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kernel/linux-rt-4.4.41/arch/sh/mm/tlbex_32.c 1.94 KB
5113f6f70   김현기   kernel add
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  /*
   * TLB miss handler for SH with an MMU.
   *
   *  Copyright (C) 1999  Niibe Yutaka
   *  Copyright (C) 2003 - 2012  Paul Mundt
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/kprobes.h>
  #include <linux/kdebug.h>
  #include <asm/mmu_context.h>
  #include <asm/thread_info.h>
  
  /*
   * Called with interrupts disabled.
   */
  asmlinkage int __kprobes
  handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,
  	       unsigned long address)
  {
  	pgd_t *pgd;
  	pud_t *pud;
  	pmd_t *pmd;
  	pte_t *pte;
  	pte_t entry;
  
  	/*
  	 * We don't take page faults for P1, P2, and parts of P4, these
  	 * are always mapped, whether it be due to legacy behaviour in
  	 * 29-bit mode, or due to PMB configuration in 32-bit mode.
  	 */
  	if (address >= P3SEG && address < P3_ADDR_MAX) {
  		pgd = pgd_offset_k(address);
  	} else {
  		if (unlikely(address >= TASK_SIZE || !current->mm))
  			return 1;
  
  		pgd = pgd_offset(current->mm, address);
  	}
  
  	pud = pud_offset(pgd, address);
  	if (pud_none_or_clear_bad(pud))
  		return 1;
  	pmd = pmd_offset(pud, address);
  	if (pmd_none_or_clear_bad(pmd))
  		return 1;
  	pte = pte_offset_kernel(pmd, address);
  	entry = *pte;
  	if (unlikely(pte_none(entry) || pte_not_present(entry)))
  		return 1;
  	if (unlikely(error_code && !pte_write(entry)))
  		return 1;
  
  	if (error_code)
  		entry = pte_mkdirty(entry);
  	entry = pte_mkyoung(entry);
  
  	set_pte(pte, entry);
  
  #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
  	/*
  	 * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
  	 * the case of an initial page write exception, so we need to
  	 * flush it in order to avoid potential TLB entry duplication.
  	 */
  	if (error_code == FAULT_CODE_INITIAL)
  		local_flush_tlb_one(get_asid(), address & PAGE_MASK);
  #endif
  
  	set_thread_fault_code(error_code);
  	update_mmu_cache(NULL, address, pte);
  
  	return 0;
  }