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/pgtable.h>
18#include <linux/init.h>
19#include <asm/reg.h>
20#include <asm/page.h>
21#include <asm/cputable.h>
22#include <asm/ppc_asm.h>
23#include <asm/thread_info.h>
24#include <asm/asm-offsets.h>
25#include <asm/export.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 an access flag:
40 * _PAGE_RW (0x400) if a write.
41 * r9 contains the SRR1 value, from which we use the MSR_PR bit.
42 * SPRG_THREAD contains the physical address of the current task's thread.
43 *
44 * Returns to the caller if the access is illegal or there is no
45 * mapping for the address.  Otherwise it places an appropriate PTE
46 * in the hash table and returns from the exception.
47 * Uses r0, r3 - r6, r8, r10, ctr, lr.
48 */
49	.text
50_GLOBAL(hash_page)
51#ifdef CONFIG_SMP
52	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@h
53	ori	r8, r8, (mmu_hash_lock - PAGE_OFFSET)@l
54	lis	r0,0x0fff
55	b	10f
5611:	lwz	r6,0(r8)
57	cmpwi	0,r6,0
58	bne	11b
5910:	lwarx	r6,0,r8
60	cmpwi	0,r6,0
61	bne-	11b
62	stwcx.	r0,0,r8
63	bne-	10b
64	isync
65#endif
66	/* Get PTE (linux-style) and check access */
67	lis	r0, TASK_SIZE@h		/* check if kernel address */
68	cmplw	0,r4,r0
69	mfspr	r8,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
70	ori	r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
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	addi	r5,r5,swapper_pg_dir@l	/* kernel page table */
75	rlwimi	r3,r9,32-12,29,29	/* MSR_PR -> _PAGE_USER */
76112:	tophys(r5, r5)
77#ifndef CONFIG_PTE_64BIT
78	rlwimi	r5,r4,12,20,29		/* insert top 10 bits of address */
79	lwz	r8,0(r5)		/* get pmd entry */
80	rlwinm.	r8,r8,0,0,19		/* extract address of pte page */
81#else
82	rlwinm	r8,r4,13,19,29		/* Compute pgdir/pmd offset */
83	lwzx	r8,r8,r5		/* Get L1 entry */
84	rlwinm.	r8,r8,0,0,20		/* extract pt base address */
85#endif
86#ifdef CONFIG_SMP
87	beq-	.Lhash_page_out		/* return if no mapping */
88#else
89	/* XXX it seems like the 601 will give a machine fault on the
90	   rfi if its alignment is wrong (bottom 4 bits of address are
91	   8 or 0xc) and we have had a not-taken conditional branch
92	   to the address following the rfi. */
93	beqlr-
94#endif
95#ifndef CONFIG_PTE_64BIT
96	rlwimi	r8,r4,22,20,29		/* insert next 10 bits of address */
97#else
98	rlwimi	r8,r4,23,20,28		/* compute pte address */
99	/*
100	 * If PTE_64BIT is set, the low word is the flags word; use that
101	 * word for locking since it contains all the interesting bits.
102	 */
103	addi	r8,r8,PTE_FLAGS_OFFSET
104#endif
105
106	/*
107	 * Update the linux PTE atomically.  We do the lwarx up-front
108	 * because almost always, there won't be a permission violation
109	 * and there won't already be an HPTE, and thus we will have
110	 * to update the PTE to set _PAGE_HASHPTE.  -- paulus.
111	 */
112.Lretry:
113	lwarx	r6,0,r8			/* get linux-style pte, flag word */
114#ifdef CONFIG_PPC_KUAP
115	mfsrin	r5,r4
116	rlwinm	r0,r9,28,_PAGE_RW	/* MSR[PR] => _PAGE_RW */
117	rlwinm	r5,r5,12,_PAGE_RW	/* Ks => _PAGE_RW */
118	andc	r5,r5,r0		/* Ks & ~MSR[PR] */
119	andc	r5,r6,r5		/* Clear _PAGE_RW when Ks = 1 && MSR[PR] = 0 */
120	andc.	r5,r3,r5		/* check access & ~permission */
121#else
122	andc.	r5,r3,r6		/* check access & ~permission */
123#endif
124	rlwinm	r0,r3,32-3,24,24	/* _PAGE_RW access -> _PAGE_DIRTY */
125	ori	r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE
126#ifdef CONFIG_SMP
127	bne-	.Lhash_page_out		/* return if access not permitted */
128#else
129	bnelr-
130#endif
131	or	r5,r0,r6		/* set accessed/dirty bits */
132#ifdef CONFIG_PTE_64BIT
133#ifdef CONFIG_SMP
134	subf	r10,r6,r8		/* create false data dependency */
135	subi	r10,r10,PTE_FLAGS_OFFSET
136	lwzx	r10,r6,r10		/* Get upper PTE word */
137#else
138	lwz	r10,-PTE_FLAGS_OFFSET(r8)
139#endif /* CONFIG_SMP */
140#endif /* CONFIG_PTE_64BIT */
141	stwcx.	r5,0,r8			/* attempt to update PTE */
142	bne-	.Lretry			/* retry if someone got there first */
143
144	mfsrin	r3,r4			/* get segment reg for segment */
145	bl	create_hpte		/* add the hash table entry */
146
147#ifdef CONFIG_SMP
148	eieio
149	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
150	li	r0,0
151	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
152#endif
153	b	fast_hash_page_return
154
155#ifdef CONFIG_SMP
156.Lhash_page_out:
157	eieio
158	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
159	li	r0,0
160	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
161	blr
162#endif /* CONFIG_SMP */
163_ASM_NOKPROBE_SYMBOL(hash_page)
164
165/*
166 * Add an entry for a particular page to the hash table.
167 *
168 * add_hash_page(unsigned context, unsigned long va, unsigned long pmdval)
169 *
170 * We assume any necessary modifications to the pte (e.g. setting
171 * the accessed bit) have already been done and that there is actually
172 * a hash table in use (i.e. we're not on a 603).
173 */
174_GLOBAL(add_hash_page)
175	mflr	r0
176	stw	r0,4(r1)
177
178#ifdef CONFIG_SMP
179	lwz	r8,TASK_CPU(r2)		/* to go in mmu_hash_lock */
180	oris	r8,r8,12
181#endif /* CONFIG_SMP */
182
183	/*
184	 * We disable interrupts here, even on UP, because we don't
185	 * want to race with hash_page, and because we want the
186	 * _PAGE_HASHPTE bit to be a reliable indication of whether
187	 * the HPTE exists (or at least whether one did once).
188	 * We also turn off the MMU for data accesses so that we
189	 * we can't take a hash table miss (assuming the code is
190	 * covered by a BAT).  -- paulus
191	 */
192	mfmsr	r9
193	rlwinm	r0,r9,0,17,15		/* clear bit 16 (MSR_EE) */
194	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
195	mtmsr	r0
196	isync
197
198#ifdef CONFIG_SMP
199	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
200	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
20110:	lwarx	r0,0,r6			/* take the mmu_hash_lock */
202	cmpi	0,r0,0
203	bne-	11f
204	stwcx.	r8,0,r6
205	beq+	12f
20611:	lwz	r0,0(r6)
207	cmpi	0,r0,0
208	beq	10b
209	b	11b
21012:	isync
211#endif
212
213	/*
214	 * Fetch the linux pte and test and set _PAGE_HASHPTE atomically.
215	 * If _PAGE_HASHPTE was already set, we don't replace the existing
216	 * HPTE, so we just unlock and return.
217	 */
218	mr	r8,r5
219#ifndef CONFIG_PTE_64BIT
220	rlwimi	r8,r4,22,20,29
221#else
222	rlwimi	r8,r4,23,20,28
223	addi	r8,r8,PTE_FLAGS_OFFSET
224#endif
2251:	lwarx	r6,0,r8
226	andi.	r0,r6,_PAGE_HASHPTE
227	bne	9f			/* if HASHPTE already set, done */
228#ifdef CONFIG_PTE_64BIT
229#ifdef CONFIG_SMP
230	subf	r10,r6,r8		/* create false data dependency */
231	subi	r10,r10,PTE_FLAGS_OFFSET
232	lwzx	r10,r6,r10		/* Get upper PTE word */
233#else
234	lwz	r10,-PTE_FLAGS_OFFSET(r8)
235#endif /* CONFIG_SMP */
236#endif /* CONFIG_PTE_64BIT */
237	ori	r5,r6,_PAGE_HASHPTE
238	stwcx.	r5,0,r8
239	bne-	1b
240
241	/* Convert context and va to VSID */
242	mulli	r3,r3,897*16		/* multiply context by context skew */
243	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
244	mulli	r0,r0,0x111		/* multiply by ESID skew */
245	add	r3,r3,r0		/* note create_hpte trims to 24 bits */
246
247	bl	create_hpte
248
2499:
250#ifdef CONFIG_SMP
251	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
252	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
253	eieio
254	li	r0,0
255	stw	r0,0(r6)		/* clear mmu_hash_lock */
256#endif
257
258	/* reenable interrupts and DR */
259	mtmsr	r9
260	isync
261
262	lwz	r0,4(r1)
263	mtlr	r0
264	blr
265_ASM_NOKPROBE_SYMBOL(add_hash_page)
266
267/*
268 * This routine adds a hardware PTE to the hash table.
269 * It is designed to be called with the MMU either on or off.
270 * r3 contains the VSID, r4 contains the virtual address,
271 * r5 contains the linux PTE, r6 contains the old value of the
272 * linux PTE (before setting _PAGE_HASHPTE). r10 contains the
273 * upper half of the PTE if CONFIG_PTE_64BIT.
274 * On SMP, the caller should have the mmu_hash_lock held.
275 * We assume that the caller has (or will) set the _PAGE_HASHPTE
276 * bit in the linux PTE in memory.  The value passed in r6 should
277 * be the old linux PTE value; if it doesn't have _PAGE_HASHPTE set
278 * this routine will skip the search for an existing HPTE.
279 * This procedure modifies r0, r3 - r6, r8, cr0.
280 *  -- paulus.
281 *
282 * For speed, 4 of the instructions get patched once the size and
283 * physical address of the hash table are known.  These definitions
284 * of Hash_base and Hash_bits below are for the early hash table.
285 */
286Hash_base = early_hash
287Hash_bits = 12				/* e.g. 256kB hash table */
288Hash_msk = (((1 << Hash_bits) - 1) * 64)
289
290/* defines for the PTE format for 32-bit PPCs */
291#define HPTE_SIZE	8
292#define PTEG_SIZE	64
293#define LG_PTEG_SIZE	6
294#define LDPTEu		lwzu
295#define LDPTE		lwz
296#define STPTE		stw
297#define CMPPTE		cmpw
298#define PTE_H		0x40
299#define PTE_V		0x80000000
300#define TST_V(r)	rlwinm. r,r,0,0,0
301#define SET_V(r)	oris r,r,PTE_V@h
302#define CLR_V(r,t)	rlwinm r,r,0,1,31
303
304#define HASH_LEFT	31-(LG_PTEG_SIZE+Hash_bits-1)
305#define HASH_RIGHT	31-LG_PTEG_SIZE
306
307__REF
308_GLOBAL(create_hpte)
309	/* Convert linux-style PTE (r5) to low word of PPC-style PTE (r8) */
310	rlwinm	r8,r5,32-9,30,30	/* _PAGE_RW -> PP msb */
311	rlwinm	r0,r5,32-6,30,30	/* _PAGE_DIRTY -> PP msb */
312	and	r8,r8,r0		/* writable if _RW & _DIRTY */
313	rlwimi	r5,r5,32-1,30,30	/* _PAGE_USER -> PP msb */
314	rlwimi	r5,r5,32-2,31,31	/* _PAGE_USER -> PP lsb */
315	ori	r8,r8,0xe04		/* clear out reserved bits */
316	andc	r8,r5,r8		/* PP = user? (rw&dirty? 1: 3): 0 */
317BEGIN_FTR_SECTION
318	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
319END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
320#ifdef CONFIG_PTE_64BIT
321	/* Put the XPN bits into the PTE */
322	rlwimi	r8,r10,8,20,22
323	rlwimi	r8,r10,2,29,29
324#endif
325
326	/* Construct the high word of the PPC-style PTE (r5) */
327	rlwinm	r5,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
328	rlwimi	r5,r4,10,26,31		/* put in API (abbrev page index) */
329	SET_V(r5)			/* set V (valid) bit */
330
331	patch_site	0f, patch__hash_page_A0
332	patch_site	1f, patch__hash_page_A1
333	patch_site	2f, patch__hash_page_A2
334	/* Get the address of the primary PTE group in the hash table (r3) */
3350:	lis	r0, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
3361:	rlwimi	r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
3372:	rlwinm	r3,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
338	xor	r3,r3,r0		/* make primary hash */
339	li	r0,8			/* PTEs/group */
340
341	/*
342	 * Test the _PAGE_HASHPTE bit in the old linux PTE, and skip the search
343	 * if it is clear, meaning that the HPTE isn't there already...
344	 */
345	andi.	r6,r6,_PAGE_HASHPTE
346	beq+	10f			/* no PTE: go look for an empty slot */
347	tlbie	r4
348
349	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
350	mtctr	r0
351	addi	r4,r3,-HPTE_SIZE
3521:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
353	CMPPTE	0,r6,r5
354	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
355	beq+	.Lfound_slot
356
357	patch_site	0f, patch__hash_page_B
358	/* Search the secondary PTEG for a matching PTE */
359	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
3600:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
361	xori	r4,r4,(-PTEG_SIZE & 0xffff)
362	addi	r4,r4,-HPTE_SIZE
363	mtctr	r0
3642:	LDPTEu	r6,HPTE_SIZE(r4)
365	CMPPTE	0,r6,r5
366	bdnzf	2,2b
367	beq+	.Lfound_slot
368	xori	r5,r5,PTE_H		/* clear H bit again */
369
370	/* Search the primary PTEG for an empty slot */
37110:	mtctr	r0
372	addi	r4,r3,-HPTE_SIZE	/* search primary PTEG */
3731:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
374	TST_V(r6)			/* test valid bit */
375	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
376	beq+	.Lfound_empty
377
378	patch_site	0f, patch__hash_page_C
379	/* Search the secondary PTEG for an empty slot */
380	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
3810:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
382	xori	r4,r4,(-PTEG_SIZE & 0xffff)
383	addi	r4,r4,-HPTE_SIZE
384	mtctr	r0
3852:	LDPTEu	r6,HPTE_SIZE(r4)
386	TST_V(r6)
387	bdnzf	2,2b
388	beq+	.Lfound_empty
389	xori	r5,r5,PTE_H		/* clear H bit again */
390
391	/*
392	 * Choose an arbitrary slot in the primary PTEG to overwrite.
393	 * Since both the primary and secondary PTEGs are full, and we
394	 * have no information that the PTEs in the primary PTEG are
395	 * more important or useful than those in the secondary PTEG,
396	 * and we know there is a definite (although small) speed
397	 * advantage to putting the PTE in the primary PTEG, we always
398	 * put the PTE in the primary PTEG.
399	 */
400
401	lis	r4, (next_slot - PAGE_OFFSET)@ha	/* get next evict slot */
402	lwz	r6, (next_slot - PAGE_OFFSET)@l(r4)
403	addi	r6,r6,HPTE_SIZE			/* search for candidate */
404	andi.	r6,r6,7*HPTE_SIZE
405	stw	r6,next_slot@l(r4)
406	add	r4,r3,r6
407
408#ifndef CONFIG_SMP
409	/* Store PTE in PTEG */
410.Lfound_empty:
411	STPTE	r5,0(r4)
412.Lfound_slot:
413	STPTE	r8,HPTE_SIZE/2(r4)
414
415#else /* CONFIG_SMP */
416/*
417 * Between the tlbie above and updating the hash table entry below,
418 * another CPU could read the hash table entry and put it in its TLB.
419 * There are 3 cases:
420 * 1. using an empty slot
421 * 2. updating an earlier entry to change permissions (i.e. enable write)
422 * 3. taking over the PTE for an unrelated address
423 *
424 * In each case it doesn't really matter if the other CPUs have the old
425 * PTE in their TLB.  So we don't need to bother with another tlbie here,
426 * which is convenient as we've overwritten the register that had the
427 * address. :-)  The tlbie above is mainly to make sure that this CPU comes
428 * and gets the new PTE from the hash table.
429 *
430 * We do however have to make sure that the PTE is never in an invalid
431 * state with the V bit set.
432 */
433.Lfound_empty:
434.Lfound_slot:
435	CLR_V(r5,r0)		/* clear V (valid) bit in PTE */
436	STPTE	r5,0(r4)
437	sync
438	TLBSYNC
439	STPTE	r8,HPTE_SIZE/2(r4) /* put in correct RPN, WIMG, PP bits */
440	sync
441	SET_V(r5)
442	STPTE	r5,0(r4)	/* finally set V bit in PTE */
443#endif /* CONFIG_SMP */
444
445	sync		/* make sure pte updates get to memory */
446	blr
447	.previous
448_ASM_NOKPROBE_SYMBOL(create_hpte)
449
450	.section .bss
451	.align	2
452next_slot:
453	.space	4
454	.previous
455
456/*
457 * Flush the entry for a particular page from the hash table.
458 *
459 * flush_hash_pages(unsigned context, unsigned long va, unsigned long pmdval,
460 *		    int count)
461 *
462 * We assume that there is a hash table in use (Hash != 0).
463 */
464__REF
465_GLOBAL(flush_hash_pages)
466	/*
467	 * We disable interrupts here, even on UP, because we want
468	 * the _PAGE_HASHPTE bit to be a reliable indication of
469	 * whether the HPTE exists (or at least whether one did once).
470	 * We also turn off the MMU for data accesses so that we
471	 * we can't take a hash table miss (assuming the code is
472	 * covered by a BAT).  -- paulus
473	 */
474	mfmsr	r10
475	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
476	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
477	mtmsr	r0
478	isync
479
480	/* First find a PTE in the range that has _PAGE_HASHPTE set */
481#ifndef CONFIG_PTE_64BIT
482	rlwimi	r5,r4,22,20,29
483#else
484	rlwimi	r5,r4,23,20,28
485	addi	r5,r5,PTE_FLAGS_OFFSET
486#endif
4871:	lwz	r0,0(r5)
488	cmpwi	cr1,r6,1
489	andi.	r0,r0,_PAGE_HASHPTE
490	bne	2f
491	ble	cr1,19f
492	addi	r4,r4,0x1000
493	addi	r5,r5,PTE_T_SIZE
494	addi	r6,r6,-1
495	b	1b
496
497	/* Convert context and va to VSID */
4982:	mulli	r3,r3,897*16		/* multiply context by context skew */
499	rlwinm	r0,r4,4,28,31		/* get ESID (top 4 bits of va) */
500	mulli	r0,r0,0x111		/* multiply by ESID skew */
501	add	r3,r3,r0		/* note code below trims to 24 bits */
502
503	/* Construct the high word of the PPC-style PTE (r11) */
504	rlwinm	r11,r3,7,1,24		/* put VSID in 0x7fffff80 bits */
505	rlwimi	r11,r4,10,26,31		/* put in API (abbrev page index) */
506	SET_V(r11)			/* set V (valid) bit */
507
508#ifdef CONFIG_SMP
509	lis	r9, (mmu_hash_lock - PAGE_OFFSET)@ha
510	addi	r9, r9, (mmu_hash_lock - PAGE_OFFSET)@l
511	tophys	(r8, r2)
512	lwz	r8, TASK_CPU(r8)
513	oris	r8,r8,9
51410:	lwarx	r0,0,r9
515	cmpi	0,r0,0
516	bne-	11f
517	stwcx.	r8,0,r9
518	beq+	12f
51911:	lwz	r0,0(r9)
520	cmpi	0,r0,0
521	beq	10b
522	b	11b
52312:	isync
524#endif
525
526	/*
527	 * Check the _PAGE_HASHPTE bit in the linux PTE.  If it is
528	 * already clear, we're done (for this pte).  If not,
529	 * clear it (atomically) and proceed.  -- paulus.
530	 */
53133:	lwarx	r8,0,r5			/* fetch the pte flags word */
532	andi.	r0,r8,_PAGE_HASHPTE
533	beq	8f			/* done if HASHPTE is already clear */
534	rlwinm	r8,r8,0,31,29		/* clear HASHPTE bit */
535	stwcx.	r8,0,r5			/* update the pte */
536	bne-	33b
537
538	patch_site	0f, patch__flush_hash_A0
539	patch_site	1f, patch__flush_hash_A1
540	patch_site	2f, patch__flush_hash_A2
541	/* Get the address of the primary PTE group in the hash table (r3) */
5420:	lis	r8, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
5431:	rlwimi	r8,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
5442:	rlwinm	r0,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
545	xor	r8,r0,r8		/* make primary hash */
546
547	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
548	li	r0,8			/* PTEs/group */
549	mtctr	r0
550	addi	r12,r8,-HPTE_SIZE
5511:	LDPTEu	r0,HPTE_SIZE(r12)	/* get next PTE */
552	CMPPTE	0,r0,r11
553	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
554	beq+	3f
555
556	patch_site	0f, patch__flush_hash_B
557	/* Search the secondary PTEG for a matching PTE */
558	ori	r11,r11,PTE_H		/* set H (secondary hash) bit */
559	li	r0,8			/* PTEs/group */
5600:	xoris	r12,r8,Hash_msk>>16	/* compute secondary hash */
561	xori	r12,r12,(-PTEG_SIZE & 0xffff)
562	addi	r12,r12,-HPTE_SIZE
563	mtctr	r0
5642:	LDPTEu	r0,HPTE_SIZE(r12)
565	CMPPTE	0,r0,r11
566	bdnzf	2,2b
567	xori	r11,r11,PTE_H		/* clear H again */
568	bne-	4f			/* should rarely fail to find it */
569
5703:	li	r0,0
571	STPTE	r0,0(r12)		/* invalidate entry */
5724:	sync
573	tlbie	r4			/* in hw tlb too */
574	sync
575
5768:	ble	cr1,9f			/* if all ptes checked */
57781:	addi	r6,r6,-1
578	addi	r5,r5,PTE_T_SIZE
579	addi	r4,r4,0x1000
580	lwz	r0,0(r5)		/* check next pte */
581	cmpwi	cr1,r6,1
582	andi.	r0,r0,_PAGE_HASHPTE
583	bne	33b
584	bgt	cr1,81b
585
5869:
587#ifdef CONFIG_SMP
588	TLBSYNC
589	li	r0,0
590	stw	r0,0(r9)		/* clear mmu_hash_lock */
591#endif
592
59319:	mtmsr	r10
594	isync
595	blr
596	.previous
597EXPORT_SYMBOL(flush_hash_pages)
598_ASM_NOKPROBE_SYMBOL(flush_hash_pages)
599