Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 598 insertions, 0 deletions

diff --git a/arch/powerpc/mm/book3s32/hash_low.S b/arch/powerpc/mm/book3s32/hash_low.S
new file mode 100644
index 0000000000..8b804e1a9f
--- /dev/null
+++ b/arch/powerpc/mm/book3s32/hash_low.S
@@ -0,0 +1,598 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  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.)
+ */
+
+#include <linux/export.h>
+#include <linux/pgtable.h>
+#include <linux/init.h>
+#include <asm/reg.h>
+#include <asm/page.h>
+#include <asm/cputable.h>
+#include <asm/ppc_asm.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/feature-fixups.h>
+#include <asm/code-patching-asm.h>
+
+#ifdef CONFIG_PTE_64BIT
+#define PTE_T_SIZE		8
+#define PTE_FLAGS_OFFSET	4	/* offset of PTE flags, in bytes */
+#else
+#define PTE_T_SIZE		4
+#define PTE_FLAGS_OFFSET	0
+#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.
+ * SPRG_THREAD 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 - r6, r8, r10, ctr, lr.
+ */
+	.text
+_GLOBAL(hash_page)
+#ifdef CONFIG_SMP
+	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@h
+	ori	r8, r8, (mmu_hash_lock - PAGE_OFFSET)@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, TASK_SIZE@h		/* check if kernel address */
+	cmplw	0,r4,r0
+	mfspr	r8,SPRN_SPRG_THREAD	/* 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:	tophys(r5, r5)
+#ifndef CONFIG_PTE_64BIT
+	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 */
+#else
+	rlwinm	r8,r4,13,19,29		/* Compute pgdir/pmd offset */
+	lwzx	r8,r8,r5		/* Get L1 entry */
+	rlwinm.	r8,r8,0,0,20		/* extract pt base address */
+#endif
+#ifdef CONFIG_SMP
+	beq-	.Lhash_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
+#ifndef CONFIG_PTE_64BIT
+	rlwimi	r8,r4,22,20,29		/* insert next 10 bits of address */
+#else
+	rlwimi	r8,r4,23,20,28		/* compute pte address */
+	/*
+	 * If PTE_64BIT is set, the low word is the flags word; use that
+	 * word for locking since it contains all the interesting bits.
+	 */
+	addi	r8,r8,PTE_FLAGS_OFFSET
+#endif
+
+	/*
+	 * 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.
+	 */
+.Lretry:
+	lwarx	r6,0,r8			/* get linux-style pte, flag word */
+#ifdef CONFIG_PPC_KUAP
+	mfsrin	r5,r4
+	rlwinm	r0,r9,28,_PAGE_RW	/* MSR[PR] => _PAGE_RW */
+	rlwinm	r5,r5,12,_PAGE_RW	/* Ks => _PAGE_RW */
+	andc	r5,r5,r0		/* Ks & ~MSR[PR] */
+	andc	r5,r6,r5		/* Clear _PAGE_RW when Ks = 1 && MSR[PR] = 0 */
+	andc.	r5,r3,r5		/* check access & ~permission */
+#else
+	andc.	r5,r3,r6		/* check access & ~permission */
+#endif
+	rlwinm	r0,r3,32-3,24,24	/* _PAGE_RW access -> _PAGE_DIRTY */
+	ori	r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE
+#ifdef CONFIG_SMP
+	bne-	.Lhash_page_out		/* return if access not permitted */
+#else
+	bnelr-
+#endif
+	or	r5,r0,r6		/* set accessed/dirty bits */
+#ifdef CONFIG_PTE_64BIT
+#ifdef CONFIG_SMP
+	subf	r10,r6,r8		/* create false data dependency */
+	subi	r10,r10,PTE_FLAGS_OFFSET
+	lwzx	r10,r6,r10		/* Get upper PTE word */
+#else
+	lwz	r10,-PTE_FLAGS_OFFSET(r8)
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_PTE_64BIT */
+	stwcx.	r5,0,r8			/* attempt to update PTE */
+	bne-	.Lretry			/* retry if someone got there first */
+
+	mfsrin	r3,r4			/* get segment reg for segment */
+	bl	create_hpte		/* add the hash table entry */
+
+#ifdef CONFIG_SMP
+	eieio
+	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
+	li	r0,0
+	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
+#endif
+	b	fast_hash_page_return
+
+#ifdef CONFIG_SMP
+.Lhash_page_out:
+	eieio
+	lis	r8, (mmu_hash_lock - PAGE_OFFSET)@ha
+	li	r0,0
+	stw	r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
+	blr
+#endif /* CONFIG_SMP */
+_ASM_NOKPROBE_SYMBOL(hash_page)
+
+/*
+ * 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)
+
+#ifdef CONFIG_SMP
+	lwz	r8,TASK_CPU(r2)		/* 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	r9
+	rlwinm	r0,r9,0,17,15		/* clear bit 16 (MSR_EE) */
+	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
+	mtmsr	r0
+	isync
+
+#ifdef CONFIG_SMP
+	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
+	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
+10:	lwarx	r0,0,r6			/* take the mmu_hash_lock */
+	cmpwi	0,r0,0
+	bne-	11f
+	stwcx.	r8,0,r6
+	beq+	12f
+11:	lwz	r0,0(r6)
+	cmpwi	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
+#ifndef CONFIG_PTE_64BIT
+	rlwimi	r8,r4,22,20,29
+#else
+	rlwimi	r8,r4,23,20,28
+	addi	r8,r8,PTE_FLAGS_OFFSET
+#endif
+1:	lwarx	r6,0,r8
+	andi.	r0,r6,_PAGE_HASHPTE
+	bne	9f			/* if HASHPTE already set, done */
+#ifdef CONFIG_PTE_64BIT
+#ifdef CONFIG_SMP
+	subf	r10,r6,r8		/* create false data dependency */
+	subi	r10,r10,PTE_FLAGS_OFFSET
+	lwzx	r10,r6,r10		/* Get upper PTE word */
+#else
+	lwz	r10,-PTE_FLAGS_OFFSET(r8)
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_PTE_64BIT */
+	ori	r5,r6,_PAGE_HASHPTE
+	stwcx.	r5,0,r8
+	bne-	1b
+
+	/* 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 */
+
+	bl	create_hpte
+
+9:
+#ifdef CONFIG_SMP
+	lis	r6, (mmu_hash_lock - PAGE_OFFSET)@ha
+	addi	r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l
+	eieio
+	li	r0,0
+	stw	r0,0(r6)		/* clear mmu_hash_lock */
+#endif
+
+	/* reenable interrupts and DR */
+	mtmsr	r9
+	isync
+
+	lwz	r0,4(r1)
+	mtlr	r0
+	blr
+_ASM_NOKPROBE_SYMBOL(add_hash_page)
+
+/*
+ * 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). r10 contains the
+ * upper half of the PTE if CONFIG_PTE_64BIT.
+ * 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 for the early hash table.
+ */
+Hash_base = early_hash
+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 HPTE_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
+
+__REF
+_GLOBAL(create_hpte)
+	/* Convert linux-style PTE (r5) to low word of PPC-style PTE (r8) */
+	rlwinm	r8,r5,32-9,30,30	/* _PAGE_RW -> PP msb */
+	rlwinm	r0,r5,32-6,30,30	/* _PAGE_DIRTY -> PP msb */
+	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,r8,0xe04		/* clear out reserved bits */
+	andc	r8,r5,r8		/* PP = user? (rw&dirty? 1: 3): 0 */
+BEGIN_FTR_SECTION
+	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
+END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
+#ifdef CONFIG_PTE_64BIT
+	/* Put the XPN bits into the PTE */
+	rlwimi	r8,r10,8,20,22
+	rlwimi	r8,r10,2,29,29
+#endif
+
+	/* 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 */
+
+	patch_site	0f, patch__hash_page_A0
+	patch_site	1f, patch__hash_page_A1
+	patch_site	2f, patch__hash_page_A2
+	/* Get the address of the primary PTE group in the hash table (r3) */
+0:	lis	r0, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
+1:	rlwimi	r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
+2:	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
+
+	/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
+	mtctr	r0
+	addi	r4,r3,-HPTE_SIZE
+1:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
+	CMPPTE	0,r6,r5
+	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
+	beq+	.Lfound_slot
+
+	patch_site	0f, patch__hash_page_B
+	/* Search the secondary PTEG for a matching PTE */
+	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
+0:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
+	xori	r4,r4,(-PTEG_SIZE & 0xffff)
+	addi	r4,r4,-HPTE_SIZE
+	mtctr	r0
+2:	LDPTEu	r6,HPTE_SIZE(r4)
+	CMPPTE	0,r6,r5
+	bdnzf	2,2b
+	beq+	.Lfound_slot
+	xori	r5,r5,PTE_H		/* clear H bit again */
+
+	/* Search the primary PTEG for an empty slot */
+10:	mtctr	r0
+	addi	r4,r3,-HPTE_SIZE	/* search primary PTEG */
+1:	LDPTEu	r6,HPTE_SIZE(r4)	/* get next PTE */
+	TST_V(r6)			/* test valid bit */
+	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
+	beq+	.Lfound_empty
+
+	patch_site	0f, patch__hash_page_C
+	/* Search the secondary PTEG for an empty slot */
+	ori	r5,r5,PTE_H		/* set H (secondary hash) bit */
+0:	xoris	r4,r3,Hash_msk>>16	/* compute secondary hash */
+	xori	r4,r4,(-PTEG_SIZE & 0xffff)
+	addi	r4,r4,-HPTE_SIZE
+	mtctr	r0
+2:	LDPTEu	r6,HPTE_SIZE(r4)
+	TST_V(r6)
+	bdnzf	2,2b
+	beq+	.Lfound_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.
+	 */
+
+	lis	r4, (next_slot - PAGE_OFFSET)@ha	/* get next evict slot */
+	lwz	r6, (next_slot - PAGE_OFFSET)@l(r4)
+	addi	r6,r6,HPTE_SIZE			/* search for candidate */
+	andi.	r6,r6,7*HPTE_SIZE
+	stw	r6,next_slot@l(r4)
+	add	r4,r3,r6
+
+#ifndef CONFIG_SMP
+	/* Store PTE in PTEG */
+.Lfound_empty:
+	STPTE	r5,0(r4)
+.Lfound_slot:
+	STPTE	r8,HPTE_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.
+ */
+.Lfound_empty:
+.Lfound_slot:
+	CLR_V(r5,r0)		/* clear V (valid) bit in PTE */
+	STPTE	r5,0(r4)
+	sync
+	TLBSYNC
+	STPTE	r8,HPTE_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
+	.previous
+_ASM_NOKPROBE_SYMBOL(create_hpte)
+
+	.section .bss
+	.align	2
+next_slot:
+	.space	4
+	.previous
+
+/*
+ * 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).
+ */
+__REF
+_GLOBAL(flush_hash_pages)
+	/*
+	 * 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
+	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
+	rlwinm	r0,r0,0,28,26		/* clear MSR_DR */
+	mtmsr	r0
+	isync
+
+	/* First find a PTE in the range that has _PAGE_HASHPTE set */
+#ifndef CONFIG_PTE_64BIT
+	rlwimi	r5,r4,22,20,29
+#else
+	rlwimi	r5,r4,23,20,28
+	addi	r5,r5,PTE_FLAGS_OFFSET
+#endif
+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,PTE_T_SIZE
+	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
+	lis	r9, (mmu_hash_lock - PAGE_OFFSET)@ha
+	addi	r9, r9, (mmu_hash_lock - PAGE_OFFSET)@l
+	tophys	(r8, r2)
+	lwz	r8, TASK_CPU(r8)
+	oris	r8,r8,9
+10:	lwarx	r0,0,r9
+	cmpwi	0,r0,0
+	bne-	11f
+	stwcx.	r8,0,r9
+	beq+	12f
+11:	lwz	r0,0(r9)
+	cmpwi	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 flags word */
+	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
+
+	patch_site	0f, patch__flush_hash_A0
+	patch_site	1f, patch__flush_hash_A1
+	patch_site	2f, patch__flush_hash_A2
+	/* Get the address of the primary PTE group in the hash table (r3) */
+0:	lis	r8, (Hash_base - PAGE_OFFSET)@h	/* base address of hash table */
+1:	rlwimi	r8,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT    /* VSID -> hash */
+2:	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,-HPTE_SIZE
+1:	LDPTEu	r0,HPTE_SIZE(r12)	/* get next PTE */
+	CMPPTE	0,r0,r11
+	bdnzf	2,1b			/* loop while ctr != 0 && !cr0.eq */
+	beq+	3f
+
+	patch_site	0f, patch__flush_hash_B
+	/* Search the secondary PTEG for a matching PTE */
+	ori	r11,r11,PTE_H		/* set H (secondary hash) bit */
+	li	r0,8			/* PTEs/group */
+0:	xoris	r12,r8,Hash_msk>>16	/* compute secondary hash */
+	xori	r12,r12,(-PTEG_SIZE & 0xffff)
+	addi	r12,r12,-HPTE_SIZE
+	mtctr	r0
+2:	LDPTEu	r0,HPTE_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,PTE_T_SIZE
+	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
+	isync
+	blr
+	.previous
+EXPORT_SYMBOL(flush_hash_pages)
+_ASM_NOKPROBE_SYMBOL(flush_hash_pages)