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kernel/linux-rt-4.4.41/arch/sh/mm/tlb-urb.c 2.02 KB
5113f6f70   김현기   kernel add
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  /*
   * arch/sh/mm/tlb-urb.c
   *
   * TLB entry wiring helpers for URB-equipped parts.
   *
   * Copyright (C) 2010  Matt Fleming
   *
   * 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/mm.h>
  #include <linux/io.h>
  #include <asm/tlb.h>
  #include <asm/mmu_context.h>
  
  /*
   * Load the entry for 'addr' into the TLB and wire the entry.
   */
  void tlb_wire_entry(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
  {
  	unsigned long status, flags;
  	int urb;
  
  	local_irq_save(flags);
  
  	status = __raw_readl(MMUCR);
  	urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT;
  	status &= ~MMUCR_URC;
  
  	/*
  	 * Make sure we're not trying to wire the last TLB entry slot.
  	 */
  	BUG_ON(!--urb);
  
  	urb = urb % MMUCR_URB_NENTRIES;
  
  	/*
  	 * Insert this entry into the highest non-wired TLB slot (via
  	 * the URC field).
  	 */
  	status |= (urb << MMUCR_URC_SHIFT);
  	__raw_writel(status, MMUCR);
  	ctrl_barrier();
  
  	/* Load the entry into the TLB */
  	__update_tlb(vma, addr, pte);
  
  	/* ... and wire it up. */
  	status = __raw_readl(MMUCR);
  
  	status &= ~MMUCR_URB;
  	status |= (urb << MMUCR_URB_SHIFT);
  
  	__raw_writel(status, MMUCR);
  	ctrl_barrier();
  
  	local_irq_restore(flags);
  }
  
  /*
   * Unwire the last wired TLB entry.
   *
   * It should also be noted that it is not possible to wire and unwire
   * TLB entries in an arbitrary order. If you wire TLB entry N, followed
   * by entry N+1, you must unwire entry N+1 first, then entry N. In this
   * respect, it works like a stack or LIFO queue.
   */
  void tlb_unwire_entry(void)
  {
  	unsigned long status, flags;
  	int urb;
  
  	local_irq_save(flags);
  
  	status = __raw_readl(MMUCR);
  	urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT;
  	status &= ~MMUCR_URB;
  
  	/*
  	 * Make sure we're not trying to unwire a TLB entry when none
  	 * have been wired.
  	 */
  	BUG_ON(urb++ == MMUCR_URB_NENTRIES);
  
  	urb = urb % MMUCR_URB_NENTRIES;
  
  	status |= (urb << MMUCR_URB_SHIFT);
  	__raw_writel(status, MMUCR);
  	ctrl_barrier();
  
  	local_irq_restore(flags);
  }