summaryrefslogtreecommitdiff
path: root/arch/s390/include/asm/mmu_context.h
blob: f77c638bf3974063a941b5d9b8e537a2c7cfb1a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/*
 *  S390 version
 *
 *  Derived from "include/asm-i386/mmu_context.h"
 */

#ifndef __S390_MMU_CONTEXT_H
#define __S390_MMU_CONTEXT_H

#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>
#include <asm/ctl_reg.h>

static inline int init_new_context(struct task_struct *tsk,
				   struct mm_struct *mm)
{
	spin_lock_init(&mm->context.list_lock);
	INIT_LIST_HEAD(&mm->context.pgtable_list);
	INIT_LIST_HEAD(&mm->context.gmap_list);
	cpumask_clear(&mm->context.cpu_attach_mask);
	atomic_set(&mm->context.flush_count, 0);
	mm->context.flush_mm = 0;
#ifdef CONFIG_PGSTE
	mm->context.alloc_pgste = page_table_allocate_pgste;
	mm->context.has_pgste = 0;
	mm->context.use_skey = 0;
#endif
	switch (mm->context.asce_limit) {
	case 1UL << 42:
		/*
		 * forked 3-level task, fall through to set new asce with new
		 * mm->pgd
		 */
	case 0:
		/* context created by exec, set asce limit to 4TB */
		mm->context.asce_limit = STACK_TOP_MAX;
		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
		break;
	case 1UL << 53:
		/* forked 4-level task, set new asce with new mm->pgd */
		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
				   _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
		break;
	case 1UL << 31:
		/* forked 2-level compat task, set new asce with new mm->pgd */
		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
				   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
		/* pgd_alloc() did not increase mm->nr_pmds */
		mm_inc_nr_pmds(mm);
	}
	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
	return 0;
}

#define destroy_context(mm)             do { } while (0)

static inline void set_user_asce(struct mm_struct *mm)
{
	S390_lowcore.user_asce = mm->context.asce;
	if (current->thread.mm_segment.ar4)
		__ctl_load(S390_lowcore.user_asce, 7, 7);
	set_cpu_flag(CIF_ASCE);
}

static inline void clear_user_asce(void)
{
	S390_lowcore.user_asce = S390_lowcore.kernel_asce;

	__ctl_load(S390_lowcore.user_asce, 1, 1);
	__ctl_load(S390_lowcore.user_asce, 7, 7);
}

static inline void load_kernel_asce(void)
{
	unsigned long asce;

	__ctl_store(asce, 1, 1);
	if (asce != S390_lowcore.kernel_asce)
		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
	set_cpu_flag(CIF_ASCE);
}

static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
			     struct task_struct *tsk)
{
	int cpu = smp_processor_id();

	S390_lowcore.user_asce = next->context.asce;
	if (prev == next)
		return;
	cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
	cpumask_set_cpu(cpu, mm_cpumask(next));
	/* Clear old ASCE by loading the kernel ASCE. */
	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
	cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
}

#define finish_arch_post_lock_switch finish_arch_post_lock_switch
static inline void finish_arch_post_lock_switch(void)
{
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->mm;

	load_kernel_asce();
	if (mm) {
		preempt_disable();
		while (atomic_read(&mm->context.flush_count))
			cpu_relax();

		if (mm->context.flush_mm)
			__tlb_flush_mm(mm);
		preempt_enable();
	}
	set_fs(current->thread.mm_segment);
}

#define enter_lazy_tlb(mm,tsk)	do { } while (0)
#define deactivate_mm(tsk,mm)	do { } while (0)

static inline void activate_mm(struct mm_struct *prev,
                               struct mm_struct *next)
{
	switch_mm(prev, next, current);
	set_user_asce(next);
}

static inline void arch_dup_mmap(struct mm_struct *oldmm,
				 struct mm_struct *mm)
{
}

static inline void arch_exit_mmap(struct mm_struct *mm)
{
}

static inline void arch_unmap(struct mm_struct *mm,
			struct vm_area_struct *vma,
			unsigned long start, unsigned long end)
{
}

static inline void arch_bprm_mm_init(struct mm_struct *mm,
				     struct vm_area_struct *vma)
{
}

static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
		bool write, bool execute, bool foreign)
{
	/* by default, allow everything */
	return true;
}

static inline bool arch_pte_access_permitted(pte_t pte, bool write)
{
	/* by default, allow everything */
	return true;
}
#endif /* __S390_MMU_CONTEXT_H */