/* * 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 "ppc_asm.h" #include #include #include /* * Load a PTE into the hash table, if possible. * The address is in r3, and r4 contains access flags: * _PAGE_USER (4) if a user-mode access, ored with * _PAGE_RW (2) if a write. r20 contains DSISR or SRR1, * so bit 1 (0x40000000) is set if the exception was due * to no matching PTE being found in the hash table. * 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 - r6, ctr, lr. * * 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 = 0x180000 Hash_bits = 12 /* e.g. 256kB hash table */ Hash_msk = (((1 << Hash_bits) - 1) * 64) .globl hash_page hash_page: #ifdef __SMP__ SAVE_2GPRS(7,r21) eieio lis r2,hash_table_lock@h ori r2,r2,hash_table_lock@l tophys(r2,r2) lis r6,0x0fff0000@h mtctr r6 mfspr r5,SPRG3 lwz r0,PROCESSOR-THREAD(r5) or r0,r0,r6 10: lwarx r6,0,r2 cmpi 0,r6,0 bne- 12f stwcx. r0,0,r2 beq+ 11f /* spin here a bit */ 12: mfctr r7 li r8,1000 mtctr r8 13: bdnz 13b mtctr r7 cmpw r6,r0 bdnzf 2,10b tw 31,31,31 11: eieio REST_2GPRS(7, r21) #endif /* Get PTE (linux-style) and check access */ mfspr r2,SPRG3 /* current task's THREAD (phys) */ lwz r5,PGDIR(r2) /* virt page-table root */ tophys(r5,r5) /* convert to phys addr */ rlwimi r5,r3,12,20,29 /* 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 __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 tophys(r2,r5) rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */ lwz r6,0(r2) /* get linux-style pte */ ori r4,r4,1 /* set _PAGE_PRESENT bit in access */ andc. r0,r4,r6 /* check access & ~permission */ #ifdef __SMP__ bne- hash_page_out /* return if access not permitted */ #else bnelr- #endif ori r6,r6,0x100 /* set _PAGE_ACCESSED in pte */ rlwinm r5,r4,5,24,24 /* _PAGE_RW access -> _PAGE_DIRTY */ rlwimi r5,r4,7,22,22 /* _PAGE_RW -> _PAGE_HWWRITE */ or r6,r6,r5 stw r6,0(r2) /* update PTE (accessed/dirty bits) */ /* Convert linux-style PTE to low word of PPC-style PTE */ #ifdef CONFIG_PPC64 /* clear the high 32 bits just in case */ clrldi r6,r6,32 clrldi r4,r4,32 #endif /* CONFIG_PPC64 */ rlwinm r4,r6,32-9,31,31 /* _PAGE_HWWRITE -> PP lsb */ rlwimi r6,r6,32-1,31,31 /* _PAGE_USER -> PP (both bits now) */ ori r4,r4,0xe04 /* clear out reserved bits */ andc r6,r6,r4 /* PP=2 or 0, when _PAGE_HWWRITE */ /* Construct the high word of the PPC-style PTE */ mfsrin r5,r3 /* get segment reg for segment */ #ifdef CONFIG_PPC64 sldi r5,r5,12 #else /* CONFIG_PPC64 */ rlwinm r5,r5,7,1,24 /* put VSID in 0x7fffff80 bits */ #endif /* CONFIG_PPC64 */ #ifndef __SMP__ /* do this later for SMP */ #ifdef CONFIG_PPC64 ori r5,r5,1 /* set V (valid) bit */ #else /* CONFIG_PPC64 */ oris r5,r5,0x8000 /* set V (valid) bit */ #endif /* CONFIG_PPC64 */ #endif #ifdef CONFIG_PPC64 /* XXX: does this insert the api correctly? -- Cort */ rlwimi r5,r3,17,21,25 /* put in API (abbrev page index) */ #else /* CONFIG_PPC64 */ rlwimi r5,r3,10,26,31 /* put in API (abbrev page index) */ #endif /* CONFIG_PPC64 */ /* Get the address of the primary PTE group in the hash table */ .globl hash_page_patch_A hash_page_patch_A: lis r4,Hash_base@h /* base address of hash table */ #ifdef CONFIG_PPC64 /* just in case */ clrldi r4,r4,32 #endif rlwimi r4,r5,32-1,26-Hash_bits,25 /* (VSID & hash_mask) << 6 */ rlwinm r0,r3,32-6,26-Hash_bits,25 /* (PI & hash_mask) << 6 */ xor r4,r4,r0 /* make primary hash */ /* See whether it was a PTE not found exception or a protection violation. */ andis. r0,r20,0x4000 li r2,8 /* PTEs/group */ bne 10f /* no PTE: go look for an empty slot */ tlbie r3 /* invalidate TLB entry */ /* Search the primary PTEG for a PTE whose 1st word matches r5 */ mtctr r2 addi r3,r4,-8 1: lwzu r0,8(r3) /* get next PTE */ cmp 0,r0,r5 bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ beq+ found_slot /* Search the secondary PTEG for a matching PTE */ ori r5,r5,0x40 /* set H (secondary hash) bit */ .globl hash_page_patch_B hash_page_patch_B: xoris r3,r4,Hash_msk>>16 /* compute secondary hash */ xori r3,r3,0xffc0 addi r3,r3,-8 mtctr r2 2: lwzu r0,8(r3) cmp 0,r0,r5 bdnzf 2,2b beq+ found_slot xori r5,r5,0x40 /* clear H bit again */ /* Search the primary PTEG for an empty slot */ 10: mtctr r2 addi r3,r4,-8 /* search primary PTEG */ 1: lwzu r0,8(r3) /* get next PTE */ rlwinm. r0,r0,0,0,0 /* only want to check valid bit */ bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ beq+ found_empty /* Search the secondary PTEG for an empty slot */ ori r5,r5,0x40 /* set H (secondary hash) bit */ .globl hash_page_patch_C hash_page_patch_C: xoris r3,r4,Hash_msk>>16 /* compute secondary hash */ xori r3,r3,0xffc0 addi r3,r3,-8 mtctr r2 2: lwzu r0,8(r3) rlwinm. r0,r0,0,0,0 /* only want to check valid bit */ bdnzf 2,2b beq+ found_empty /* * 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. */ xori r5,r5,0x40 /* clear H bit again */ lis r3,next_slot@ha tophys(r3,r3) lwz r2,next_slot@l(r3) addi r2,r2,8 andi. r2,r2,0x38 stw r2,next_slot@l(r3) add r3,r4,r2 11: /* update counter of evicted pages */ lis r2,htab_evicts@ha tophys(r2,r2) lwz r4,htab_evicts@l(r2) addi r4,r4,1 stw r4,htab_evicts@l(r2) #ifndef __SMP__ /* Store PTE in PTEG */ found_empty: stw r5,0(r3) found_slot: stw r6,4(r3) sync #else /* __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: stw r5,0(r3) /* clear V (valid) bit in PTE */ sync tlbsync sync stw r6,4(r3) /* put in correct RPN, WIMG, PP bits */ sync oris r5,r5,0x8000 stw r5,0(r3) /* finally set V bit in PTE */ #endif /* __SMP__ */ /* * Update the hash table miss count. We only want misses here * that _are_ valid addresses and have a pte otherwise we don't * count it as a reload. do_page_fault() takes care of bad addrs * and entries that need linux-style pte's created. * * safe to use r2 here since we're not using it as current yet * update the htab misses count * -- Cort */ lis r2,htab_reloads@ha tophys(r2,r2) lwz r3,htab_reloads@l(r2) addi r3,r3,1 stw r3,htab_reloads@l(r2) #ifdef __SMP__ lis r2,hash_table_lock@ha tophys(r2,r2) li r0,0 stw r0,hash_table_lock@l(r2) eieio #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) /* 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 __SMP__ hash_page_out: lis r2,hash_table_lock@ha tophys(r2,r2) li r0,0 stw r0,hash_table_lock@l(r2) eieio blr .data .globl hash_table_lock hash_table_lock: .long 0 #endif /* __SMP__ */ .data next_slot: .long 0 .text /* * Flush entries from the hash table with VSIDs in the range * given. */ _GLOBAL(flush_hash_segments) lis r5,Hash@ha lwz r5,Hash@l(r5) /* base of hash table */ cmpwi 0,r5,0 bne+ 99f tlbia sync #ifdef __SMP__ tlbsync sync #endif blr 99: #ifdef __SMP__ /* Note - we had better not do anything which could generate a hash table miss while we have the hash table locked, or we'll get a deadlock. -paulus */ mfmsr r10 sync rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ mtmsr r0 SYNC lis r9,hash_table_lock@h ori r9,r9,hash_table_lock@l lwz r8,PROCESSOR(r2) oris r8,r8,8 10: lwarx r6,0,r9 cmpi 0,r6,0 bne- 10b stwcx. r8,0,r9 bne- 10b eieio #endif rlwinm r3,r3,7,1,24 /* put VSID lower limit in position */ oris r3,r3,0x8000 /* set V bit */ rlwinm r4,r4,7,1,24 /* put VSID upper limit in position */ oris r4,r4,0x8000 ori r4,r4,0x7f lis r6,Hash_size@ha lwz r6,Hash_size@l(r6) /* size in bytes */ srwi r6,r6,3 /* # PTEs */ mtctr r6 addi r5,r5,-8 li r0,0 1: lwzu r6,8(r5) /* get next tag word */ cmplw 0,r6,r3 cmplw 1,r6,r4 cror 0,0,5 /* set cr0.lt if out of range */ blt 2f /* branch if out of range */ stw r0,0(r5) /* invalidate entry */ 2: bdnz 1b /* continue with loop */ sync tlbia sync #ifdef __SMP__ tlbsync sync lis r3,hash_table_lock@ha stw r0,hash_table_lock@l(r3) mtmsr r10 SYNC #endif blr /* * Flush the entry for a particular page from the hash table. * * flush_hash_page(unsigned context, unsigned long va) */ _GLOBAL(flush_hash_page) lis r6,Hash@ha lwz r6,Hash@l(r6) /* hash table base */ cmpwi 0,r6,0 /* hash table in use? */ bne+ 99f tlbie r4 /* in hw tlb too */ sync #ifdef __SMP__ tlbsync sync #endif blr 99: #ifdef __SMP__ /* Note - we had better not do anything which could generate a hash table miss while we have the hash table locked, or we'll get a deadlock. -paulus */ mfmsr r10 sync rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ mtmsr r0 SYNC 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- 10b stwcx. r8,0,r9 bne- 10b eieio #endif rlwinm r3,r3,11,1,20 /* put context into vsid */ rlwimi r3,r4,11,21,24 /* put top 4 bits of va into vsid */ oris r3,r3,0x8000 /* set V (valid) bit */ rlwimi r3,r4,10,26,31 /* put in API (abbrev page index) */ rlwinm r7,r4,32-6,10,25 /* get page index << 6 */ rlwinm r5,r3,32-1,7,25 /* vsid << 6 */ xor r7,r7,r5 /* primary hash << 6 */ lis r5,Hash_mask@ha lwz r5,Hash_mask@l(r5) /* hash mask */ slwi r5,r5,6 /* << 6 */ and r7,r7,r5 add r6,r6,r7 /* address of primary PTEG */ li r8,8 mtctr r8 addi r7,r6,-8 1: lwzu r0,8(r7) /* get next PTE */ cmpw 0,r0,r3 /* see if tag matches */ bdnzf 2,1b /* while --ctr != 0 && !cr0.eq */ beq 3f /* if we found it */ ori r3,r3,0x40 /* set H (alt. hash) bit */ xor r6,r6,r5 /* address of secondary PTEG */ mtctr r8 addi r7,r6,-8 2: lwzu r0,8(r7) /* get next PTE */ cmpw 0,r0,r3 /* see if tag matches */ bdnzf 2,2b /* while --ctr != 0 && !cr0.eq */ bne 4f /* if we didn't find it */ 3: li r0,0 stw r0,0(r7) /* invalidate entry */ 4: sync tlbie r4 /* in hw tlb too */ sync #ifdef __SMP__ tlbsync sync li r0,0 stw r0,0(r9) /* clear hash_table_lock */ mtmsr r10 SYNC #endif blr