| /* |
| * $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 <asm/reg.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/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) |
| 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 */ |
| |
| #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 |
| |
| 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) |
| |
| /* 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 |
| |
| #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) */ |
| 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 */ |
| |
| /* 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 |
| |
| #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) */ |
| 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 |
| 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 |
