Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  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>

static DEFINE_SPINLOCK(cpu_asid_lock);

unsigned int cpu_last_asid = ASID_FIRST_VERSION;

/*

 * 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;

        spin_lock(&cpu_asid_lock);

        asid = ++cpu_last_asid;

        if (asid == 0)

                asid = cpu_last_asid = ASID_FIRST_VERSION;

        /*

         * If we've used up all our ASIDs, we need

         * to start a new version and flush the TLB.

         */

        if (unlikely((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();

                if (icache_is_vivt_asid_tagged()) {

                        asm("mcr        p15, 0, %0, c7, c5, 0   @ invalidate I-cache\n"

                            "mcr        p15, 0, %0, c7, c5, 6   @ flush BTAC/BTB\n"

                            :

                            : "r" (0));

                        dsb();

                }

        }

        spin_unlock(&cpu_asid_lock);

        mm->cpu_vm_mask = cpumask_of_cpu(smp_processor_id());

        mm->context.id = asid;

}