aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/hash_low_32.S
blob: ddceefc06ecc0a5554a650e5dbe690959274943a (plain) (blame)
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
/*
 *  $Id: hashtable.S,v 1.6 1999/10/08 01:56:15 paulus Exp $
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
 *  Adapted for Power Macintosh by Paul Mackerras.
 *  Low-level exception handlers and MMU support
 *  rewritten by Paul Mackerras.
 *    Copyright (C) 1996 Paul Mackerras.
 *
 *  This file contains low-level assembler routines for managing
 *  the PowerPC MMU hash table.  (PPC 8xx processors don't use a
 *  hash table, so this file is not used on them.)
 *
 *  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 <asm/reg.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/ppc_asm.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>

#ifdef CONFIG_SMP
	.comm	mmu_hash_lock,4
#endif /* CONFIG_SMP */

/*
 * Sync CPUs with hash_page taking & releasing the hash
 * table lock
 */
#ifdef CONFIG_SMP
	.text
_GLOBAL(hash_page_sync)
	lis	r8,mmu_hash_lock@h
	ori	r8,r8,mmu_hash_lock@l
	lis	r0,0x0fff
	b	10f
11:	lwz	r6,0(r8)
	cmpwi	0,r6,0
	bne	11b
10:	lwarx	r6,0,r8
	cmpwi	0,r6,0
	bne-	11b
	stwcx.	r0,0,r8
	bne-	10b
	isync
	eieio
	li	r0,0
	stw	r0,0(r8)
	blr	
#endif

/*
 * Load a PTE into the hash table, if possible.
 * The address is in r4, and r3 contains an access flag:
 * _PAGE_RW (0x400) if a write.
 * r9 contains the SRR1 value, from which we use the MSR_PR bit.
 * SPRG3 contains the physical address of the current task's thread.
 *
 * Returns to the caller if the access is illegal or there is no
 * mapping for the address.  Otherwise it places an appropriate PTE
 * in the hash table and returns from the exception.
 * Uses r0, r3 - r8, ctr, lr.
 */
	.text
_GLOBAL(hash_page)
	tophys(r7,0)			/* gets -KERNELBASE into r7 */
#ifdef CONFIG_SMP
	addis	r8,r7,mmu_hash_lock@h
	ori	r8,r8,mmu_hash_lock@l
	lis	r0,0x0fff
	b	10f
11:	lwz	r6,0(r8)
	cmpwi	0,r6,0
	bne	11b
10:	lwarx	r6,0,r8
	cmpwi	0,r6,0
	bne-	11b
	stwcx.	r0,0,r8
	bne-	10b
	isync
#endif
	/* Get PTE (linux-style) and check access */
	lis	r0,KERNELBASE@h		/* check if kernel address */
	cmplw	0,r4,r0
	mfspr	r8,SPRN_SPRG3		/* current task's THREAD (phys) */
	ori	r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
	lwz	r5,PGDIR(r8)		/* virt page-table root */
	blt+	112f			/* assume user more likely */
	lis	r5,swapper_pg_dir@ha	/* if kernel address, use */
	addi	r5,r5,swapper_pg_dir@l	/* kernel page table */
	rlwimi	r3,r9,32-12,29,29	/* MSR_PR -> _PAGE_USER */
112:	add	r5,r5,r7		/* convert to phys addr */
	rlwimi	r5,r4,12,20,29		/* insert top 10 bits of address */
	lwz	r8,0(r5)		/* get pmd entry */
	rlwinm.	r8,r8,0,0,19		/* extract address of pte page */
#ifdef CONFIG_SMP
	beq-	hash_page_out		/* return if no mapping */
#else
	/* XXX it seems like the 601 will give a machine fault on the
	   rfi if its alignment is wrong (bottom 4 bits of address are
	   8 or 0xc) and we have had a not-taken conditional branch
	   to the address following the rfi. */
	beqlr-
#endif
	rlwimi	r8,r4,22,20,29		/* insert next 10 bits of address */
	rlwinm	r0,r3,32-3,24,24	/* _PAGE_RW access -> _PAGE_DIRTY */
	ori	r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE

	/*
	 * Update the linux PTE atomically.  We do the lwarx up-front
	 * because almost always, there won't be a permission violation
	 * and there won't already be an HPTE, and thus we will have
	 * to update the PTE to set _PAGE_HASHPTE.  -- paulus.
	 */
retry:
	lwarx	r6,0,r8			/* get linux-style pte */
	andc.	r5,r3,r6		/* check access & ~permission */
#ifdef CONFIG_SMP
	bne-	hash_page_out		/* return if access not permitted */
#else
	bnelr-
#endif
	or	r5,r0,r6		/* set accessed/dirty bits */
	stwcx.	r5,0,r8			/* attempt to update PTE */
	bne-	retry			/* retry if someone got there first */

	mfsrin	r3,r4			/* get segment reg for segment */
	mfctr	r0
	stw	r0,_CTR(r11)
	bl	create_hpte		/* add the hash table entry */

#ifdef CONFIG_SMP
	eieio
	addis	r8,r7,mmu_hash_lock@ha
	li	r0,0
	stw	r0,mmu_hash_lock@l(r8)
#endif

	/* Return from the exception */
	lwz	r5,_CTR(r11)
	mtctr	r5
	lwz	r0,GPR0(r11)
	lwz	r7,GPR7(r11)
	lwz	r8,GPR8(r11)
	b	fast_exception_return

#ifdef CONFIG_SMP
hash_page_out:
	eieio
	addis	r8,r7,mmu_hash_lock@ha
	li	r0,0
	stw	r0,mmu_hash_lock@l(r8)
	blr
#endif /* CONFIG_SMP */

/*
 * Add an entry for a particular page to the hash table.
 *
 * add_hash_page(unsigned context, unsigned long va, unsigned long pmdval)
 *
 * We assume any necessary modifications to the pte (e.g. setting
 * the accessed bit) have already been done and that there is actually
 * a hash table in use (i.e. we're not on a 603).
 */
_GLOBAL(add_hash_page)
	mflr	r0
	stw	r0,4(r1)

	/* Convert context and va to VSID */
	mulli	r3,r3,897*16		/* multiply context by context skew */
	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
	mulli	r0,r0,0x111		/* multiply by ESID skew */
	add	r3,r3,r0		/* note create_hpte trims to 24 bits */

#ifdef CONFIG_SMP
	rlwinm	r8,r1,0,0,18		/* use cpu number to make tag */
	lwz	r8,TI_CPU(r8)		/* to go in mmu_hash_lock */
	oris	r8,r8,12
#endif /* CONFIG_SMP */

	/*
	 * We disable interrupts here, even on UP, because we don't
	 * want to race with hash_page, and because we want the
	 * _PAGE_HASHPTE bit to be a reliable indication of whether
	 * the HPTE exists (or at least whether one did once).
	 * We also turn off the MMU for data accesses so that we
	 * we can't take a hash table miss (assuming the code is
	 * covered by a BAT).  -- paulus
	 */
	mfmsr	r10
	SYNC
	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
	mtmsr	r0
	SYNC_601
	isync

	tophys(r7,0)

#ifdef CONFIG_SMP
	addis	r9,r7,mmu_hash_lock@ha
	addi	r9,r9,mmu_hash_lock@l
10:	lwarx	r0,0,r9			/* take the mmu_hash_lock */
	cmpi	0,r0,0
	bne-	11f
	stwcx.	r8,0,r9
	beq+	12f
11:	lwz	r0,0(r9)
	cmpi	0,r0,0
	beq	10b
	b	11b
12:	isync
#endif

	/*
	 * Fetch the linux pte and test and set _PAGE_HASHPTE atomically.
	 * If _PAGE_HASHPTE was already set, we don't replace the existing
	 * HPTE, so we just unlock and return.
	 */
	mr	r8,r5
	rlwimi	r8,r4,22,20,29
1:	lwarx	r6,0,r8
	andi.	r0,r6,_PAGE_HASHPTE
	bne	9f			/* if HASHPTE already set, done */
	ori	r5,r6,_PAGE_HASHPTE
	stwcx.	r5,0,r8
	bne-	1b

	bl	create_hpte

9:
#ifdef CONFIG_SMP
	eieio
	li	r0,0
	stw	r0,0(r9)		/* clear mmu_hash_lock */
#endif

	/* reenable interrupts and DR */
	mtmsr	r10
	SYNC_601
	isync

	lwz	r0,4(r1)
	mtlr	r0
	blr

/*
 * This routine adds a hardware PTE to the hash table.
 * It is designed to be called with the MMU either on or off.
 * r3 contains the VSID, r4 contains the virtual address,
 * r5 contains the linux PTE, r6 contains the old value of the
 * linux PTE (before setting _PAGE_HASHPTE) and r7 contains the
 * offset to be added to addresses (0 if the MMU is on,
 * -KERNELBASE if it is off).
 * On SMP, the caller should have the mmu_hash_lock held.
 * We assume that the caller has (or will) set the _PAGE_HASHPTE
 * bit in the linux PTE in memory.  The value passed in r6 should
 * be the old linux PTE value; if it doesn't have _PAGE_HASHPTE set
 * this routine will skip the search for an existing HPTE.
 * This procedure modifies r0, r3 - r6, r8, cr0.
 *  -- paulus.
 *
 * For speed, 4 of the instructions get patched once the size and
 * physical address of the hash table are known.  These definitions
 * of Hash_base and Hash_bits below are just an example.
 */
Hash_base = 0xc0180000
Hash_bits = 12				/* e.g. 256kB hash table */
Hash_msk = (((1 << Hash_bits) - 1) * 64)

/* defines for the PTE format for 32-bit PPCs */
#define PTE_SIZE	8
#define PTEG_SIZE	64
#define LG_PTEG_SIZE	6
#define LDPTEu		lwzu
#define LDPTE		lwz
#define STPTE		stw
#define CMPPTE		cmpw
#define PTE_H		0x40
#define PTE_V		0x80000000
#define TST_V(r)	rlwinm. r,r,0,0,0
#define SET_V(r)	oris r,r,PTE_V@h
#define CLR_V(r,t)	rlwinm r,r,0,1,31

#define HASH_LEFT	31-(LG_PTEG_SIZE+Hash_bits-1)
#define HASH_RIGHT	31-LG_PTEG_SIZE

_GLOBAL(create_hpte)
	/* Convert linux-style PTE (r5) to low word of PPC-style PTE (r8) */
	rlwinm	r8,r5,32-10,31,31	/* _PAGE_RW -> PP lsb */
	rlwinm	r0,r5,32-7,31,31	/* _PAGE_DIRTY -> PP lsb */
	and	r8,r8,r0		/* writable if _RW & _DIRTY */
	rlwimi	r5,r5,32-1,30,30	/* _PAGE_USER -> PP msb */
	rlwimi	r5,r5,32-2,31,31	/* _PAGE_USER -> PP lsb */
	ori	r8,r8,0xe14		/* clear out reserved bits and M */
	andc	r8,r5,r8		/* PP = user? (rw&dirty? 2: 3): 0 */
BEGIN_FTR_SECTION
	ori	r8,r8,_PAGE_COHERENT	/* set M (coherence required) */
END_FTR_SECTION_IFSET(CPU_FTR_NEED_COHERENT)

	/* Construct the high word of the PPC-style PTE (r5) */
	rlwinm	r5,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
	rlwimi	r5,r4,10,26,31		/* put in API (abbrev page index) */
	SET_V(r5)			/* set V (valid) bit */

	/* Get the address of the primary PTE group in the hash table (r3) */
_GLOBAL(hash_page_patch_A)
	addis	r0,r7,Hash_base@h	/* base address of hash table */
	rlwimi	r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
	rlwinm	r3,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
	xor	r3,r3,r0		/* make primary hash */
	li	r0,8			/* PTEs/group */

	/*
	 * Test the _PAGE_HASHPTE bit in the old linux PTE, and skip the search
	 * if it is clear, meaning that the HPTE isn't there already...
	 */
	andi.	r6,r6,_PAGE_HASHPTE
	beq+	10f			/* no PTE: go look for an empty slot */
	tlbie	r4

	addis	r4,r7,htab_hash_searches@ha
	lwz	r6,htab_hash_searches@l(r4)
	addi	r6,r6,1			/* count how many searches we do */
	stw	r6,htab_hash_searches@l(r4)

	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
	mtctr	r0
	addi	r4,r3,-PTE_SIZE
1:	LDPTEu	r6,PTE_SIZE(r4)		/* get next PTE */
	CMPPTE	0,r6,r5
	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
	beq+	found_slot

	/* Search the secondary PTEG for a matching PTE */
	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
_GLOBAL(hash_page_patch_B)
	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
	xori	r4,r4,(-PTEG_SIZE & 0xffff)
	addi	r4,r4,-PTE_SIZE
	mtctr	r0
2:	LDPTEu	r6,PTE_SIZE(r4)
	CMPPTE	0,r6,r5
	bdnzf	2,2b
	beq+	found_slot
	xori	r5,r5,PTE_H		/* clear H bit again */

	/* Search the primary PTEG for an empty slot */
10:	mtctr	r0
	addi	r4,r3,-PTE_SIZE		/* search primary PTEG */
1:	LDPTEu	r6,PTE_SIZE(r4)		/* get next PTE */
	TST_V(r6)			/* test valid bit */
	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
	beq+	found_empty

	/* update counter of times that the primary PTEG is full */
	addis	r4,r7,primary_pteg_full@ha
	lwz	r6,primary_pteg_full@l(r4)
	addi	r6,r6,1
	stw	r6,primary_pteg_full@l(r4)

	/* Search the secondary PTEG for an empty slot */
	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
_GLOBAL(hash_page_patch_C)
	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
	xori	r4,r4,(-PTEG_SIZE & 0xffff)
	addi	r4,r4,-PTE_SIZE
	mtctr	r0
2:	LDPTEu	r6,PTE_SIZE(r4)
	TST_V(r6)
	bdnzf	2,2b
	beq+	found_empty
	xori	r5,r5,PTE_H		/* clear H bit again */

	/*
	 * Choose an arbitrary slot in the primary PTEG to overwrite.
	 * Since both the primary and secondary PTEGs are full, and we
	 * have no information that the PTEs in the primary PTEG are
	 * more important or useful than those in the secondary PTEG,
	 * and we know there is a definite (although small) speed
	 * advantage to putting the PTE in the primary PTEG, we always
	 * put the PTE in the primary PTEG.
	 *
	 * In addition, we skip any slot that is mapping kernel text in
	 * order to avoid a deadlock when not using BAT mappings if
	 * trying to hash in the kernel hash code itself after it has
	 * already taken the hash table lock. This works in conjunction
	 * with pre-faulting of the kernel text.
	 *
	 * If the hash table bucket is full of kernel text entries, we'll
	 * lockup here but that shouldn't happen
	 */

1:	addis	r4,r7,next_slot@ha		/* get next evict slot */
	lwz	r6,next_slot@l(r4)
	addi	r6,r6,PTE_SIZE			/* search for candidate */
	andi.	r6,r6,7*PTE_SIZE
	stw	r6,next_slot@l(r4)
	add	r4,r3,r6
	LDPTE	r0,PTE_SIZE/2(r4)		/* get PTE second word */
	clrrwi	r0,r0,12
	lis	r6,etext@h
	ori	r6,r6,etext@l			/* get etext */
	tophys(r6,r6)
	cmpl	cr0,r0,r6			/* compare and try again */
	blt	1b

#ifndef CONFIG_SMP
	/* Store PTE in PTEG */
found_empty:
	STPTE	r5,0(r4)
found_slot:
	STPTE	r8,PTE_SIZE/2(r4)

#else /* CONFIG_SMP */
/*
 * Between the tlbie above and updating the hash table entry below,
 * another CPU could read the hash table entry and put it in its TLB.
 * There are 3 cases:
 * 1. using an empty slot
 * 2. updating an earlier entry to change permissions (i.e. enable write)
 * 3. taking over the PTE for an unrelated address
 *
 * In each case it doesn't really matter if the other CPUs have the old
 * PTE in their TLB.  So we don't need to bother with another tlbie here,
 * which is convenient as we've overwritten the register that had the
 * address. :-)  The tlbie above is mainly to make sure that this CPU comes
 * and gets the new PTE from the hash table.
 *
 * We do however have to make sure that the PTE is never in an invalid
 * state with the V bit set.
 */
found_empty:
found_slot:
	CLR_V(r5,r0)		/* clear V (valid) bit in PTE */
	STPTE	r5,0(r4)
	sync
	TLBSYNC
	STPTE	r8,PTE_SIZE/2(r4) /* put in correct RPN, WIMG, PP bits */
	sync
	SET_V(r5)
	STPTE	r5,0(r4)	/* finally set V bit in PTE */
#endif /* CONFIG_SMP */

	sync		/* make sure pte updates get to memory */
	blr

	.comm	next_slot,4
	.comm	primary_pteg_full,4
	.comm	htab_hash_searches,4

/*
 * Flush the entry for a particular page from the hash table.
 *
 * flush_hash_pages(unsigned context, unsigned long va, unsigned long pmdval,
 *		    int count)
 *
 * We assume that there is a hash table in use (Hash != 0).
 */
_GLOBAL(flush_hash_pages)
	tophys(r7,0)

	/*
	 * We disable interrupts here, even on UP, because we want
	 * the _PAGE_HASHPTE bit to be a reliable indication of
	 * whether the HPTE exists (or at least whether one did once).
	 * We also turn off the MMU for data accesses so that we
	 * we can't take a hash table miss (assuming the code is
	 * covered by a BAT).  -- paulus
	 */
	mfmsr	r10
	SYNC
	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
	mtmsr	r0
	SYNC_601
	isync

	/* First find a PTE in the range that has _PAGE_HASHPTE set */
	rlwimi	r5,r4,22,20,29
1:	lwz	r0,0(r5)
	cmpwi	cr1,r6,1
	andi.	r0,r0,_PAGE_HASHPTE
	bne	2f
	ble	cr1,19f
	addi	r4,r4,0x1000
	addi	r5,r5,4
	addi	r6,r6,-1
	b	1b

	/* Convert context and va to VSID */
2:	mulli	r3,r3,897*16		/* multiply context by context skew */
	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
	mulli	r0,r0,0x111		/* multiply by ESID skew */
	add	r3,r3,r0		/* note code below trims to 24 bits */

	/* Construct the high word of the PPC-style PTE (r11) */
	rlwinm	r11,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
	rlwimi	r11,r4,10,26,31		/* put in API (abbrev page index) */
	SET_V(r11)			/* set V (valid) bit */

#ifdef CONFIG_SMP
	addis	r9,r7,mmu_hash_lock@ha
	addi	r9,r9,mmu_hash_lock@l
	rlwinm	r8,r1,0,0,18
	add	r8,r8,r7
	lwz	r8,TI_CPU(r8)
	oris	r8,r8,9
10:	lwarx	r0,0,r9
	cmpi	0,r0,0
	bne-	11f
	stwcx.	r8,0,r9
	beq+	12f
11:	lwz	r0,0(r9)
	cmpi	0,r0,0
	beq	10b
	b	11b
12:	isync
#endif

	/*
	 * Check the _PAGE_HASHPTE bit in the linux PTE.  If it is
	 * already clear, we're done (for this pte).  If not,
	 * clear it (atomically) and proceed.  -- paulus.
	 */
33:	lwarx	r8,0,r5			/* fetch the pte */
	andi.	r0,r8,_PAGE_HASHPTE
	beq	8f			/* done if HASHPTE is already clear */
	rlwinm	r8,r8,0,31,29		/* clear HASHPTE bit */
	stwcx.	r8,0,r5			/* update the pte */
	bne-	33b

	/* Get the address of the primary PTE group in the hash table (r3) */
_GLOBAL(flush_hash_patch_A)
	addis	r8,r7,Hash_base@h	/* base address of hash table */
	rlwimi	r8,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
	rlwinm	r0,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
	xor	r8,r0,r8		/* make primary hash */

	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
	li	r0,8			/* PTEs/group */
	mtctr	r0
	addi	r12,r8,-PTE_SIZE
1:	LDPTEu	r0,PTE_SIZE(r12)	/* get next PTE */
	CMPPTE	0,r0,r11
	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
	beq+	3f

	/* Search the secondary PTEG for a matching PTE */
	ori	r11,r11,PTE_H		/* set H (secondary hash) bit */
	li	r0,8			/* PTEs/group */
_GLOBAL(flush_hash_patch_B)
	xoris	r12,r8,Hash_msk>>16	/* compute secondary hash */
	xori	r12,r12,(-PTEG_SIZE & 0xffff)
	addi	r12,r12,-PTE_SIZE
	mtctr	r0
2:	LDPTEu	r0,PTE_SIZE(r12)
	CMPPTE	0,r0,r11
	bdnzf	2,2b
	xori	r11,r11,PTE_H		/* clear H again */
	bne-	4f			/* should rarely fail to find it */

3:	li	r0,0
	STPTE	r0,0(r12)		/* invalidate entry */
4:	sync
	tlbie	r4			/* in hw tlb too */
	sync

8:	ble	cr1,9f			/* if all ptes checked */
81:	addi	r6,r6,-1
	addi	r5,r5,4			/* advance to next pte */
	addi	r4,r4,0x1000
	lwz	r0,0(r5)		/* check next pte */
	cmpwi	cr1,r6,1
	andi.	r0,r0,_PAGE_HASHPTE
	bne	33b
	bgt	cr1,81b

9:
#ifdef CONFIG_SMP
	TLBSYNC
	li	r0,0
	stw	r0,0(r9)		/* clear mmu_hash_lock */
#endif

19:	mtmsr	r10
	SYNC_601
	isync
	blr