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 #ifdef CONFIG_ARM_ERRATA_798181
31 void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
33 #else /* !CONFIG_ARM_ERRATA_798181 */
34 static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
38 #endif /* CONFIG_ARM_ERRATA_798181 */
40 #else /* !CONFIG_CPU_HAS_ASID */
44 static inline void check_and_switch_context(struct mm_struct *mm,
45 struct task_struct *tsk)
47 if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq))
48 __check_vmalloc_seq(mm);
52 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
53 * high interrupt latencies, defer the call and continue
54 * running with the old mm. Since we only support UP systems
55 * on non-ASID CPUs, the old mm will remain valid until the
56 * finish_arch_post_lock_switch() call.
58 mm->context.switch_pending = 1;
60 cpu_switch_mm(mm->pgd, mm);
63 #define finish_arch_post_lock_switch \
64 finish_arch_post_lock_switch
65 static inline void finish_arch_post_lock_switch(void)
67 struct mm_struct *mm = current->mm;
69 if (mm && mm->context.switch_pending) {
71 * Preemption must be disabled during cpu_switch_mm() as we
72 * have some stateful cache flush implementations. Check
73 * switch_pending again in case we were preempted and the
74 * switch to this mm was already done.
77 if (mm->context.switch_pending) {
78 mm->context.switch_pending = 0;
79 cpu_switch_mm(mm->pgd, mm);
81 preempt_enable_no_resched();
85 #endif /* CONFIG_MMU */
87 #define init_new_context(tsk,mm) 0
89 #endif /* CONFIG_CPU_HAS_ASID */
91 #define destroy_context(mm) do { } while(0)
92 #define activate_mm(prev,next) switch_mm(prev, next, NULL)
95 * This is called when "tsk" is about to enter lazy TLB mode.
97 * mm: describes the currently active mm context
98 * tsk: task which is entering lazy tlb
99 * cpu: cpu number which is entering lazy tlb
101 * tsk->mm will be NULL
104 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
109 * This is the actual mm switch as far as the scheduler
110 * is concerned. No registers are touched. We avoid
111 * calling the CPU specific function when the mm hasn't
115 switch_mm(struct mm_struct *prev, struct mm_struct *next,
116 struct task_struct *tsk)
119 unsigned int cpu = smp_processor_id();
122 /* check for possible thread migration */
123 if (!cpumask_empty(mm_cpumask(next)) &&
124 !cpumask_test_cpu(cpu, mm_cpumask(next)))
125 __flush_icache_all();
127 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
128 check_and_switch_context(next, tsk);
130 cpumask_clear_cpu(cpu, mm_cpumask(prev));
135 #define deactivate_mm(tsk,mm) do { } while (0)