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14cf11af PM |
1 | /* |
2 | * MMU context allocation for 64-bit kernels. | |
3 | * | |
4 | * Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/config.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/string.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/spinlock.h> | |
21 | #include <linux/idr.h> | |
22 | ||
23 | #include <asm/mmu_context.h> | |
24 | ||
25 | static DEFINE_SPINLOCK(mmu_context_lock); | |
26 | static DEFINE_IDR(mmu_context_idr); | |
27 | ||
28 | int init_new_context(struct task_struct *tsk, struct mm_struct *mm) | |
29 | { | |
30 | int index; | |
31 | int err; | |
32 | ||
33 | again: | |
34 | if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL)) | |
35 | return -ENOMEM; | |
36 | ||
37 | spin_lock(&mmu_context_lock); | |
38 | err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index); | |
39 | spin_unlock(&mmu_context_lock); | |
40 | ||
41 | if (err == -EAGAIN) | |
42 | goto again; | |
43 | else if (err) | |
44 | return err; | |
45 | ||
46 | if (index > MAX_CONTEXT) { | |
47 | idr_remove(&mmu_context_idr, index); | |
48 | return -ENOMEM; | |
49 | } | |
50 | ||
51 | mm->context.id = index; | |
bf72aeba PM |
52 | mm->context.user_psize = mmu_virtual_psize; |
53 | mm->context.sllp = SLB_VSID_USER | | |
54 | mmu_psize_defs[mmu_virtual_psize].sllp; | |
14cf11af PM |
55 | |
56 | return 0; | |
57 | } | |
58 | ||
59 | void destroy_context(struct mm_struct *mm) | |
60 | { | |
61 | spin_lock(&mmu_context_lock); | |
62 | idr_remove(&mmu_context_idr, mm->context.id); | |
63 | spin_unlock(&mmu_context_lock); | |
64 | ||
65 | mm->context.id = NO_CONTEXT; | |
66 | } |