arch/arm/mm/mmu.c

   1 /*
   2  *  linux/arch/arm/mm/mmu.c
   3  *
   4  *  Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/init.h>
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13
  14 #include <asm/mmu_context.h>
  15 #include <asm/tlbflush.h>
  16
  17 unsigned int cpu_last_asid = { 1 << ASID_BITS };
  18
  19 /*
  20  * We fork()ed a process, and we need a new context for the child
  21  * to run in.  We reserve version 0 for initial tasks so we will
  22  * always allocate an ASID.
  23  */
  24 void __init_new_context(struct task_struct *tsk, struct mm_struct *mm)
  25 {
  26         mm->context.id = 0;
  27 }
  28
  29 void __new_context(struct mm_struct *mm)
  30 {
  31         unsigned int asid;
  32
  33         asid = ++cpu_last_asid;
  34         if (asid == 0)
  35                 asid = cpu_last_asid = 1 << ASID_BITS;
  36
  37         /*
  38          * If we've used up all our ASIDs, we need
  39          * to start a new version and flush the TLB.
  40          */
  41         if ((asid & ~ASID_MASK) == 0)
  42                 flush_tlb_all();
  43
  44         mm->context.id = asid;
  45 }