xref: /openbmc/linux/arch/arm/mm/mmu.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 }
46