/* * BK Id: %F% %I% %G% %U% %#% */ /* * 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 * 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 #include #include #include #include #include #include #include #ifdef CONFIG_SMP .comm hash_table_lock,4 #endif /* CONFIG_SMP */ /* * 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. * r23 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, r2 - r7, ctr, lr. */ .text .globl hash_page 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 r2,r7,hash_table_lock@h ori r2,r2,hash_table_lock@l mfspr r5,SPRG3 lwz r0,PROCESSOR-THREAD(r5) oris r0,r0,0x0fff b 10f 11: lwz r6,0(r2) cmpwi 0,r6,0 bne 11b 10: lwarx r6,0,r2 cmpwi 0,r6,0 bne- 11b stwcx. r0,0,r2 bne- 10b isync #endif /* Get PTE (linux-style) and check access */ lis r0,KERNELBASE@h /* check if kernel address */ cmplw 0,r4,r0 mfspr r2,SPRG3 /* current task's THREAD (phys) */ ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */ lwz r5,PGDIR(r2) /* 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,r23,32-12,29,29 /* 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 r5,0(r5) /* get pmd entry */ rlwinm. r5,r5,0,0,19 /* 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 add r2,r5,r7 /* convert to phys addr */ rlwimi r2,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,r2 /* 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,r2 /* attempt to update PTE */ bne- retry /* retry if someone got there first */ mfsrin r3,r4 /* get segment reg for segment */ mr r2,r8 /* we have saved r2 but not r8 */ bl create_hpte /* add the hash table entry */ mr r8,r2 /* * 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 r2,r7,htab_reloads@ha lwz r3,htab_reloads@l(r2) addi r3,r3,1 stw r3,htab_reloads@l(r2) #ifdef CONFIG_SMP eieio addis r2,r7,hash_table_lock@ha li r0,0 stw r0,hash_table_lock@l(r2) #endif /* Return from the exception */ lwz r3,_CCR(r21) lwz r4,_LINK(r21) lwz r5,_CTR(r21) mtcrf 0xff,r3 mtlr r4 mtctr r5 lwz r0,GPR0(r21) lwz r1,GPR1(r21) lwz r2,GPR2(r21) lwz r3,GPR3(r21) lwz r4,GPR4(r21) lwz r5,GPR5(r21) lwz r6,GPR6(r21) lwz r7,GPR7(r21) /* we haven't used xer */ mtspr SRR1,r23 mtspr SRR0,r22 lwz r20,GPR20(r21) lwz r22,GPR22(r21) lwz r23,GPR23(r21) lwz r21,GPR21(r21) RFI #ifdef CONFIG_SMP hash_page_out: eieio addis r2,r7,hash_table_lock@ha li r0,0 stw r0,hash_table_lock@l(r2) blr #endif /* CONFIG_SMP */ /* * Add an entry for a particular page to the hash table. * * add_hash_page(unsigned context, unsigned long va, pte_t pte) * * 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 */ /* * 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). -- paulus */ mfmsr r10 SYNC rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ mtmsr r0 SYNC #ifdef CONFIG_SMP lis r9,hash_table_lock@h ori r9,r9,hash_table_lock@l lwz r8,PROCESSOR(r2) oris r8,r8,10 10: lwarx r7,0,r9 cmpi 0,r7,0 bne- 11f stwcx. r8,0,r9 beq+ 12f 11: lwz r7,0(r9) cmpi 0,r7,0 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 r7,r5 1: lwarx r6,0,r7 andi. r0,r6,_PAGE_HASHPTE bne 9f /* if HASHPTE already set, done */ ori r5,r6,_PAGE_ACCESSED|_PAGE_HASHPTE stwcx. r5,0,r7 bne- 1b li r7,0 /* no address offset needed */ bl create_hpte lis r8,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 hash_table_lock */ #endif lwz r0,4(r1) mtlr r0 /* reenable interrupts */ mtmsr r10 SYNC 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 hash_table_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 */ #ifdef CONFIG_SMP ori r8,r8,_PAGE_COHERENT /* set M (coherence required) */ #endif #ifdef CONFIG_POWER4 /* * XXX hack hack hack - translate 32-bit "physical" addresses * in the linux page tables to 42-bit real addresses in such * a fashion that we can get at the I/O we need to access. * -- paulus */ cmpwi r8,0 rlwinm r0,r8,16,16,30 bge 57f cmplwi r0,0xfe00 li r0,0x3fd bne 56f li r0,0x3ff 56: sldi r0,r0,32 or r8,r8,r0 57: #endif /* 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) */ .globl hash_page_patch_A 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 */ .globl hash_page_patch_B 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 */ .globl hash_page_patch_C 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 #ifdef CONFIG_POWER4 /* * Since we don't have BATs on POWER4, we rely on always having * PTEs in the hash table to map the hash table and the code * that manipulates it in virtual mode, namely flush_hash_page and * flush_hash_segments. Otherwise we can get a DSI inside those * routines which leads to a deadlock on the hash_table_lock on * SMP machines. We avoid this by never overwriting the first * PTE of each PTEG if it is already valid. * -- paulus. */ bne 102f li r6,PTE_SIZE 102: #endif /* CONFIG_POWER4 */ 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_page(unsigned context, unsigned long va, pte_t *ptep) * * We assume that there is a hash table in use (Hash != 0). */ _GLOBAL(flush_hash_page) /* 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 code below trims to 24 bits */ /* * We disable interrupts here, even on UP, because we want * the _PAGE_HASHPTE bit to be a reliable indication of * whether the HPTE exists. -- paulus */ mfmsr r10 rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ SYNC mtmsr r0 SYNC #ifdef CONFIG_SMP lis r9,hash_table_lock@h ori r9,r9,hash_table_lock@l lwz r8,PROCESSOR(r2) oris r8,r8,9 10: lwarx r7,0,r9 cmpi 0,r7,0 bne- 11f stwcx. r8,0,r9 beq+ 12f 11: lwz r7,0(r9) cmpi 0,r7,0 beq 10b b 11b 12: isync #endif /* * Check the _PAGE_HASHPTE bit in the linux PTE. If it is * already clear, we're done. If not, clear it (atomically) * and proceed. -- paulus. */ 1: lwarx r6,0,r5 /* fetch the pte */ andi. r0,r6,_PAGE_HASHPTE beq 9f /* done if HASHPTE is already clear */ rlwinm r6,r6,0,31,29 /* clear HASHPTE bit */ stwcx. r6,0,r5 /* update the pte */ bne- 1b /* 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) */ .globl flush_hash_patch_A flush_hash_patch_A: lis r8,Hash_base@h /* base address of hash table */ rlwimi r8,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,r8 /* make primary hash */ li r8,8 /* PTEs/group */ /* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */ mtctr r8 addi r7,r3,-PTE_SIZE 1: LDPTEu r0,PTE_SIZE(r7) /* get next PTE */ CMPPTE 0,r0,r5 bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ beq+ 3f /* Search the secondary PTEG for a matching PTE */ ori r5,r5,PTE_H /* set H (secondary hash) bit */ .globl flush_hash_patch_B flush_hash_patch_B: xoris r7,r3,Hash_msk>>16 /* compute secondary hash */ xori r7,r7,(-PTEG_SIZE & 0xffff) addi r7,r7,-PTE_SIZE mtctr r8 2: LDPTEu r0,PTE_SIZE(r7) CMPPTE 0,r0,r5 bdnzf 2,2b bne- 4f /* should never fail to find it */ 3: li r0,0 STPTE r0,0(r7) /* invalidate entry */ 4: sync tlbie r4 /* in hw tlb too */ sync #ifdef CONFIG_SMP TLBSYNC 9: li r0,0 stw r0,0(r9) /* clear hash_table_lock */ #endif 9: mtmsr r10 SYNC blr