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tlb_32.c

/*
 * This file contains the routines for TLB flushing.
 * On machines where the MMU uses a hash table to store virtual to
 * physical translations, these routines flush entries from the
 * hash table also.
 *  -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  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 <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>

#include <asm/tlbflush.h>
#include <asm/tlb.h>

#include "mmu_decl.h"

/*
 * Called when unmapping pages to flush entries from the TLB/hash table.
 */
void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
{
      unsigned long ptephys;

      if (Hash != 0) {
            ptephys = __pa(ptep) & PAGE_MASK;
            flush_hash_pages(mm->context.id, addr, ptephys, 1);
      }
}
EXPORT_SYMBOL(flush_hash_entry);

/*
 * Called by ptep_set_access_flags, must flush on CPUs for which the
 * DSI handler can't just "fixup" the TLB on a write fault
 */
void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr)
{
      if (Hash != 0)
            return;
      _tlbie(addr);
}

/*
 * Called at the end of a mmu_gather operation to make sure the
 * TLB flush is completely done.
 */
void tlb_flush(struct mmu_gather *tlb)
{
      if (Hash == 0) {
            /*
             * 603 needs to flush the whole TLB here since
             * it doesn't use a hash table.
             */
            _tlbia();
      }
}

/*
 * TLB flushing:
 *
 *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
 *  - flush_tlb_page(vma, vmaddr) flushes one page
 *  - flush_tlb_range(vma, start, end) flushes a range of pages
 *  - flush_tlb_kernel_range(start, end) flushes kernel pages
 *
 * since the hardware hash table functions as an extension of the
 * tlb as far as the linux tables are concerned, flush it too.
 *    -- Cort
 */

/*
 * 750 SMP is a Bad Idea because the 750 doesn't broadcast all
 * the cache operations on the bus.  Hence we need to use an IPI
 * to get the other CPU(s) to invalidate their TLBs.
 */
#ifdef CONFIG_SMP_750
#define FINISH_FLUSH    smp_send_tlb_invalidate(0)
#else
#define FINISH_FLUSH    do { } while (0)
#endif

static void flush_range(struct mm_struct *mm, unsigned long start,
                  unsigned long end)
{
      pmd_t *pmd;
      unsigned long pmd_end;
      int count;
      unsigned int ctx = mm->context.id;

      if (Hash == 0) {
            _tlbia();
            return;
      }
      start &= PAGE_MASK;
      if (start >= end)
            return;
      end = (end - 1) | ~PAGE_MASK;
      pmd = pmd_offset(pud_offset(pgd_offset(mm, start), start), start);
      for (;;) {
            pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
            if (pmd_end > end)
                  pmd_end = end;
            if (!pmd_none(*pmd)) {
                  count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
                  flush_hash_pages(ctx, start, pmd_val(*pmd), count);
            }
            if (pmd_end == end)
                  break;
            start = pmd_end + 1;
            ++pmd;
      }
}

/*
 * Flush kernel TLB entries in the given range
 */
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
      flush_range(&init_mm, start, end);
      FINISH_FLUSH;
}

/*
 * Flush all the (user) entries for the address space described by mm.
 */
void flush_tlb_mm(struct mm_struct *mm)
{
      struct vm_area_struct *mp;

      if (Hash == 0) {
            _tlbia();
            return;
      }

      /*
       * It is safe to go down the mm's list of vmas when called
       * from dup_mmap, holding mmap_sem.  It would also be safe from
       * unmap_region or exit_mmap, but not from vmtruncate on SMP -
       * but it seems dup_mmap is the only SMP case which gets here.
       */
      for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
            flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
      FINISH_FLUSH;
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
{
      struct mm_struct *mm;
      pmd_t *pmd;

      if (Hash == 0) {
            _tlbie(vmaddr);
            return;
      }
      mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
      pmd = pmd_offset(pud_offset(pgd_offset(mm, vmaddr), vmaddr), vmaddr);
      if (!pmd_none(*pmd))
            flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
      FINISH_FLUSH;
}

/*
 * For each address in the range, find the pte for the address
 * and check _PAGE_HASHPTE bit; if it is set, find and destroy
 * the corresponding HPTE.
 */
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
                 unsigned long end)
{
      flush_range(vma->vm_mm, start, end);
      FINISH_FLUSH;
}

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