aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/mm/hash_low_64.S
blob: a242b5d7cbe477c109a78152a344b663444738a1 (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
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
/*
 * ppc64 MMU hashtable management routines
 *
 * (c) Copyright IBM Corp. 2003, 2005
 *
 * Maintained by: Benjamin Herrenschmidt
 *                <benh@kernel.crashing.org>
 *
 * This file is covered by the GNU Public Licence v2 as
 * described in the kernel's COPYING file.
 */

#include <asm/reg.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/types.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>

	.text

/*
 * Stackframe:
 *		
 *         +-> Back chain			(SP + 256)
 *         |   General register save area	(SP + 112)
 *         |   Parameter save area		(SP + 48)
 *         |   TOC save area			(SP + 40)
 *         |   link editor doubleword		(SP + 32)
 *         |   compiler doubleword		(SP + 24)
 *         |   LR save area			(SP + 16)
 *         |   CR save area			(SP + 8)
 * SP ---> +-- Back chain			(SP + 0)
 */
#define STACKFRAMESIZE	256

/* Save parameters offsets */
#define STK_PARM(i)	(STACKFRAMESIZE + 48 + ((i)-3)*8)

/* Save non-volatile offsets */
#define STK_REG(i)	(112 + ((i)-14)*8)


#ifndef CONFIG_PPC_64K_PAGES

/*****************************************************************************
 *                                                                           *
 *           4K SW & 4K HW pages implementation                              *
 *                                                                           *
 *****************************************************************************/


/*
 * _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 *		 pte_t *ptep, unsigned long trap, int local, int ssize)
 *
 * Adds a 4K page to the hash table in a segment of 4K pages only
 */

_GLOBAL(__hash_page_4K)
	mflr	r0
	std	r0,16(r1)
	stdu	r1,-STACKFRAMESIZE(r1)
	/* Save all params that we need after a function call */
	std	r6,STK_PARM(r6)(r1)
	std	r8,STK_PARM(r8)(r1)
	std	r9,STK_PARM(r9)(r1)
	
	/* Save non-volatile registers.
	 * r31 will hold "old PTE"
	 * r30 is "new PTE"
	 * r29 is "va"
	 * r28 is a hash value
	 * r27 is hashtab mask (maybe dynamic patched instead ?)
	 */
	std	r27,STK_REG(r27)(r1)
	std	r28,STK_REG(r28)(r1)
	std	r29,STK_REG(r29)(r1)
	std	r30,STK_REG(r30)(r1)
	std	r31,STK_REG(r31)(r1)
	
	/* Step 1:
	 *
	 * Check permissions, atomically mark the linux PTE busy
	 * and hashed.
	 */ 
1:
	ldarx	r31,0,r6
	/* Check access rights (access & ~(pte_val(*ptep))) */
	andc.	r0,r4,r31
	bne-	htab_wrong_access
	/* Check if PTE is busy */
	andi.	r0,r31,_PAGE_BUSY
	/* If so, just bail out and refault if needed. Someone else
	 * is changing this PTE anyway and might hash it.
	 */
	bne-	htab_bail_ok

	/* Prepare new PTE value (turn access RW into DIRTY, then
	 * add BUSY,HASHPTE and ACCESSED)
	 */
	rlwinm	r30,r4,32-9+7,31-7,31-7	/* _PAGE_RW -> _PAGE_DIRTY */
	or	r30,r30,r31
	ori	r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE
	/* Write the linux PTE atomically (setting busy) */
	stdcx.	r30,0,r6
	bne-	1b
	isync

	/* Step 2:
	 *
	 * Insert/Update the HPTE in the hash table. At this point,
	 * r4 (access) is re-useable, we use it for the new HPTE flags
	 */

BEGIN_FTR_SECTION
	cmpdi	r9,0			/* check segment size */
	bne	3f
END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
	/* Calc va and put it in r29 */
	rldicr	r29,r5,28,63-28
	rldicl	r3,r3,0,36
	or	r29,r3,r29

	/* Calculate hash value for primary slot and store it in r28 */
	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
	rldicl	r0,r3,64-12,48		/* (ea >> 12) & 0xffff */
	xor	r28,r5,r0
	b	4f

3:	/* Calc VA and hash in r29 and r28 for 1T segment */
	sldi	r29,r5,40		/* vsid << 40 */
	clrldi	r3,r3,24		/* ea & 0xffffffffff */
	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
	clrldi	r5,r5,40		/* vsid & 0xffffff */
	rldicl	r0,r3,64-12,36		/* (ea >> 12) & 0xfffffff */
	xor	r28,r28,r5
	or	r29,r3,r29		/* VA */
	xor	r28,r28,r0		/* hash */

	/* Convert linux PTE bits into HW equivalents */
4:	andi.	r3,r30,0x1fe		/* Get basic set of flags */
	xori	r3,r3,HPTE_R_N		/* _PAGE_EXEC -> NOEXEC */
	rlwinm	r0,r30,32-9+1,30,30	/* _PAGE_RW -> _PAGE_USER (r0) */
	rlwinm	r4,r30,32-7+1,30,30	/* _PAGE_DIRTY -> _PAGE_USER (r4) */
	and	r0,r0,r4		/* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
	andc	r0,r30,r0		/* r0 = pte & ~r0 */
	rlwimi	r3,r0,32-1,31,31	/* Insert result into PP lsb */
	ori	r3,r3,HPTE_R_C		/* Always add "C" bit for perf. */

	/* We eventually do the icache sync here (maybe inline that
	 * code rather than call a C function...) 
	 */
BEGIN_FTR_SECTION
	mr	r4,r30
	mr	r5,r7
	bl	.hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)

	/* At this point, r3 contains new PP bits, save them in
	 * place of "access" in the param area (sic)
	 */
	std	r3,STK_PARM(r4)(r1)

	/* Get htab_hash_mask */
	ld	r4,htab_hash_mask@got(2)
	ld	r27,0(r4)	/* htab_hash_mask -> r27 */

	/* Check if we may already be in the hashtable, in this case, we
	 * go to out-of-line code to try to modify the HPTE
	 */
	andi.	r0,r31,_PAGE_HASHPTE
	bne	htab_modify_pte

htab_insert_pte:
	/* Clear hpte bits in new pte (we also clear BUSY btw) and
	 * add _PAGE_HASHPTE
	 */
	lis	r0,_PAGE_HPTEFLAGS@h
	ori	r0,r0,_PAGE_HPTEFLAGS@l
	andc	r30,r30,r0
	ori	r30,r30,_PAGE_HASHPTE

	/* physical address r5 */
	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
	sldi	r5,r5,PAGE_SHIFT

	/* Calculate primary group hash */
	and	r0,r28,r27
	rldicr	r3,r0,3,63-3		/* r3 = (hash & mask) << 3 */

	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,0			/* !bolted, !secondary */
	li	r8,MMU_PAGE_4K		/* page size */
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(htab_call_hpte_insert1)
	bl	.			/* Patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge	htab_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	htab_pte_insert_failure

	/* Now try secondary slot */
	
	/* physical address r5 */
	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
	sldi	r5,r5,PAGE_SHIFT

	/* Calculate secondary group hash */
	andc	r0,r27,r28
	rldicr	r3,r0,3,63-3	/* r0 = (~hash & mask) << 3 */
	
	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
	li	r8,MMU_PAGE_4K		/* page size */
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(htab_call_hpte_insert2)
	bl	.			/* Patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge+	htab_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	htab_pte_insert_failure

	/* Both are full, we need to evict something */
	mftb	r0
	/* Pick a random group based on TB */
	andi.	r0,r0,1
	mr	r5,r28
	bne	2f
	not	r5,r5
2:	and	r0,r5,r27
	rldicr	r3,r0,3,63-3	/* r0 = (hash & mask) << 3 */	
	/* Call ppc_md.hpte_remove */
_GLOBAL(htab_call_hpte_remove)
	bl	.			/* Patched by htab_finish_init() */

	/* Try all again */
	b	htab_insert_pte	

htab_bail_ok:
	li	r3,0
	b	htab_bail

htab_pte_insert_ok:
	/* Insert slot number & secondary bit in PTE */
	rldimi	r30,r3,12,63-15
		
	/* Write out the PTE with a normal write
	 * (maybe add eieio may be good still ?)
	 */
htab_write_out_pte:
	ld	r6,STK_PARM(r6)(r1)
	std	r30,0(r6)
	li	r3, 0
htab_bail:
	ld	r27,STK_REG(r27)(r1)
	ld	r28,STK_REG(r28)(r1)
	ld	r29,STK_REG(r29)(r1)
	ld      r30,STK_REG(r30)(r1)
	ld      r31,STK_REG(r31)(r1)
	addi    r1,r1,STACKFRAMESIZE
	ld      r0,16(r1)
	mtlr    r0
	blr

htab_modify_pte:
	/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
	mr	r4,r3
	rlwinm	r3,r31,32-12,29,31

	/* Secondary group ? if yes, get a inverted hash value */
	mr	r5,r28
	andi.	r0,r31,_PAGE_SECONDARY
	beq	1f
	not	r5,r5
1:
	/* Calculate proper slot value for ppc_md.hpte_updatepp */
	and	r0,r5,r27
	rldicr	r0,r0,3,63-3	/* r0 = (hash & mask) << 3 */
	add	r3,r0,r3	/* add slot idx */

	/* Call ppc_md.hpte_updatepp */
	mr	r5,r29			/* va */
	li	r6,MMU_PAGE_4K		/* page size */
	ld	r7,STK_PARM(r9)(r1)	/* segment size */
	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
_GLOBAL(htab_call_hpte_updatepp)
	bl	.			/* Patched by htab_finish_init() */

	/* if we failed because typically the HPTE wasn't really here
	 * we try an insertion. 
	 */
	cmpdi	0,r3,-1
	beq-	htab_insert_pte

	/* Clear the BUSY bit and Write out the PTE */
	li	r0,_PAGE_BUSY
	andc	r30,r30,r0
	b	htab_write_out_pte

htab_wrong_access:
	/* Bail out clearing reservation */
	stdcx.	r31,0,r6
	li	r3,1
	b	htab_bail

htab_pte_insert_failure:
	/* Bail out restoring old PTE */
	ld	r6,STK_PARM(r6)(r1)
	std	r31,0(r6)
	li	r3,-1
	b	htab_bail


#else /* CONFIG_PPC_64K_PAGES */


/*****************************************************************************
 *                                                                           *
 *           64K SW & 4K or 64K HW in a 4K segment pages implementation      *
 *                                                                           *
 *****************************************************************************/

/* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 *		 pte_t *ptep, unsigned long trap, int local, int ssize,
 *		 int subpg_prot)
 */

/*
 * For now, we do NOT implement Admixed pages
 */
_GLOBAL(__hash_page_4K)
	mflr	r0
	std	r0,16(r1)
	stdu	r1,-STACKFRAMESIZE(r1)
	/* Save all params that we need after a function call */
	std	r6,STK_PARM(r6)(r1)
	std	r8,STK_PARM(r8)(r1)
	std	r9,STK_PARM(r9)(r1)

	/* Save non-volatile registers.
	 * r31 will hold "old PTE"
	 * r30 is "new PTE"
	 * r29 is "va"
	 * r28 is a hash value
	 * r27 is hashtab mask (maybe dynamic patched instead ?)
	 * r26 is the hidx mask
	 * r25 is the index in combo page
	 */
	std	r25,STK_REG(r25)(r1)
	std	r26,STK_REG(r26)(r1)
	std	r27,STK_REG(r27)(r1)
	std	r28,STK_REG(r28)(r1)
	std	r29,STK_REG(r29)(r1)
	std	r30,STK_REG(r30)(r1)
	std	r31,STK_REG(r31)(r1)

	/* Step 1:
	 *
	 * Check permissions, atomically mark the linux PTE busy
	 * and hashed.
	 */
1:
	ldarx	r31,0,r6
	/* Check access rights (access & ~(pte_val(*ptep))) */
	andc.	r0,r4,r31
	bne-	htab_wrong_access
	/* Check if PTE is busy */
	andi.	r0,r31,_PAGE_BUSY
	/* If so, just bail out and refault if needed. Someone else
	 * is changing this PTE anyway and might hash it.
	 */
	bne-	htab_bail_ok
	/* Prepare new PTE value (turn access RW into DIRTY, then
	 * add BUSY and ACCESSED)
	 */
	rlwinm	r30,r4,32-9+7,31-7,31-7	/* _PAGE_RW -> _PAGE_DIRTY */
	or	r30,r30,r31
	ori	r30,r30,_PAGE_BUSY | _PAGE_ACCESSED
	oris	r30,r30,_PAGE_COMBO@h
	/* Write the linux PTE atomically (setting busy) */
	stdcx.	r30,0,r6
	bne-	1b
	isync

	/* Step 2:
	 *
	 * Insert/Update the HPTE in the hash table. At this point,
	 * r4 (access) is re-useable, we use it for the new HPTE flags
	 */

	/* Load the hidx index */
	rldicl	r25,r3,64-12,60

BEGIN_FTR_SECTION
	cmpdi	r9,0			/* check segment size */
	bne	3f
END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
	/* Calc va and put it in r29 */
	rldicr	r29,r5,28,63-28		/* r29 = (vsid << 28) */
	rldicl	r3,r3,0,36		/* r3 = (ea & 0x0fffffff) */
	or	r29,r3,r29		/* r29 = va */

	/* Calculate hash value for primary slot and store it in r28 */
	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
	rldicl	r0,r3,64-12,48		/* (ea >> 12) & 0xffff */
	xor	r28,r5,r0
	b	4f

3:	/* Calc VA and hash in r29 and r28 for 1T segment */
	sldi	r29,r5,40		/* vsid << 40 */
	clrldi	r3,r3,24		/* ea & 0xffffffffff */
	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
	clrldi	r5,r5,40		/* vsid & 0xffffff */
	rldicl	r0,r3,64-12,36		/* (ea >> 12) & 0xfffffff */
	xor	r28,r28,r5
	or	r29,r3,r29		/* VA */
	xor	r28,r28,r0		/* hash */

	/* Convert linux PTE bits into HW equivalents */
4:
#ifdef CONFIG_PPC_SUBPAGE_PROT
	andc	r10,r30,r10
	andi.	r3,r10,0x1fe		/* Get basic set of flags */
	rlwinm	r0,r10,32-9+1,30,30	/* _PAGE_RW -> _PAGE_USER (r0) */
#else
	andi.	r3,r30,0x1fe		/* Get basic set of flags */
	rlwinm	r0,r30,32-9+1,30,30	/* _PAGE_RW -> _PAGE_USER (r0) */
#endif
	xori	r3,r3,HPTE_R_N		/* _PAGE_EXEC -> NOEXEC */
	rlwinm	r4,r30,32-7+1,30,30	/* _PAGE_DIRTY -> _PAGE_USER (r4) */
	and	r0,r0,r4		/* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
	andc	r0,r3,r0		/* r0 = pte & ~r0 */
	rlwimi	r3,r0,32-1,31,31	/* Insert result into PP lsb */
	ori	r3,r3,HPTE_R_C		/* Always add "C" bit for perf. */

	/* We eventually do the icache sync here (maybe inline that
	 * code rather than call a C function...)
	 */
BEGIN_FTR_SECTION
	mr	r4,r30
	mr	r5,r7
	bl	.hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)

	/* At this point, r3 contains new PP bits, save them in
	 * place of "access" in the param area (sic)
	 */
	std	r3,STK_PARM(r4)(r1)

	/* Get htab_hash_mask */
	ld	r4,htab_hash_mask@got(2)
	ld	r27,0(r4)	/* htab_hash_mask -> r27 */

	/* Check if we may already be in the hashtable, in this case, we
	 * go to out-of-line code to try to modify the HPTE. We look for
	 * the bit at (1 >> (index + 32))
	 */
	rldicl.	r0,r31,64-12,48
	li	r26,0			/* Default hidx */
	beq	htab_insert_pte

	/*
	 * Check if the pte was already inserted into the hash table
	 * as a 64k HW page, and invalidate the 64k HPTE if so.
	 */
	andis.	r0,r31,_PAGE_COMBO@h
	beq	htab_inval_old_hpte

	ld	r6,STK_PARM(r6)(r1)
	ori	r26,r6,0x8000		/* Load the hidx mask */
	ld	r26,0(r26)
	addi	r5,r25,36		/* Check actual HPTE_SUB bit, this */
	rldcr.	r0,r31,r5,0		/* must match pgtable.h definition */
	bne	htab_modify_pte

htab_insert_pte:
	/* real page number in r5, PTE RPN value + index */
	andis.	r0,r31,_PAGE_4K_PFN@h
	srdi	r5,r31,PTE_RPN_SHIFT
	bne-	htab_special_pfn
	sldi	r5,r5,PAGE_SHIFT-HW_PAGE_SHIFT
	add	r5,r5,r25
htab_special_pfn:
	sldi	r5,r5,HW_PAGE_SHIFT

	/* Calculate primary group hash */
	and	r0,r28,r27
	rldicr	r3,r0,3,63-3		/* r0 = (hash & mask) << 3 */

	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,0			/* !bolted, !secondary */
	li	r8,MMU_PAGE_4K		/* page size */
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(htab_call_hpte_insert1)
	bl	.			/* patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge	htab_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	htab_pte_insert_failure

	/* Now try secondary slot */

	/* real page number in r5, PTE RPN value + index */
	andis.	r0,r31,_PAGE_4K_PFN@h
	srdi	r5,r31,PTE_RPN_SHIFT
	bne-	3f
	sldi	r5,r5,PAGE_SHIFT-HW_PAGE_SHIFT
	add	r5,r5,r25
3:	sldi	r5,r5,HW_PAGE_SHIFT

	/* Calculate secondary group hash */
	andc	r0,r27,r28
	rldicr	r3,r0,3,63-3		/* r0 = (~hash & mask) << 3 */

	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
	li	r8,MMU_PAGE_4K		/* page size */
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(htab_call_hpte_insert2)
	bl	.			/* patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge+	htab_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	htab_pte_insert_failure

	/* Both are full, we need to evict something */
	mftb	r0
	/* Pick a random group based on TB */
	andi.	r0,r0,1
	mr	r5,r28
	bne	2f
	not	r5,r5
2:	and	r0,r5,r27
	rldicr	r3,r0,3,63-3		/* r0 = (hash & mask) << 3 */
	/* Call ppc_md.hpte_remove */
_GLOBAL(htab_call_hpte_remove)
	bl	.			/* patched by htab_finish_init() */

	/* Try all again */
	b	htab_insert_pte

	/*
	 * Call out to C code to invalidate an 64k HW HPTE that is
	 * useless now that the segment has been switched to 4k pages.
	 */
htab_inval_old_hpte:
	mr	r3,r29			/* virtual addr */
	mr	r4,r31			/* PTE.pte */
	li	r5,0			/* PTE.hidx */
	li	r6,MMU_PAGE_64K		/* psize */
	ld	r7,STK_PARM(r9)(r1)	/* ssize */
	ld	r8,STK_PARM(r8)(r1)	/* local */
	bl	.flush_hash_page
	/* Clear out _PAGE_HPTE_SUB bits in the new linux PTE */
	lis	r0,_PAGE_HPTE_SUB@h
	ori	r0,r0,_PAGE_HPTE_SUB@l
	andc	r30,r30,r0
	b	htab_insert_pte
	
htab_bail_ok:
	li	r3,0
	b	htab_bail

htab_pte_insert_ok:
	/* Insert slot number & secondary bit in PTE second half,
	 * clear _PAGE_BUSY and set approriate HPTE slot bit
	 */
	ld	r6,STK_PARM(r6)(r1)
	li	r0,_PAGE_BUSY
	andc	r30,r30,r0
	/* HPTE SUB bit */
	li	r0,1
	subfic	r5,r25,27		/* Must match bit position in */
	sld	r0,r0,r5		/* pgtable.h */
	or	r30,r30,r0
	/* hindx */
	sldi	r5,r25,2
	sld	r3,r3,r5
	li	r4,0xf
	sld	r4,r4,r5
	andc	r26,r26,r4
	or	r26,r26,r3
	ori	r5,r6,0x8000
	std	r26,0(r5)
	lwsync
	std	r30,0(r6)
	li	r3, 0
htab_bail:
	ld	r25,STK_REG(r25)(r1)
	ld	r26,STK_REG(r26)(r1)
	ld	r27,STK_REG(r27)(r1)
	ld	r28,STK_REG(r28)(r1)
	ld	r29,STK_REG(r29)(r1)
	ld      r30,STK_REG(r30)(r1)
	ld      r31,STK_REG(r31)(r1)
	addi    r1,r1,STACKFRAMESIZE
	ld      r0,16(r1)
	mtlr    r0
	blr

htab_modify_pte:
	/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
	mr	r4,r3
	sldi	r5,r25,2
	srd	r3,r26,r5

	/* Secondary group ? if yes, get a inverted hash value */
	mr	r5,r28
	andi.	r0,r3,0x8 /* page secondary ? */
	beq	1f
	not	r5,r5
1:	andi.	r3,r3,0x7 /* extract idx alone */

	/* Calculate proper slot value for ppc_md.hpte_updatepp */
	and	r0,r5,r27
	rldicr	r0,r0,3,63-3	/* r0 = (hash & mask) << 3 */
	add	r3,r0,r3	/* add slot idx */

	/* Call ppc_md.hpte_updatepp */
	mr	r5,r29			/* va */
	li	r6,MMU_PAGE_4K		/* page size */
	ld	r7,STK_PARM(r9)(r1)	/* segment size */
	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
_GLOBAL(htab_call_hpte_updatepp)
	bl	.			/* patched by htab_finish_init() */

	/* if we failed because typically the HPTE wasn't really here
	 * we try an insertion.
	 */
	cmpdi	0,r3,-1
	beq-	htab_insert_pte

	/* Clear the BUSY bit and Write out the PTE */
	li	r0,_PAGE_BUSY
	andc	r30,r30,r0
	ld	r6,STK_PARM(r6)(r1)
	std	r30,0(r6)
	li	r3,0
	b	htab_bail

htab_wrong_access:
	/* Bail out clearing reservation */
	stdcx.	r31,0,r6
	li	r3,1
	b	htab_bail

htab_pte_insert_failure:
	/* Bail out restoring old PTE */
	ld	r6,STK_PARM(r6)(r1)
	std	r31,0(r6)
	li	r3,-1
	b	htab_bail

#endif /* CONFIG_PPC_64K_PAGES */

#ifdef CONFIG_PPC_HAS_HASH_64K

/*****************************************************************************
 *                                                                           *
 *           64K SW & 64K HW in a 64K segment pages implementation           *
 *                                                                           *
 *****************************************************************************/

_GLOBAL(__hash_page_64K)
	mflr	r0
	std	r0,16(r1)
	stdu	r1,-STACKFRAMESIZE(r1)
	/* Save all params that we need after a function call */
	std	r6,STK_PARM(r6)(r1)
	std	r8,STK_PARM(r8)(r1)
	std	r9,STK_PARM(r9)(r1)

	/* Save non-volatile registers.
	 * r31 will hold "old PTE"
	 * r30 is "new PTE"
	 * r29 is "va"
	 * r28 is a hash value
	 * r27 is hashtab mask (maybe dynamic patched instead ?)
	 */
	std	r27,STK_REG(r27)(r1)
	std	r28,STK_REG(r28)(r1)
	std	r29,STK_REG(r29)(r1)
	std	r30,STK_REG(r30)(r1)
	std	r31,STK_REG(r31)(r1)

	/* Step 1:
	 *
	 * Check permissions, atomically mark the linux PTE busy
	 * and hashed.
	 */
1:
	ldarx	r31,0,r6
	/* Check access rights (access & ~(pte_val(*ptep))) */
	andc.	r0,r4,r31
	bne-	ht64_wrong_access
	/* Check if PTE is busy */
	andi.	r0,r31,_PAGE_BUSY
	/* If so, just bail out and refault if needed. Someone else
	 * is changing this PTE anyway and might hash it.
	 */
	bne-	ht64_bail_ok
BEGIN_FTR_SECTION
	/* Check if PTE has the cache-inhibit bit set */
	andi.	r0,r31,_PAGE_NO_CACHE
	/* If so, bail out and refault as a 4k page */
	bne-	ht64_bail_ok
END_MMU_FTR_SECTION_IFCLR(MMU_FTR_CI_LARGE_PAGE)
	/* Prepare new PTE value (turn access RW into DIRTY, then
	 * add BUSY and ACCESSED)
	 */
	rlwinm	r30,r4,32-9+7,31-7,31-7	/* _PAGE_RW -> _PAGE_DIRTY */
	or	r30,r30,r31
	ori	r30,r30,_PAGE_BUSY | _PAGE_ACCESSED
	/* Write the linux PTE atomically (setting busy) */
	stdcx.	r30,0,r6
	bne-	1b
	isync

	/* Step 2:
	 *
	 * Insert/Update the HPTE in the hash table. At this point,
	 * r4 (access) is re-useable, we use it for the new HPTE flags
	 */

BEGIN_FTR_SECTION
	cmpdi	r9,0			/* check segment size */
	bne	3f
END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
	/* Calc va and put it in r29 */
	rldicr	r29,r5,28,63-28
	rldicl	r3,r3,0,36
	or	r29,r3,r29

	/* Calculate hash value for primary slot and store it in r28 */
	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
	rldicl	r0,r3,64-16,52		/* (ea >> 16) & 0xfff */
	xor	r28,r5,r0
	b	4f

3:	/* Calc VA and hash in r29 and r28 for 1T segment */
	sldi	r29,r5,40		/* vsid << 40 */
	clrldi	r3,r3,24		/* ea & 0xffffffffff */
	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
	clrldi	r5,r5,40		/* vsid & 0xffffff */
	rldicl	r0,r3,64-16,40		/* (ea >> 16) & 0xffffff */
	xor	r28,r28,r5
	or	r29,r3,r29		/* VA */
	xor	r28,r28,r0		/* hash */

	/* Convert linux PTE bits into HW equivalents */
4:	andi.	r3,r30,0x1fe		/* Get basic set of flags */
	xori	r3,r3,HPTE_R_N		/* _PAGE_EXEC -> NOEXEC */
	rlwinm	r0,r30,32-9+1,30,30	/* _PAGE_RW -> _PAGE_USER (r0) */
	rlwinm	r4,r30,32-7+1,30,30	/* _PAGE_DIRTY -> _PAGE_USER (r4) */
	and	r0,r0,r4		/* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
	andc	r0,r30,r0		/* r0 = pte & ~r0 */
	rlwimi	r3,r0,32-1,31,31	/* Insert result into PP lsb */
	ori	r3,r3,HPTE_R_C		/* Always add "C" bit for perf. */

	/* We eventually do the icache sync here (maybe inline that
	 * code rather than call a C function...)
	 */
BEGIN_FTR_SECTION
	mr	r4,r30
	mr	r5,r7
	bl	.hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)

	/* At this point, r3 contains new PP bits, save them in
	 * place of "access" in the param area (sic)
	 */
	std	r3,STK_PARM(r4)(r1)

	/* Get htab_hash_mask */
	ld	r4,htab_hash_mask@got(2)
	ld	r27,0(r4)	/* htab_hash_mask -> r27 */

	/* Check if we may already be in the hashtable, in this case, we
	 * go to out-of-line code to try to modify the HPTE
	 */
	rldicl.	r0,r31,64-12,48
	bne	ht64_modify_pte

ht64_insert_pte:
	/* Clear hpte bits in new pte (we also clear BUSY btw) and
	 * add _PAGE_HPTE_SUB0
	 */
	lis	r0,_PAGE_HPTEFLAGS@h
	ori	r0,r0,_PAGE_HPTEFLAGS@l
	andc	r30,r30,r0
#ifdef CONFIG_PPC_64K_PAGES
	oris	r30,r30,_PAGE_HPTE_SUB0@h
#else
	ori	r30,r30,_PAGE_HASHPTE
#endif
	/* Phyical address in r5 */
	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
	sldi	r5,r5,PAGE_SHIFT

	/* Calculate primary group hash */
	and	r0,r28,r27
	rldicr	r3,r0,3,63-3	/* r0 = (hash & mask) << 3 */

	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,0			/* !bolted, !secondary */
	li	r8,MMU_PAGE_64K
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(ht64_call_hpte_insert1)
	bl	.			/* patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge	ht64_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	ht64_pte_insert_failure

	/* Now try secondary slot */

	/* Phyical address in r5 */
	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
	sldi	r5,r5,PAGE_SHIFT

	/* Calculate secondary group hash */
	andc	r0,r27,r28
	rldicr	r3,r0,3,63-3	/* r0 = (~hash & mask) << 3 */

	/* Call ppc_md.hpte_insert */
	ld	r6,STK_PARM(r4)(r1)	/* Retrieve new pp bits */
	mr	r4,r29			/* Retrieve va */
	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
	li	r8,MMU_PAGE_64K
	ld	r9,STK_PARM(r9)(r1)	/* segment size */
_GLOBAL(ht64_call_hpte_insert2)
	bl	.			/* patched by htab_finish_init() */
	cmpdi	0,r3,0
	bge+	ht64_pte_insert_ok	/* Insertion successful */
	cmpdi	0,r3,-2			/* Critical failure */
	beq-	ht64_pte_insert_failure

	/* Both are full, we need to evict something */
	mftb	r0
	/* Pick a random group based on TB */
	andi.	r0,r0,1
	mr	r5,r28
	bne	2f
	not	r5,r5
2:	and	r0,r5,r27
	rldicr	r3,r0,3,63-3	/* r0 = (hash & mask) << 3 */
	/* Call ppc_md.hpte_remove */
_GLOBAL(ht64_call_hpte_remove)
	bl	.			/* patched by htab_finish_init() */

	/* Try all again */
	b	ht64_insert_pte

ht64_bail_ok:
	li	r3,0
	b	ht64_bail

ht64_pte_insert_ok:
	/* Insert slot number & secondary bit in PTE */
	rldimi	r30,r3,12,63-15

	/* Write out the PTE with a normal write
	 * (maybe add eieio may be good still ?)
	 */
ht64_write_out_pte:
	ld	r6,STK_PARM(r6)(r1)
	std	r30,0(r6)
	li	r3, 0
ht64_bail:
	ld	r27,STK_REG(r27)(r1)
	ld	r28,STK_REG(r28)(r1)
	ld	r29,STK_REG(r29)(r1)
	ld      r30,STK_REG(r30)(r1)
	ld      r31,STK_REG(r31)(r1)
	addi    r1,r1,STACKFRAMESIZE
	ld      r0,16(r1)
	mtlr    r0
	blr

ht64_modify_pte:
	/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
	mr	r4,r3
	rlwinm	r3,r31,32-12,29,31

	/* Secondary group ? if yes, get a inverted hash value */
	mr	r5,r28
	andi.	r0,r31,_PAGE_F_SECOND
	beq	1f
	not	r5,r5
1:
	/* Calculate proper slot value for ppc_md.hpte_updatepp */
	and	r0,r5,r27
	rldicr	r0,r0,3,63-3	/* r0 = (hash & mask) << 3 */
	add	r3,r0,r3	/* add slot idx */

	/* Call ppc_md.hpte_updatepp */
	mr	r5,r29			/* va */
	li	r6,MMU_PAGE_64K
	ld	r7,STK_PARM(r9)(r1)	/* segment size */
	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
_GLOBAL(ht64_call_hpte_updatepp)
	bl	.			/* patched by htab_finish_init() */

	/* if we failed because typically the HPTE wasn't really here
	 * we try an insertion.
	 */
	cmpdi	0,r3,-1
	beq-	ht64_insert_pte

	/* Clear the BUSY bit and Write out the PTE */
	li	r0,_PAGE_BUSY
	andc	r30,r30,r0
	b	ht64_write_out_pte

ht64_wrong_access:
	/* Bail out clearing reservation */
	stdcx.	r31,0,r6
	li	r3,1
	b	ht64_bail

ht64_pte_insert_failure:
	/* Bail out restoring old PTE */
	ld	r6,STK_PARM(r6)(r1)
	std	r31,0(r6)
	li	r3,-1
	b	ht64_bail


#endif /* CONFIG_PPC_HAS_HASH_64K */


/*****************************************************************************
 *                                                                           *
 *           Huge pages implementation is in hugetlbpage.c                   *
 *                                                                           *
 *****************************************************************************/