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