes the TLB, so even if the
110 * HW doesn't do the flushing, this flag is safe to use.
111 */
112#define CPUIDLE_FLAG_TLB_FLUSHED 0x10000
113
114/*
115 * MWAIT takes an 8-bit "hint" in EAX "suggesting"
116 * the C-state (top nibble) and sub-state (bottom nibble)
117 * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
118 *
119 * We store the hint at the top of our "flags" for each state.
120 */
121#define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)
122#define MWAIT2flg(eax) ((eax & 0xFF) << 24)
123
124/*
125 * States are indexed by the cstate number,
126 * which is also the index into the MWAIT hint array.
127 * Thus C0 is a dummy.
128 */
129static struct cpuidle_state nehalem_cstates[] = {
130 {
131 .name = "C1-NHM",
132 .desc = "MWAIT 0x00",
133 .flags = MWAIT2flg(0x00),
134 .exit_latency = 3,
135 .target_residency = 6,
136 .enter = &intel_idle,
137 .enter_freeze = intel_idle_freeze, },
138 {
139 .name = "C1E-NHM",
140 .desc = "MWAIT 0x01",
141 .flags = MWAIT2flg(0x01),
142 .exit_latency = 10,
143 .target_residency = 20,
144 .enter = &intel_idle,
145 .enter_freeze = intel_idle_freeze, },
146 {
147 .name = "C3-NHM",
148 .desc = "MWAIT 0x10",
149 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
150 .exit_latency = 20,
151 .target_residency = 80,
152 .enter = &intel_idle,
153 .enter_freeze = intel_idle_freeze, },
154 {
155 .name = "C6-NHM",
156 .desc = "MWAIT 0x20",
157 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
158 .exit_latency = 200,
159 .target_residency = 800,
160 .enter = &intel_idle,
161 .enter_freeze = intel_idle_freeze, },
162 {
163 .enter = NULL }
164};
165
166static struct cpuidle_state snb_cstates[] = {
167 {
168 .name = "C1-SNB",
169 .desc = "MWAIT 0x00",
170 .flags = MWAIT2flg(0x00),
171 .exit_latency = 2,
172 .target_residency = 2,
173 .enter = &intel_idle,
174 .enter_freeze = intel_idle_freeze, },
175 {
176 .name = "C1E-SNB",
177 .desc = "MWAIT 0x01",
178 .flags = MWAIT2flg(0x01),
179 .exit_latency = 10,
180 .target_residency = 20,
181 .enter = &intel_idle,
182 .enter_freeze = intel_idle_freeze, },
183 {
184 .name = "C3-SNB",
185 .desc = "MWAIT 0x10",
186 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
187 .exit_latency = 80,
188 .target_residency = 211,
189 .enter = &intel_idle,
190 .enter_freeze = intel_idle_freeze, },
191 {
192 .name = "C6-SNB",
193 .desc = "MWAIT 0x20",
194 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
195 .exit_latency = 104,
196 .target_residency = 345,
197 .enter = &intel_idle,
198 .enter_freeze = intel_idle_freeze, },
199 {
200 .name = "C7-SNB",
201 .desc = "MWAIT 0x30",
202 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
203 .exit_latency = 109,
204 .target_residency = 345,
205 .enter = &intel_idle,
206 .enter_freeze = intel_idle_freeze, },
207 {
208 .enter = NULL }
209};
210
211static struct cpuidle_state byt_cstates[] = {
212 {
213 .name = "C1-BYT",
214 .desc = "MWAIT 0x00",
215 .flags = MWAIT2flg(0x00),
216 .exit_latency = 1,
217 .target_residency = 1,
218 .enter = &intel_idle,
219 .enter_freeze = intel_idle_freeze, },
220 {
221 .name = "C6N-BYT",
222 .desc = "MWAIT 0x58",
223 .flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
224 .exit_latency = 300,
225 .target_residency = 275,
226 .enter = &intel_idle,
227 .enter_freeze = intel_idle_freeze, },
228 {
229 .name = "C6S-BYT",
230 .desc = "MWAIT 0x52",
231 .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
232 .exit_latency = 500,
233 .target_residency = 560,
234 .enter = &intel_idle,
235 .enter_freeze = intel_idle_freeze, },
236 {
237 .name = "C7-BYT",
238 .desc = "MWAIT 0x60",
239 .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
240 .exit_latency = 1200,
241 .target_residency = 4000,
242 .enter = &intel_idle,
243 .enter_freeze = intel_idle_freeze, },
244 {
245 .name = "C7S-BYT",
246 .desc = "MWAIT 0x64",
247 .flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
248 .exit_latency = 10000,
249 .target_residency = 20000,
250 .enter = &intel_idle,
251 .enter_freeze = intel_idle_freeze, },
252 {
253 .enter = NULL }
254};
255
256static struct cpuidle_state cht_cstates[] = {
257 {
258 .name = "C1-CHT",
259 .desc = "MWAIT 0x00",
260 .flags = MWAIT2flg(0x00),
261 .exit_latency = 1,
262 .target_residency = 1,
263 .enter = &intel_idle,
264 .enter_freeze = intel_idle_freeze, },
265 {
266 .name = "C6N-CHT",
267 .desc = "MWAIT 0x58",
268 .flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
269 .exit_latency = 80,
270 .target_residency = 275,
271 .enter = &intel_idle,
272 .enter_freeze = intel_idle_freeze, },
273 {
274 .name = "C6S-CHT",
275 .desc = "MWAIT 0x52",
276 .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
277 .exit_latency = 200,
278 .target_residency = 560,
279 .enter = &intel_idle,
280 .enter_freeze = intel_idle_freeze, },
281 {
282 .name = "C7-CHT",
283 .desc = "MWAIT 0x60",
284 .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
285 .exit_latency = 1200,
286 .target_residency = 4000,
287 .enter = &intel_idle,
288 .enter_freeze = intel_idle_freeze, },
289 {
290 .name = "C7S-CHT",
291 .desc = "MWAIT 0x64",
292 .flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
293 .exit_latency = 10000,
294 .target_residency = 20000,
295 .enter = &intel_idle,
296 .enter_freeze = intel_idle_freeze, },
297 {
298 .enter = NULL }
299};
300
301static struct cpuidle_state ivb_cstates[] = {
302 {
303 .name = "C1-IVB",
304 .desc = "MWAIT 0x00",
305 .flags = MWAIT2flg(0x00),
306 .exit_latency = 1,
307 .target_residency = 1,
308 .enter = &intel_idle,
309 .enter_freeze = intel_idle_freeze, },
310 {
311 .name = "C1E-IVB",
312 .desc = "MWAIT 0x01",
313 .flags = MWAIT2flg(0x01),
314 .exit_latency = 10,
315 .target_residency = 20,
316 .enter = &intel_idle,
317 .enter_freeze = intel_idle_freeze, },
318 {
319 .name = "C3-IVB",
320 .desc = "MWAIT 0x10",
321 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
322 .exit_latency = 59,
323 .target_residency = 156,
324 .enter = &intel_idle,
325 .enter_freeze = intel_idle_freeze, },
326 {
327 .name = "C6-IVB",
328 .desc = "MWAIT 0x20",
329 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
330 .exit_latency = 80,
331 .target_residency = 300,
332 .enter = &intel_idle,
333 .enter_freeze = intel_idle_freeze, },
334 {
335 .name = "C7-IVB",
336 .desc = "MWAIT 0x30",
337 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
338 .exit_latency = 87,
339 .target_residency = 300,
340 .enter = &intel_idle,
341 .enter_freeze = intel_idle_freeze, },
342 {
343 .enter = NULL }
344};
345
346static struct cpuidle_state ivt_cstates[] = {
347 {
348 .name = "C1-IVT",
349 .desc = "MWAIT 0x00",
350 .flags = MWAIT2flg(0x00),
351 .exit_latency = 1,
352 .target_residency = 1,
353 .enter = &intel_idle,
354 .enter_freeze = intel_idle_freeze, },
355 {
356 .name = "C1E-IVT",
357 .desc = "MWAIT 0x01",
358 .flags = MWAIT2flg(0x01),
359 .exit_latency = 10,
360 .target_residency = 80,
361 .enter = &intel_idle,
362 .enter_freeze = intel_idle_freeze, },
363 {
364 .name = "C3-IVT",
365 .desc = "MWAIT 0x10",
366 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
367 .exit_latency = 59,
368 .target_residency = 156,
369 .enter = &intel_idle,
370 .enter_freeze = intel_idle_freeze, },
371 {
372 .name = "C6-IVT",
373 .desc = "MWAIT 0x20",
374 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
375 .exit_latency = 82,
376 .target_residency = 300,
377 .enter = &intel_idle,
378 .enter_freeze = intel_idle_freeze, },
379 {
380 .enter = NULL }
381};
382
383static struct cpuidle_state ivt_cstates_4s[] = {
384 {
385 .name = "C1-IVT-4S",
386 .desc = "MWAIT 0x00",
387 .flags = MWAIT2flg(0x00),
388 .exit_latency = 1,
389 .target_residency = 1,
390 .enter = &intel_idle,
391 .enter_freeze = intel_idle_freeze, },
392 {
393 .name = "C1E-IVT-4S",
394 .desc = "MWAIT 0x01",
395 .flags = MWAIT2flg(0x01),
396 .exit_latency = 10,
397 .target_residency = 250,
398 .enter = &intel_idle,
399 .enter_freeze = intel_idle_freeze, },
400 {
401 .name = "C3-IVT-4S",
402 .desc = "MWAIT 0x10",
403 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
404 .exit_latency = 59,
405 .target_residency = 300,
406 .enter = &intel_idle,
407 .enter_freeze = intel_idle_freeze, },
408 {
409 .name = "C6-IVT-4S",
410 .desc = "MWAIT 0x20",
411 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
412 .exit_latency = 84,
413 .target_residency = 400,
414 .enter = &intel_idle,
415 .enter_freeze = intel_idle_freeze, },
416 {
417 .enter = NULL }
418};
419
420static struct cpuidle_state ivt_cstates_8s[] = {
421 {
422 .name = "C1-IVT-8S",
423 .desc = "MWAIT 0x00",
424 .flags = MWAIT2flg(0x00),
425 .exit_latency = 1,
426 .target_residency = 1,
427 .enter = &intel_idle,
428 .enter_freeze = intel_idle_freeze, },
429 {
430 .name = "C1E-IVT-8S",
431 .desc = "MWAIT 0x01",
432 .flags = MWAIT2flg(0x01),
433 .exit_latency = 10,
434 .target_residency = 500,
435 .enter = &intel_idle,
436 .enter_freeze = intel_idle_freeze, },
437 {
438 .name = "C3-IVT-8S",
439 .desc = "MWAIT 0x10",
440 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
441 .exit_latency = 59,
442 .target_residency = 600,
443 .enter = &intel_idle,
444 .enter_freeze = intel_idle_freeze, },
445 {
446 .name = "C6-IVT-8S",
447 .desc = "MWAIT 0x20",
448 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
449 .exit_latency = 88,
450 .target_residency = 700,
451 .enter = &intel_idle,
452 .enter_freeze = intel_idle_freeze, },
453 {
454 .enter = NULL }
455};
456
457static struct cpuidle_state hsw_cstates[] = {
458 {
459 .name = "C1-HSW",
460 .desc = "MWAIT 0x00",
461 .flags = MWAIT2flg(0x00),
462 .exit_latency = 2,
463 .target_residency = 2,
464 .enter = &intel_idle,
465 .enter_freeze = intel_idle_freeze, },
466 {
467 .name = "C1E-HSW",
468 .desc = "MWAIT 0x01",
469 .flags = MWAIT2flg(0x01),
470 .exit_latency = 10,
471 .target_residency = 20,
472 .enter = &intel_idle,
473 .enter_freeze = intel_idle_freeze, },
474 {
475 .name = "C3-HSW",
476 .desc = "MWAIT 0x10",
477 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
478 .exit_latency = 33,
479 .target_residency = 100,
480 .enter = &intel_idle,
481 .enter_freeze = intel_idle_freeze, },
482 {
483 .name = "C6-HSW",
484 .desc = "MWAIT 0x20",
485 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
486 .exit_latency = 133,
487 .target_residency = 400,
488 .enter = &intel_idle,
489 .enter_freeze = intel_idle_freeze, },
490 {
491 .name = "C7s-HSW",
492 .desc = "MWAIT 0x32",
493 .flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
494 .exit_latency = 166,
495 .target_residency = 500,
496 .enter = &intel_idle,
497 .enter_freeze = intel_idle_freeze, },
498 {
499 .name = "C8-HSW",
500 .desc = "MWAIT 0x40",
501 .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
502 .exit_latency = 300,
503 .target_residency = 900,
504 .enter = &intel_idle,
505 .enter_freeze = intel_idle_freeze, },
506 {
507 .name = "C9-HSW",
508 .desc = "MWAIT 0x50",
509 .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
510 .exit_latency = 600,
511 .target_residency = 1800,
512 .enter = &intel_idle,
513 .enter_freeze = intel_idle_freeze, },
514 {
515 .name = "C10-HSW",
516 .desc = "MWAIT 0x60",
517 .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
518 .exit_latency = 2600,
519 .target_residency = 7700,
520 .enter = &intel_idle,
521 .enter_freeze = intel_idle_freeze, },
522 {
523 .enter = NULL }
524};
525static struct cpuidle_state bdw_cstates[] = {
526 {
527 .name = "C1-BDW",
528 .desc = "MWAIT 0x00",
529 .flags = MWAIT2flg(0x00),
530 .exit_latency = 2,
531 .target_residency = 2,
532 .enter = &intel_idle,
533 .enter_freeze = intel_idle_freeze, },
534 {
535 .name = "C1E-BDW",
536 .desc = "MWAIT 0x01",
537 .flags = MWAIT2flg(0x01),
538 .exit_latency = 10,
539 .target_residency = 20,
540 .enter = &intel_idle,
541 .enter_freeze = intel_idle_freeze, },
542 {
543 .name = "C3-BDW",
544 .desc = "MWAIT 0x10",
545 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
546 .exit_latency = 40,
547 .target_residency = 100,
548 .enter = &intel_idle,
549 .enter_freeze = intel_idle_freeze, },
550 {
551 .name = "C6-BDW",
552 .desc = "MWAIT 0x20",
553 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
554 .exit_latency = 133,
555 .target_residency = 400,
556 .enter = &intel_idle,
557 .enter_freeze = intel_idle_freeze, },
558 {
559 .name = "C7s-BDW",
560 .desc = "MWAIT 0x32",
561 .flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
562 .exit_latency = 166,
563 .target_residency = 500,
564 .enter = &intel_idle,
565 .enter_freeze = intel_idle_freeze, },
566 {
567 .name = "C8-BDW",
568 .desc = "MWAIT 0x40",
569 .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
570 .exit_latency = 300,
571 .target_residency = 900,
572 .enter = &intel_idle,
573 .enter_freeze = intel_idle_freeze, },
574 {
575 .name = "C9-BDW",
576 .desc = "MWAIT 0x50",
577 .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
578 .exit_latency = 600,
579 .target_residency = 1800,
580 .enter = &intel_idle,
581 .enter_freeze = intel_idle_freeze, },
582 {
583 .name = "C10-BDW",
584 .desc = "MWAIT 0x60",
585 .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
586 .exit_latency = 2600,
587 .target_residency = 7700,
588 .enter = &intel_idle,
589 .enter_freeze = intel_idle_freeze, },
590 {
591 .enter = NULL }
592};
593
594static struct cpuidle_state skl_cstates[] = {
595 {
596 .name = "C1-SKL",
597 .desc = "MWAIT 0x00",
598 .flags = MWAIT2flg(0x00),
599 .exit_latency = 2,
600 .target_residency = 2,
601 .enter = &intel_idle,
602 .enter_freeze = intel_idle_freeze, },
603 {
604 .name = "C1E-SKL",
605 .desc = "MWAIT 0x01",
606 .flags = MWAIT2flg(0x01),
607 .exit_latency = 10,
608 .target_residency = 20,
609 .enter = &intel_idle,
610 .enter_freeze = intel_idle_freeze, },
611 {
612 .name = "C3-SKL",
613 .desc = "MWAIT 0x10",
614 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
615 .exit_latency = 70,
616 .target_residency = 100,
617 .enter = &intel_idle,
618 .enter_freeze = intel_idle_freeze, },
619 {
620 .name = "C6-SKL",
621 .desc = "MWAIT 0x20",
622 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
623 .exit_latency = 85,
624 .target_residency = 200,
625 .enter = &intel_idle,
626 .enter_freeze = intel_idle_freeze, },
627 {
628 .name = "C7s-SKL",
629 .desc = "MWAIT 0x33",
630 .flags = MWAIT2flg(0x33) | CPUIDLE_FLAG_TLB_FLUSHED,
631 .exit_latency = 124,
632 .target_residency = 800,
633 .enter = &intel_idle,
634 .enter_freeze = intel_idle_freeze, },
635 {
636 .name = "C8-SKL",
637 .desc = "MWAIT 0x40",
638 .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
639 .exit_latency = 200,
640 .target_residency = 800,
641 .enter = &intel_idle,
642 .enter_freeze = intel_idle_freeze, },
643 {
644 .name = "C9-SKL",
645 .desc = "MWAIT 0x50",
646 .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
647 .exit_latency = 480,
648 .target_residency = 5000,
649 .enter = &intel_idle,
650 .enter_freeze = intel_idle_freeze, },
651 {
652 .name = "C10-SKL",
653 .desc = "MWAIT 0x60",
654 .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
655 .exit_latency = 890,
656 .target_residency = 5000,
657 .enter = &intel_idle,
658 .enter_freeze = intel_idle_freeze, },
659 {
660 .enter = NULL }
661};
662
663static struct cpuidle_state skx_cstates[] = {
664 {
665 .name = "C1-SKX",
666 .desc = "MWAIT 0x00",
667 .flags = MWAIT2flg(0x00),
668 .exit_latency = 2,
669 .target_residency = 2,
670 .enter = &intel_idle,
671 .enter_freeze = intel_idle_freeze, },
672 {
673 .name = "C1E-SKX",
674 .desc = "MWAIT 0x01",
675 .flags = MWAIT2flg(0x01),
676 .exit_latency = 10,
677 .target_residency = 20,
678 .enter = &intel_idle,
679 .enter_freeze = intel_idle_freeze, },
680 {
681 .name = "C6-SKX",
682 .desc = "MWAIT 0x20",
683 .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
684 .exit_latency = 133,
685 .target_residency = 600,
686 .enter = &intel_idle,
687 .enter_freeze = intel_idle_freeze, },
688 {
689 .enter = NULL }
690};
691
692static struct cpuidle_state atom_cstates[] = {
693 {
694 .name = "C1E-ATM",
695 .desc = "MWAIT 0x00",
696 .flags = MWAIT2flg(0x00),
697 .exit_latency = 10,
698 .target_residency = 20,
699 .enter = &intel_idle,
700 .enter_freeze = intel_idle_freeze, },
701 {
702 .name = "C2-ATM",
703 .desc = "MWAIT 0x10",
704 .flags = MWAIT2flg(0x10),
705 .exit_latency = 20,
706 .target_residency = 80,
707 .enter = &intel_idle,
708 .enter_freeze = intel_idle_freeze, },
709 {
710 .name = "C4-ATM",
711 .desc = "MWAIT 0x30",
712 .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
713 .exit_latency = 100,
714 .target_residency = 400,
715 .enter = &intel_idle,
716 .enter_freeze = intel_idle_freeze, },
717 {
718 .name = "C6-ATM",
719 .desc = "MWAIT 0x52",
720 .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
721 .exit_latency = 140,
722 .target_residency = 560,
723 .enter = &intel_idle,
724 .enter_freeze = intel_idle_freeze, },
725 {
726 .enter = NULL }
727};
728static struct cpuidle_state avn_cstates[] = {
729 {
730 .name = "C1-AVN",
731 .desc = "MWAIT 0x00",
732 .flags = MWAIT2flg(0x00),
733 .exit_latency = 2,
734 .target_residency = 2,
735 .enter = &intel_idle,
736 .enter_freeze = intel_idle_freeze, },
737 {
738 .name = "C6-AVN",
739 .desc = "MWAIT 0x51",
740 .flags = MWAIT2flg(0x51) | CPUIDLE_FLAG_TLB_FLUSHED,
741 .exit_latency = 15,
742 .target_residency = 45,
743 .enter = &intel_idle,
744 .enter_freeze = intel_idle_freeze, },
745 {
746 .enter = NULL }
747};
748static struct cpuidle_state knl_cstates[] = {
749 {
750 .name = "C1-KNL",
751 .desc = "MWAIT 0x00",
752 .flags = MWAIT2flg(0x00),
753 .exit_latency = 1,
754 .target_residency = 2,
755 .enter = &intel_idle,
756 .enter_freeze = intel_idle_freeze },
757 {
758 .name = "C6-KNL",
759 .desc = "MWAIT 0x10",
760 .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
761 .exit_latency = 120,
762 .target_residency = 500,
763 .enter = &intel_idle,
764 .enter_freeze = intel_idle_freeze },
765 {
766 .enter = NULL }
767};
768
769/**
770 * intel_idle
771 * @dev: cpuidle_device
772 * @drv: cpuidle driver
773 * @index: index of cpuidle state
774 *
775 * Must be called under local_irq_disable().
776 */
777static int intel_idle(struct cpuidle_device *dev,
778 struct cpuidle_driver *drv, int index)
779{
780 unsigned long ecx = 1; /* break on interrupt flag */
781 struct cpuidle_state *state = &drv->states[index];
782 unsigned long eax = flg2MWAIT(state->flags);
783 unsigned int cstate;
784 int cpu = smp_processor_id();
785
786 cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
787
788 /*
789 * leave_mm() to avoid costly and often unnecessary wakeups
790 * for flushing the user TLB's associated with the active mm.
791 */
792 if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
793 leave_mm(cpu);
794
795 if (!(lapic_timer_reliable_states & (1 << (cstate))))
796 tick_broadcast_enter();
797
798 mwait_idle_with_hints(eax, ecx);
799
800 if (!(lapic_timer_reliable_states & (1 << (cstate))))
801 tick_broadcast_exit();
802
803 return index;
804}
805
806/**
807 * intel_idle_freeze - simplified "enter" callback routine for suspend-to-idle
808 * @dev: cpuidle_device
809 * @drv: cpuidle driver
810 * @index: state index
811 */
812static void intel_idle_freeze(struct cpuidle_device *dev,
813 struct cpuidle_driver *drv, int index)
814{
815 unsigned long ecx = 1; /* break on interrupt flag */
816 unsigned long eax = flg2MWAIT(drv->states[index].flags);
817
818 mwait_idle_with_hints(eax, ecx);
819}
820
821static void __setup_broadcast_timer(void *arg)
822{
823 unsigned long on = (unsigned long)arg;
824
825 if (on)
826 tick_broadcast_enable();
827 else
828 tick_broadcast_disable();
829}
830
831static int cpu_hotplug_notify(struct notifier_block *n,
832 unsigned long action, void *hcpu)
833{
834 int hotcpu = (unsigned long)hcpu;
835 struct cpuidle_device *dev;
836
837 switch (action & ~CPU_TASKS_FROZEN) {
838 case CPU_ONLINE:
839
840 if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
841 smp_call_function_single(hotcpu, __setup_broadcast_timer,
842 (void *)true, 1);
843
844 /*
845 * Some systems can hotplug a cpu at runtime after
846 * the kernel has booted, we have to initialize the
847 * driver in this case
848 */
849 dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);
850 if (dev->registered)
851 break;
852
853 if (intel_idle_cpu_init(hotcpu))
854 return NOTIFY_BAD;
855
856 break;
857 }
858 return NOTIFY_OK;
859}
860
861static struct notifier_block cpu_hotplug_notifier = {
862 .notifier_call = cpu_hotplug_notify,
863};
864
865static void auto_demotion_disable(void *dummy)
866{
867 unsigned long long msr_bits;
868
869 rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
870 msr_bits &= ~(icpu->auto_demotion_disable_flags);
871 wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
872}
873static void c1e_promotion_disable(void *dummy)
874{
875 unsigned long long msr_bits;
876
877 rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
878 msr_bits &= ~0x2;
879 wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
880}
881
882static const struct idle_cpu idle_cpu_nehalem = {
883 .state_table = nehalem_cstates,
884 .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
885 .disable_promotion_to_c1e = true,
886};
887
888static const struct idle_cpu idle_cpu_atom = {
889 .state_table = atom_cstates,
890};
891
892static const struct idle_cpu idle_cpu_lincroft = {
893 .state_table = atom_cstates,
894 .auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE,
895};
896
897static const struct idle_cpu idle_cpu_snb = {
898 .state_table = snb_cstates,
899 .disable_promotion_to_c1e = true,
900};
901
902static const struct idle_cpu idle_cpu_byt = {
903 .state_table = byt_cstates,
904 .disable_promotion_to_c1e = true,
905 .byt_auto_demotion_disable_flag = true,
906};
907
908static const struct idle_cpu idle_cpu_cht = {
909 .state_table = cht_cstates,
910 .disable_promotion_to_c1e = true,
911 .byt_auto_demotion_disable_flag = true,
912};
913
914static const struct idle_cpu idle_cpu_ivb = {
915 .state_table = ivb_cstates,
916 .disable_promotion_to_c1e = true,
917};
918
919static const struct idle_cpu idle_cpu_ivt = {
920 .state_table = ivt_cstates,
921 .disable_promotion_to_c1e = true,
922};
923
924static const struct idle_cpu idle_cpu_hsw = {
925 .state_table = hsw_cstates,
926 .disable_promotion_to_c1e = true,
927};
928
929static const struct idle_cpu idle_cpu_bdw = {
930 .state_table = bdw_cstates,
931 .disable_promotion_to_c1e = true,
932};
933
934static const struct idle_cpu idle_cpu_skl = {
935 .state_table = skl_cstates,
936 .disable_promotion_to_c1e = true,
937};
938
939static const struct idle_cpu idle_cpu_skx = {
940 .state_table = skx_cstates,
941 .disable_promotion_to_c1e = true,
942};
943
944static const struct idle_cpu idle_cpu_avn = {
945 .state_table = avn_cstates,
946 .disable_promotion_to_c1e = true,
947};
948
949static const struct idle_cpu idle_cpu_knl = {
950 .state_table = knl_cstates,
951};
952
953#define ICPU(model, cpu) \
954 { X86_VENDOR_INTEL, 6, model, X86_FEATURE_MWAIT, (unsigned long)&cpu }
955
956static const struct x86_cpu_id intel_idle_ids[] __initconst = {
957 ICPU(0x1a, idle_cpu_nehalem),
958 ICPU(0x1e, idle_cpu_nehalem),
959 ICPU(0x1f, idle_cpu_nehalem),
960 ICPU(0x25, idle_cpu_nehalem),
961 ICPU(0x2c, idle_cpu_nehalem),
962 ICPU(0x2e, idle_cpu_nehalem),
963 ICPU(0x1c, idle_cpu_atom),
964 ICPU(0x26, idle_cpu_lincroft),
965 ICPU(0x2f, idle_cpu_nehalem),
966 ICPU(0x2a, idle_cpu_snb),
967 ICPU(0x2d, idle_cpu_snb),
968 ICPU(0x36, idle_cpu_atom),
969 ICPU(0x37, idle_cpu_byt),
970 ICPU(0x4c, idle_cpu_cht),
971 ICPU(0x3a, idle_cpu_ivb),
972 ICPU(0x3e, idle_cpu_ivt),
973 ICPU(0x3c, idle_cpu_hsw),
974 ICPU(0x3f, idle_cpu_hsw),
975 ICPU(0x45, idle_cpu_hsw),
976 ICPU(0x46, idle_cpu_hsw),
977 ICPU(0x4d, idle_cpu_avn),
978 ICPU(0x3d, idle_cpu_bdw),
979 ICPU(0x47, idle_cpu_bdw),
980 ICPU(0x4f, idle_cpu_bdw),
981 ICPU(0x56, idle_cpu_bdw),
982 ICPU(0x4e, idle_cpu_skl),
983 ICPU(0x5e, idle_cpu_skl),
984 ICPU(0x8e, idle_cpu_skl),
985 ICPU(0x9e, idle_cpu_skl),
986 ICPU(0x55, idle_cpu_skx),
987 ICPU(0x57, idle_cpu_knl),
988 {}
989};
990MODULE_DEVICE_TABLE(x86cpu, intel_idle_ids);
991
992/*
993 * intel_idle_probe()
994 */
995static int __init intel_idle_probe(void)
996{
997 unsigned int eax, ebx, ecx;
998 const struct x86_cpu_id *id;
999
1000 if (max_cstate == 0) {
1001 pr_debug(PREFIX "disabled\n");
1002 return -EPERM;
1003 }
1004
1005 id = x86_match_cpu(intel_idle_ids);
1006 if (!id) {
1007 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
1008 boot_cpu_data.x86 == 6)
1009 pr_debug(PREFIX "does not run on family %d model %d\n",
1010 boot_cpu_data.x86, boot_cpu_data.x86_model);
1011 return -ENODEV;
1012 }
1013
1014 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
1015 return -ENODEV;
1016
1017 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
1018
1019 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
1020 !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
1021 !mwait_substates)
1022 return -ENODEV;
1023
1024 pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);
1025
1026 icpu = (const struct idle_cpu *)id->driver_data;
1027 cpuidle_state_table = icpu->state_table;
1028
1029 pr_debug(PREFIX "v" INTEL_IDLE_VERSION
1030 " model 0x%X\n", boot_cpu_data.x86_model);
1031
1032 return 0;
1033}
1034
1035/*
1036 * intel_idle_cpuidle_devices_uninit()
1037 * Unregisters the cpuidle devices.
1038 */
1039static void intel_idle_cpuidle_devices_uninit(void)
1040{
1041 int i;
1042 struct cpuidle_device *dev;
1043
1044 for_each_online_cpu(i) {
1045 dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
1046 cpuidle_unregister_device(dev);
1047 }
1048}
1049
1050/*
1051 * ivt_idle_state_table_update(void)
1052 *
1053 * Tune IVT multi-socket targets
1054 * Assumption: num_sockets == (max_package_num + 1)
1055 */
1056static void ivt_idle_state_table_update(void)
1057{
1058 /* IVT uses a different table for 1-2, 3-4, and > 4 sockets */
1059 int cpu, package_num, num_sockets = 1;
1060
1061 for_each_online_cpu(cpu) {
1062 package_num = topology_physical_package_id(cpu);
1063 if (package_num + 1 > num_sockets) {
1064 num_sockets = package_num + 1;
1065
1066 if (num_sockets > 4) {
1067 cpuidle_state_table = ivt_cstates_8s;
1068 return;
1069 }
1070 }
1071 }
1072
1073 if (num_sockets > 2)
1074 cpuidle_state_table = ivt_cstates_4s;
1075
1076 /* else, 1 and 2 socket systems use default ivt_cstates */
1077}
1078/*
1079 * sklh_idle_state_table_update(void)
1080 *
1081 * On SKL-H (model 0x5e) disable C8 and C9 if:
1082 * C10 is enabled and SGX disabled
1083 */
1084static void sklh_idle_state_table_update(void)
1085{
1086 unsigned long long msr;
1087 unsigned int eax, ebx, ecx, edx;
1088
1089
1090 /* if PC10 disabled via cmdline intel_idle.max_cstate=7 or shallower */
1091 if (max_cstate <= 7)
1092 return;
1093
1094 /* if PC10 not present in CPUID.MWAIT.EDX */
1095 if ((mwait_substates & (0xF << 28)) == 0)
1096 return;
1097
1098 rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr);
1099
1100 /* PC10 is not enabled in PKG C-state limit */
1101 if ((msr & 0xF) != 8)
1102 return;
1103
1104 ecx = 0;
1105 cpuid(7, &eax, &ebx, &ecx, &edx);
1106
1107 /* if SGX is present */
1108 if (ebx & (1 << 2)) {
1109
1110 rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
1111
1112 /* if SGX is enabled */
1113 if (msr & (1 << 18))
1114 return;
1115 }
1116
1117 skl_cstates[5].disabled = 1; /* C8-SKL */
1118 skl_cstates[6].disabled = 1; /* C9-SKL */
1119}
1120/*
1121 * intel_idle_state_table_update()
1122 *
1123 * Update the default state_table for this CPU-id
1124 */
1125
1126static void intel_idle_state_table_update(void)
1127{
1128 switch (boot_cpu_data.x86_model) {
1129
1130 case 0x3e: /* IVT */
1131 ivt_idle_state_table_update();
1132 break;
1133 case 0x5e: /* SKL-H */
1134 sklh_idle_state_table_update();
1135 break;
1136 }
1137}
1138
1139/*
1140 * intel_idle_cpuidle_driver_init()
1141 * allocate, initialize cpuidle_states
1142 */
1143static void __init intel_idle_cpuidle_driver_init(void)
1144{
1145 int cstate;
1146 struct cpuidle_driver *drv = &intel_idle_driver;
1147
1148 intel_idle_state_table_update();
1149
1150 drv->state_count = 1;
1151
1152 for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
1153 int num_substates, mwait_hint, mwait_cstate;
1154
1155 if ((cpuidle_state_table[cstate].enter == NULL) &&
1156 (cpuidle_state_table[cstate].enter_freeze == NULL))
1157 break;
1158
1159 if (cstate + 1 > max_cstate) {
1160 printk(PREFIX "max_cstate %d reached\n",
1161 max_cstate);
1162 break;
1163 }
1164
1165 mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
1166 mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);
1167
1168 /* number of sub-states for this state in CPUID.MWAIT */
1169 num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
1170 & MWAIT_SUBSTATE_MASK;
1171
1172 /* if NO sub-states for this state in CPUID, skip it */
1173 if (num_substates == 0)
1174 continue;
1175
1176 /* if state marked as disabled, skip it */
1177 if (cpuidle_state_table[cstate].disabled != 0) {
1178 pr_debug(PREFIX "state %s is disabled",
1179 cpuidle_state_table[cstate].name);
1180 continue;
1181 }
1182
1183
1184 if (((mwait_cstate + 1) > 2) &&
1185 !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
1186 mark_tsc_unstable("TSC halts in idle"
1187 " states deeper than C2");
1188
1189 drv->states[drv->state_count] = /* structure copy */
1190 cpuidle_state_table[cstate];
1191
1192 drv->state_count += 1;
1193 }
1194
1195 if (icpu->byt_auto_demotion_disable_flag) {
1196 wrmsrl(MSR_CC6_DEMOTION_POLICY_CONFIG, 0);
1197 wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0);
1198 }
1199}
1200
1201
1202/*
1203 * intel_idle_cpu_init()
1204 * allocate, initialize, register cpuidle_devices
1205 * @cpu: cpu/core to initialize
1206 */
1207static int intel_idle_cpu_init(int cpu)
1208{
1209 struct cpuidle_device *dev;
1210
1211 dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
1212
1213 dev->cpu = cpu;
1214
1215 if (cpuidle_register_device(dev)) {
1216 pr_debug(PREFIX "cpuidle_register_device %d failed!\n", cpu);
1217 return -EIO;
1218 }
1219
1220 if (icpu->auto_demotion_disable_flags)
1221 smp_call_function_single(cpu, auto_demotion_disable, NULL, 1);
1222
1223 if (icpu->disable_promotion_to_c1e)
1224 smp_call_function_single(cpu, c1e_promotion_disable, NULL, 1);
1225
1226 return 0;
1227}
1228
1229static int __init intel_idle_init(void)
1230{
1231 int retval, i;
1232
1233 /* Do not load intel_idle at all for now if idle= is passed */
1234 if (boot_option_idle_override != IDLE_NO_OVERRIDE)
1235 return -ENODEV;
1236
1237 retval = intel_idle_probe();
1238 if (retval)
1239 return retval;
1240
1241 intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
1242 if (intel_idle_cpuidle_devices == NULL)
1243 return -ENOMEM;
1244
1245 intel_idle_cpuidle_driver_init();
1246 retval = cpuidle_register_driver(&intel_idle_driver);
1247 if (retval) {
1248 struct cpuidle_driver *drv = cpuidle_get_driver();
1249 printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
1250 drv ? drv->name : "none");
1251 free_percpu(intel_idle_cpuidle_devices);
1252 return retval;
1253 }
1254
1255 cpu_notifier_register_begin();
1256
1257 for_each_online_cpu(i) {
1258 retval = intel_idle_cpu_init(i);
1259 if (retval) {
1260 intel_idle_cpuidle_devices_uninit();
1261 cpu_notifier_register_done();
1262 cpuidle_unregister_driver(&intel_idle_driver);
1263 free_percpu(intel_idle_cpuidle_devices);
1264 return retval;
1265 }
1266 }
1267 __register_cpu_notifier(&cpu_hotplug_notifier);
1268
1269 if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
1270 lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
1271 else
1272 on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
1273
1274 cpu_notifier_register_done();
1275
1276 pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
1277 lapic_timer_reliable_states);
1278
1279 return 0;
1280}
1281
1282static void __exit intel_idle_exit(void)
1283{
1284 struct cpuidle_device *dev;
1285 int i;
1286
1287 cpu_notifier_register_begin();
1288
1289 if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
1290 on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
1291 __unregister_cpu_notifier(&cpu_hotplug_notifier);
1292
1293 for_each_possible_cpu(i) {
1294 dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
1295 cpuidle_unregister_device(dev);
1296 }
1297
1298 cpu_notifier_register_done();
1299
1300 cpuidle_unregister_driver(&intel_idle_driver);
1301 free_percpu(intel_idle_cpuidle_devices);
1302}
1303
1304module_init(intel_idle_init);
1305module_exit(intel_idle_exit);
1306
1307module_param(max_cstate, int, 0444);
1308
1309MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
1310MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
1311MODULE_LICENSE("GPL");
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 <linux/hrtimer.h> /* ktime_get_real() */
60#include <trace/events/power.h>
61#include <linux/sched.h>
62#include <linux/notifier.h>
63#include <linux/cpu.h>
64#include <asm/mwait.h>
65#include <asm/msr.h>
66
67#define INTEL_IDLE_VERSION "0.4"
68#define PREFIX "intel_idle: "
69
70static struct cpuidle_driver intel_idle_driver = {
71 .name = "intel_idle",
72 .owner = THIS_MODULE,
73};
74/* intel_idle.max_cstate=0 disables driver */
75static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
76
77static unsigned int mwait_substates;
78
79#define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
80/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
81static unsigned int lapic_timer_reliable_states = (1 << 1); /* Default to only C1 */
82
83static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
84static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state);
85
86static struct cpuidle_state *cpuidle_state_table;
87
88/*
89 * Hardware C-state auto-demotion may not always be optimal.
90 * Indicate which enable bits to clear here.
91 */
92static unsigned long long auto_demotion_disable_flags;
93
94/*
95 * Set this flag for states where the HW flushes the TLB for us
96 * and so we don't need cross-calls to keep it consistent.
97 * If this flag is set, SW flushes the TLB, so even if the
98 * HW doesn't do the flushing, this flag is safe to use.
99 */
100#define CPUIDLE_FLAG_TLB_FLUSHED 0x10000
101
102/*
103 * States are indexed by the cstate number,
104 * which is also the index into the MWAIT hint array.
105 * Thus C0 is a dummy.
106 */
107static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = {
108 { /* MWAIT C0 */ },
109 { /* MWAIT C1 */
110 .name = "C1-NHM",
111 .desc = "MWAIT 0x00",
112 .driver_data = (void *) 0x00,
113 .flags = CPUIDLE_FLAG_TIME_VALID,
114 .exit_latency = 3,
115 .target_residency = 6,
116 .enter = &intel_idle },
117 { /* MWAIT C2 */
118 .name = "C3-NHM",
119 .desc = "MWAIT 0x10",
120 .driver_data = (void *) 0x10,
121 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
122 .exit_latency = 20,
123 .target_residency = 80,
124 .enter = &intel_idle },
125 { /* MWAIT C3 */
126 .name = "C6-NHM",
127 .desc = "MWAIT 0x20",
128 .driver_data = (void *) 0x20,
129 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
130 .exit_latency = 200,
131 .target_residency = 800,
132 .enter = &intel_idle },
133};
134
135static struct cpuidle_state snb_cstates[MWAIT_MAX_NUM_CSTATES] = {
136 { /* MWAIT C0 */ },
137 { /* MWAIT C1 */
138 .name = "C1-SNB",
139 .desc = "MWAIT 0x00",
140 .driver_data = (void *) 0x00,
141 .flags = CPUIDLE_FLAG_TIME_VALID,
142 .exit_latency = 1,
143 .target_residency = 1,
144 .enter = &intel_idle },
145 { /* MWAIT C2 */
146 .name = "C3-SNB",
147 .desc = "MWAIT 0x10",
148 .driver_data = (void *) 0x10,
149 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
150 .exit_latency = 80,
151 .target_residency = 211,
152 .enter = &intel_idle },
153 { /* MWAIT C3 */
154 .name = "C6-SNB",
155 .desc = "MWAIT 0x20",
156 .driver_data = (void *) 0x20,
157 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
158 .exit_latency = 104,
159 .target_residency = 345,
160 .enter = &intel_idle },
161 { /* MWAIT C4 */
162 .name = "C7-SNB",
163 .desc = "MWAIT 0x30",
164 .driver_data = (void *) 0x30,
165 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
166 .exit_latency = 109,
167 .target_residency = 345,
168 .enter = &intel_idle },
169};
170
171static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
172 { /* MWAIT C0 */ },
173 { /* MWAIT C1 */
174 .name = "C1-ATM",
175 .desc = "MWAIT 0x00",
176 .driver_data = (void *) 0x00,
177 .flags = CPUIDLE_FLAG_TIME_VALID,
178 .exit_latency = 1,
179 .target_residency = 4,
180 .enter = &intel_idle },
181 { /* MWAIT C2 */
182 .name = "C2-ATM",
183 .desc = "MWAIT 0x10",
184 .driver_data = (void *) 0x10,
185 .flags = CPUIDLE_FLAG_TIME_VALID,
186 .exit_latency = 20,
187 .target_residency = 80,
188 .enter = &intel_idle },
189 { /* MWAIT C3 */ },
190 { /* MWAIT C4 */
191 .name = "C4-ATM",
192 .desc = "MWAIT 0x30",
193 .driver_data = (void *) 0x30,
194 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
195 .exit_latency = 100,
196 .target_residency = 400,
197 .enter = &intel_idle },
198 { /* MWAIT C5 */ },
199 { /* MWAIT C6 */
200 .name = "C6-ATM",
201 .desc = "MWAIT 0x52",
202 .driver_data = (void *) 0x52,
203 .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
204 .exit_latency = 140,
205 .target_residency = 560,
206 .enter = &intel_idle },
207};
208
209/**
210 * intel_idle
211 * @dev: cpuidle_device
212 * @state: cpuidle state
213 *
214 */
215static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
216{
217 unsigned long ecx = 1; /* break on interrupt flag */
218 unsigned long eax = (unsigned long)cpuidle_get_statedata(state);
219 unsigned int cstate;
220 ktime_t kt_before, kt_after;
221 s64 usec_delta;
222 int cpu = smp_processor_id();
223
224 cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
225
226 local_irq_disable();
227
228 /*
229 * leave_mm() to avoid costly and often unnecessary wakeups
230 * for flushing the user TLB's associated with the active mm.
231 */
232 if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
233 leave_mm(cpu);
234
235 if (!(lapic_timer_reliable_states & (1 << (cstate))))
236 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
237
238 kt_before = ktime_get_real();
239
240 stop_critical_timings();
241 if (!need_resched()) {
242
243 __monitor((void *)¤t_thread_info()->flags, 0, 0);
244 smp_mb();
245 if (!need_resched())
246 __mwait(eax, ecx);
247 }
248
249 start_critical_timings();
250
251 kt_after = ktime_get_real();
252 usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before));
253
254 local_irq_enable();
255
256 if (!(lapic_timer_reliable_states & (1 << (cstate))))
257 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
258
259 return usec_delta;
260}
261
262static void __setup_broadcast_timer(void *arg)
263{
264 unsigned long reason = (unsigned long)arg;
265 int cpu = smp_processor_id();
266
267 reason = reason ?
268 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
269
270 clockevents_notify(reason, &cpu);
271}
272
273static int setup_broadcast_cpuhp_notify(struct notifier_block *n,
274 unsigned long action, void *hcpu)
275{
276 int hotcpu = (unsigned long)hcpu;
277
278 switch (action & 0xf) {
279 case CPU_ONLINE:
280 smp_call_function_single(hotcpu, __setup_broadcast_timer,
281 (void *)true, 1);
282 break;
283 }
284 return NOTIFY_OK;
285}
286
287static struct notifier_block setup_broadcast_notifier = {
288 .notifier_call = setup_broadcast_cpuhp_notify,
289};
290
291static void auto_demotion_disable(void *dummy)
292{
293 unsigned long long msr_bits;
294
295 rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
296 msr_bits &= ~auto_demotion_disable_flags;
297 wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
298}
299
300/*
301 * intel_idle_probe()
302 */
303static int intel_idle_probe(void)
304{
305 unsigned int eax, ebx, ecx;
306
307 if (max_cstate == 0) {
308 pr_debug(PREFIX "disabled\n");
309 return -EPERM;
310 }
311
312 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
313 return -ENODEV;
314
315 if (!boot_cpu_has(X86_FEATURE_MWAIT))
316 return -ENODEV;
317
318 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
319 return -ENODEV;
320
321 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
322
323 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
324 !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
325 return -ENODEV;
326
327 pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);
328
329
330 if (boot_cpu_data.x86 != 6) /* family 6 */
331 return -ENODEV;
332
333 switch (boot_cpu_data.x86_model) {
334
335 case 0x1A: /* Core i7, Xeon 5500 series */
336 case 0x1E: /* Core i7 and i5 Processor - Lynnfield Jasper Forest */
337 case 0x1F: /* Core i7 and i5 Processor - Nehalem */
338 case 0x2E: /* Nehalem-EX Xeon */
339 case 0x2F: /* Westmere-EX Xeon */
340 case 0x25: /* Westmere */
341 case 0x2C: /* Westmere */
342 cpuidle_state_table = nehalem_cstates;
343 auto_demotion_disable_flags =
344 (NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE);
345 break;
346
347 case 0x1C: /* 28 - Atom Processor */
348 cpuidle_state_table = atom_cstates;
349 break;
350
351 case 0x26: /* 38 - Lincroft Atom Processor */
352 cpuidle_state_table = atom_cstates;
353 auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE;
354 break;
355
356 case 0x2A: /* SNB */
357 case 0x2D: /* SNB Xeon */
358 cpuidle_state_table = snb_cstates;
359 break;
360
361 default:
362 pr_debug(PREFIX "does not run on family %d model %d\n",
363 boot_cpu_data.x86, boot_cpu_data.x86_model);
364 return -ENODEV;
365 }
366
367 if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
368 lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
369 else {
370 smp_call_function(__setup_broadcast_timer, (void *)true, 1);
371 register_cpu_notifier(&setup_broadcast_notifier);
372 }
373
374 pr_debug(PREFIX "v" INTEL_IDLE_VERSION
375 " model 0x%X\n", boot_cpu_data.x86_model);
376
377 pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
378 lapic_timer_reliable_states);
379 return 0;
380}
381
382/*
383 * intel_idle_cpuidle_devices_uninit()
384 * unregister, free cpuidle_devices
385 */
386static void intel_idle_cpuidle_devices_uninit(void)
387{
388 int i;
389 struct cpuidle_device *dev;
390
391 for_each_online_cpu(i) {
392 dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
393 cpuidle_unregister_device(dev);
394 }
395
396 free_percpu(intel_idle_cpuidle_devices);
397 return;
398}
399/*
400 * intel_idle_cpuidle_devices_init()
401 * allocate, initialize, register cpuidle_devices
402 */
403static int intel_idle_cpuidle_devices_init(void)
404{
405 int i, cstate;
406 struct cpuidle_device *dev;
407
408 intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
409 if (intel_idle_cpuidle_devices == NULL)
410 return -ENOMEM;
411
412 for_each_online_cpu(i) {
413 dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
414
415 dev->state_count = 1;
416
417 for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) {
418 int num_substates;
419
420 if (cstate > max_cstate) {
421 printk(PREFIX "max_cstate %d reached\n",
422 max_cstate);
423 break;
424 }
425
426 /* does the state exist in CPUID.MWAIT? */
427 num_substates = (mwait_substates >> ((cstate) * 4))
428 & MWAIT_SUBSTATE_MASK;
429 if (num_substates == 0)
430 continue;
431 /* is the state not enabled? */
432 if (cpuidle_state_table[cstate].enter == NULL) {
433 /* does the driver not know about the state? */
434 if (*cpuidle_state_table[cstate].name == '\0')
435 pr_debug(PREFIX "unaware of model 0x%x"
436 " MWAIT %d please"
437 " contact lenb@kernel.org",
438 boot_cpu_data.x86_model, cstate);
439 continue;
440 }
441
442 if ((cstate > 2) &&
443 !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
444 mark_tsc_unstable("TSC halts in idle"
445 " states deeper than C2");
446
447 dev->states[dev->state_count] = /* structure copy */
448 cpuidle_state_table[cstate];
449
450 dev->state_count += 1;
451 }
452
453 dev->cpu = i;
454 if (cpuidle_register_device(dev)) {
455 pr_debug(PREFIX "cpuidle_register_device %d failed!\n",
456 i);
457 intel_idle_cpuidle_devices_uninit();
458 return -EIO;
459 }
460 }
461 if (auto_demotion_disable_flags)
462 smp_call_function(auto_demotion_disable, NULL, 1);
463
464 return 0;
465}
466
467
468static int __init intel_idle_init(void)
469{
470 int retval;
471
472 /* Do not load intel_idle at all for now if idle= is passed */
473 if (boot_option_idle_override != IDLE_NO_OVERRIDE)
474 return -ENODEV;
475
476 retval = intel_idle_probe();
477 if (retval)
478 return retval;
479
480 retval = cpuidle_register_driver(&intel_idle_driver);
481 if (retval) {
482 printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
483 cpuidle_get_driver()->name);
484 return retval;
485 }
486
487 retval = intel_idle_cpuidle_devices_init();
488 if (retval) {
489 cpuidle_unregister_driver(&intel_idle_driver);
490 return retval;
491 }
492
493 return 0;
494}
495
496static void __exit intel_idle_exit(void)
497{
498 intel_idle_cpuidle_devices_uninit();
499 cpuidle_unregister_driver(&intel_idle_driver);
500
501 if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
502 smp_call_function(__setup_broadcast_timer, (void *)false, 1);
503 unregister_cpu_notifier(&setup_broadcast_notifier);
504 }
505
506 return;
507}
508
509module_init(intel_idle_init);
510module_exit(intel_idle_exit);
511
512module_param(max_cstate, int, 0444);
513
514MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
515MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
516MODULE_LICENSE("GPL");