projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 | ||
| 14cf11af PM |
13 | #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> | |
| e85a4710 | 21 | #include <linux/module.h> |
| 14cf11af PM |
22 | |
| 23 | #include <asm/mmu_context.h> | |
| 24 | ||
| 25 | static DEFINE_SPINLOCK(mmu_context_lock); | |
| 26 | static DEFINE_IDR(mmu_context_idr); | |
| 27 | ||
| 5e696617 BH |
28 | /* |
| 29 | * The proto-VSID space has 2^35 - 1 segments available for user mappings. | |
| 30 | * Each segment contains 2^28 bytes. Each context maps 2^44 bytes, | |
| 31 | * so we can support 2^19-1 contexts (19 == 35 + 28 - 44). | |
| 32 | */ | |
| 33 | #define NO_CONTEXT 0 | |
| 34 | #define MAX_CONTEXT ((1UL << 19) - 1) | |
| 35 | ||
| e85a4710 | 36 | int __init_new_context(void) |
| 14cf11af PM |
37 | { |
| 38 | int index; | |
| 39 | int err; | |
| 40 | ||
| 41 | again: | |
| 42 | if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL)) | |
| 43 | return -ENOMEM; | |
| 44 | ||
| 45 | spin_lock(&mmu_context_lock); | |
| 46 | err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index); | |
| 47 | spin_unlock(&mmu_context_lock); | |
| 48 | ||
| 49 | if (err == -EAGAIN) | |
| 50 | goto again; | |
| 51 | else if (err) | |
| 52 | return err; | |
| 53 | ||
| 54 | if (index > MAX_CONTEXT) { | |
| f86c9747 | 55 | spin_lock(&mmu_context_lock); |
| 14cf11af | 56 | idr_remove(&mmu_context_idr, index); |
| f86c9747 | 57 | spin_unlock(&mmu_context_lock); |
| 14cf11af PM |
58 | return -ENOMEM; |
| 59 | } | |
| 60 | ||
| e85a4710 AG |
61 | return index; |
| 62 | } | |
| 63 | EXPORT_SYMBOL_GPL(__init_new_context); | |
| 64 | ||
| 65 | int init_new_context(struct task_struct *tsk, struct mm_struct *mm) | |
| 66 | { | |
| 67 | int index; | |
| 68 | ||
| 69 | index = __init_new_context(); | |
| 70 | if (index < 0) | |
| 71 | return index; | |
| 72 | ||
| d0f13e3c BH |
73 | /* The old code would re-promote on fork, we don't do that |
| 74 | * when using slices as it could cause problem promoting slices | |
| 75 | * that have been forced down to 4K | |
| 76 | */ | |
| e8ff0646 | 77 | if (slice_mm_new_context(mm)) |
| d0f13e3c | 78 | slice_set_user_psize(mm, mmu_virtual_psize); |
| 9dfe5c53 | 79 | mm->context.id = index; |
| 14cf11af PM |
80 | |
| 81 | return 0; | |
| 82 | } | |
| 83 | ||
| e85a4710 | 84 | void __destroy_context(int context_id) |
| 14cf11af PM |
85 | { |
| 86 | spin_lock(&mmu_context_lock); | |
| e85a4710 | 87 | idr_remove(&mmu_context_idr, context_id); |
| 14cf11af | 88 | spin_unlock(&mmu_context_lock); |
| e85a4710 AG |
89 | } |
| 90 | EXPORT_SYMBOL_GPL(__destroy_context); | |
| 14cf11af | 91 | |
| e85a4710 AG |
92 | void destroy_context(struct mm_struct *mm) |
| 93 | { | |
| 94 | __destroy_context(mm->context.id); | |
| 14cf11af PM |
95 | mm->context.id = NO_CONTEXT; |
| 96 | } |