Loading...
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
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
22void __check_kvm_seq(struct mm_struct *mm);
23
24#ifdef CONFIG_CPU_HAS_ASID
25
26/*
27 * On ARMv6, we have the following structure in the Context ID:
28 *
29 * 31 7 0
30 * +-------------------------+-----------+
31 * | process ID | ASID |
32 * +-------------------------+-----------+
33 * | context ID |
34 * +-------------------------------------+
35 *
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.
39 */
40#define ASID_BITS 8
41#define ASID_MASK ((~0) << ASID_BITS)
42#define ASID_FIRST_VERSION (1 << ASID_BITS)
43
44extern unsigned int cpu_last_asid;
45#ifdef CONFIG_SMP
46DECLARE_PER_CPU(struct mm_struct *, current_mm);
47#endif
48
49void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
50void __new_context(struct mm_struct *mm);
51
52static inline void check_context(struct mm_struct *mm)
53{
54 /*
55 * This code is executed with interrupts enabled. Therefore,
56 * mm->context.id cannot be updated to the latest ASID version
57 * on a different CPU (and condition below not triggered)
58 * without first getting an IPI to reset the context. The
59 * alternative is to take a read_lock on mm->context.id_lock
60 * (after changing its type to rwlock_t).
61 */
62 if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
63 __new_context(mm);
64
65 if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
66 __check_kvm_seq(mm);
67}
68
69#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
70
71#else
72
73static inline void check_context(struct mm_struct *mm)
74{
75#ifdef CONFIG_MMU
76 if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
77 __check_kvm_seq(mm);
78#endif
79}
80
81#define init_new_context(tsk,mm) 0
82
83#endif
84
85#define destroy_context(mm) do { } while(0)
86
87/*
88 * This is called when "tsk" is about to enter lazy TLB mode.
89 *
90 * mm: describes the currently active mm context
91 * tsk: task which is entering lazy tlb
92 * cpu: cpu number which is entering lazy tlb
93 *
94 * tsk->mm will be NULL
95 */
96static inline void
97enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
98{
99}
100
101/*
102 * This is the actual mm switch as far as the scheduler
103 * is concerned. No registers are touched. We avoid
104 * calling the CPU specific function when the mm hasn't
105 * actually changed.
106 */
107static inline void
108switch_mm(struct mm_struct *prev, struct mm_struct *next,
109 struct task_struct *tsk)
110{
111#ifdef CONFIG_MMU
112 unsigned int cpu = smp_processor_id();
113
114#ifdef CONFIG_SMP
115 /* check for possible thread migration */
116 if (!cpumask_empty(mm_cpumask(next)) &&
117 !cpumask_test_cpu(cpu, mm_cpumask(next)))
118 __flush_icache_all();
119#endif
120 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
121#ifdef CONFIG_SMP
122 struct mm_struct **crt_mm = &per_cpu(current_mm, cpu);
123 *crt_mm = next;
124#endif
125 check_context(next);
126 cpu_switch_mm(next->pgd, next);
127 if (cache_is_vivt())
128 cpumask_clear_cpu(cpu, mm_cpumask(prev));
129 }
130#endif
131}
132
133#define deactivate_mm(tsk,mm) do { } while (0)
134#define activate_mm(prev,next) switch_mm(prev, next, NULL)
135
136/*
137 * We are inserting a "fake" vma for the user-accessible vector page so
138 * gdb and friends can get to it through ptrace and /proc/<pid>/mem.
139 * But we also want to remove it before the generic code gets to see it
140 * during process exit or the unmapping of it would cause total havoc.
141 * (the macro is used as remove_vma() is static to mm/mmap.c)
142 */
143#define arch_exit_mmap(mm) \
144do { \
145 struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
146 if (high_vma) { \
147 BUG_ON(high_vma->vm_next); /* it should be last */ \
148 if (high_vma->vm_prev) \
149 high_vma->vm_prev->vm_next = NULL; \
150 else \
151 mm->mmap = NULL; \
152 rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
153 mm->mmap_cache = NULL; \
154 mm->map_count--; \
155 remove_vma(high_vma); \
156 } \
157} while (0)
158
159static inline void arch_dup_mmap(struct mm_struct *oldmm,
160 struct mm_struct *mm)
161{
162}
163
164#endif