| /* | 
 |  *  arch/ppc/kernel/hashtable.S | 
 |  * | 
 |  *  $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 <linux/config.h> | 
 | #include <asm/processor.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/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) | 
 | #ifdef CONFIG_PPC64BRIDGE | 
 | 	mfmsr	r0 | 
 | 	clrldi	r0,r0,1		/* make sure it's in 32-bit mode */ | 
 | 	MTMSRD(r0) | 
 | 	isync | 
 | #endif | 
 | 	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 */ | 
 |  | 
 | /* | 
 |  * htab_reloads counts the number of times we have to fault an | 
 |  * HPTE into the hash table.  This should only happen after a | 
 |  * fork (because fork does a flush_tlb_mm) or a vmalloc or ioremap. | 
 |  * Where a page is faulted into a process's address space, | 
 |  * update_mmu_cache gets called to put the HPTE into the hash table | 
 |  * and those are counted as preloads rather than reloads. | 
 |  */ | 
 | 	addis	r8,r7,htab_reloads@ha | 
 | 	lwz	r3,htab_reloads@l(r8) | 
 | 	addi	r3,r3,1 | 
 | 	stw	r3,htab_reloads@l(r8) | 
 |  | 
 | #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 | 
 |  | 
 | 	addis	r8,r7,htab_preloads@ha | 
 | 	lwz	r3,htab_preloads@l(r8) | 
 | 	addi	r3,r3,1 | 
 | 	stw	r3,htab_preloads@l(r8) | 
 |  | 
 | 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) | 
 |  | 
 | #ifndef CONFIG_PPC64BRIDGE | 
 | /* 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 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 | 
 |  | 
 | #else | 
 | /* defines for the PTE format for 64-bit PPCs */ | 
 | #define PTE_SIZE	16 | 
 | #define PTEG_SIZE	128 | 
 | #define LG_PTEG_SIZE	7 | 
 | #define LDPTEu		ldu | 
 | #define STPTE		std | 
 | #define CMPPTE		cmpd | 
 | #define PTE_H		2 | 
 | #define PTE_V		1 | 
 | #define TST_V(r)	andi. r,r,PTE_V | 
 | #define SET_V(r)	ori r,r,PTE_V | 
 | #define CLR_V(r,t)	li t,PTE_V; andc r,r,t | 
 | #endif /* CONFIG_PPC64BRIDGE */ | 
 |  | 
 | #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) */ | 
 | #ifndef CONFIG_PPC64BRIDGE | 
 | 	rlwinm	r5,r3,7,1,24		/* put VSID in 0x7fffff80 bits */ | 
 | 	rlwimi	r5,r4,10,26,31		/* put in API (abbrev page index) */ | 
 | #else /* CONFIG_PPC64BRIDGE */ | 
 | 	clrlwi	r3,r3,8			/* reduce vsid to 24 bits */ | 
 | 	sldi	r5,r3,12		/* shift vsid into position */ | 
 | 	rlwimi	r5,r4,16,20,24		/* put in API (abbrev page index) */ | 
 | #endif /* CONFIG_PPC64BRIDGE */ | 
 | 	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. | 
 | 	 */ | 
 | 	addis	r4,r7,next_slot@ha | 
 | 	lwz	r6,next_slot@l(r4) | 
 | 	addi	r6,r6,PTE_SIZE | 
 | 	andi.	r6,r6,7*PTE_SIZE | 
 | 	stw	r6,next_slot@l(r4) | 
 | 	add	r4,r3,r6 | 
 |  | 
 | 	/* update counter of evicted pages */ | 
 | 	addis	r6,r7,htab_evicts@ha | 
 | 	lwz	r3,htab_evicts@l(r6) | 
 | 	addi	r3,r3,1 | 
 | 	stw	r3,htab_evicts@l(r6) | 
 |  | 
 | #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) */ | 
 | #ifndef CONFIG_PPC64BRIDGE | 
 | 	rlwinm	r11,r3,7,1,24		/* put VSID in 0x7fffff80 bits */ | 
 | 	rlwimi	r11,r4,10,26,31		/* put in API (abbrev page index) */ | 
 | #else /* CONFIG_PPC64BRIDGE */ | 
 | 	clrlwi	r3,r3,8			/* reduce vsid to 24 bits */ | 
 | 	sldi	r11,r3,12		/* shift vsid into position */ | 
 | 	rlwimi	r11,r4,16,20,24		/* put in API (abbrev page index) */ | 
 | #endif /* CONFIG_PPC64BRIDGE */ | 
 | 	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 |