2 * arch/arm/include/asm/mmu_context.h
4 * Copyright (C) 1996 Russell King.
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.
11 * 27-06-1996 RMK Created
13 #ifndef __ASM_ARM_MMU_CONTEXT_H
14 #define __ASM_ARM_MMU_CONTEXT_H
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-generic/mm_hooks.h>
23 void __check_vmalloc_seq(struct mm_struct *mm);
25 #ifdef CONFIG_CPU_HAS_ASID
27 void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);
28 #define init_new_context(tsk,mm) ({ atomic64_set(&mm->context.id, 0); 0; })
30 DECLARE_PER_CPU(atomic64_t, active_asids);
32 #else /* !CONFIG_CPU_HAS_ASID */
36 static inline void check_and_switch_context(struct mm_struct *mm,
37 struct task_struct *tsk)
39 if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq))
40 __check_vmalloc_seq(mm);
44 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
45 * high interrupt latencies, defer the call and continue
46 * running with the old mm. Since we only support UP systems
47 * on non-ASID CPUs, the old mm will remain valid until the
48 * finish_arch_post_lock_switch() call.
50 set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM);
52 cpu_switch_mm(mm->pgd, mm);
55 #define finish_arch_post_lock_switch \
56 finish_arch_post_lock_switch
57 static inline void finish_arch_post_lock_switch(void)
59 if (test_and_clear_thread_flag(TIF_SWITCH_MM)) {
60 struct mm_struct *mm = current->mm;
61 cpu_switch_mm(mm->pgd, mm);
65 #endif /* CONFIG_MMU */
67 #define init_new_context(tsk,mm) 0
69 #endif /* CONFIG_CPU_HAS_ASID */
71 #define destroy_context(mm) do { } while(0)
72 #define activate_mm(prev,next) switch_mm(prev, next, NULL)
75 * This is called when "tsk" is about to enter lazy TLB mode.
77 * mm: describes the currently active mm context
78 * tsk: task which is entering lazy tlb
79 * cpu: cpu number which is entering lazy tlb
81 * tsk->mm will be NULL
84 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
89 * This is the actual mm switch as far as the scheduler
90 * is concerned. No registers are touched. We avoid
91 * calling the CPU specific function when the mm hasn't
95 switch_mm(struct mm_struct *prev, struct mm_struct *next,
96 struct task_struct *tsk)
99 unsigned int cpu = smp_processor_id();
102 /* check for possible thread migration */
103 if (!cpumask_empty(mm_cpumask(next)) &&
104 !cpumask_test_cpu(cpu, mm_cpumask(next)))
105 __flush_icache_all();
107 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
108 check_and_switch_context(next, tsk);
110 cpumask_clear_cpu(cpu, mm_cpumask(prev));
115 #define deactivate_mm(tsk,mm) do { } while (0)