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 _MMCR0	GPR0
34#define _SDR1	GPR3
35#define _PTCR	GPR3
36#define _RPR	GPR4
37#define _SPURR	GPR5
38#define _PURR	GPR6
39#define _TSCR	GPR7
40#define _DSCR	GPR8
41#define _AMOR	GPR9
42#define _WORT	GPR10
43#define _WORC	GPR11
44#define _LPCR	GPR12
45
46#define PSSCR_EC_ESL_MASK_SHIFTED          (PSSCR_EC | PSSCR_ESL) >> 16
47
48	.text
49
50/*
51 * Used by threads before entering deep idle states. Saves SPRs
52 * in interrupt stack frame
53 */
54save_sprs_to_stack:
55	/*
56	 * Note all register i.e per-core, per-subcore or per-thread is saved
57	 * here since any thread in the core might wake up first
58	 */
59BEGIN_FTR_SECTION
60	/*
61	 * Note - SDR1 is dropped in Power ISA v3. Hence not restoring
62	 * SDR1 here
63	 */
64	mfspr	r3,SPRN_PTCR
65	std	r3,_PTCR(r1)
66	mfspr	r3,SPRN_LPCR
67	std	r3,_LPCR(r1)
68FTR_SECTION_ELSE
69	mfspr	r3,SPRN_SDR1
70	std	r3,_SDR1(r1)
71ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
72	mfspr	r3,SPRN_RPR
73	std	r3,_RPR(r1)
74	mfspr	r3,SPRN_SPURR
75	std	r3,_SPURR(r1)
76	mfspr	r3,SPRN_PURR
77	std	r3,_PURR(r1)
78	mfspr	r3,SPRN_TSCR
79	std	r3,_TSCR(r1)
80	mfspr	r3,SPRN_DSCR
81	std	r3,_DSCR(r1)
82	mfspr	r3,SPRN_AMOR
83	std	r3,_AMOR(r1)
84	mfspr	r3,SPRN_WORT
85	std	r3,_WORT(r1)
86	mfspr	r3,SPRN_WORC
87	std	r3,_WORC(r1)
88
89	blr
90
91/*
92 * Used by threads when the lock bit of core_idle_state is set.
93 * Threads will spin in HMT_LOW until the lock bit is cleared.
94 * r14 - pointer to core_idle_state
95 * r15 - used to load contents of core_idle_state
96 * r9  - used as a temporary variable
97 */
98
99core_idle_lock_held:
100	HMT_LOW
1013:	lwz	r15,0(r14)
102	andis.	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
103	bne	3b
104	HMT_MEDIUM
105	lwarx	r15,0,r14
106	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
107	bne-	core_idle_lock_held
108	blr
109
110/*
111 * Pass requested state in r3:
112 *	r3 - PNV_THREAD_NAP/SLEEP/WINKLE in POWER8
113 *	   - Requested PSSCR value in POWER9
114 *
115 * Address of idle handler to branch to in realmode in r4
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	mtctr	r4
126
127	mflr	r0
128	std	r0,16(r1)
129	stdu	r1,-INT_FRAME_SIZE(r1)
130	std	r0,_LINK(r1)
131	std	r0,_NIP(r1)
132
133	/* We haven't lost state ... yet */
134	li	r0,0
135	stb	r0,PACA_NAPSTATELOST(r13)
136
137	/* Continue saving state */
138	SAVE_GPR(2, r1)
139	SAVE_NVGPRS(r1)
140	mfcr	r5
141	std	r5,_CCR(r1)
142	std	r1,PACAR1(r13)
143
144	/*
145	 * Go to real mode to do the nap, as required by the architecture.
146	 * Also, we need to be in real mode before setting hwthread_state,
147	 * because as soon as we do that, another thread can switch
148	 * the MMU context to the guest.
149	 */
150	LOAD_REG_IMMEDIATE(r7, MSR_IDLE)
151	mtmsrd	r7,0
152	bctr
153
154	.globl pnv_enter_arch207_idle_mode
155pnv_enter_arch207_idle_mode:
156#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
157	/* Tell KVM we're entering idle */
158	li	r4,KVM_HWTHREAD_IN_IDLE
159	/******************************************************/
160	/*  N O T E   W E L L    ! ! !    N O T E   W E L L   */
161	/* The following store to HSTATE_HWTHREAD_STATE(r13)  */
162	/* MUST occur in real mode, i.e. with the MMU off,    */
163	/* and the MMU must stay off until we clear this flag */
164	/* and test HSTATE_HWTHREAD_REQ(r13) in               */
165	/* pnv_powersave_wakeup in this file.                 */
166	/* The reason is that another thread can switch the   */
167	/* MMU to a guest context whenever this flag is set   */
168	/* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on,    */
169	/* that would potentially cause this thread to start  */
170	/* executing instructions from guest memory in        */
171	/* hypervisor mode, leading to a host crash or data   */
172	/* corruption, or worse.                              */
173	/******************************************************/
174	stb	r4,HSTATE_HWTHREAD_STATE(r13)
175#endif
176	stb	r3,PACA_THREAD_IDLE_STATE(r13)
177	cmpwi	cr3,r3,PNV_THREAD_SLEEP
178	bge	cr3,2f
179	IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP)
180	/* No return */
1812:
182	/* Sleep or winkle */
183	lbz	r7,PACA_THREAD_MASK(r13)
184	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
185	li	r5,0
186	beq	cr3,3f
187	lis	r5,PNV_CORE_IDLE_WINKLE_COUNT@h
1883:
189lwarx_loop1:
190	lwarx	r15,0,r14
191
192	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
193	bnel-	core_idle_lock_held
194
195	add	r15,r15,r5			/* Add if winkle */
196	andc	r15,r15,r7			/* Clear thread bit */
197
198	andi.	r9,r15,PNV_CORE_IDLE_THREAD_BITS
199
200/*
201 * If cr0 = 0, then current thread is the last thread of the core entering
202 * sleep. Last thread needs to execute the hardware bug workaround code if
203 * required by the platform.
204 * Make the workaround call unconditionally here. The below branch call is
205 * patched out when the idle states are discovered if the platform does not
206 * require it.
207 */
208.global pnv_fastsleep_workaround_at_entry
209pnv_fastsleep_workaround_at_entry:
210	beq	fastsleep_workaround_at_entry
211
212	stwcx.	r15,0,r14
213	bne-	lwarx_loop1
214	isync
215
216common_enter: /* common code for all the threads entering sleep or winkle */
217	bgt	cr3,enter_winkle
218	IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP)
219
220fastsleep_workaround_at_entry:
221	oris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
222	stwcx.	r15,0,r14
223	bne-	lwarx_loop1
224	isync
225
226	/* Fast sleep workaround */
227	li	r3,1
228	li	r4,1
229	bl	opal_config_cpu_idle_state
230
231	/* Unlock */
232	xoris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
233	lwsync
234	stw	r15,0(r14)
235	b	common_enter
236
237enter_winkle:
238	bl	save_sprs_to_stack
239
240	IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE)
241
242/*
243 * r3 - PSSCR value corresponding to the requested stop state.
244 */
245power_enter_stop:
246#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
247	/* Tell KVM we're entering idle */
248	li	r4,KVM_HWTHREAD_IN_IDLE
249	/* DO THIS IN REAL MODE!  See comment above. */
250	stb	r4,HSTATE_HWTHREAD_STATE(r13)
251#endif
252/*
253 * Check if we are executing the lite variant with ESL=EC=0
254 */
255	andis.   r4,r3,PSSCR_EC_ESL_MASK_SHIFTED
256	clrldi   r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */
257	bne	 .Lhandle_esl_ec_set
258	IDLE_STATE_ENTER_SEQ(PPC_STOP)
259	li	r3,0  /* Since we didn't lose state, return 0 */
260
261	/*
262	 * pnv_wakeup_noloss() expects r12 to contain the SRR1 value so
263	 * it can determine if the wakeup reason is an HMI in
264	 * CHECK_HMI_INTERRUPT.
265	 *
266	 * However, when we wakeup with ESL=0, SRR1 will not contain the wakeup
267	 * reason, so there is no point setting r12 to SRR1.
268	 *
269	 * Further, we clear r12 here, so that we don't accidentally enter the
270	 * HMI in pnv_wakeup_noloss() if the value of r12[42:45] == WAKE_HMI.
271	 */
272	li	r12, 0
273	b 	pnv_wakeup_noloss
274
275.Lhandle_esl_ec_set:
276	/*
277	 * POWER9 DD2 can incorrectly set PMAO when waking up after a
278	 * state-loss idle. Saving and restoring MMCR0 over idle is a
279	 * workaround.
280	 */
281	mfspr	r4,SPRN_MMCR0
282	std	r4,_MMCR0(r1)
283
284/*
285 * Check if the requested state is a deep idle state.
286 */
287	LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
288	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
289	cmpd	r3,r4
290	bge	.Lhandle_deep_stop
291	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
292.Lhandle_deep_stop:
293/*
294 * Entering deep idle state.
295 * Clear thread bit in PACA_CORE_IDLE_STATE, save SPRs to
296 * stack and enter stop
297 */
298	lbz     r7,PACA_THREAD_MASK(r13)
299	ld      r14,PACA_CORE_IDLE_STATE_PTR(r13)
300
301lwarx_loop_stop:
302	lwarx   r15,0,r14
303	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
304	bnel-	core_idle_lock_held
305	andc    r15,r15,r7                      /* Clear thread bit */
306
307	stwcx.  r15,0,r14
308	bne-    lwarx_loop_stop
309	isync
310
311	bl	save_sprs_to_stack
312
313	IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
314
315/*
316 * Entered with MSR[EE]=0 and no soft-masked interrupts pending.
317 * r3 contains desired idle state (PNV_THREAD_NAP/SLEEP/WINKLE).
318 */
319_GLOBAL(power7_idle_insn)
320	/* Now check if user or arch enabled NAP mode */
321	LOAD_REG_ADDR(r4, pnv_enter_arch207_idle_mode)
322	b	pnv_powersave_common
323
324#define CHECK_HMI_INTERRUPT						\
325BEGIN_FTR_SECTION_NESTED(66);						\
326	rlwinm	r0,r12,45-31,0xf;  /* extract wake reason field (P8) */	\
327FTR_SECTION_ELSE_NESTED(66);						\
328	rlwinm	r0,r12,45-31,0xe;  /* P7 wake reason field is 3 bits */	\
329ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
330	cmpwi	r0,0xa;			/* Hypervisor maintenance ? */	\
331	bne+	20f;							\
332	/* Invoke opal call to handle hmi */				\
333	ld	r2,PACATOC(r13);					\
334	ld	r1,PACAR1(r13);						\
335	std	r3,ORIG_GPR3(r1);	/* Save original r3 */		\
336	li	r3,0;			/* NULL argument */		\
337	bl	hmi_exception_realmode;					\
338	nop;								\
339	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
34020:	nop;
341
342/*
343 * Entered with MSR[EE]=0 and no soft-masked interrupts pending.
344 * r3 contains desired PSSCR register value.
345 */
346_GLOBAL(power9_idle_stop)
347	std	r3, PACA_REQ_PSSCR(r13)
348	mtspr 	SPRN_PSSCR,r3
349	LOAD_REG_ADDR(r4,power_enter_stop)
350	b	pnv_powersave_common
351	/* No return */
352
353/*
354 * On waking up from stop 0,1,2 with ESL=1 on POWER9 DD1,
355 * HSPRG0 will be set to the HSPRG0 value of one of the
356 * threads in this core. Thus the value we have in r13
357 * may not be this thread's paca pointer.
358 *
359 * Fortunately, the TIR remains invariant. Since this thread's
360 * paca pointer is recorded in all its sibling's paca, we can
361 * correctly recover this thread's paca pointer if we
362 * know the index of this thread in the core.
363 *
364 * This index can be obtained from the TIR.
365 *
366 * i.e, thread's position in the core = TIR.
367 * If this value is i, then this thread's paca is
368 * paca->thread_sibling_pacas[i].
369 */
370power9_dd1_recover_paca:
371	mfspr	r4, SPRN_TIR
372	/*
373	 * Since each entry in thread_sibling_pacas is 8 bytes
374	 * we need to left-shift by 3 bits. Thus r4 = i * 8
375	 */
376	sldi	r4, r4, 3
377	/* Get &paca->thread_sibling_pacas[0] in r5 */
378	ld	r5, PACA_SIBLING_PACA_PTRS(r13)
379	/* Load paca->thread_sibling_pacas[i] into r13 */
380	ldx	r13, r4, r5
381	SET_PACA(r13)
382	/*
383	 * Indicate that we have lost NVGPR state
384	 * which needs to be restored from the stack.
385	 */
386	li	r3, 1
387	stb	r3,PACA_NAPSTATELOST(r13)
388	blr
389
390/*
391 * Called from machine check handler for powersave wakeups.
392 * Low level machine check processing has already been done. Now just
393 * go through the wake up path to get everything in order.
394 *
395 * r3 - The original SRR1 value.
396 * Original SRR[01] have been clobbered.
397 * MSR_RI is clear.
398 */
399.global pnv_powersave_wakeup_mce
400pnv_powersave_wakeup_mce:
401	/* Set cr3 for pnv_powersave_wakeup */
402	rlwinm	r11,r3,47-31,30,31
403	cmpwi	cr3,r11,2
404
405	/*
406	 * Now put the original SRR1 with SRR1_WAKEMCE_RESVD as the wake
407	 * reason into r12, which allows reuse of the system reset wakeup
408	 * code without being mistaken for another type of wakeup.
409	 */
410	oris	r12,r3,SRR1_WAKEMCE_RESVD@h
411
412	b	pnv_powersave_wakeup
413
414/*
415 * Called from reset vector for powersave wakeups.
416 * cr3 - set to gt if waking up with partial/complete hypervisor state loss
417 * r12 - SRR1
418 */
419.global pnv_powersave_wakeup
420pnv_powersave_wakeup:
421	ld	r2, PACATOC(r13)
422
423BEGIN_FTR_SECTION
424BEGIN_FTR_SECTION_NESTED(70)
425	bl	power9_dd1_recover_paca
426END_FTR_SECTION_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70)
427	bl	pnv_restore_hyp_resource_arch300
428FTR_SECTION_ELSE
429	bl	pnv_restore_hyp_resource_arch207
430ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
431
432	li	r0,PNV_THREAD_RUNNING
433	stb	r0,PACA_THREAD_IDLE_STATE(r13)	/* Clear thread state */
434
435	mr	r3,r12
436
437#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
438	li	r0,KVM_HWTHREAD_IN_KERNEL
439	stb	r0,HSTATE_HWTHREAD_STATE(r13)
440	/* Order setting hwthread_state vs. testing hwthread_req */
441	sync
442	lbz	r0,HSTATE_HWTHREAD_REQ(r13)
443	cmpwi	r0,0
444	beq	1f
445	b	kvm_start_guest
4461:
447#endif
448
449	/* Return SRR1 from power7_nap() */
450	blt	cr3,pnv_wakeup_noloss
451	b	pnv_wakeup_loss
452
453/*
454 * Check whether we have woken up with hypervisor state loss.
455 * If yes, restore hypervisor state and return back to link.
456 *
457 * cr3 - set to gt if waking up with partial/complete hypervisor state loss
458 */
459pnv_restore_hyp_resource_arch300:
460	/*
461	 * Workaround for POWER9, if we lost resources, the ERAT
462	 * might have been mixed up and needs flushing. We also need
463	 * to reload MMCR0 (see comment above). We also need to set
464	 * then clear bit 60 in MMCRA to ensure the PMU starts running.
465	 */
466	blt	cr3,1f
467	PPC_INVALIDATE_ERAT
468	ld	r1,PACAR1(r13)
469	mfspr	r4,SPRN_MMCRA
470	ori	r4,r4,(1 << (63-60))
471	mtspr	SPRN_MMCRA,r4
472	xori	r4,r4,(1 << (63-60))
473	mtspr	SPRN_MMCRA,r4
474	ld	r4,_MMCR0(r1)
475	mtspr	SPRN_MMCR0,r4
4761:
477	/*
478	 * POWER ISA 3. Use PSSCR to determine if we
479	 * are waking up from deep idle state
480	 */
481	LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
482	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
483
484BEGIN_FTR_SECTION_NESTED(71)
485	/*
486	 * Assume that we are waking up from the state
487	 * same as the Requested Level (RL) in the PSSCR
488	 * which are Bits 60-63
489	 */
490	ld	r5,PACA_REQ_PSSCR(r13)
491	rldicl  r5,r5,0,60
492FTR_SECTION_ELSE_NESTED(71)
493	/*
494	 * 0-3 bits correspond to Power-Saving Level Status
495	 * which indicates the idle state we are waking up from
496	 */
497	mfspr	r5, SPRN_PSSCR
498	rldicl  r5,r5,4,60
499ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_POWER9_DD1, 71)
500	cmpd	cr4,r5,r4
501	bge	cr4,pnv_wakeup_tb_loss /* returns to caller */
502
503	blr	/* Waking up without hypervisor state loss. */
504
505/* Same calling convention as arch300 */
506pnv_restore_hyp_resource_arch207:
507	/*
508	 * POWER ISA 2.07 or less.
509	 * Check if we slept with sleep or winkle.
510	 */
511	lbz	r4,PACA_THREAD_IDLE_STATE(r13)
512	cmpwi	cr2,r4,PNV_THREAD_NAP
513	bgt	cr2,pnv_wakeup_tb_loss	/* Either sleep or Winkle */
514
515	/*
516	 * We fall through here if PACA_THREAD_IDLE_STATE shows we are waking
517	 * up from nap. At this stage CR3 shouldn't contains 'gt' since that
518	 * indicates we are waking with hypervisor state loss from nap.
519	 */
520	bgt	cr3,.
521
522	blr	/* Waking up without hypervisor state loss */
523
524/*
525 * Called if waking up from idle state which can cause either partial or
526 * complete hyp state loss.
527 * In POWER8, called if waking up from fastsleep or winkle
528 * In POWER9, called if waking up from stop state >= pnv_first_deep_stop_state
529 *
530 * r13 - PACA
531 * cr3 - gt if waking up with partial/complete hypervisor state loss
532 *
533 * If ISA300:
534 * cr4 - gt or eq if waking up from complete hypervisor state loss.
535 *
536 * If ISA207:
537 * r4 - PACA_THREAD_IDLE_STATE
538 */
539pnv_wakeup_tb_loss:
540	ld	r1,PACAR1(r13)
541	/*
542	 * Before entering any idle state, the NVGPRs are saved in the stack.
543	 * If there was a state loss, or PACA_NAPSTATELOST was set, then the
544	 * NVGPRs are restored. If we are here, it is likely that state is lost,
545	 * but not guaranteed -- neither ISA207 nor ISA300 tests to reach
546	 * here are the same as the test to restore NVGPRS:
547	 * PACA_THREAD_IDLE_STATE test for ISA207, PSSCR test for ISA300,
548	 * and SRR1 test for restoring NVGPRs.
549	 *
550	 * We are about to clobber NVGPRs now, so set NAPSTATELOST to
551	 * guarantee they will always be restored. This might be tightened
552	 * with careful reading of specs (particularly for ISA300) but this
553	 * is already a slow wakeup path and it's simpler to be safe.
554	 */
555	li	r0,1
556	stb	r0,PACA_NAPSTATELOST(r13)
557
558	/*
559	 *
560	 * Save SRR1 and LR in NVGPRs as they might be clobbered in
561	 * opal_call() (called in CHECK_HMI_INTERRUPT). SRR1 is required
562	 * to determine the wakeup reason if we branch to kvm_start_guest. LR
563	 * is required to return back to reset vector after hypervisor state
564	 * restore is complete.
565	 */
566	mr	r19,r12
567	mr	r18,r4
568	mflr	r17
569BEGIN_FTR_SECTION
570	CHECK_HMI_INTERRUPT
571END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
572
573	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
574	lbz	r7,PACA_THREAD_MASK(r13)
575
576	/*
577	 * Take the core lock to synchronize against other threads.
578	 *
579	 * Lock bit is set in one of the 2 cases-
580	 * a. In the sleep/winkle enter path, the last thread is executing
581	 * fastsleep workaround code.
582	 * b. In the wake up path, another thread is executing fastsleep
583	 * workaround undo code or resyncing timebase or restoring context
584	 * In either case loop until the lock bit is cleared.
585	 */
5861:
587	lwarx	r15,0,r14
588	andis.	r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
589	bnel-	core_idle_lock_held
590	oris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
591	stwcx.	r15,0,r14
592	bne-	1b
593	isync
594
595	andi.	r9,r15,PNV_CORE_IDLE_THREAD_BITS
596	cmpwi	cr2,r9,0
597
598	/*
599	 * At this stage
600	 * cr2 - eq if first thread to wakeup in core
601	 * cr3-  gt if waking up with partial/complete hypervisor state loss
602	 * ISA300:
603	 * cr4 - gt or eq if waking up from complete hypervisor state loss.
604	 */
605
606BEGIN_FTR_SECTION
607	/*
608	 * Were we in winkle?
609	 * If yes, check if all threads were in winkle, decrement our
610	 * winkle count, set all thread winkle bits if all were in winkle.
611	 * Check if our thread has a winkle bit set, and set cr4 accordingly
612	 * (to match ISA300, above). Pseudo-code for core idle state
613	 * transitions for ISA207 is as follows (everything happens atomically
614	 * due to store conditional and/or lock bit):
615	 *
616	 * nap_idle() { }
617	 * nap_wake() { }
618	 *
619	 * sleep_idle()
620	 * {
621	 *	core_idle_state &= ~thread_in_core
622	 * }
623	 *
624	 * sleep_wake()
625	 * {
626	 *     bool first_in_core, first_in_subcore;
627	 *
628	 *     first_in_core = (core_idle_state & IDLE_THREAD_BITS) == 0;
629	 *     first_in_subcore = (core_idle_state & SUBCORE_SIBLING_MASK) == 0;
630	 *
631	 *     core_idle_state |= thread_in_core;
632	 * }
633	 *
634	 * winkle_idle()
635	 * {
636	 *	core_idle_state &= ~thread_in_core;
637	 *	core_idle_state += 1 << WINKLE_COUNT_SHIFT;
638	 * }
639	 *
640	 * winkle_wake()
641	 * {
642	 *     bool first_in_core, first_in_subcore, winkle_state_lost;
643	 *
644	 *     first_in_core = (core_idle_state & IDLE_THREAD_BITS) == 0;
645	 *     first_in_subcore = (core_idle_state & SUBCORE_SIBLING_MASK) == 0;
646	 *
647	 *     core_idle_state |= thread_in_core;
648	 *
649	 *     if ((core_idle_state & WINKLE_MASK) == (8 << WINKLE_COUNT_SIHFT))
650	 *         core_idle_state |= THREAD_WINKLE_BITS;
651	 *     core_idle_state -= 1 << WINKLE_COUNT_SHIFT;
652	 *
653	 *     winkle_state_lost = core_idle_state &
654	 *				(thread_in_core << WINKLE_THREAD_SHIFT);
655	 *     core_idle_state &= ~(thread_in_core << WINKLE_THREAD_SHIFT);
656	 * }
657	 *
658	 */
659	cmpwi	r18,PNV_THREAD_WINKLE
660	bne	2f
661	andis.	r9,r15,PNV_CORE_IDLE_WINKLE_COUNT_ALL_BIT@h
662	subis	r15,r15,PNV_CORE_IDLE_WINKLE_COUNT@h
663	beq	2f
664	ori	r15,r15,PNV_CORE_IDLE_THREAD_WINKLE_BITS /* all were winkle */
6652:
666	/* Shift thread bit to winkle mask, then test if this thread is set,
667	 * and remove it from the winkle bits */
668	slwi	r8,r7,8
669	and	r8,r8,r15
670	andc	r15,r15,r8
671	cmpwi	cr4,r8,1 /* cr4 will be gt if our bit is set, lt if not */
672
673	lbz	r4,PACA_SUBCORE_SIBLING_MASK(r13)
674	and	r4,r4,r15
675	cmpwi	r4,0	/* Check if first in subcore */
676
677	or	r15,r15,r7		/* Set thread bit */
678	beq	first_thread_in_subcore
679END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
680
681	or	r15,r15,r7		/* Set thread bit */
682	beq	cr2,first_thread_in_core
683
684	/* Not first thread in core or subcore to wake up */
685	b	clear_lock
686
687first_thread_in_subcore:
688	/*
689	 * If waking up from sleep, subcore state is not lost. Hence
690	 * skip subcore state restore
691	 */
692	blt	cr4,subcore_state_restored
693
694	/* Restore per-subcore state */
695	ld      r4,_SDR1(r1)
696	mtspr   SPRN_SDR1,r4
697
698	ld      r4,_RPR(r1)
699	mtspr   SPRN_RPR,r4
700	ld	r4,_AMOR(r1)
701	mtspr	SPRN_AMOR,r4
702
703subcore_state_restored:
704	/*
705	 * Check if the thread is also the first thread in the core. If not,
706	 * skip to clear_lock.
707	 */
708	bne	cr2,clear_lock
709
710first_thread_in_core:
711
712	/*
713	 * First thread in the core waking up from any state which can cause
714	 * partial or complete hypervisor state loss. It needs to
715	 * call the fastsleep workaround code if the platform requires it.
716	 * Call it unconditionally here. The below branch instruction will
717	 * be patched out if the platform does not have fastsleep or does not
718	 * require the workaround. Patching will be performed during the
719	 * discovery of idle-states.
720	 */
721.global pnv_fastsleep_workaround_at_exit
722pnv_fastsleep_workaround_at_exit:
723	b	fastsleep_workaround_at_exit
724
725timebase_resync:
726	/*
727	 * Use cr3 which indicates that we are waking up with atleast partial
728	 * hypervisor state loss to determine if TIMEBASE RESYNC is needed.
729	 */
730	ble	cr3,.Ltb_resynced
731	/* Time base re-sync */
732	bl	opal_resync_timebase;
733	/*
734	 * If waking up from sleep (POWER8), per core state
735	 * is not lost, skip to clear_lock.
736	 */
737.Ltb_resynced:
738	blt	cr4,clear_lock
739
740	/*
741	 * First thread in the core to wake up and its waking up with
742	 * complete hypervisor state loss. Restore per core hypervisor
743	 * state.
744	 */
745BEGIN_FTR_SECTION
746	ld	r4,_PTCR(r1)
747	mtspr	SPRN_PTCR,r4
748	ld	r4,_RPR(r1)
749	mtspr	SPRN_RPR,r4
750END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
751
752	ld	r4,_TSCR(r1)
753	mtspr	SPRN_TSCR,r4
754	ld	r4,_WORC(r1)
755	mtspr	SPRN_WORC,r4
756
757clear_lock:
758	xoris	r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
759	lwsync
760	stw	r15,0(r14)
761
762common_exit:
763	/*
764	 * Common to all threads.
765	 *
766	 * If waking up from sleep, hypervisor state is not lost. Hence
767	 * skip hypervisor state restore.
768	 */
769	blt	cr4,hypervisor_state_restored
770
771	/* Waking up from winkle */
772
773BEGIN_MMU_FTR_SECTION
774	b	no_segments
775END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
776	/* Restore SLB  from PACA */
777	ld	r8,PACA_SLBSHADOWPTR(r13)
778
779	.rept	SLB_NUM_BOLTED
780	li	r3, SLBSHADOW_SAVEAREA
781	LDX_BE	r5, r8, r3
782	addi	r3, r3, 8
783	LDX_BE	r6, r8, r3
784	andis.	r7,r5,SLB_ESID_V@h
785	beq	1f
786	slbmte	r6,r5
7871:	addi	r8,r8,16
788	.endr
789no_segments:
790
791	/* Restore per thread state */
792
793	ld	r4,_SPURR(r1)
794	mtspr	SPRN_SPURR,r4
795	ld	r4,_PURR(r1)
796	mtspr	SPRN_PURR,r4
797	ld	r4,_DSCR(r1)
798	mtspr	SPRN_DSCR,r4
799	ld	r4,_WORT(r1)
800	mtspr	SPRN_WORT,r4
801
802	/* Call cur_cpu_spec->cpu_restore() */
803	LOAD_REG_ADDR(r4, cur_cpu_spec)
804	ld	r4,0(r4)
805	ld	r12,CPU_SPEC_RESTORE(r4)
806#ifdef PPC64_ELF_ABI_v1
807	ld	r12,0(r12)
808#endif
809	mtctr	r12
810	bctrl
811
812BEGIN_FTR_SECTION
813	ld	r4,_LPCR(r1)
814	mtspr	SPRN_LPCR,r4
815END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
816hypervisor_state_restored:
817
818	mr	r12,r19
819	mtlr	r17
820	blr		/* return to pnv_powersave_wakeup */
821
822fastsleep_workaround_at_exit:
823	li	r3,1
824	li	r4,0
825	bl	opal_config_cpu_idle_state
826	b	timebase_resync
827
828/*
829 * R3 here contains the value that will be returned to the caller
830 * of power7_nap.
831 * R12 contains SRR1 for CHECK_HMI_INTERRUPT.
832 */
833.global pnv_wakeup_loss
834pnv_wakeup_loss:
835	ld	r1,PACAR1(r13)
836BEGIN_FTR_SECTION
837	CHECK_HMI_INTERRUPT
838END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
839	REST_NVGPRS(r1)
840	REST_GPR(2, r1)
841	ld	r4,PACAKMSR(r13)
842	ld	r5,_LINK(r1)
843	ld	r6,_CCR(r1)
844	addi	r1,r1,INT_FRAME_SIZE
845	mtlr	r5
846	mtcr	r6
847	mtmsrd	r4
848	blr
849
850/*
851 * R3 here contains the value that will be returned to the caller
852 * of power7_nap.
853 * R12 contains SRR1 for CHECK_HMI_INTERRUPT.
854 */
855pnv_wakeup_noloss:
856	lbz	r0,PACA_NAPSTATELOST(r13)
857	cmpwi	r0,0
858	bne	pnv_wakeup_loss
859	ld	r1,PACAR1(r13)
860BEGIN_FTR_SECTION
861	CHECK_HMI_INTERRUPT
862END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
863	ld	r4,PACAKMSR(r13)
864	ld	r5,_NIP(r1)
865	ld	r6,_CCR(r1)
866	addi	r1,r1,INT_FRAME_SIZE
867	mtlr	r5
868	mtcr	r6
869	mtmsrd	r4
870	blr
871