blob: 1db38ba1f544e003a40c48a9b5652834bfa4bf27 [file] [log] [blame]
Paul Mackerras14cf11a2005-09-26 16:04:21 +10001/*
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
Paul Mackerras14cf11a2005-09-26 16:04:21 +100013#include <linux/sched.h>
14#include <linux/kernel.h>
15#include <linux/errno.h>
16#include <linux/string.h>
17#include <linux/types.h>
18#include <linux/mm.h>
19#include <linux/spinlock.h>
20#include <linux/idr.h>
21
22#include <asm/mmu_context.h>
23
24static DEFINE_SPINLOCK(mmu_context_lock);
25static DEFINE_IDR(mmu_context_idr);
26
27int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
28{
29 int index;
30 int err;
31
32again:
33 if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL))
34 return -ENOMEM;
35
36 spin_lock(&mmu_context_lock);
37 err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index);
38 spin_unlock(&mmu_context_lock);
39
40 if (err == -EAGAIN)
41 goto again;
42 else if (err)
43 return err;
44
45 if (index > MAX_CONTEXT) {
Sonny Raof86c97472006-06-27 08:46:09 -040046 spin_lock(&mmu_context_lock);
Paul Mackerras14cf11a2005-09-26 16:04:21 +100047 idr_remove(&mmu_context_idr, index);
Sonny Raof86c97472006-06-27 08:46:09 -040048 spin_unlock(&mmu_context_lock);
Paul Mackerras14cf11a2005-09-26 16:04:21 +100049 return -ENOMEM;
50 }
51
Benjamin Herrenschmidtd0f13e32007-05-08 16:27:27 +100052 /* The old code would re-promote on fork, we don't do that
53 * when using slices as it could cause problem promoting slices
54 * that have been forced down to 4K
55 */
Stephen Rothwelle8ff0642007-08-15 16:51:18 +100056 if (slice_mm_new_context(mm))
Benjamin Herrenschmidtd0f13e32007-05-08 16:27:27 +100057 slice_set_user_psize(mm, mmu_virtual_psize);
Stephen Rothwell9dfe5c532007-08-15 16:33:55 +100058 mm->context.id = index;
Paul Mackerras14cf11a2005-09-26 16:04:21 +100059
60 return 0;
61}
62
63void destroy_context(struct mm_struct *mm)
64{
65 spin_lock(&mmu_context_lock);
66 idr_remove(&mmu_context_idr, mm->context.id);
67 spin_unlock(&mmu_context_lock);
68
69 mm->context.id = NO_CONTEXT;
70}