tlb_hash32.c

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/*
 * 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 ([email protected])
 *
 *  Modifications by Paul Mackerras (PowerMac) ([email protected])
 *  and Cort Dougan (PReP) ([email protected])
 *    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 <linux/export.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
 */

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);
}
EXPORT_SYMBOL(flush_tlb_kernel_range);

/*
 * 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);
}
EXPORT_SYMBOL(flush_tlb_mm);

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);
}
EXPORT_SYMBOL(flush_tlb_page);

/*
 * 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);
}
EXPORT_SYMBOL(flush_tlb_range);

void __init early_init_mmu(void)
{
}