1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * arch/arm/include/asm/mmu_context.h
4 *
5 * Copyright (C) 1996 Russell King.
6 *
7 * Changelog:
8 * 27-06-1996 RMK Created
9 */
10 #ifndef __ASM_ARM_MMU_CONTEXT_H
11 #define __ASM_ARM_MMU_CONTEXT_H
12
13 #include <linux/compiler.h>
14 #include <linux/sched.h>
15 #include <linux/mm_types.h>
16 #include <linux/preempt.h>
17
18 #include <asm/cacheflush.h>
19 #include <asm/cachetype.h>
20 #include <asm/proc-fns.h>
21 #include <asm/smp_plat.h>
22 #include <asm-generic/mm_hooks.h>
23
24 void __check_vmalloc_seq(struct mm_struct *mm);
25
26 #ifdef CONFIG_MMU
27 static inline void check_vmalloc_seq(struct mm_struct *mm)
28 {
29 if (!IS_ENABLED(CONFIG_ARM_LPAE) &&
30 unlikely(atomic_read(&mm->context.vmalloc_seq) !=
31 atomic_read(&init_mm.context.vmalloc_seq)))
32 __check_vmalloc_seq(mm);
33 }
34 #endif
35
36 #ifdef CONFIG_CPU_HAS_ASID
37
38 void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);
39
40 #define init_new_context init_new_context
41 static inline int
42 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
43 {
44 atomic64_set(&mm->context.id, 0);
45 return 0;
46 }
47
48 #ifdef CONFIG_ARM_ERRATA_798181
49 void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
50 cpumask_t *mask);
51 #else /* !CONFIG_ARM_ERRATA_798181 */
52 static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
53 cpumask_t *mask)
54 {
55 }
56 #endif /* CONFIG_ARM_ERRATA_798181 */
57
58 #else /* !CONFIG_CPU_HAS_ASID */
59
60 #ifdef CONFIG_MMU
61
62 static inline void check_and_switch_context(struct mm_struct *mm,
63 struct task_struct *tsk)
64 {
65 check_vmalloc_seq(mm);
66
67 if (irqs_disabled())
68 /*
69 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
70 * high interrupt latencies, defer the call and continue
71 * running with the old mm. Since we only support UP systems
72 * on non-ASID CPUs, the old mm will remain valid until the
73 * finish_arch_post_lock_switch() call.
74 */
75 mm->context.switch_pending = 1;
76 else
77 cpu_switch_mm(mm->pgd, mm);
78 }
79
80 #ifndef MODULE
81 #define finish_arch_post_lock_switch \
82 finish_arch_post_lock_switch
83 static inline void finish_arch_post_lock_switch(void)
84 {
85 struct mm_struct *mm = current->mm;
86
87 if (mm && mm->context.switch_pending) {
88 /*
89 * Preemption must be disabled during cpu_switch_mm() as we
90 * have some stateful cache flush implementations. Check
91 * switch_pending again in case we were preempted and the
92 * switch to this mm was already done.
93 */
94 preempt_disable();
95 if (mm->context.switch_pending) {
96 mm->context.switch_pending = 0;
97 cpu_switch_mm(mm->pgd, mm);
98 }
99 preempt_enable_no_resched();
100 }
101 }
102 #endif /* !MODULE */
103
104 #endif /* CONFIG_MMU */
105
106 #endif /* CONFIG_CPU_HAS_ASID */
107
108 #define activate_mm(prev,next) switch_mm(prev, next, NULL)
109
110 /*
111 * This is the actual mm switch as far as the scheduler
112 * is concerned. No registers are touched. We avoid
113 * calling the CPU specific function when the mm hasn't
114 * actually changed.
115 */
116 static inline void
117 switch_mm(struct mm_struct *prev, struct mm_struct *next,
118 struct task_struct *tsk)
119 {
120 #ifdef CONFIG_MMU
121 unsigned int cpu = smp_processor_id();
122
123 /*
124 * __sync_icache_dcache doesn't broadcast the I-cache invalidation,
125 * so check for possible thread migration and invalidate the I-cache
126 * if we're new to this CPU.
127 */
128 if (cache_ops_need_broadcast() &&
129 !cpumask_empty(mm_cpumask(next)) &&
130 !cpumask_test_cpu(cpu, mm_cpumask(next)))
131 __flush_icache_all();
132
133 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
134 check_and_switch_context(next, tsk);
135 if (cache_is_vivt())
136 cpumask_clear_cpu(cpu, mm_cpumask(prev));
137 }
138 #endif
139 }
140
141 #ifdef CONFIG_VMAP_STACK
142 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
143 {
144 if (mm != &init_mm)
145 check_vmalloc_seq(mm);
146 }
147 #define enter_lazy_tlb enter_lazy_tlb
148 #endif
149
150 #include <asm-generic/mmu_context.h>
151
152 #endif
153
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