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  *
  15  *  Derived from "arch/i386/mm/init.c"
  16  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  17  *
  18  *  This program is free software; you can redistribute it and/or
  19  *  modify it under the terms of the GNU General Public License
  20  *  as published by the Free Software Foundation; either version
  21  *  2 of the License, or (at your option) any later version.
  22  *
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/init.h>
  28 #include <linux/highmem.h>
  29 #include <linux/pagemap.h>
  30
  31 #include <asm/tlbflush.h>
  32 #include <asm/tlb.h>
  33
  34 #include "mmu_decl.h"
  35
  36 /*
  37  * Called when unmapping pages to flush entries from the TLB/hash table.
  38  */
  39 void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
  40 {
  41         unsigned long ptephys;
  42
  43         if (Hash != 0) {
  44                 ptephys = __pa(ptep) & PAGE_MASK;
  45                 flush_hash_pages(mm->context.id, addr, ptephys, 1);
  46         }
  47 }
  48
  49 /*
  50  * Called by ptep_set_access_flags, must flush on CPUs for which the
  51  * DSI handler can't just "fixup" the TLB on a write fault
  52  */
  53 void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr)
  54 {
  55         if (Hash != 0)
  56                 return;
  57         _tlbie(addr);
  58 }
  59
  60 /*
  61  * Called at the end of a mmu_gather operation to make sure the
  62  * TLB flush is completely done.
  63  */
  64 void tlb_flush(struct mmu_gather *tlb)
  65 {
  66         if (Hash == 0) {
  67                 /*
  68                  * 603 needs to flush the whole TLB here since
  69                  * it doesn't use a hash table.
  70                  */
  71                 _tlbia();
  72         }
  73 }
  74
  75 /*
  76  * TLB flushing:
  77  *
  78  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
  79  *  - flush_tlb_page(vma, vmaddr) flushes one page
  80  *  - flush_tlb_range(vma, start, end) flushes a range of pages
  81  *  - flush_tlb_kernel_range(start, end) flushes kernel pages
  82  *
  83  * since the hardware hash table functions as an extension of the
  84  * tlb as far as the linux tables are concerned, flush it too.
  85  *    -- Cort
  86  */
  87
  88 /*
  89  * 750 SMP is a Bad Idea because the 750 doesn't broadcast all
  90  * the cache operations on the bus.  Hence we need to use an IPI
  91  * to get the other CPU(s) to invalidate their TLBs.
  92  */
  93 #ifdef CONFIG_SMP_750
  94 #define FINISH_FLUSH    smp_send_tlb_invalidate(0)
  95 #else
  96 #define FINISH_FLUSH    do { } while (0)
  97 #endif
  98
  99 static void flush_range(struct mm_struct *mm, unsigned long start,
 100                         unsigned long end)
 101 {
 102         pmd_t *pmd;
 103         unsigned long pmd_end;
 104         int count;
 105         unsigned int ctx = mm->context.id;
 106
 107         if (Hash == 0) {
 108                 _tlbia();
 109                 return;
 110         }
 111         start &= PAGE_MASK;
 112         if (start >= end)
 113                 return;
 114         end = (end - 1) | ~PAGE_MASK;
 115         pmd = pmd_offset(pud_offset(pgd_offset(mm, start), start), start);
 116         for (;;) {
 117                 pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
 118                 if (pmd_end > end)
 119                         pmd_end = end;
 120                 if (!pmd_none(*pmd)) {
 121                         count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
 122                         flush_hash_pages(ctx, start, pmd_val(*pmd), count);
 123                 }
 124                 if (pmd_end == end)
 125                         break;
 126                 start = pmd_end + 1;
 127                 ++pmd;
 128         }
 129 }
 130
 131 /*
 132  * Flush kernel TLB entries in the given range
 133  */
 134 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 135 {
 136         flush_range(&init_mm, start, end);
 137         FINISH_FLUSH;
 138 }
 139
 140 /*
 141  * Flush all the (user) entries for the address space described by mm.
 142  */
 143 void flush_tlb_mm(struct mm_struct *mm)
 144 {
 145         struct vm_area_struct *mp;
 146
 147         if (Hash == 0) {
 148                 _tlbia();
 149                 return;
 150         }
 151
 152         /*
 153          * It is safe to go down the mm's list of vmas when called
 154          * from dup_mmap, holding mmap_sem.  It would also be safe from
 155          * unmap_region or exit_mmap, but not from vmtruncate on SMP -
 156          * but it seems dup_mmap is the only SMP case which gets here.
 157          */
 158         for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
 159                 flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
 160         FINISH_FLUSH;
 161 }
 162
 163 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 164 {
 165         struct mm_struct *mm;
 166         pmd_t *pmd;
 167
 168         if (Hash == 0) {
 169                 _tlbie(vmaddr);
 170                 return;
 171         }
 172         mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
 173         pmd = pmd_offset(pud_offset(pgd_offset(mm, vmaddr), vmaddr), vmaddr);
 174         if (!pmd_none(*pmd))
 175                 flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
 176         FINISH_FLUSH;
 177 }
 178
 179 /*
 180  * For each address in the range, find the pte for the address
 181  * and check _PAGE_HASHPTE bit; if it is set, find and destroy
 182  * the corresponding HPTE.
 183  */
 184 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 185                      unsigned long end)
 186 {
 187         flush_range(vma->vm_mm, start, end);
 188         FINISH_FLUSH;
 189 }