summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/idle_power7.S
blob: cf4fb5429cf12fe097590d570d7c9a6b0bce2571 (plain)
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
/*
 *  This file contains the power_save function for Power7 CPUs.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/threads.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ppc-opcode.h>
#include <asm/hw_irq.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/opal.h>
#include <asm/cpuidle.h>
#include <asm/mmu-hash64.h>

#undef DEBUG

/*
 * Use unused space in the interrupt stack to save and restore
 * registers for winkle support.
 */
#define _SDR1	GPR3
#define _RPR	GPR4
#define _SPURR	GPR5
#define _PURR	GPR6
#define _TSCR	GPR7
#define _DSCR	GPR8
#define _AMOR	GPR9
#define _WORT	GPR10
#define _WORC	GPR11

/* Idle state entry routines */

#define	IDLE_STATE_ENTER_SEQ(IDLE_INST)				\
	/* Magic NAP/SLEEP/WINKLE mode enter sequence */	\
	std	r0,0(r1);					\
	ptesync;						\
	ld	r0,0(r1);					\
1:	cmp	cr0,r0,r0;					\
	bne	1b;						\
	IDLE_INST;						\
	b	.

	.text

/*
 * Used by threads when the lock bit of core_idle_state is set.
 * Threads will spin in HMT_LOW until the lock bit is cleared.
 * r14 - pointer to core_idle_state
 * r15 - used to load contents of core_idle_state
 */

core_idle_lock_held:
	HMT_LOW
3:	lwz	r15,0(r14)
	andi.   r15,r15,PNV_CORE_IDLE_LOCK_BIT
	bne	3b
	HMT_MEDIUM
	lwarx	r15,0,r14
	blr

/*
 * Pass requested state in r3:
 *	r3 - PNV_THREAD_NAP/SLEEP/WINKLE
 *
 * To check IRQ_HAPPENED in r4
 * 	0 - don't check
 * 	1 - check
 */
_GLOBAL(power7_powersave_common)
	/* Use r3 to pass state nap/sleep/winkle */
	/* NAP is a state loss, we create a regs frame on the
	 * stack, fill it up with the state we care about and
	 * stick a pointer to it in PACAR1. We really only
	 * need to save PC, some CR bits and the NV GPRs,
	 * but for now an interrupt frame will do.
	 */
	mflr	r0
	std	r0,16(r1)
	stdu	r1,-INT_FRAME_SIZE(r1)
	std	r0,_LINK(r1)
	std	r0,_NIP(r1)

	/* Hard disable interrupts */
	mfmsr	r9
	rldicl	r9,r9,48,1
	rotldi	r9,r9,16
	mtmsrd	r9,1			/* hard-disable interrupts */

	/* Check if something happened while soft-disabled */
	lbz	r0,PACAIRQHAPPENED(r13)
	andi.	r0,r0,~PACA_IRQ_HARD_DIS@l
	beq	1f
	cmpwi	cr0,r4,0
	beq	1f
	addi	r1,r1,INT_FRAME_SIZE
	ld	r0,16(r1)
	li	r3,0			/* Return 0 (no nap) */
	mtlr	r0
	blr

1:	/* We mark irqs hard disabled as this is the state we'll
	 * be in when returning and we need to tell arch_local_irq_restore()
	 * about it
	 */
	li	r0,PACA_IRQ_HARD_DIS
	stb	r0,PACAIRQHAPPENED(r13)

	/* We haven't lost state ... yet */
	li	r0,0
	stb	r0,PACA_NAPSTATELOST(r13)

	/* Continue saving state */
	SAVE_GPR(2, r1)
	SAVE_NVGPRS(r1)
	mfcr	r4
	std	r4,_CCR(r1)
	std	r9,_MSR(r1)
	std	r1,PACAR1(r13)

	/*
	 * Go to real mode to do the nap, as required by the architecture.
	 * Also, we need to be in real mode before setting hwthread_state,
	 * because as soon as we do that, another thread can switch
	 * the MMU context to the guest.
	 */
	LOAD_REG_IMMEDIATE(r5, MSR_IDLE)
	li	r6, MSR_RI
	andc	r6, r9, r6
	LOAD_REG_ADDR(r7, power7_enter_nap_mode)
	mtmsrd	r6, 1		/* clear RI before setting SRR0/1 */
	mtspr	SPRN_SRR0, r7
	mtspr	SPRN_SRR1, r5
	rfid

	.globl	power7_enter_nap_mode
power7_enter_nap_mode:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
	/* Tell KVM we're napping */
	li	r4,KVM_HWTHREAD_IN_NAP
	stb	r4,HSTATE_HWTHREAD_STATE(r13)
#endif
	stb	r3,PACA_THREAD_IDLE_STATE(r13)
	cmpwi	cr3,r3,PNV_THREAD_SLEEP
	bge	cr3,2f
	IDLE_STATE_ENTER_SEQ(PPC_NAP)
	/* No return */
2:
	/* Sleep or winkle */
	lbz	r7,PACA_THREAD_MASK(r13)
	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
lwarx_loop1:
	lwarx	r15,0,r14

	andi.   r9,r15,PNV_CORE_IDLE_LOCK_BIT
	bnel	core_idle_lock_held

	andc	r15,r15,r7			/* Clear thread bit */

	andi.	r15,r15,PNV_CORE_IDLE_THREAD_BITS

/*
 * If cr0 = 0, then current thread is the last thread of the core entering
 * sleep. Last thread needs to execute the hardware bug workaround code if
 * required by the platform.
 * Make the workaround call unconditionally here. The below branch call is
 * patched out when the idle states are discovered if the platform does not
 * require it.
 */
.global pnv_fastsleep_workaround_at_entry
pnv_fastsleep_workaround_at_entry:
	beq	fastsleep_workaround_at_entry

	stwcx.	r15,0,r14
	bne-	lwarx_loop1
	isync

common_enter: /* common code for all the threads entering sleep or winkle */
	bgt	cr3,enter_winkle
	IDLE_STATE_ENTER_SEQ(PPC_SLEEP)

fastsleep_workaround_at_entry:
	ori	r15,r15,PNV_CORE_IDLE_LOCK_BIT
	stwcx.	r15,0,r14
	bne-	lwarx_loop1
	isync

	/* Fast sleep workaround */
	li	r3,1
	li	r4,1
	li	r0,OPAL_CONFIG_CPU_IDLE_STATE
	bl	opal_call_realmode

	/* Clear Lock bit */
	li	r0,0
	lwsync
	stw	r0,0(r14)
	b	common_enter

enter_winkle:
	/*
	 * Note all register i.e per-core, per-subcore or per-thread is saved
	 * here since any thread in the core might wake up first
	 */
	mfspr	r3,SPRN_SDR1
	std	r3,_SDR1(r1)
	mfspr	r3,SPRN_RPR
	std	r3,_RPR(r1)
	mfspr	r3,SPRN_SPURR
	std	r3,_SPURR(r1)
	mfspr	r3,SPRN_PURR
	std	r3,_PURR(r1)
	mfspr	r3,SPRN_TSCR
	std	r3,_TSCR(r1)
	mfspr	r3,SPRN_DSCR
	std	r3,_DSCR(r1)
	mfspr	r3,SPRN_AMOR
	std	r3,_AMOR(r1)
	mfspr	r3,SPRN_WORT
	std	r3,_WORT(r1)
	mfspr	r3,SPRN_WORC
	std	r3,_WORC(r1)
	IDLE_STATE_ENTER_SEQ(PPC_WINKLE)

_GLOBAL(power7_idle)
	/* Now check if user or arch enabled NAP mode */
	LOAD_REG_ADDRBASE(r3,powersave_nap)
	lwz	r4,ADDROFF(powersave_nap)(r3)
	cmpwi	0,r4,0
	beqlr
	li	r3, 1
	/* fall through */

_GLOBAL(power7_nap)
	mr	r4,r3
	li	r3,PNV_THREAD_NAP
	b	power7_powersave_common
	/* No return */

_GLOBAL(power7_sleep)
	li	r3,PNV_THREAD_SLEEP
	li	r4,1
	b	power7_powersave_common
	/* No return */

_GLOBAL(power7_winkle)
	li	r3,3
	li	r4,1
	b	power7_powersave_common
	/* No return */

#define CHECK_HMI_INTERRUPT						\
	mfspr	r0,SPRN_SRR1;						\
BEGIN_FTR_SECTION_NESTED(66);						\
	rlwinm	r0,r0,45-31,0xf;  /* extract wake reason field (P8) */	\
FTR_SECTION_ELSE_NESTED(66);						\
	rlwinm	r0,r0,45-31,0xe;  /* P7 wake reason field is 3 bits */	\
ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
	cmpwi	r0,0xa;			/* Hypervisor maintenance ? */	\
	bne	20f;							\
	/* Invoke opal call to handle hmi */				\
	ld	r2,PACATOC(r13);					\
	ld	r1,PACAR1(r13);						\
	std	r3,ORIG_GPR3(r1);	/* Save original r3 */		\
	li	r0,OPAL_HANDLE_HMI;	/* Pass opal token argument*/	\
	bl	opal_call_realmode;					\
	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
20:	nop;


_GLOBAL(power7_wakeup_tb_loss)
	ld	r2,PACATOC(r13);
	ld	r1,PACAR1(r13)
	/*
	 * Before entering any idle state, the NVGPRs are saved in the stack
	 * and they are restored before switching to the process context. Hence
	 * until they are restored, they are free to be used.
	 *
	 * Save SRR1 in a NVGPR as it might be clobbered in opal_call_realmode
	 * (called in CHECK_HMI_INTERRUPT). SRR1 is required to determine the
	 * wakeup reason if we branch to kvm_start_guest.
	 */

	mfspr	r16,SPRN_SRR1
BEGIN_FTR_SECTION
	CHECK_HMI_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)

	lbz	r7,PACA_THREAD_MASK(r13)
	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
lwarx_loop2:
	lwarx	r15,0,r14
	andi.	r9,r15,PNV_CORE_IDLE_LOCK_BIT
	/*
	 * Lock bit is set in one of the 2 cases-
	 * a. In the sleep/winkle enter path, the last thread is executing
	 * fastsleep workaround code.
	 * b. In the wake up path, another thread is executing fastsleep
	 * workaround undo code or resyncing timebase or restoring context
	 * In either case loop until the lock bit is cleared.
	 */
	bnel	core_idle_lock_held

	cmpwi	cr2,r15,0
	lbz	r4,PACA_SUBCORE_SIBLING_MASK(r13)
	and	r4,r4,r15
	cmpwi	cr1,r4,0	/* Check if first in subcore */

	/*
	 * At this stage
	 * cr1 - 0b0100 if first thread to wakeup in subcore
	 * cr2 - 0b0100 if first thread to wakeup in core
	 * cr3-  0b0010 if waking up from sleep or winkle
	 * cr4 - 0b0100 if waking up from winkle
	 */

	or	r15,r15,r7		/* Set thread bit */

	beq	cr1,first_thread_in_subcore

	/* Not first thread in subcore to wake up */
	stwcx.	r15,0,r14
	bne-	lwarx_loop2
	isync
	b	common_exit

first_thread_in_subcore:
	/* First thread in subcore to wakeup */
	ori	r15,r15,PNV_CORE_IDLE_LOCK_BIT
	stwcx.	r15,0,r14
	bne-	lwarx_loop2
	isync

	/*
	 * If waking up from sleep, subcore state is not lost. Hence
	 * skip subcore state restore
	 */
	bne	cr4,subcore_state_restored

	/* Restore per-subcore state */
	ld      r4,_SDR1(r1)
	mtspr   SPRN_SDR1,r4
	ld      r4,_RPR(r1)
	mtspr   SPRN_RPR,r4
	ld	r4,_AMOR(r1)
	mtspr	SPRN_AMOR,r4

subcore_state_restored:
	/*
	 * Check if the thread is also the first thread in the core. If not,
	 * skip to clear_lock.
	 */
	bne	cr2,clear_lock

first_thread_in_core:

	/*
	 * First thread in the core waking up from fastsleep. It needs to
	 * call the fastsleep workaround code if the platform requires it.
	 * Call it unconditionally here. The below branch instruction will
	 * be patched out when the idle states are discovered if platform
	 * does not require workaround.
	 */
.global pnv_fastsleep_workaround_at_exit
pnv_fastsleep_workaround_at_exit:
	b	fastsleep_workaround_at_exit

timebase_resync:
	/* Do timebase resync if we are waking up from sleep. Use cr3 value
	 * set in exceptions-64s.S */
	ble	cr3,clear_lock
	/* Time base re-sync */
	li	r0,OPAL_RESYNC_TIMEBASE
	bl	opal_call_realmode;
	/* TODO: Check r3 for failure */

	/*
	 * If waking up from sleep, per core state is not lost, skip to
	 * clear_lock.
	 */
	bne	cr4,clear_lock

	/* Restore per core state */
	ld	r4,_TSCR(r1)
	mtspr	SPRN_TSCR,r4
	ld	r4,_WORC(r1)
	mtspr	SPRN_WORC,r4

clear_lock:
	andi.	r15,r15,PNV_CORE_IDLE_THREAD_BITS
	lwsync
	stw	r15,0(r14)

common_exit:
	/*
	 * Common to all threads.
	 *
	 * If waking up from sleep, hypervisor state is not lost. Hence
	 * skip hypervisor state restore.
	 */
	bne	cr4,hypervisor_state_restored

	/* Waking up from winkle */

	/* Restore per thread state */
	bl	__restore_cpu_power8

	/* Restore SLB  from PACA */
	ld	r8,PACA_SLBSHADOWPTR(r13)

	.rept	SLB_NUM_BOLTED
	li	r3, SLBSHADOW_SAVEAREA
	LDX_BE	r5, r8, r3
	addi	r3, r3, 8
	LDX_BE	r6, r8, r3
	andis.	r7,r5,SLB_ESID_V@h
	beq	1f
	slbmte	r6,r5
1:	addi	r8,r8,16
	.endr

	ld	r4,_SPURR(r1)
	mtspr	SPRN_SPURR,r4
	ld	r4,_PURR(r1)
	mtspr	SPRN_PURR,r4
	ld	r4,_DSCR(r1)
	mtspr	SPRN_DSCR,r4
	ld	r4,_WORT(r1)
	mtspr	SPRN_WORT,r4

hypervisor_state_restored:

	li	r5,PNV_THREAD_RUNNING
	stb     r5,PACA_THREAD_IDLE_STATE(r13)

	mtspr	SPRN_SRR1,r16
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
	li      r0,KVM_HWTHREAD_IN_KERNEL
	stb     r0,HSTATE_HWTHREAD_STATE(r13)
	/* Order setting hwthread_state vs. testing hwthread_req */
	sync
	lbz     r0,HSTATE_HWTHREAD_REQ(r13)
	cmpwi   r0,0
	beq     6f
	b       kvm_start_guest
6:
#endif

	REST_NVGPRS(r1)
	REST_GPR(2, r1)
	ld	r3,_CCR(r1)
	ld	r4,_MSR(r1)
	ld	r5,_NIP(r1)
	addi	r1,r1,INT_FRAME_SIZE
	mtcr	r3
	mfspr	r3,SPRN_SRR1		/* Return SRR1 */
	mtspr	SPRN_SRR1,r4
	mtspr	SPRN_SRR0,r5
	rfid

fastsleep_workaround_at_exit:
	li	r3,1
	li	r4,0
	li	r0,OPAL_CONFIG_CPU_IDLE_STATE
	bl	opal_call_realmode
	b	timebase_resync

/*
 * R3 here contains the value that will be returned to the caller
 * of power7_nap.
 */
_GLOBAL(power7_wakeup_loss)
	ld	r1,PACAR1(r13)
BEGIN_FTR_SECTION
	CHECK_HMI_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
	REST_NVGPRS(r1)
	REST_GPR(2, r1)
	ld	r6,_CCR(r1)
	ld	r4,_MSR(r1)
	ld	r5,_NIP(r1)
	addi	r1,r1,INT_FRAME_SIZE
	mtcr	r6
	mtspr	SPRN_SRR1,r4
	mtspr	SPRN_SRR0,r5
	rfid

/*
 * R3 here contains the value that will be returned to the caller
 * of power7_nap.
 */
_GLOBAL(power7_wakeup_noloss)
	lbz	r0,PACA_NAPSTATELOST(r13)
	cmpwi	r0,0
	bne	power7_wakeup_loss
BEGIN_FTR_SECTION
	CHECK_HMI_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
	ld	r1,PACAR1(r13)
	ld	r6,_CCR(r1)
	ld	r4,_MSR(r1)
	ld	r5,_NIP(r1)
	addi	r1,r1,INT_FRAME_SIZE
	mtcr	r6
	mtspr	SPRN_SRR1,r4
	mtspr	SPRN_SRR0,r5
	rfid