1/*
2 *  This file contains idle entry/exit functions for POWER7,
3 *  POWER8 and POWER9 CPUs.
4 *
5 *  This program is free software; you can redistribute it and/or
6 *  modify it under the terms of the GNU General Public License
7 *  as published by the Free Software Foundation; either version
8 *  2 of the License, or (at your option) any later version.
9 */
10
11#include <linux/threads.h>
12#include <asm/processor.h>
13#include <asm/page.h>
14#include <asm/cputable.h>
15#include <asm/thread_info.h>
16#include <asm/ppc_asm.h>
17#include <asm/asm-offsets.h>
18#include <asm/ppc-opcode.h>
19#include <asm/hw_irq.h>
20#include <asm/kvm_book3s_asm.h>
21#include <asm/opal.h>
22#include <asm/cpuidle.h>
23#include <asm/exception-64s.h>
24#include <asm/book3s/64/mmu-hash.h>
25#include <asm/mmu.h>
26
27#undef DEBUG
28
29/*
30 * Use unused space in the interrupt stack to save and restore
31 * registers for winkle support.
32 */
33#define _SDR1	GPR3
34#define _RPR	GPR4
35#define _SPURR	GPR5
36#define _PURR	GPR6
37#define _TSCR	GPR7
38#define _DSCR	GPR8
39#define _AMOR	GPR9
40#define _WORT	GPR10
41#define _WORC	GPR11
42#define _PTCR	GPR12
43
44#define PSSCR_EC_ESL_MASK_SHIFTED          (PSSCR_EC | PSSCR_ESL) >> 16
45
46	.text
47
48/*
49 * Used by threads before entering deep idle states. Saves SPRs
50 * in interrupt stack frame
51 */
52save_sprs_to_stack:
53	/*
54	 * Note all register i.e per-core, per-subcore or per-thread is saved
55	 * here since any thread in the core might wake up first
56	 */
57BEGIN_FTR_SECTION
58	mfspr	r3,SPRN_PTCR
59	std	r3,_PTCR(r1)
60	/*
61	 * Note - SDR1 is dropped in Power ISA v3. Hence not restoring
62	 * SDR1 here
63	 */
64FTR_SECTION_ELSE
65	mfspr	r3,SPRN_SDR1
66	std	r3,_SDR1(r1)
67ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
68	mfspr	r3,SPRN_RPR
69	std	r3,_RPR(r1)
70	mfspr	r3,SPRN_SPURR
71	std	r3,_SPURR(r1)
72	mfspr	r3,SPRN_PURR
73	std	r3,_PURR(r1)
74	mfspr	r3,SPRN_TSCR
75	std	r3,_TSCR(r1)
76	mfspr	r3,SPRN_DSCR
77	std	r3,_DSCR(r1)
78	mfspr	r3,SPRN_AMOR
79	std	r3,_AMOR(r1)
80	mfspr	r3,SPRN_WORT
81	std	r3,_WORT(r1)
82	mfspr	r3,SPRN_WORC
83	std	r3,_WORC(r1)
84
85	blr
86
87/*
88 * Used by threads when the lock bit of core_idle_state is set.
89 * Threads will spin in HMT_LOW until the lock bit is cleared.
90 * r14 - pointer to core_idle_state
91 * r15 - used to load contents of core_idle_state
92 * r9  - used as a temporary variable
93 */
94
95core_idle_lock_held:
96	HMT_LOW
973:	lwz	r15,0(r14)
98	andis.	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
99	bne	3b
100	HMT_MEDIUM
101	lwarx	r15,0,r14
102	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
103	bne-	core_idle_lock_held
104	blr
105
106/*
107 * Pass requested state in r3:
108 *	r3 - PNV_THREAD_NAP/SLEEP/WINKLE in POWER8
109 *	   - Requested STOP state in POWER9
110 *
111 * To check IRQ_HAPPENED in r4
112 * 	0 - don't check
113 * 	1 - check
114 *
115 * Address to 'rfid' to in r5
116 */
117pnv_powersave_common:
118	/* Use r3 to pass state nap/sleep/winkle */
119	/* NAP is a state loss, we create a regs frame on the
120	 * stack, fill it up with the state we care about and
121	 * stick a pointer to it in PACAR1. We really only
122	 * need to save PC, some CR bits and the NV GPRs,
123	 * but for now an interrupt frame will do.
124	 */
125	mflr	r0
126	std	r0,16(r1)
127	stdu	r1,-INT_FRAME_SIZE(r1)
128	std	r0,_LINK(r1)
129	std	r0,_NIP(r1)
130
131	/* Hard disable interrupts */
132	mfmsr	r9
133	rldicl	r9,r9,48,1
134	rotldi	r9,r9,16
135	mtmsrd	r9,1			/* hard-disable interrupts */
136
137	/* Check if something happened while soft-disabled */
138	lbz	r0,PACAIRQHAPPENED(r13)
139	andi.	r0,r0,~PACA_IRQ_HARD_DIS@l
140	beq	1f
141	cmpwi	cr0,r4,0
142	beq	1f
143	addi	r1,r1,INT_FRAME_SIZE
144	ld	r0,16(r1)
145	li	r3,0			/* Return 0 (no nap) */
146	mtlr	r0
147	blr
148
1491:	/* We mark irqs hard disabled as this is the state we'll
150	 * be in when returning and we need to tell arch_local_irq_restore()
151	 * about it
152	 */
153	li	r0,PACA_IRQ_HARD_DIS
154	stb	r0,PACAIRQHAPPENED(r13)
155
156	/* We haven't lost state ... yet */
157	li	r0,0
158	stb	r0,PACA_NAPSTATELOST(r13)
159
160	/* Continue saving state */
161	SAVE_GPR(2, r1)
162	SAVE_NVGPRS(r1)
163	mfcr	r4
164	std	r4,_CCR(r1)
165	std	r9,_MSR(r1)
166	std	r1,PACAR1(r13)
167
168	/*
169	 * Go to real mode to do the nap, as required by the architecture.
170	 * Also, we need to be in real mode before setting hwthread_state,
171	 * because as soon as we do that, another thread can switch
172	 * the MMU context to the guest.
173	 */
174	LOAD_REG_IMMEDIATE(r7, MSR_IDLE)
175	li	r6, MSR_RI
176	andc	r6, r9, r6
177	mtmsrd	r6, 1		/* clear RI before setting SRR0/1 */
178	mtspr	SPRN_SRR0, r5
179	mtspr	SPRN_SRR1, r7
180	rfid
181
182	.globl pnv_enter_arch207_idle_mode
183pnv_enter_arch207_idle_mode:
184#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
185	/* Tell KVM we're entering idle */
186	li	r4,KVM_HWTHREAD_IN_IDLE
187	/******************************************************/
188	/*  N O T E   W E L L    ! ! !    N O T E   W E L L   */
189	/* The following store to HSTATE_HWTHREAD_STATE(r13)  */
190	/* MUST occur in real mode, i.e. with the MMU off,    */
191	/* and the MMU must stay off until we clear this flag */
192	/* and test HSTATE_HWTHREAD_REQ(r13) in               */
193	/* pnv_powersave_wakeup in this file.                 */
194	/* The reason is that another thread can switch the   */
195	/* MMU to a guest context whenever this flag is set   */
196	/* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on,    */
197	/* that would potentially cause this thread to start  */
198	/* executing instructions from guest memory in        */
199	/* hypervisor mode, leading to a host crash or data   */
200	/* corruption, or worse.                              */
201	/******************************************************/
202	stb	r4,HSTATE_HWTHREAD_STATE(r13)
203#endif
204	stb	r3,PACA_THREAD_IDLE_STATE(r13)
205	cmpwi	cr3,r3,PNV_THREAD_SLEEP
206	bge	cr3,2f
207	IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP)
208	/* No return */
2092:
210	/* Sleep or winkle */
211	lbz	r7,PACA_THREAD_MASK(r13)
212	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
213	li	r5,0
214	beq	cr3,3f
215	lis	r5,PNV_CORE_IDLE_WINKLE_COUNT@h
2163:
217lwarx_loop1:
218	lwarx	r15,0,r14
219
220	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
221	bnel-	core_idle_lock_held
222
223	add	r15,r15,r5			/* Add if winkle */
224	andc	r15,r15,r7			/* Clear thread bit */
225
226	andi.	r9,r15,PNV_CORE_IDLE_THREAD_BITS
227
228/*
229 * If cr0 = 0, then current thread is the last thread of the core entering
230 * sleep. Last thread needs to execute the hardware bug workaround code if
231 * required by the platform.
232 * Make the workaround call unconditionally here. The below branch call is
233 * patched out when the idle states are discovered if the platform does not
234 * require it.
235 */
236.global pnv_fastsleep_workaround_at_entry
237pnv_fastsleep_workaround_at_entry:
238	beq	fastsleep_workaround_at_entry
239
240	stwcx.	r15,0,r14
241	bne-	lwarx_loop1
242	isync
243
244common_enter: /* common code for all the threads entering sleep or winkle */
245	bgt	cr3,enter_winkle
246	IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
247
248fastsleep_workaround_at_entry:
249	oris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
250	stwcx.	r15,0,r14
251	bne-	lwarx_loop1
252	isync
253
254	/* Fast sleep workaround */
255	li	r3,1
256	li	r4,1
257	bl	opal_config_cpu_idle_state
258
259	/* Unlock */
260	xoris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
261	lwsync
262	stw	r15,0(r14)
263	b	common_enter
264
265enter_winkle:
266	bl	save_sprs_to_stack
267
268	IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
269
270/*
271 * r3 - PSSCR value corresponding to the requested stop state.
272 */
273power_enter_stop:
274#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
275	/* Tell KVM we're entering idle */
276	li	r4,KVM_HWTHREAD_IN_IDLE
277	/* DO THIS IN REAL MODE!  See comment above. */
278	stb	r4,HSTATE_HWTHREAD_STATE(r13)
279#endif
280/*
281 * Check if we are executing the lite variant with ESL=EC=0
282 */
283	andis.   r4,r3,PSSCR_EC_ESL_MASK_SHIFTED
284	clrldi   r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */
285	bne	 .Lhandle_esl_ec_set
286	IDLE_STATE_ENTER_SEQ(PPC_STOP)
287	li	r3,0  /* Since we didn't lose state, return 0 */
288	b 	pnv_wakeup_noloss
289
290.Lhandle_esl_ec_set:
291/*
292 * Check if the requested state is a deep idle state.
293 */
294	LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
295	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
296	cmpd	r3,r4
297	bge	.Lhandle_deep_stop
298	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
299.Lhandle_deep_stop:
300/*
301 * Entering deep idle state.
302 * Clear thread bit in PACA_CORE_IDLE_STATE, save SPRs to
303 * stack and enter stop
304 */
305	lbz     r7,PACA_THREAD_MASK(r13)
306	ld      r14,PACA_CORE_IDLE_STATE_PTR(r13)
307
308lwarx_loop_stop:
309	lwarx   r15,0,r14
310	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
311	bnel-	core_idle_lock_held
312	andc    r15,r15,r7                      /* Clear thread bit */
313
314	stwcx.  r15,0,r14
315	bne-    lwarx_loop_stop
316	isync
317
318	bl	save_sprs_to_stack
319
320	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
321
322_GLOBAL(power7_idle)
323	/* Now check if user or arch enabled NAP mode */
324	LOAD_REG_ADDRBASE(r3,powersave_nap)
325	lwz	r4,ADDROFF(powersave_nap)(r3)
326	cmpwi	0,r4,0
327	beqlr
328	li	r3, 1
329	/* fall through */
330
331_GLOBAL(power7_nap)
332	mr	r4,r3
333	li	r3,PNV_THREAD_NAP
334	LOAD_REG_ADDR(r5, pnv_enter_arch207_idle_mode)
335	b	pnv_powersave_common
336	/* No return */
337
338_GLOBAL(power7_sleep)
339	li	r3,PNV_THREAD_SLEEP
340	li	r4,1
341	LOAD_REG_ADDR(r5, pnv_enter_arch207_idle_mode)
342	b	pnv_powersave_common
343	/* No return */
344
345_GLOBAL(power7_winkle)
346	li	r3,PNV_THREAD_WINKLE
347	li	r4,1
348	LOAD_REG_ADDR(r5, pnv_enter_arch207_idle_mode)
349	b	pnv_powersave_common
350	/* No return */
351
352#define CHECK_HMI_INTERRUPT						\
353	mfspr	r0,SPRN_SRR1;						\
354BEGIN_FTR_SECTION_NESTED(66);						\
355	rlwinm	r0,r0,45-31,0xf;  /* extract wake reason field (P8) */	\
356FTR_SECTION_ELSE_NESTED(66);						\
357	rlwinm	r0,r0,45-31,0xe;  /* P7 wake reason field is 3 bits */	\
358ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
359	cmpwi	r0,0xa;			/* Hypervisor maintenance ? */	\
360	bne	20f;							\
361	/* Invoke opal call to handle hmi */				\
362	ld	r2,PACATOC(r13);					\
363	ld	r1,PACAR1(r13);						\
364	std	r3,ORIG_GPR3(r1);	/* Save original r3 */		\
365	li	r3,0;			/* NULL argument */		\
366	bl	hmi_exception_realmode;					\
367	nop;								\
368	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
36920:	nop;
370
371/*
372 * r3 - The PSSCR value corresponding to the stop state.
373 * r4 - The PSSCR mask corrresonding to the stop state.
374 */
375_GLOBAL(power9_idle_stop)
376	mfspr   r5,SPRN_PSSCR
377	andc    r5,r5,r4
378	or      r3,r3,r5
379	mtspr 	SPRN_PSSCR,r3
380	LOAD_REG_ADDR(r5,power_enter_stop)
381	li	r4,1
382	b	pnv_powersave_common
383	/* No return */
384
385/*
386 * On waking up from stop 0,1,2 with ESL=1 on POWER9 DD1,
387 * HSPRG0 will be set to the HSPRG0 value of one of the
388 * threads in this core. Thus the value we have in r13
389 * may not be this thread's paca pointer.
390 *
391 * Fortunately, the TIR remains invariant. Since this thread's
392 * paca pointer is recorded in all its sibling's paca, we can
393 * correctly recover this thread's paca pointer if we
394 * know the index of this thread in the core.
395 *
396 * This index can be obtained from the TIR.
397 *
398 * i.e, thread's position in the core = TIR.
399 * If this value is i, then this thread's paca is
400 * paca->thread_sibling_pacas[i].
401 */
402power9_dd1_recover_paca:
403	mfspr	r4, SPRN_TIR
404	/*
405	 * Since each entry in thread_sibling_pacas is 8 bytes
406	 * we need to left-shift by 3 bits. Thus r4 = i * 8
407	 */
408	sldi	r4, r4, 3
409	/* Get &paca->thread_sibling_pacas[0] in r5 */
410	ld	r5, PACA_SIBLING_PACA_PTRS(r13)
411	/* Load paca->thread_sibling_pacas[i] into r13 */
412	ldx	r13, r4, r5
413	SET_PACA(r13)
414	/*
415	 * Indicate that we have lost NVGPR state
416	 * which needs to be restored from the stack.
417	 */
418	li	r3, 1
419	stb	r3,PACA_NAPSTATELOST(r13)
420	blr
421
422/*
423 * Called from machine check handler for powersave wakeups.
424 * Low level machine check processing has already been done. Now just
425 * go through the wake up path to get everything in order.
426 *
427 * r3 - The original SRR1 value.
428 * Original SRR[01] have been clobbered.
429 * MSR_RI is clear.
430 */
431.global pnv_powersave_wakeup_mce
432pnv_powersave_wakeup_mce:
433	/* Set cr3 for pnv_powersave_wakeup */
434	rlwinm	r11,r3,47-31,30,31
435	cmpwi	cr3,r11,2
436
437	/*
438	 * Now put the original SRR1 with SRR1_WAKEMCE_RESVD as the wake
439	 * reason into SRR1, which allows reuse of the system reset wakeup
440	 * code without being mistaken for another type of wakeup.
441	 */
442	oris	r3,r3,SRR1_WAKEMCE_RESVD@h
443	mtspr	SPRN_SRR1,r3
444
445	b	pnv_powersave_wakeup
446
447/*
448 * Called from reset vector for powersave wakeups.
449 * cr3 - set to gt if waking up with partial/complete hypervisor state loss
450 */
451.global pnv_powersave_wakeup
452pnv_powersave_wakeup:
453	ld	r2, PACATOC(r13)
454
455BEGIN_FTR_SECTION
456BEGIN_FTR_SECTION_NESTED(70)
457	bl	power9_dd1_recover_paca
458END_FTR_SECTION_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70)
459	bl	pnv_restore_hyp_resource_arch300
460FTR_SECTION_ELSE
461	bl	pnv_restore_hyp_resource_arch207
462ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
463
464	li	r0,PNV_THREAD_RUNNING
465	stb	r0,PACA_THREAD_IDLE_STATE(r13)	/* Clear thread state */
466
467#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
468	li	r0,KVM_HWTHREAD_IN_KERNEL
469	stb	r0,HSTATE_HWTHREAD_STATE(r13)
470	/* Order setting hwthread_state vs. testing hwthread_req */
471	sync
472	lbz	r0,HSTATE_HWTHREAD_REQ(r13)
473	cmpwi	r0,0
474	beq	1f
475	b	kvm_start_guest
4761:
477#endif
478
479	/* Return SRR1 from power7_nap() */
480	mfspr	r3,SPRN_SRR1
481	blt	cr3,pnv_wakeup_noloss
482	b	pnv_wakeup_loss
483
484/*
485 * Check whether we have woken up with hypervisor state loss.
486 * If yes, restore hypervisor state and return back to link.
487 *
488 * cr3 - set to gt if waking up with partial/complete hypervisor state loss
489 */
490pnv_restore_hyp_resource_arch300:
491	/*
492	 * POWER ISA 3. Use PSSCR to determine if we
493	 * are waking up from deep idle state
494	 */
495	LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
496	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
497
498	mfspr	r5,SPRN_PSSCR
499	/*
500	 * 0-3 bits correspond to Power-Saving Level Status
501	 * which indicates the idle state we are waking up from
502	 */
503	rldicl  r5,r5,4,60
504	cmpd	cr4,r5,r4
505	bge	cr4,pnv_wakeup_tb_loss /* returns to caller */
506
507	blr	/* Waking up without hypervisor state loss. */
508
509/* Same calling convention as arch300 */
510pnv_restore_hyp_resource_arch207:
511	/*
512	 * POWER ISA 2.07 or less.
513	 * Check if we slept with sleep or winkle.
514	 */
515	lbz	r4,PACA_THREAD_IDLE_STATE(r13)
516	cmpwi	cr2,r4,PNV_THREAD_NAP
517	bgt	cr2,pnv_wakeup_tb_loss	/* Either sleep or Winkle */
518
519	/*
520	 * We fall through here if PACA_THREAD_IDLE_STATE shows we are waking
521	 * up from nap. At this stage CR3 shouldn't contains 'gt' since that
522	 * indicates we are waking with hypervisor state loss from nap.
523	 */
524	bgt	cr3,.
525
526	blr	/* Waking up without hypervisor state loss */
527
528/*
529 * Called if waking up from idle state which can cause either partial or
530 * complete hyp state loss.
531 * In POWER8, called if waking up from fastsleep or winkle
532 * In POWER9, called if waking up from stop state >= pnv_first_deep_stop_state
533 *
534 * r13 - PACA
535 * cr3 - gt if waking up with partial/complete hypervisor state loss
536 *
537 * If ISA300:
538 * cr4 - gt or eq if waking up from complete hypervisor state loss.
539 *
540 * If ISA207:
541 * r4 - PACA_THREAD_IDLE_STATE
542 */
543pnv_wakeup_tb_loss:
544	ld	r1,PACAR1(r13)
545	/*
546	 * Before entering any idle state, the NVGPRs are saved in the stack.
547	 * If there was a state loss, or PACA_NAPSTATELOST was set, then the
548	 * NVGPRs are restored. If we are here, it is likely that state is lost,
549	 * but not guaranteed -- neither ISA207 nor ISA300 tests to reach
550	 * here are the same as the test to restore NVGPRS:
551	 * PACA_THREAD_IDLE_STATE test for ISA207, PSSCR test for ISA300,
552	 * and SRR1 test for restoring NVGPRs.
553	 *
554	 * We are about to clobber NVGPRs now, so set NAPSTATELOST to
555	 * guarantee they will always be restored. This might be tightened
556	 * with careful reading of specs (particularly for ISA300) but this
557	 * is already a slow wakeup path and it's simpler to be safe.
558	 */
559	li	r0,1
560	stb	r0,PACA_NAPSTATELOST(r13)
561
562	/*
563	 *
564	 * Save SRR1 and LR in NVGPRs as they might be clobbered in
565	 * opal_call() (called in CHECK_HMI_INTERRUPT). SRR1 is required
566	 * to determine the wakeup reason if we branch to kvm_start_guest. LR
567	 * is required to return back to reset vector after hypervisor state
568	 * restore is complete.
569	 */
570	mr	r18,r4
571	mflr	r17
572	mfspr	r16,SPRN_SRR1
573BEGIN_FTR_SECTION
574	CHECK_HMI_INTERRUPT
575END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
576
577	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
578	lbz	r7,PACA_THREAD_MASK(r13)
579
580	/*
581	 * Take the core lock to synchronize against other threads.
582	 *
583	 * Lock bit is set in one of the 2 cases-
584	 * a. In the sleep/winkle enter path, the last thread is executing
585	 * fastsleep workaround code.
586	 * b. In the wake up path, another thread is executing fastsleep
587	 * workaround undo code or resyncing timebase or restoring context
588	 * In either case loop until the lock bit is cleared.
589	 */
5901:
591	lwarx	r15,0,r14
592	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
593	bnel-	core_idle_lock_held
594	oris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
595	stwcx.	r15,0,r14
596	bne-	1b
597	isync
598
599	andi.	r9,r15,PNV_CORE_IDLE_THREAD_BITS
600	cmpwi	cr2,r9,0
601
602	/*
603	 * At this stage
604	 * cr2 - eq if first thread to wakeup in core
605	 * cr3-  gt if waking up with partial/complete hypervisor state loss
606	 * ISA300:
607	 * cr4 - gt or eq if waking up from complete hypervisor state loss.
608	 */
609
610BEGIN_FTR_SECTION
611	/*
612	 * Were we in winkle?
613	 * If yes, check if all threads were in winkle, decrement our
614	 * winkle count, set all thread winkle bits if all were in winkle.
615	 * Check if our thread has a winkle bit set, and set cr4 accordingly
616	 * (to match ISA300, above). Pseudo-code for core idle state
617	 * transitions for ISA207 is as follows (everything happens atomically
618	 * due to store conditional and/or lock bit):
619	 *
620	 * nap_idle() { }
621	 * nap_wake() { }
622	 *
623	 * sleep_idle()
624	 * {
625	 *	core_idle_state &= ~thread_in_core
626	 * }
627	 *
628	 * sleep_wake()
629	 * {
630	 *     bool first_in_core, first_in_subcore;
631	 *
632	 *     first_in_core = (core_idle_state & IDLE_THREAD_BITS) == 0;
633	 *     first_in_subcore = (core_idle_state & SUBCORE_SIBLING_MASK) == 0;
634	 *
635	 *     core_idle_state |= thread_in_core;
636	 * }
637	 *
638	 * winkle_idle()
639	 * {
640	 *	core_idle_state &= ~thread_in_core;
641	 *	core_idle_state += 1 << WINKLE_COUNT_SHIFT;
642	 * }
643	 *
644	 * winkle_wake()
645	 * {
646	 *     bool first_in_core, first_in_subcore, winkle_state_lost;
647	 *
648	 *     first_in_core = (core_idle_state & IDLE_THREAD_BITS) == 0;
649	 *     first_in_subcore = (core_idle_state & SUBCORE_SIBLING_MASK) == 0;
650	 *
651	 *     core_idle_state |= thread_in_core;
652	 *
653	 *     if ((core_idle_state & WINKLE_MASK) == (8 << WINKLE_COUNT_SIHFT))
654	 *         core_idle_state |= THREAD_WINKLE_BITS;
655	 *     core_idle_state -= 1 << WINKLE_COUNT_SHIFT;
656	 *
657	 *     winkle_state_lost = core_idle_state &
658	 *				(thread_in_core << WINKLE_THREAD_SHIFT);
659	 *     core_idle_state &= ~(thread_in_core << WINKLE_THREAD_SHIFT);
660	 * }
661	 *
662	 */
663	cmpwi	r18,PNV_THREAD_WINKLE
664	bne	2f
665	andis.	r9,r15,PNV_CORE_IDLE_WINKLE_COUNT_ALL_BIT@h
666	subis	r15,r15,PNV_CORE_IDLE_WINKLE_COUNT@h
667	beq	2f
668	ori	r15,r15,PNV_CORE_IDLE_THREAD_WINKLE_BITS /* all were winkle */
6692:
670	/* Shift thread bit to winkle mask, then test if this thread is set,
671	 * and remove it from the winkle bits */
672	slwi	r8,r7,8
673	and	r8,r8,r15
674	andc	r15,r15,r8
675	cmpwi	cr4,r8,1 /* cr4 will be gt if our bit is set, lt if not */
676
677	lbz	r4,PACA_SUBCORE_SIBLING_MASK(r13)
678	and	r4,r4,r15
679	cmpwi	r4,0	/* Check if first in subcore */
680
681	or	r15,r15,r7		/* Set thread bit */
682	beq	first_thread_in_subcore
683END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
684
685	or	r15,r15,r7		/* Set thread bit */
686	beq	cr2,first_thread_in_core
687
688	/* Not first thread in core or subcore to wake up */
689	b	clear_lock
690
691first_thread_in_subcore:
692	/*
693	 * If waking up from sleep, subcore state is not lost. Hence
694	 * skip subcore state restore
695	 */
696	blt	cr4,subcore_state_restored
697
698	/* Restore per-subcore state */
699	ld      r4,_SDR1(r1)
700	mtspr   SPRN_SDR1,r4
701
702	ld      r4,_RPR(r1)
703	mtspr   SPRN_RPR,r4
704	ld	r4,_AMOR(r1)
705	mtspr	SPRN_AMOR,r4
706
707subcore_state_restored:
708	/*
709	 * Check if the thread is also the first thread in the core. If not,
710	 * skip to clear_lock.
711	 */
712	bne	cr2,clear_lock
713
714first_thread_in_core:
715
716	/*
717	 * First thread in the core waking up from any state which can cause
718	 * partial or complete hypervisor state loss. It needs to
719	 * call the fastsleep workaround code if the platform requires it.
720	 * Call it unconditionally here. The below branch instruction will
721	 * be patched out if the platform does not have fastsleep or does not
722	 * require the workaround. Patching will be performed during the
723	 * discovery of idle-states.
724	 */
725.global pnv_fastsleep_workaround_at_exit
726pnv_fastsleep_workaround_at_exit:
727	b	fastsleep_workaround_at_exit
728
729timebase_resync:
730	/*
731	 * Use cr3 which indicates that we are waking up with atleast partial
732	 * hypervisor state loss to determine if TIMEBASE RESYNC is needed.
733	 */
734	ble	cr3,clear_lock
735	/* Time base re-sync */
736	bl	opal_resync_timebase;
737	/*
738	 * If waking up from sleep, per core state is not lost, skip to
739	 * clear_lock.
740	 */
741	blt	cr4,clear_lock
742
743	/*
744	 * First thread in the core to wake up and its waking up with
745	 * complete hypervisor state loss. Restore per core hypervisor
746	 * state.
747	 */
748BEGIN_FTR_SECTION
749	ld	r4,_PTCR(r1)
750	mtspr	SPRN_PTCR,r4
751	ld	r4,_RPR(r1)
752	mtspr	SPRN_RPR,r4
753END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
754
755	ld	r4,_TSCR(r1)
756	mtspr	SPRN_TSCR,r4
757	ld	r4,_WORC(r1)
758	mtspr	SPRN_WORC,r4
759
760clear_lock:
761	xoris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
762	lwsync
763	stw	r15,0(r14)
764
765common_exit:
766	/*
767	 * Common to all threads.
768	 *
769	 * If waking up from sleep, hypervisor state is not lost. Hence
770	 * skip hypervisor state restore.
771	 */
772	blt	cr4,hypervisor_state_restored
773
774	/* Waking up from winkle */
775
776BEGIN_MMU_FTR_SECTION
777	b	no_segments
778END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
779	/* Restore SLB  from PACA */
780	ld	r8,PACA_SLBSHADOWPTR(r13)
781
782	.rept	SLB_NUM_BOLTED
783	li	r3, SLBSHADOW_SAVEAREA
784	LDX_BE	r5, r8, r3
785	addi	r3, r3, 8
786	LDX_BE	r6, r8, r3
787	andis.	r7,r5,SLB_ESID_V@h
788	beq	1f
789	slbmte	r6,r5
7901:	addi	r8,r8,16
791	.endr
792no_segments:
793
794	/* Restore per thread state */
795
796	ld	r4,_SPURR(r1)
797	mtspr	SPRN_SPURR,r4
798	ld	r4,_PURR(r1)
799	mtspr	SPRN_PURR,r4
800	ld	r4,_DSCR(r1)
801	mtspr	SPRN_DSCR,r4
802	ld	r4,_WORT(r1)
803	mtspr	SPRN_WORT,r4
804
805	/* Call cur_cpu_spec->cpu_restore() */
806	LOAD_REG_ADDR(r4, cur_cpu_spec)
807	ld	r4,0(r4)
808	ld	r12,CPU_SPEC_RESTORE(r4)
809#ifdef PPC64_ELF_ABI_v1
810	ld	r12,0(r12)
811#endif
812	mtctr	r12
813	bctrl
814
815hypervisor_state_restored:
816
817	mtspr	SPRN_SRR1,r16
818	mtlr	r17
819	blr		/* return to pnv_powersave_wakeup */
820
821fastsleep_workaround_at_exit:
822	li	r3,1
823	li	r4,0
824	bl	opal_config_cpu_idle_state
825	b	timebase_resync
826
827/*
828 * R3 here contains the value that will be returned to the caller
829 * of power7_nap.
830 */
831.global pnv_wakeup_loss
832pnv_wakeup_loss:
833	ld	r1,PACAR1(r13)
834BEGIN_FTR_SECTION
835	CHECK_HMI_INTERRUPT
836END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
837	REST_NVGPRS(r1)
838	REST_GPR(2, r1)
839	ld	r6,_CCR(r1)
840	ld	r4,_MSR(r1)
841	ld	r5,_NIP(r1)
842	addi	r1,r1,INT_FRAME_SIZE
843	mtcr	r6
844	mtspr	SPRN_SRR1,r4
845	mtspr	SPRN_SRR0,r5
846	rfid
847
848/*
849 * R3 here contains the value that will be returned to the caller
850 * of power7_nap.
851 */
852pnv_wakeup_noloss:
853	lbz	r0,PACA_NAPSTATELOST(r13)
854	cmpwi	r0,0
855	bne	pnv_wakeup_loss
856BEGIN_FTR_SECTION
857	CHECK_HMI_INTERRUPT
858END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
859	ld	r1,PACAR1(r13)
860	ld	r6,_CCR(r1)
861	ld	r4,_MSR(r1)
862	ld	r5,_NIP(r1)
863	addi	r1,r1,INT_FRAME_SIZE
864	mtcr	r6
865	mtspr	SPRN_SRR1,r4
866	mtspr	SPRN_SRR0,r5
867	rfid
868