Commit | Line | Data |
---|---|---|
fc34d1eb MS |
1 | /* |
2 | * This file contains the routines for handling the MMU. | |
3 | * | |
4 | * Copyright (C) 2007 Xilinx, Inc. All rights reserved. | |
5 | * | |
6 | * Derived from arch/ppc/mm/4xx_mmu.c: | |
7 | * -- paulus | |
8 | * | |
9 | * Derived from arch/ppc/mm/init.c: | |
10 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) | |
11 | * | |
12 | * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) | |
13 | * and Cort Dougan (PReP) (cort@cs.nmt.edu) | |
14 | * Copyright (C) 1996 Paul Mackerras | |
15 | * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk). | |
16 | * | |
17 | * Derived from "arch/i386/mm/init.c" | |
18 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
19 | * | |
20 | * This program is free software; you can redistribute it and/or | |
21 | * modify it under the terms of the GNU General Public License | |
22 | * as published by the Free Software Foundation; either version | |
23 | * 2 of the License, or (at your option) any later version. | |
24 | * | |
25 | */ | |
26 | ||
27 | #include <linux/mm.h> | |
28 | #include <linux/init.h> | |
29 | ||
30 | #include <asm/tlbflush.h> | |
31 | #include <asm/mmu_context.h> | |
32 | ||
33 | mm_context_t next_mmu_context; | |
34 | unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; | |
35 | atomic_t nr_free_contexts; | |
36 | struct mm_struct *context_mm[LAST_CONTEXT+1]; | |
37 | ||
38 | /* | |
39 | * Initialize the context management stuff. | |
40 | */ | |
41 | void __init mmu_context_init(void) | |
42 | { | |
43 | /* | |
44 | * The use of context zero is reserved for the kernel. | |
45 | * This code assumes FIRST_CONTEXT < 32. | |
46 | */ | |
47 | context_map[0] = (1 << FIRST_CONTEXT) - 1; | |
48 | next_mmu_context = FIRST_CONTEXT; | |
49 | atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); | |
50 | } | |
51 | ||
52 | /* | |
53 | * Steal a context from a task that has one at the moment. | |
54 | * | |
55 | * This isn't an LRU system, it just frees up each context in | |
56 | * turn (sort-of pseudo-random replacement :). This would be the | |
57 | * place to implement an LRU scheme if anyone were motivated to do it. | |
58 | */ | |
59 | void steal_context(void) | |
60 | { | |
61 | struct mm_struct *mm; | |
62 | ||
63 | /* free up context `next_mmu_context' */ | |
64 | /* if we shouldn't free context 0, don't... */ | |
65 | if (next_mmu_context < FIRST_CONTEXT) | |
66 | next_mmu_context = FIRST_CONTEXT; | |
67 | mm = context_mm[next_mmu_context]; | |
68 | flush_tlb_mm(mm); | |
69 | destroy_context(mm); | |
70 | } |