1 /*
2 * Copyright (C) 1999 Niibe Yutaka
3 * Copyright (C) 2003 - 2007 Paul Mundt
4 *
5 * ASID handling idea taken from MIPS implementation.
6 */
7 #ifndef __ASM_SH_MMU_CONTEXT_H
8 #define __ASM_SH_MMU_CONTEXT_H
9
10 #ifdef __KERNEL__
11 #include <cpu/mmu_context.h>
12 #include <asm/tlbflush.h>
13 #include <asm/uaccess.h>
14 #include <asm/io.h>
15 #include <asm-generic/mm_hooks.h>
16
17 /*
18 * The MMU "context" consists of two things:
19 * (a) TLB cache version (or round, cycle whatever expression you like)
20 * (b) ASID (Address Space IDentifier)
21 */
22 #ifdef CONFIG_CPU_HAS_PTEAEX
23 #define MMU_CONTEXT_ASID_MASK 0x0000ffff
24 #else
25 #define MMU_CONTEXT_ASID_MASK 0x000000ff
26 #endif
27
28 #define MMU_CONTEXT_VERSION_MASK (~0UL & ~MMU_CONTEXT_ASID_MASK)
29 #define MMU_CONTEXT_FIRST_VERSION (MMU_CONTEXT_ASID_MASK + 1)
30
31 /* Impossible ASID value, to differentiate from NO_CONTEXT. */
32 #define MMU_NO_ASID MMU_CONTEXT_FIRST_VERSION
33 #define NO_CONTEXT 0UL
34
35 #define asid_cache(cpu) (cpu_data[cpu].asid_cache)
36
37 #ifdef CONFIG_MMU
38 #define cpu_context(cpu, mm) ((mm)->context.id[cpu])
39
40 #define cpu_asid(cpu, mm) \
41 (cpu_context((cpu), (mm)) & MMU_CONTEXT_ASID_MASK)
42
43 /*
44 * Virtual Page Number mask
45 */
46 #define MMU_VPN_MASK 0xfffff000
47
48 #if defined(CONFIG_SUPERH32)
49 #include "mmu_context_32.h"
50 #else
51 #include "mmu_context_64.h"
52 #endif
53
54 /*
55 * Get MMU context if needed.
56 */
get_mmu_context(struct mm_struct * mm,unsigned int cpu)57 static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu)
58 {
59 unsigned long asid = asid_cache(cpu);
60
61 /* Check if we have old version of context. */
62 if (((cpu_context(cpu, mm) ^ asid) & MMU_CONTEXT_VERSION_MASK) == 0)
63 /* It's up to date, do nothing */
64 return;
65
66 /* It's old, we need to get new context with new version. */
67 if (!(++asid & MMU_CONTEXT_ASID_MASK)) {
68 /*
69 * We exhaust ASID of this version.
70 * Flush all TLB and start new cycle.
71 */
72 local_flush_tlb_all();
73
74 #ifdef CONFIG_SUPERH64
75 /*
76 * The SH-5 cache uses the ASIDs, requiring both the I and D
77 * cache to be flushed when the ASID is exhausted. Weak.
78 */
79 flush_cache_all();
80 #endif
81
82 /*
83 * Fix version; Note that we avoid version #0
84 * to distingush NO_CONTEXT.
85 */
86 if (!asid)
87 asid = MMU_CONTEXT_FIRST_VERSION;
88 }
89
90 cpu_context(cpu, mm) = asid_cache(cpu) = asid;
91 }
92
93 /*
94 * Initialize the context related info for a new mm_struct
95 * instance.
96 */
init_new_context(struct task_struct * tsk,struct mm_struct * mm)97 static inline int init_new_context(struct task_struct *tsk,
98 struct mm_struct *mm)
99 {
100 int i;
101
102 for (i = 0; i < num_online_cpus(); i++)
103 cpu_context(i, mm) = NO_CONTEXT;
104
105 return 0;
106 }
107
108 /*
109 * After we have set current->mm to a new value, this activates
110 * the context for the new mm so we see the new mappings.
111 */
activate_context(struct mm_struct * mm,unsigned int cpu)112 static inline void activate_context(struct mm_struct *mm, unsigned int cpu)
113 {
114 get_mmu_context(mm, cpu);
115 set_asid(cpu_asid(cpu, mm));
116 }
117
switch_mm(struct mm_struct * prev,struct mm_struct * next,struct task_struct * tsk)118 static inline void switch_mm(struct mm_struct *prev,
119 struct mm_struct *next,
120 struct task_struct *tsk)
121 {
122 unsigned int cpu = smp_processor_id();
123
124 if (likely(prev != next)) {
125 cpumask_set_cpu(cpu, mm_cpumask(next));
126 set_TTB(next->pgd);
127 activate_context(next, cpu);
128 } else
129 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)))
130 activate_context(next, cpu);
131 }
132
133 #define activate_mm(prev, next) switch_mm((prev),(next),NULL)
134 #define deactivate_mm(tsk,mm) do { } while (0)
135 #define enter_lazy_tlb(mm,tsk) do { } while (0)
136
137 #else
138
139 #define set_asid(asid) do { } while (0)
140 #define get_asid() (0)
141 #define cpu_asid(cpu, mm) ({ (void)cpu; NO_CONTEXT; })
142 #define switch_and_save_asid(asid) (0)
143 #define set_TTB(pgd) do { } while (0)
144 #define get_TTB() (0)
145
146 #include <asm-generic/mmu_context.h>
147
148 #endif /* CONFIG_MMU */
149
150 #if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
151 /*
152 * If this processor has an MMU, we need methods to turn it off/on ..
153 * paging_init() will also have to be updated for the processor in
154 * question.
155 */
enable_mmu(void)156 static inline void enable_mmu(void)
157 {
158 unsigned int cpu = smp_processor_id();
159
160 /* Enable MMU */
161 __raw_writel(MMU_CONTROL_INIT, MMUCR);
162 ctrl_barrier();
163
164 if (asid_cache(cpu) == NO_CONTEXT)
165 asid_cache(cpu) = MMU_CONTEXT_FIRST_VERSION;
166
167 set_asid(asid_cache(cpu) & MMU_CONTEXT_ASID_MASK);
168 }
169
disable_mmu(void)170 static inline void disable_mmu(void)
171 {
172 unsigned long cr;
173
174 cr = __raw_readl(MMUCR);
175 cr &= ~MMU_CONTROL_INIT;
176 __raw_writel(cr, MMUCR);
177
178 ctrl_barrier();
179 }
180 #else
181 /*
182 * MMU control handlers for processors lacking memory
183 * management hardware.
184 */
185 #define enable_mmu() do { } while (0)
186 #define disable_mmu() do { } while (0)
187 #endif
188
189 #endif /* __KERNEL__ */
190 #endif /* __ASM_SH_MMU_CONTEXT_H */
191