arch/powerpc/mm/tlb_32.c

   1 /*
   2  * This file contains the routines for TLB flushing.
   3  * On machines where the MMU uses a hash table to store virtual to
   4  * physical translations, these routines flush entries from the
   5  * hash table also.
   6  *  -- paulus
   7  *
   8  *  Derived from arch/ppc/mm/init.c:
   9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  10  *
  11  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  12  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  13  *    Copyright (C) 1996 Paul Mackerras
  14  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  15  *
  16  *  Derived from "arch/i386/mm/init.c"
  17  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  18  *
  19  *  This program is free software; you can redistribute it and/or
  20  *  modify it under the terms of the GNU General Public License
  21  *  as published by the Free Software Foundation; either version
  22  *  2 of the License, or (at your option) any later version.
  23  *
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/highmem.h>
  30 #include <asm/tlbflush.h>
  31 #include <asm/tlb.h>
  32
  33 #include "mmu_decl.h"
  34
  35 /*
  36  * Called when unmapping pages to flush entries from the TLB/hash table.
  37  */
  38 void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
  39 {
  40         unsigned long ptephys;
  41
  42         if (Hash != 0) {
  43                 ptephys = __pa(ptep) & PAGE_MASK;
  44                 flush_hash_pages(mm->context.id, addr, ptephys, 1);
  45         }
  46 }
  47
  48 /*
  49  * Called by ptep_set_access_flags, must flush on CPUs for which the
  50  * DSI handler can't just "fixup" the TLB on a write fault
  51  */
  52 void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr)
  53 {
  54         if (Hash != 0)
  55                 return;
  56         _tlbie(addr);
  57 }
  58
  59 /*
  60  * Called at the end of a mmu_gather operation to make sure the
  61  * TLB flush is completely done.
  62  */
  63 void tlb_flush(struct mmu_gather *tlb)
  64 {
  65         if (Hash == 0) {
  66                 /*
  67                  * 603 needs to flush the whole TLB here since
  68                  * it doesn't use a hash table.
  69                  */
  70                 _tlbia();
  71         }
  72 }
  73
  74 /*
  75  * TLB flushing:
  76  *
  77  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
  78  *  - flush_tlb_page(vma, vmaddr) flushes one page
  79  *  - flush_tlb_range(vma, start, end) flushes a range of pages
  80  *  - flush_tlb_kernel_range(start, end) flushes kernel pages
  81  *
  82  * since the hardware hash table functions as an extension of the
  83  * tlb as far as the linux tables are concerned, flush it too.
  84  *    -- Cort
  85  */
  86
  87 /*
  88  * 750 SMP is a Bad Idea because the 750 doesn't broadcast all
  89  * the cache operations on the bus.  Hence we need to use an IPI
  90  * to get the other CPU(s) to invalidate their TLBs.
  91  */
  92 #ifdef CONFIG_SMP_750
  93 #define FINISH_FLUSH    smp_send_tlb_invalidate(0)
  94 #else
  95 #define FINISH_FLUSH    do { } while (0)
  96 #endif
  97
  98 static void flush_range(struct mm_struct *mm, unsigned long start,
  99                         unsigned long end)
 100 {
 101         pmd_t *pmd;
 102         unsigned long pmd_end;
 103         int count;
 104         unsigned int ctx = mm->context.id;
 105
 106         if (Hash == 0) {
 107                 _tlbia();
 108                 return;
 109         }
 110         start &= PAGE_MASK;
 111         if (start >= end)
 112                 return;
 113         end = (end - 1) | ~PAGE_MASK;
 114         pmd = pmd_offset(pgd_offset(mm, start), start);
 115         for (;;) {
 116                 pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
 117                 if (pmd_end > end)
 118                         pmd_end = end;
 119                 if (!pmd_none(*pmd)) {
 120                         count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
 121                         flush_hash_pages(ctx, start, pmd_val(*pmd), count);
 122                 }
 123                 if (pmd_end == end)
 124                         break;
 125                 start = pmd_end + 1;
 126                 ++pmd;
 127         }
 128 }
 129
 130 /*
 131  * Flush kernel TLB entries in the given range
 132  */
 133 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 134 {
 135         flush_range(&init_mm, start, end);
 136         FINISH_FLUSH;
 137 }
 138
 139 /*
 140  * Flush all the (user) entries for the address space described by mm.
 141  */
 142 void flush_tlb_mm(struct mm_struct *mm)
 143 {
 144         struct vm_area_struct *mp;
 145
 146         if (Hash == 0) {
 147                 _tlbia();
 148                 return;
 149         }
 150
 151         /*
 152          * It is safe to go down the mm's list of vmas when called
 153          * from dup_mmap, holding mmap_sem.  It would also be safe from
 154          * unmap_region or exit_mmap, but not from vmtruncate on SMP -
 155          * but it seems dup_mmap is the only SMP case which gets here.
 156          */
 157         for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
 158                 flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
 159         FINISH_FLUSH;
 160 }
 161
 162 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 163 {
 164         struct mm_struct *mm;
 165         pmd_t *pmd;
 166
 167         if (Hash == 0) {
 168                 _tlbie(vmaddr);
 169                 return;
 170         }
 171         mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
 172         pmd = pmd_offset(pgd_offset(mm, vmaddr), vmaddr);
 173         if (!pmd_none(*pmd))
 174                 flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
 175         FINISH_FLUSH;
 176 }
 177
 178 /*
 179  * For each address in the range, find the pte for the address
 180  * and check _PAGE_HASHPTE bit; if it is set, find and destroy
 181  * the corresponding HPTE.
 182  */
 183 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 184                      unsigned long end)
 185 {
 186         flush_range(vma->vm_mm, start, end);
 187         FINISH_FLUSH;
 188 }