54 lines
1.3 KiB
C
54 lines
1.3 KiB
C
/*
|
|
* linux/arch/arm/mm/context.c
|
|
*
|
|
* Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/init.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/mm.h>
|
|
|
|
#include <asm/mmu_context.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
unsigned int cpu_last_asid = { 1 << ASID_BITS };
|
|
|
|
/*
|
|
* We fork()ed a process, and we need a new context for the child
|
|
* to run in. We reserve version 0 for initial tasks so we will
|
|
* always allocate an ASID. The ASID 0 is reserved for the TTBR
|
|
* register changing sequence.
|
|
*/
|
|
void __init_new_context(struct task_struct *tsk, struct mm_struct *mm)
|
|
{
|
|
mm->context.id = 0;
|
|
}
|
|
|
|
void __new_context(struct mm_struct *mm)
|
|
{
|
|
unsigned int asid;
|
|
|
|
asid = ++cpu_last_asid;
|
|
if (asid == 0)
|
|
asid = cpu_last_asid = 1 << ASID_BITS;
|
|
|
|
/*
|
|
* If we've used up all our ASIDs, we need
|
|
* to start a new version and flush the TLB.
|
|
*/
|
|
if ((asid & ~ASID_MASK) == 0) {
|
|
asid = ++cpu_last_asid;
|
|
/* set the reserved ASID before flushing the TLB */
|
|
asm("mcr p15, 0, %0, c13, c0, 1 @ set reserved context ID\n"
|
|
:
|
|
: "r" (0));
|
|
isb();
|
|
flush_tlb_all();
|
|
}
|
|
|
|
mm->context.id = asid;
|
|
}
|