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 <asm/cacheflush.h>
18 #include <asm/cachetype.h>
19 #include <asm/proc-fns.h>
20 #include <asm-generic/mm_hooks.h>
22 void __check_kvm_seq(struct mm_struct *mm);
24 #ifdef CONFIG_CPU_HAS_ASID
27 * On ARMv6, we have the following structure in the Context ID:
30 * +-------------------------+-----------+
31 * | process ID | ASID |
32 * +-------------------------+-----------+
34 * +-------------------------------------+
36 * The ASID is used to tag entries in the CPU caches and TLBs.
37 * The context ID is used by debuggers and trace logic, and
38 * should be unique within all running processes.
41 #define ASID_MASK ((~0) << ASID_BITS)
42 #define ASID_FIRST_VERSION (1 << ASID_BITS)
44 extern unsigned int cpu_last_asid;
46 void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
47 void __new_context(struct mm_struct *mm);
49 static inline void check_context(struct mm_struct *mm)
51 if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
54 if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
58 #define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
62 static inline void check_context(struct mm_struct *mm)
64 if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
68 #define init_new_context(tsk,mm) 0
72 #define destroy_context(mm) do { } while(0)
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 (!cpus_empty(next->cpu_vm_mask) && !cpu_isset(cpu, next->cpu_vm_mask))
104 __flush_icache_all();
106 if (!cpu_test_and_set(cpu, next->cpu_vm_mask) || prev != next) {
108 cpu_switch_mm(next->pgd, next);
110 cpu_clear(cpu, prev->cpu_vm_mask);
115 #define deactivate_mm(tsk,mm) do { } while (0)
116 #define activate_mm(prev,next) switch_mm(prev, next, NULL)