1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 1999 Niibe Yutaka
4 * Copyright (C) 2003 - 2007 Paul Mundt
5 *
6 * ASID handling idea taken from MIPS implementation.
7 */
8 #ifndef __ASM_SH_MMU_CONTEXT_H
9 #define __ASM_SH_MMU_CONTEXT_H
10
11 #include <cpu/mmu_context.h>
12 #include <asm/tlbflush.h>
13 #include <linux/uaccess.h>
14 #include <linux/mm_types.h>
15
16 #include <asm/io.h>
17 #include <asm-generic/mm_hooks.h>
18
19 /*
20 * The MMU "context" consists of two things:
21 * (a) TLB cache version (or round, cycle whatever expression you like)
22 * (b) ASID (Address Space IDentifier)
23 */
24 #ifdef CONFIG_CPU_HAS_PTEAEX
25 #define MMU_CONTEXT_ASID_MASK 0x0000ffff
26 #else
27 #define MMU_CONTEXT_ASID_MASK 0x000000ff
28 #endif
29
30 #define MMU_CONTEXT_VERSION_MASK (~0UL & ~MMU_CONTEXT_ASID_MASK)
31 #define MMU_CONTEXT_FIRST_VERSION (MMU_CONTEXT_ASID_MASK + 1)
32
33 /* Impossible ASID value, to differentiate from NO_CONTEXT. */
34 #define MMU_NO_ASID MMU_CONTEXT_FIRST_VERSION
35 #define NO_CONTEXT 0UL
36
37 #define asid_cache(cpu) (cpu_data[cpu].asid_cache)
38
39 #ifdef CONFIG_MMU
40 #define cpu_context(cpu, mm) ((mm)->context.id[cpu])
41
42 #define cpu_asid(cpu, mm) \
43 (cpu_context((cpu), (mm)) & MMU_CONTEXT_ASID_MASK)
44
45 /*
46 * Virtual Page Number mask
47 */
48 #define MMU_VPN_MASK 0xfffff000
49
50 #include <asm/mmu_context_32.h>
51
52 /*
53 * Get MMU context if needed.
54 */
get_mmu_context(struct mm_struct * mm,unsigned int cpu)55 static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu)
56 {
57 unsigned long asid = asid_cache(cpu);
58
59 /* Check if we have old version of context. */
60 if (((cpu_context(cpu, mm) ^ asid) & MMU_CONTEXT_VERSION_MASK) == 0)
61 /* It's up to date, do nothing */
62 return;
63
64 /* It's old, we need to get new context with new version. */
65 if (!(++asid & MMU_CONTEXT_ASID_MASK)) {
66 /*
67 * We exhaust ASID of this version.
68 * Flush all TLB and start new cycle.
69 */
70 local_flush_tlb_all();
71
72 /*
73 * Fix version; Note that we avoid version #0
74 * to distinguish NO_CONTEXT.
75 */
76 if (!asid)
77 asid = MMU_CONTEXT_FIRST_VERSION;
78 }
79
80 cpu_context(cpu, mm) = asid_cache(cpu) = asid;
81 }
82
83 /*
84 * Initialize the context related info for a new mm_struct
85 * instance.
86 */
87 #define init_new_context init_new_context
init_new_context(struct task_struct * tsk,struct mm_struct * mm)88 static inline int init_new_context(struct task_struct *tsk,
89 struct mm_struct *mm)
90 {
91 int i;
92
93 for_each_online_cpu(i)
94 cpu_context(i, mm) = NO_CONTEXT;
95
96 return 0;
97 }
98
99 /*
100 * After we have set current->mm to a new value, this activates
101 * the context for the new mm so we see the new mappings.
102 */
activate_context(struct mm_struct * mm,unsigned int cpu)103 static inline void activate_context(struct mm_struct *mm, unsigned int cpu)
104 {
105 get_mmu_context(mm, cpu);
106 set_asid(cpu_asid(cpu, mm));
107 }
108
switch_mm(struct mm_struct * prev,struct mm_struct * next,struct task_struct * tsk)109 static inline void switch_mm(struct mm_struct *prev,
110 struct mm_struct *next,
111 struct task_struct *tsk)
112 {
113 unsigned int cpu = smp_processor_id();
114
115 if (likely(prev != next)) {
116 cpumask_set_cpu(cpu, mm_cpumask(next));
117 set_TTB(next->pgd);
118 activate_context(next, cpu);
119 } else
120 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)))
121 activate_context(next, cpu);
122 }
123
124 #include <asm-generic/mmu_context.h>
125
126 #else
127
128 #define set_asid(asid) do { } while (0)
129 #define get_asid() (0)
130 #define cpu_asid(cpu, mm) ({ (void)cpu; NO_CONTEXT; })
131 #define switch_and_save_asid(asid) (0)
132 #define set_TTB(pgd) do { } while (0)
133 #define get_TTB() (0)
134
135 #include <asm-generic/nommu_context.h>
136
137 #endif /* CONFIG_MMU */
138
139 #if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
140 /*
141 * If this processor has an MMU, we need methods to turn it off/on ..
142 * paging_init() will also have to be updated for the processor in
143 * question.
144 */
enable_mmu(void)145 static inline void enable_mmu(void)
146 {
147 unsigned int cpu = smp_processor_id();
148
149 /* Enable MMU */
150 __raw_writel(MMU_CONTROL_INIT, MMUCR);
151 ctrl_barrier();
152
153 if (asid_cache(cpu) == NO_CONTEXT)
154 asid_cache(cpu) = MMU_CONTEXT_FIRST_VERSION;
155
156 set_asid(asid_cache(cpu) & MMU_CONTEXT_ASID_MASK);
157 }
158
disable_mmu(void)159 static inline void disable_mmu(void)
160 {
161 unsigned long cr;
162
163 cr = __raw_readl(MMUCR);
164 cr &= ~MMU_CONTROL_INIT;
165 __raw_writel(cr, MMUCR);
166
167 ctrl_barrier();
168 }
169 #else
170 /*
171 * MMU control handlers for processors lacking memory
172 * management hardware.
173 */
174 #define enable_mmu() do { } while (0)
175 #define disable_mmu() do { } while (0)
176 #endif
177
178 #endif /* __ASM_SH_MMU_CONTEXT_H */
179