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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Russell Kingd84b4712006-08-21 19:23:38 +01002 * linux/arch/arm/mm/context.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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
Russell King8678c1f2007-05-08 20:03:09 +010017static DEFINE_SPINLOCK(cpu_asid_lock);
18unsigned int cpu_last_asid = ASID_FIRST_VERSION;
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20/*
21 * We fork()ed a process, and we need a new context for the child
22 * to run in. We reserve version 0 for initial tasks so we will
Catalin Marinas9d99df42007-02-05 14:47:40 +010023 * always allocate an ASID. The ASID 0 is reserved for the TTBR
24 * register changing sequence.
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 */
26void __init_new_context(struct task_struct *tsk, struct mm_struct *mm)
27{
28 mm->context.id = 0;
29}
30
31void __new_context(struct mm_struct *mm)
32{
33 unsigned int asid;
34
Russell King8678c1f2007-05-08 20:03:09 +010035 spin_lock(&cpu_asid_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 asid = ++cpu_last_asid;
37 if (asid == 0)
Russell King8678c1f2007-05-08 20:03:09 +010038 asid = cpu_last_asid = ASID_FIRST_VERSION;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40 /*
41 * If we've used up all our ASIDs, we need
42 * to start a new version and flush the TLB.
43 */
Russell King8678c1f2007-05-08 20:03:09 +010044 if (unlikely((asid & ~ASID_MASK) == 0)) {
Catalin Marinas9d99df42007-02-05 14:47:40 +010045 asid = ++cpu_last_asid;
46 /* set the reserved ASID before flushing the TLB */
47 asm("mcr p15, 0, %0, c13, c0, 1 @ set reserved context ID\n"
48 :
49 : "r" (0));
50 isb();
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 flush_tlb_all();
Catalin Marinas065cf512007-05-09 09:50:23 +010052 if (icache_is_vivt_asid_tagged()) {
53 asm("mcr p15, 0, %0, c7, c5, 0 @ invalidate I-cache\n"
54 "mcr p15, 0, %0, c7, c5, 6 @ flush BTAC/BTB\n"
55 :
56 : "r" (0));
57 dsb();
58 }
Catalin Marinas9d99df42007-02-05 14:47:40 +010059 }
Russell King8678c1f2007-05-08 20:03:09 +010060 spin_unlock(&cpu_asid_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Russell King8678c1f2007-05-08 20:03:09 +010062 mm->cpu_vm_mask = cpumask_of_cpu(smp_processor_id());
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 mm->context.id = asid;
64}