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);
29#define init_new_context(tsk,mm)	({ atomic64_set(&mm->context.id, 0); 0; })
30
31#ifdef CONFIG_ARM_ERRATA_798181
32void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
33			     cpumask_t *mask);
34#else  /* !CONFIG_ARM_ERRATA_798181 */
35static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
36					   cpumask_t *mask)
37{
38}
39#endif /* CONFIG_ARM_ERRATA_798181 */
40
41#else	/* !CONFIG_CPU_HAS_ASID */
42
43#ifdef CONFIG_MMU
44
45static inline void check_and_switch_context(struct mm_struct *mm,
46					    struct task_struct *tsk)
47{
48	if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq))
49		__check_vmalloc_seq(mm);
50
51	if (irqs_disabled())
52		/*
53		 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
54		 * high interrupt latencies, defer the call and continue
55		 * running with the old mm. Since we only support UP systems
56		 * on non-ASID CPUs, the old mm will remain valid until the
57		 * finish_arch_post_lock_switch() call.
58		 */
59		mm->context.switch_pending = 1;
60	else
61		cpu_switch_mm(mm->pgd, mm);
62}
63
64#define finish_arch_post_lock_switch \
65	finish_arch_post_lock_switch
66static inline void finish_arch_post_lock_switch(void)
67{
68	struct mm_struct *mm = current->mm;
69
70	if (mm && mm->context.switch_pending) {
71		/*
72		 * Preemption must be disabled during cpu_switch_mm() as we
73		 * have some stateful cache flush implementations. Check
74		 * switch_pending again in case we were preempted and the
75		 * switch to this mm was already done.
76		 */
77		preempt_disable();
78		if (mm->context.switch_pending) {
79			mm->context.switch_pending = 0;
80			cpu_switch_mm(mm->pgd, mm);
81		}
82		preempt_enable_no_resched();
83	}
84}
85
86#endif	/* CONFIG_MMU */
87
88#define init_new_context(tsk,mm)	0
89
90#endif	/* CONFIG_CPU_HAS_ASID */
91
92#define destroy_context(mm)		do { } while(0)
93#define activate_mm(prev,next)		switch_mm(prev, next, NULL)
94
95/*
96 * This is called when "tsk" is about to enter lazy TLB mode.
97 *
98 * mm:  describes the currently active mm context
99 * tsk: task which is entering lazy tlb
100 * cpu: cpu number which is entering lazy tlb
101 *
102 * tsk->mm will be NULL
103 */
104static inline void
105enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
106{
107}
108
109/*
110 * This is the actual mm switch as far as the scheduler
111 * is concerned.  No registers are touched.  We avoid
112 * calling the CPU specific function when the mm hasn't
113 * actually changed.
114 */
115static inline void
116switch_mm(struct mm_struct *prev, struct mm_struct *next,
117	  struct task_struct *tsk)
118{
119#ifdef CONFIG_MMU
120	unsigned int cpu = smp_processor_id();
121
122	/*
123	 * __sync_icache_dcache doesn't broadcast the I-cache invalidation,
124	 * so check for possible thread migration and invalidate the I-cache
125	 * if we're new to this CPU.
126	 */
127	if (cache_ops_need_broadcast() &&
128	    !cpumask_empty(mm_cpumask(next)) &&
129	    !cpumask_test_cpu(cpu, mm_cpumask(next)))
130		__flush_icache_all();
131
132	if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
133		check_and_switch_context(next, tsk);
134		if (cache_is_vivt())
135			cpumask_clear_cpu(cpu, mm_cpumask(prev));
136	}
137#endif
138}
139
140#define deactivate_mm(tsk,mm)	do { } while (0)
141
142#endif
143