Commit | Line | Data |
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9d670280 JX |
1 | /* |
2 | * ICSWX and ACOP/PID Management | |
3 | * | |
4 | * Copyright (C) 2011 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/sched.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/spinlock.h> | |
19 | #include <linux/idr.h> | |
20 | #include <linux/module.h> | |
21 | #include "icswx.h" | |
22 | ||
23 | #define COP_PID_MIN (COP_PID_NONE + 1) | |
24 | #define COP_PID_MAX (0xFFFF) | |
25 | ||
26 | static DEFINE_SPINLOCK(mmu_context_acop_lock); | |
27 | static DEFINE_IDA(cop_ida); | |
28 | ||
29 | static int new_cop_pid(struct ida *ida, int min_id, int max_id, | |
30 | spinlock_t *lock) | |
31 | { | |
32 | int index; | |
33 | int err; | |
34 | ||
35 | again: | |
36 | if (!ida_pre_get(ida, GFP_KERNEL)) | |
37 | return -ENOMEM; | |
38 | ||
39 | spin_lock(lock); | |
40 | err = ida_get_new_above(ida, min_id, &index); | |
41 | spin_unlock(lock); | |
42 | ||
43 | if (err == -EAGAIN) | |
44 | goto again; | |
45 | else if (err) | |
46 | return err; | |
47 | ||
48 | if (index > max_id) { | |
49 | spin_lock(lock); | |
50 | ida_remove(ida, index); | |
51 | spin_unlock(lock); | |
52 | return -ENOMEM; | |
53 | } | |
54 | ||
55 | return index; | |
56 | } | |
57 | ||
58 | int get_cop_pid(struct mm_struct *mm) | |
59 | { | |
60 | int pid; | |
61 | ||
62 | if (mm->context.cop_pid == COP_PID_NONE) { | |
63 | pid = new_cop_pid(&cop_ida, COP_PID_MIN, COP_PID_MAX, | |
64 | &mmu_context_acop_lock); | |
65 | if (pid >= 0) | |
66 | mm->context.cop_pid = pid; | |
67 | } | |
68 | return mm->context.cop_pid; | |
69 | } | |
70 | ||
71 | int disable_cop_pid(struct mm_struct *mm) | |
72 | { | |
73 | int free_pid = COP_PID_NONE; | |
74 | ||
75 | if ((!mm->context.acop) && (mm->context.cop_pid != COP_PID_NONE)) { | |
76 | free_pid = mm->context.cop_pid; | |
77 | mm->context.cop_pid = COP_PID_NONE; | |
78 | } | |
79 | return free_pid; | |
80 | } | |
81 | ||
82 | void free_cop_pid(int free_pid) | |
83 | { | |
84 | spin_lock(&mmu_context_acop_lock); | |
85 | ida_remove(&cop_ida, free_pid); | |
86 | spin_unlock(&mmu_context_acop_lock); | |
87 | } |