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5f97f7f9 HS |
1 | /* |
2 | * Copyright (C) 2004-2006 Atmel Corporation | |
3 | * | |
4 | * ASID handling taken from SH implementation. | |
5 | * Copyright (C) 1999 Niibe Yutaka | |
6 | * Copyright (C) 2003 Paul Mundt | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #ifndef __ASM_AVR32_MMU_CONTEXT_H | |
13 | #define __ASM_AVR32_MMU_CONTEXT_H | |
14 | ||
15 | #include <asm/tlbflush.h> | |
5f97f7f9 | 16 | #include <asm/sysreg.h> |
d6dd61c8 | 17 | #include <asm-generic/mm_hooks.h> |
5f97f7f9 HS |
18 | |
19 | /* | |
20 | * The MMU "context" consists of two things: | |
21 | * (a) TLB cache version | |
22 | * (b) ASID (Address Space IDentifier) | |
23 | */ | |
24 | #define MMU_CONTEXT_ASID_MASK 0x000000ff | |
25 | #define MMU_CONTEXT_VERSION_MASK 0xffffff00 | |
26 | #define MMU_CONTEXT_FIRST_VERSION 0x00000100 | |
27 | #define NO_CONTEXT 0 | |
28 | ||
29 | #define MMU_NO_ASID 0x100 | |
30 | ||
31 | /* Virtual Page Number mask */ | |
32 | #define MMU_VPN_MASK 0xfffff000 | |
33 | ||
34 | /* Cache of MMU context last used */ | |
35 | extern unsigned long mmu_context_cache; | |
36 | ||
37 | /* | |
38 | * Get MMU context if needed | |
39 | */ | |
40 | static inline void | |
41 | get_mmu_context(struct mm_struct *mm) | |
42 | { | |
43 | unsigned long mc = mmu_context_cache; | |
44 | ||
45 | if (((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK) == 0) | |
46 | /* It's up to date, do nothing */ | |
47 | return; | |
48 | ||
49 | /* It's old, we need to get new context with new version */ | |
50 | mc = ++mmu_context_cache; | |
51 | if (!(mc & MMU_CONTEXT_ASID_MASK)) { | |
52 | /* | |
53 | * We have exhausted all ASIDs of this version. | |
54 | * Flush the TLB and start new cycle. | |
55 | */ | |
56 | flush_tlb_all(); | |
57 | /* | |
58 | * Fix version. Note that we avoid version #0 | |
59 | * to distinguish NO_CONTEXT. | |
60 | */ | |
61 | if (!mc) | |
62 | mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION; | |
63 | } | |
64 | mm->context = mc; | |
65 | } | |
66 | ||
67 | /* | |
68 | * Initialize the context related info for a new mm_struct | |
69 | * instance. | |
70 | */ | |
71 | static inline int init_new_context(struct task_struct *tsk, | |
72 | struct mm_struct *mm) | |
73 | { | |
74 | mm->context = NO_CONTEXT; | |
75 | return 0; | |
76 | } | |
77 | ||
78 | /* | |
79 | * Destroy context related info for an mm_struct that is about | |
80 | * to be put to rest. | |
81 | */ | |
82 | static inline void destroy_context(struct mm_struct *mm) | |
83 | { | |
84 | /* Do nothing */ | |
85 | } | |
86 | ||
87 | static inline void set_asid(unsigned long asid) | |
88 | { | |
89 | /* XXX: We're destroying TLBEHI[8:31] */ | |
90 | sysreg_write(TLBEHI, asid & MMU_CONTEXT_ASID_MASK); | |
91 | cpu_sync_pipeline(); | |
92 | } | |
93 | ||
94 | static inline unsigned long get_asid(void) | |
95 | { | |
96 | unsigned long asid; | |
97 | ||
98 | asid = sysreg_read(TLBEHI); | |
99 | return asid & MMU_CONTEXT_ASID_MASK; | |
100 | } | |
101 | ||
102 | static inline void activate_context(struct mm_struct *mm) | |
103 | { | |
104 | get_mmu_context(mm); | |
105 | set_asid(mm->context & MMU_CONTEXT_ASID_MASK); | |
106 | } | |
107 | ||
108 | static inline void switch_mm(struct mm_struct *prev, | |
109 | struct mm_struct *next, | |
110 | struct task_struct *tsk) | |
111 | { | |
112 | if (likely(prev != next)) { | |
113 | unsigned long __pgdir = (unsigned long)next->pgd; | |
114 | ||
115 | sysreg_write(PTBR, __pgdir); | |
116 | activate_context(next); | |
117 | } | |
118 | } | |
119 | ||
120 | #define deactivate_mm(tsk,mm) do { } while(0) | |
121 | ||
122 | #define activate_mm(prev, next) switch_mm((prev), (next), NULL) | |
123 | ||
124 | static inline void | |
125 | enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) | |
126 | { | |
127 | } | |
128 | ||
129 | ||
130 | static inline void enable_mmu(void) | |
131 | { | |
132 | sysreg_write(MMUCR, (SYSREG_BIT(MMUCR_S) | |
133 | | SYSREG_BIT(E) | |
134 | | SYSREG_BIT(MMUCR_I))); | |
135 | nop(); nop(); nop(); nop(); nop(); nop(); nop(); nop(); | |
136 | ||
137 | if (mmu_context_cache == NO_CONTEXT) | |
138 | mmu_context_cache = MMU_CONTEXT_FIRST_VERSION; | |
139 | ||
140 | set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK); | |
141 | } | |
142 | ||
143 | static inline void disable_mmu(void) | |
144 | { | |
145 | sysreg_write(MMUCR, SYSREG_BIT(MMUCR_S)); | |
146 | } | |
147 | ||
148 | #endif /* __ASM_AVR32_MMU_CONTEXT_H */ |