LXR linux/arch/sh/mm/tlbex

   1/*
   2 * TLB miss handler for SH with an MMU.
   3 *
   4 *  Copyright (C) 1999  Niibe Yutaka
   5 *  Copyright (C) 2003 - 2012  Paul Mundt
   6 *
   7 * This file is subject to the terms and conditions of the GNU General Public
   8 * License.  See the file "COPYING" in the main directory of this archive
   9 * for more details.
  10 */
  11#include <linux/kernel.h>
  12#include <linux/mm.h>
  13#include <linux/kprobes.h>
  14#include <linux/kdebug.h>
  15#include <asm/mmu_context.h>
  16#include <asm/thread_info.h>
  17
  18/*
  19 * Called with interrupts disabled.
  20 */
  21asmlinkage int __kprobes
  22handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,
  23               unsigned long address)
  24{
  25        pgd_t *pgd;
  26        p4d_t *p4d;
  27        pud_t *pud;
  28        pmd_t *pmd;
  29        pte_t *pte;
  30        pte_t entry;
  31
  32        /*
  33         * We don't take page faults for P1, P2, and parts of P4, these
  34         * are always mapped, whether it be due to legacy behaviour in
  35         * 29-bit mode, or due to PMB configuration in 32-bit mode.
  36         */
  37        if (address >= P3SEG && address < P3_ADDR_MAX) {
  38                pgd = pgd_offset_k(address);
  39        } else {
  40                if (unlikely(address >= TASK_SIZE || !current->mm))
  41                        return 1;
  42
  43                pgd = pgd_offset(current->mm, address);
  44        }
  45
  46        p4d = p4d_offset(pgd, address);
  47        if (p4d_none_or_clear_bad(p4d))
  48                return 1;
  49        pud = pud_offset(p4d, address);
  50        if (pud_none_or_clear_bad(pud))
  51                return 1;
  52        pmd = pmd_offset(pud, address);
  53        if (pmd_none_or_clear_bad(pmd))
  54                return 1;
  55        pte = pte_offset_kernel(pmd, address);
  56        entry = *pte;
  57        if (unlikely(pte_none(entry) || pte_not_present(entry)))
  58                return 1;
  59        if (unlikely(error_code && !pte_write(entry)))
  60                return 1;
  61
  62        if (error_code)
  63                entry = pte_mkdirty(entry);
  64        entry = pte_mkyoung(entry);
  65
  66        set_pte(pte, entry);
  67
  68#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
  69        /*
  70         * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
  71         * the case of an initial page write exception, so we need to
  72         * flush it in order to avoid potential TLB entry duplication.
  73         */
  74        if (error_code == FAULT_CODE_INITIAL)
  75                local_flush_tlb_one(get_asid(), address & PAGE_MASK);
  76#endif
  77
  78        set_thread_fault_code(error_code);
  79        update_mmu_cache(NULL, address, pte);
  80
  81        return 0;
  82}
  83