xref: /linux/arch/powerpc/mm/book3s32/hash_low.S (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 *  PowerPC version
4 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
6 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
7 *  Adapted for Power Macintosh by Paul Mackerras.
8 *  Low-level exception handlers and MMU support
9 *  rewritten by Paul Mackerras.
10 *    Copyright (C) 1996 Paul Mackerras.
11 *
12 *  This file contains low-level assembler routines for managing
13 *  the PowerPC MMU hash table.  (PPC 8xx processors don't use a
14 *  hash table, so this file is not used on them.)
15 */
16
17#include <linux/export.h>
18#include <linux/pgtable.h>
19#include <linux/init.h>
20#include <asm/reg.h>
21#include <asm/page.h>
22#include <asm/cputable.h>
23#include <asm/ppc_asm.h>
24#include <asm/thread_info.h>
25#include <asm/asm-offsets.h>
26#include <asm/feature-fixups.h>
27#include <asm/code-patching-asm.h>
28
29#ifdef CONFIG_PTE_64BIT
30#define PTE_T_SIZE		8
31#define PTE_FLAGS_OFFSET	4	/* offset of PTE flags, in bytes */
32#else
33#define PTE_T_SIZE		4
34#define PTE_FLAGS_OFFSET	0
35#endif
36
37/*
38 * Load a PTE into the hash table, if possible.
39 * The address is in r4, and r3 contains required access flags:
40 *   - For ISI: _PAGE_PRESENT | _PAGE_EXEC
41 *   - For DSI: _PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE if a write.
42 * r9 contains the SRR1 value, from which we use the MSR_PR bit.
43 * SPRG_THREAD contains the physical address of the current task's thread.
44 *
45 * Returns to the caller if the access is illegal or there is no
46 * mapping for the address.  Otherwise it places an appropriate PTE
47 * in the hash table and returns from the exception.
48 * Uses r0, r3 - r6, r8, r10, ctr, lr.
49 */
50	.text
51_GLOBAL(hash_page)
52#ifdef CONFIG_SMP
53	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@h
54	ori	r8, r8, (mmu_hash_lock - PAGE_OFFSET)@l
55	lis	r0,0x0fff
56	b	10f
5711:	lwz	r6,0(r8)
58	cmpwi	0,r6,0
59	bne	11b
6010:	lwarx	r6,0,r8
61	cmpwi	0,r6,0
62	bne-	11b
63	stwcx.	r0,0,r8
64	bne-	10b
65	isync
66#endif
67	/* Get PTE (linux-style) and check access */
68	lis	r0, TASK_SIZE@h		/* check if kernel address */
69	cmplw	0,r4,r0
70	mfspr	r8,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
71	lwz	r5,PGDIR(r8)		/* virt page-table root */
72	blt+	112f			/* assume user more likely */
73	lis	r5,swapper_pg_dir@ha	/* if kernel address, use */
74	andi.	r0,r9,MSR_PR		/* Check usermode */
75	addi	r5,r5,swapper_pg_dir@l	/* kernel page table */
76#ifdef CONFIG_SMP
77	bne-	.Lhash_page_out		/* return if usermode */
78#else
79	bnelr-
80#endif
81112:	tophys(r5, r5)
82#ifndef CONFIG_PTE_64BIT
83	rlwimi	r5,r4,12,20,29		/* insert top 10 bits of address */
84	lwz	r8,0(r5)		/* get pmd entry */
85	rlwinm.	r8,r8,0,0,19		/* extract address of pte page */
86#else
87	rlwinm	r8,r4,13,19,29		/* Compute pgdir/pmd offset */
88	lwzx	r8,r8,r5		/* Get L1 entry */
89	rlwinm.	r8,r8,0,0,20		/* extract pt base address */
90#endif
91#ifdef CONFIG_SMP
92	beq-	.Lhash_page_out		/* return if no mapping */
93#else
94	/* XXX it seems like the 601 will give a machine fault on the
95	   rfi if its alignment is wrong (bottom 4 bits of address are
96	   8 or 0xc) and we have had a not-taken conditional branch
97	   to the address following the rfi. */
98	beqlr-
99#endif
100#ifndef CONFIG_PTE_64BIT
101	rlwimi	r8,r4,22,20,29		/* insert next 10 bits of address */
102#else
103	rlwimi	r8,r4,23,20,28		/* compute pte address */
104	/*
105	 * If PTE_64BIT is set, the low word is the flags word; use that
106	 * word for locking since it contains all the interesting bits.
107	 */
108	addi	r8,r8,PTE_FLAGS_OFFSET
109#endif
110
111	/*
112	 * Update the linux PTE atomically.  We do the lwarx up-front
113	 * because almost always, there won't be a permission violation
114	 * and there won't already be an HPTE, and thus we will have
115	 * to update the PTE to set _PAGE_HASHPTE.  -- paulus.
116	 */
117.Lretry:
118	lwarx	r6,0,r8			/* get linux-style pte, flag word */
119#ifdef CONFIG_PPC_KUAP
120	mfsrin	r5,r4
121	rlwinm	r0,r9,28,_PAGE_WRITE	/* MSR[PR] => _PAGE_WRITE */
122	rlwinm	r5,r5,12,_PAGE_WRITE	/* Ks => _PAGE_WRITE */
123	andc	r5,r5,r0		/* Ks & ~MSR[PR] */
124	andc	r5,r6,r5		/* Clear _PAGE_WRITE when Ks = 1 && MSR[PR] = 0 */
125	andc.	r5,r3,r5		/* check access & ~permission */
126#else
127	andc.	r5,r3,r6		/* check access & ~permission */
128#endif
129	rlwinm	r0,r3,32-3,24,24	/* _PAGE_WRITE access -> _PAGE_DIRTY */
130	ori	r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE
131#ifdef CONFIG_SMP
132	bne-	.Lhash_page_out		/* return if access not permitted */
133#else
134	bnelr-
135#endif
136	or	r5,r0,r6		/* set accessed/dirty bits */
137#ifdef CONFIG_PTE_64BIT
138#ifdef CONFIG_SMP
139	subf	r10,r6,r8		/* create false data dependency */
140	subi	r10,r10,PTE_FLAGS_OFFSET
141	lwzx	r10,r6,r10		/* Get upper PTE word */
142#else
143	lwz	r10,-PTE_FLAGS_OFFSET(r8)
144#endif /* CONFIG_SMP */
145#endif /* CONFIG_PTE_64BIT */
146	stwcx.	r5,0,r8			/* attempt to update PTE */
147	bne-	.Lretry			/* retry if someone got there first */
148
149	mfsrin	r3,r4			/* get segment reg for segment */
150	bl	create_hpte		/* add the hash table entry */
151
152#ifdef CONFIG_SMP
153	eieio
154	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
155	li	r0,0
156	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
157#endif
158	b	fast_hash_page_return
159
160#ifdef CONFIG_SMP
161.Lhash_page_out:
162	eieio
163	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
164	li	r0,0
165	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
166	blr
167#endif /* CONFIG_SMP */
168_ASM_NOKPROBE_SYMBOL(hash_page)
169
170/*
171 * Add an entry for a particular page to the hash table.
172 *
173 * add_hash_page(unsigned context, unsigned long va, unsigned long pmdval)
174 *
175 * We assume any necessary modifications to the pte (e.g. setting
176 * the accessed bit) have already been done and that there is actually
177 * a hash table in use (i.e. we're not on a 603).
178 */
179_GLOBAL(add_hash_page)
180	mflr	r0
181	stw	r0,4(r1)
182
183#ifdef CONFIG_SMP
184	lwz	r8,TASK_CPU(r2)		/* to go in mmu_hash_lock */
185	oris	r8,r8,12
186#endif /* CONFIG_SMP */
187
188	/*
189	 * We disable interrupts here, even on UP, because we don't
190	 * want to race with hash_page, and because we want the
191	 * _PAGE_HASHPTE bit to be a reliable indication of whether
192	 * the HPTE exists (or at least whether one did once).
193	 * We also turn off the MMU for data accesses so that we
194	 * we can't take a hash table miss (assuming the code is
195	 * covered by a BAT).  -- paulus
196	 */
197	mfmsr	r9
198	rlwinm	r0,r9,0,17,15		/* clear bit 16 (MSR_EE) */
199	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
200	mtmsr	r0
201	isync
202
203#ifdef CONFIG_SMP
204	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
205	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
20610:	lwarx	r0,0,r6			/* take the mmu_hash_lock */
207	cmpwi	0,r0,0
208	bne-	11f
209	stwcx.	r8,0,r6
210	beq+	12f
21111:	lwz	r0,0(r6)
212	cmpwi	0,r0,0
213	beq	10b
214	b	11b
21512:	isync
216#endif
217
218	/*
219	 * Fetch the linux pte and test and set _PAGE_HASHPTE atomically.
220	 * If _PAGE_HASHPTE was already set, we don't replace the existing
221	 * HPTE, so we just unlock and return.
222	 */
223	mr	r8,r5
224#ifndef CONFIG_PTE_64BIT
225	rlwimi	r8,r4,22,20,29
226#else
227	rlwimi	r8,r4,23,20,28
228	addi	r8,r8,PTE_FLAGS_OFFSET
229#endif
2301:	lwarx	r6,0,r8
231	andi.	r0,r6,_PAGE_HASHPTE
232	bne	9f			/* if HASHPTE already set, done */
233#ifdef CONFIG_PTE_64BIT
234#ifdef CONFIG_SMP
235	subf	r10,r6,r8		/* create false data dependency */
236	subi	r10,r10,PTE_FLAGS_OFFSET
237	lwzx	r10,r6,r10		/* Get upper PTE word */
238#else
239	lwz	r10,-PTE_FLAGS_OFFSET(r8)
240#endif /* CONFIG_SMP */
241#endif /* CONFIG_PTE_64BIT */
242	ori	r5,r6,_PAGE_HASHPTE
243	stwcx.	r5,0,r8
244	bne-	1b
245
246	/* Convert context and va to VSID */
247	mulli	r3,r3,897*16		/* multiply context by context skew */
248	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
249	mulli	r0,r0,0x111		/* multiply by ESID skew */
250	add	r3,r3,r0		/* note create_hpte trims to 24 bits */
251
252	bl	create_hpte
253
2549:
255#ifdef CONFIG_SMP
256	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
257	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
258	eieio
259	li	r0,0
260	stw	r0,0(r6)		/* clear mmu_hash_lock */
261#endif
262
263	/* reenable interrupts and DR */
264	mtmsr	r9
265	isync
266
267	lwz	r0,4(r1)
268	mtlr	r0
269	blr
270_ASM_NOKPROBE_SYMBOL(add_hash_page)
271
272/*
273 * This routine adds a hardware PTE to the hash table.
274 * It is designed to be called with the MMU either on or off.
275 * r3 contains the VSID, r4 contains the virtual address,
276 * r5 contains the linux PTE, r6 contains the old value of the
277 * linux PTE (before setting _PAGE_HASHPTE). r10 contains the
278 * upper half of the PTE if CONFIG_PTE_64BIT.
279 * On SMP, the caller should have the mmu_hash_lock held.
280 * We assume that the caller has (or will) set the _PAGE_HASHPTE
281 * bit in the linux PTE in memory.  The value passed in r6 should
282 * be the old linux PTE value; if it doesn't have _PAGE_HASHPTE set
283 * this routine will skip the search for an existing HPTE.
284 * This procedure modifies r0, r3 - r6, r8, cr0.
285 *  -- paulus.
286 *
287 * For speed, 4 of the instructions get patched once the size and
288 * physical address of the hash table are known.  These definitions
289 * of Hash_base and Hash_bits below are for the early hash table.
290 */
291Hash_base = early_hash
292Hash_bits = 12				/* e.g. 256kB hash table */
293Hash_msk = (((1 << Hash_bits) - 1) * 64)
294
295/* defines for the PTE format for 32-bit PPCs */
296#define HPTE_SIZE	8
297#define PTEG_SIZE	64
298#define LG_PTEG_SIZE	6
299#define LDPTEu		lwzu
300#define LDPTE		lwz
301#define STPTE		stw
302#define CMPPTE		cmpw
303#define PTE_H		0x40
304#define PTE_V		0x80000000
305#define TST_V(r)	rlwinm. r,r,0,0,0
306#define SET_V(r)	oris r,r,PTE_V@h
307#define CLR_V(r,t)	rlwinm r,r,0,1,31
308
309#define HASH_LEFT	31-(LG_PTEG_SIZE+Hash_bits-1)
310#define HASH_RIGHT	31-LG_PTEG_SIZE
311
312__REF
313_GLOBAL(create_hpte)
314	/* Convert linux-style PTE (r5) to low word of PPC-style PTE (r8) */
315	lis	r0, TASK_SIZE@h
316	rlwinm	r5,r5,0,~3		/* Clear PP bits */
317	cmplw	r4,r0
318	rlwinm	r8,r5,32-9,30,30	/* _PAGE_WRITE -> PP msb */
319	rlwinm	r0,r5,32-6,30,30	/* _PAGE_DIRTY -> PP msb */
320	and	r8,r8,r0		/* writable if _RW & _DIRTY */
321	bge-	1f			/* Kernelspace ? Skip */
322	ori	r5,r5,3			/* Userspace ? PP = 3 */
3231:	ori	r8,r8,0xe04		/* clear out reserved bits */
324	andc	r8,r5,r8		/* PP = user? (rw&dirty? 1: 3): 0 */
325BEGIN_FTR_SECTION
326	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
327END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
328#ifdef CONFIG_PTE_64BIT
329	/* Put the XPN bits into the PTE */
330	rlwimi	r8,r10,8,20,22
331	rlwimi	r8,r10,2,29,29
332#endif
333
334	/* Construct the high word of the PPC-style PTE (r5) */
335	rlwinm	r5,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
336	rlwimi	r5,r4,10,26,31		/* put in API (abbrev page index) */
337	SET_V(r5)			/* set V (valid) bit */
338
339	patch_site	0f, patch__hash_page_A0
340	patch_site	1f, patch__hash_page_A1
341	patch_site	2f, patch__hash_page_A2
342	/* Get the address of the primary PTE group in the hash table (r3) */
3430:	lis	r0, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
3441:	rlwimi	r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
3452:	rlwinm	r3,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
346	xor	r3,r3,r0		/* make primary hash */
347	li	r0,8			/* PTEs/group */
348
349	/*
350	 * Test the _PAGE_HASHPTE bit in the old linux PTE, and skip the search
351	 * if it is clear, meaning that the HPTE isn't there already...
352	 */
353	andi.	r6,r6,_PAGE_HASHPTE
354	beq+	10f			/* no PTE: go look for an empty slot */
355	tlbie	r4
356
357	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
358	mtctr	r0
359	addi	r4,r3,-HPTE_SIZE
3601:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
361	CMPPTE	0,r6,r5
362	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
363	beq+	.Lfound_slot
364
365	patch_site	0f, patch__hash_page_B
366	/* Search the secondary PTEG for a matching PTE */
367	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
3680:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
369	xori	r4,r4,(-PTEG_SIZE & 0xffff)
370	addi	r4,r4,-HPTE_SIZE
371	mtctr	r0
3722:	LDPTEu	r6,HPTE_SIZE(r4)
373	CMPPTE	0,r6,r5
374	bdnzf	2,2b
375	beq+	.Lfound_slot
376	xori	r5,r5,PTE_H		/* clear H bit again */
377
378	/* Search the primary PTEG for an empty slot */
37910:	mtctr	r0
380	addi	r4,r3,-HPTE_SIZE	/* search primary PTEG */
3811:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
382	TST_V(r6)			/* test valid bit */
383	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
384	beq+	.Lfound_empty
385
386	patch_site	0f, patch__hash_page_C
387	/* Search the secondary PTEG for an empty slot */
388	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
3890:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
390	xori	r4,r4,(-PTEG_SIZE & 0xffff)
391	addi	r4,r4,-HPTE_SIZE
392	mtctr	r0
3932:	LDPTEu	r6,HPTE_SIZE(r4)
394	TST_V(r6)
395	bdnzf	2,2b
396	beq+	.Lfound_empty
397	xori	r5,r5,PTE_H		/* clear H bit again */
398
399	/*
400	 * Choose an arbitrary slot in the primary PTEG to overwrite.
401	 * Since both the primary and secondary PTEGs are full, and we
402	 * have no information that the PTEs in the primary PTEG are
403	 * more important or useful than those in the secondary PTEG,
404	 * and we know there is a definite (although small) speed
405	 * advantage to putting the PTE in the primary PTEG, we always
406	 * put the PTE in the primary PTEG.
407	 */
408
409	lis	r4, (next_slot - PAGE_OFFSET)@ha	/* get next evict slot */
410	lwz	r6, (next_slot - PAGE_OFFSET)@l(r4)
411	addi	r6,r6,HPTE_SIZE			/* search for candidate */
412	andi.	r6,r6,7*HPTE_SIZE
413	stw	r6,next_slot@l(r4)
414	add	r4,r3,r6
415
416#ifndef CONFIG_SMP
417	/* Store PTE in PTEG */
418.Lfound_empty:
419	STPTE	r5,0(r4)
420.Lfound_slot:
421	STPTE	r8,HPTE_SIZE/2(r4)
422
423#else /* CONFIG_SMP */
424/*
425 * Between the tlbie above and updating the hash table entry below,
426 * another CPU could read the hash table entry and put it in its TLB.
427 * There are 3 cases:
428 * 1. using an empty slot
429 * 2. updating an earlier entry to change permissions (i.e. enable write)
430 * 3. taking over the PTE for an unrelated address
431 *
432 * In each case it doesn't really matter if the other CPUs have the old
433 * PTE in their TLB.  So we don't need to bother with another tlbie here,
434 * which is convenient as we've overwritten the register that had the
435 * address. :-)  The tlbie above is mainly to make sure that this CPU comes
436 * and gets the new PTE from the hash table.
437 *
438 * We do however have to make sure that the PTE is never in an invalid
439 * state with the V bit set.
440 */
441.Lfound_empty:
442.Lfound_slot:
443	CLR_V(r5,r0)		/* clear V (valid) bit in PTE */
444	STPTE	r5,0(r4)
445	sync
446	TLBSYNC
447	STPTE	r8,HPTE_SIZE/2(r4) /* put in correct RPN, WIMG, PP bits */
448	sync
449	SET_V(r5)
450	STPTE	r5,0(r4)	/* finally set V bit in PTE */
451#endif /* CONFIG_SMP */
452
453	sync		/* make sure pte updates get to memory */
454	blr
455	.previous
456_ASM_NOKPROBE_SYMBOL(create_hpte)
457
458	.section .bss
459	.align	2
460next_slot:
461	.space	4
462	.previous
463
464/*
465 * Flush the entry for a particular page from the hash table.
466 *
467 * flush_hash_pages(unsigned context, unsigned long va, unsigned long pmdval,
468 *		    int count)
469 *
470 * We assume that there is a hash table in use (Hash != 0).
471 */
472__REF
473_GLOBAL(flush_hash_pages)
474	/*
475	 * We disable interrupts here, even on UP, because we want
476	 * the _PAGE_HASHPTE bit to be a reliable indication of
477	 * whether the HPTE exists (or at least whether one did once).
478	 * We also turn off the MMU for data accesses so that we
479	 * we can't take a hash table miss (assuming the code is
480	 * covered by a BAT).  -- paulus
481	 */
482	mfmsr	r10
483	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
484	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
485	mtmsr	r0
486	isync
487
488	/* First find a PTE in the range that has _PAGE_HASHPTE set */
489#ifndef CONFIG_PTE_64BIT
490	rlwimi	r5,r4,22,20,29
491#else
492	rlwimi	r5,r4,23,20,28
493	addi	r5,r5,PTE_FLAGS_OFFSET
494#endif
4951:	lwz	r0,0(r5)
496	cmpwi	cr1,r6,1
497	andi.	r0,r0,_PAGE_HASHPTE
498	bne	2f
499	ble	cr1,19f
500	addi	r4,r4,0x1000
501	addi	r5,r5,PTE_T_SIZE
502	addi	r6,r6,-1
503	b	1b
504
505	/* Convert context and va to VSID */
5062:	mulli	r3,r3,897*16		/* multiply context by context skew */
507	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
508	mulli	r0,r0,0x111		/* multiply by ESID skew */
509	add	r3,r3,r0		/* note code below trims to 24 bits */
510
511	/* Construct the high word of the PPC-style PTE (r11) */
512	rlwinm	r11,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
513	rlwimi	r11,r4,10,26,31		/* put in API (abbrev page index) */
514	SET_V(r11)			/* set V (valid) bit */
515
516#ifdef CONFIG_SMP
517	lis	r9, (mmu_hash_lock - PAGE_OFFSET)@ha
518	addi	r9, r9, (mmu_hash_lock - PAGE_OFFSET)@l
519	tophys	(r8, r2)
520	lwz	r8, TASK_CPU(r8)
521	oris	r8,r8,9
52210:	lwarx	r0,0,r9
523	cmpwi	0,r0,0
524	bne-	11f
525	stwcx.	r8,0,r9
526	beq+	12f
52711:	lwz	r0,0(r9)
528	cmpwi	0,r0,0
529	beq	10b
530	b	11b
53112:	isync
532#endif
533
534	/*
535	 * Check the _PAGE_HASHPTE bit in the linux PTE.  If it is
536	 * already clear, we're done (for this pte).  If not,
537	 * clear it (atomically) and proceed.  -- paulus.
538	 */
53933:	lwarx	r8,0,r5			/* fetch the pte flags word */
540	andi.	r0,r8,_PAGE_HASHPTE
541	beq	8f			/* done if HASHPTE is already clear */
542	rlwinm	r8,r8,0,31,29		/* clear HASHPTE bit */
543	stwcx.	r8,0,r5			/* update the pte */
544	bne-	33b
545
546	patch_site	0f, patch__flush_hash_A0
547	patch_site	1f, patch__flush_hash_A1
548	patch_site	2f, patch__flush_hash_A2
549	/* Get the address of the primary PTE group in the hash table (r3) */
5500:	lis	r8, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
5511:	rlwimi	r8,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
5522:	rlwinm	r0,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
553	xor	r8,r0,r8		/* make primary hash */
554
555	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
556	li	r0,8			/* PTEs/group */
557	mtctr	r0
558	addi	r12,r8,-HPTE_SIZE
5591:	LDPTEu	r0,HPTE_SIZE(r12)	/* get next PTE */
560	CMPPTE	0,r0,r11
561	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
562	beq+	3f
563
564	patch_site	0f, patch__flush_hash_B
565	/* Search the secondary PTEG for a matching PTE */
566	ori	r11,r11,PTE_H		/* set H (secondary hash) bit */
567	li	r0,8			/* PTEs/group */
5680:	xoris	r12,r8,Hash_msk>>16	/* compute secondary hash */
569	xori	r12,r12,(-PTEG_SIZE & 0xffff)
570	addi	r12,r12,-HPTE_SIZE
571	mtctr	r0
5722:	LDPTEu	r0,HPTE_SIZE(r12)
573	CMPPTE	0,r0,r11
574	bdnzf	2,2b
575	xori	r11,r11,PTE_H		/* clear H again */
576	bne-	4f			/* should rarely fail to find it */
577
5783:	li	r0,0
579	STPTE	r0,0(r12)		/* invalidate entry */
5804:	sync
581	tlbie	r4			/* in hw tlb too */
582	sync
583
5848:	ble	cr1,9f			/* if all ptes checked */
58581:	addi	r6,r6,-1
586	addi	r5,r5,PTE_T_SIZE
587	addi	r4,r4,0x1000
588	lwz	r0,0(r5)		/* check next pte */
589	cmpwi	cr1,r6,1
590	andi.	r0,r0,_PAGE_HASHPTE
591	bne	33b
592	bgt	cr1,81b
593
5949:
595#ifdef CONFIG_SMP
596	TLBSYNC
597	li	r0,0
598	stw	r0,0(r9)		/* clear mmu_hash_lock */
599#endif
600
60119:	mtmsr	r10
602	isync
603	blr
604	.previous
605EXPORT_SYMBOL(flush_hash_pages)
606_ASM_NOKPROBE_SYMBOL(flush_hash_pages)
607