Merge tag 'nfs-for-4.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs
[sfrench/cifs-2.6.git] / arch / s390 / include / asm / mmu_context.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *  S390 version
4  *
5  *  Derived from "include/asm-i386/mmu_context.h"
6  */
7
8 #ifndef __S390_MMU_CONTEXT_H
9 #define __S390_MMU_CONTEXT_H
10
11 #include <asm/pgalloc.h>
12 #include <linux/uaccess.h>
13 #include <linux/mm_types.h>
14 #include <asm/tlbflush.h>
15 #include <asm/ctl_reg.h>
16 #include <asm-generic/mm_hooks.h>
17
18 static inline int init_new_context(struct task_struct *tsk,
19                                    struct mm_struct *mm)
20 {
21         spin_lock_init(&mm->context.lock);
22         INIT_LIST_HEAD(&mm->context.pgtable_list);
23         INIT_LIST_HEAD(&mm->context.gmap_list);
24         cpumask_clear(&mm->context.cpu_attach_mask);
25         atomic_set(&mm->context.flush_count, 0);
26         mm->context.gmap_asce = 0;
27         mm->context.flush_mm = 0;
28 #ifdef CONFIG_PGSTE
29         mm->context.alloc_pgste = page_table_allocate_pgste ||
30                 test_thread_flag(TIF_PGSTE) ||
31                 current->mm->context.alloc_pgste;
32         mm->context.has_pgste = 0;
33         mm->context.use_skey = 0;
34         mm->context.use_cmma = 0;
35 #endif
36         switch (mm->context.asce_limit) {
37         case _REGION2_SIZE:
38                 /*
39                  * forked 3-level task, fall through to set new asce with new
40                  * mm->pgd
41                  */
42         case 0:
43                 /* context created by exec, set asce limit to 4TB */
44                 mm->context.asce_limit = STACK_TOP_MAX;
45                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
46                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
47                 /* pgd_alloc() did not account this pud */
48                 mm_inc_nr_puds(mm);
49                 break;
50         case -PAGE_SIZE:
51                 /* forked 5-level task, set new asce with new_mm->pgd */
52                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
53                         _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
54                 break;
55         case _REGION1_SIZE:
56                 /* forked 4-level task, set new asce with new mm->pgd */
57                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
58                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
59                 break;
60         case _REGION3_SIZE:
61                 /* forked 2-level compat task, set new asce with new mm->pgd */
62                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
63                                    _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
64                 /* pgd_alloc() did not account this pmd */
65                 mm_inc_nr_pmds(mm);
66         }
67         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
68         return 0;
69 }
70
71 #define destroy_context(mm)             do { } while (0)
72
73 static inline void set_user_asce(struct mm_struct *mm)
74 {
75         S390_lowcore.user_asce = mm->context.asce;
76         if (current->thread.mm_segment.ar4)
77                 __ctl_load(S390_lowcore.user_asce, 7, 7);
78         set_cpu_flag(CIF_ASCE_PRIMARY);
79 }
80
81 static inline void clear_user_asce(void)
82 {
83         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
84
85         __ctl_load(S390_lowcore.user_asce, 1, 1);
86         __ctl_load(S390_lowcore.user_asce, 7, 7);
87 }
88
89 static inline void load_kernel_asce(void)
90 {
91         unsigned long asce;
92
93         __ctl_store(asce, 1, 1);
94         if (asce != S390_lowcore.kernel_asce)
95                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
96         set_cpu_flag(CIF_ASCE_PRIMARY);
97 }
98
99 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
100                              struct task_struct *tsk)
101 {
102         int cpu = smp_processor_id();
103
104         S390_lowcore.user_asce = next->context.asce;
105         if (prev == next)
106                 return;
107         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
108         /* Clear old ASCE by loading the kernel ASCE. */
109         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
110         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
111         cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
112 }
113
114 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
115 static inline void finish_arch_post_lock_switch(void)
116 {
117         struct task_struct *tsk = current;
118         struct mm_struct *mm = tsk->mm;
119
120         load_kernel_asce();
121         if (mm) {
122                 preempt_disable();
123                 while (atomic_read(&mm->context.flush_count))
124                         cpu_relax();
125                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
126                 __tlb_flush_mm_lazy(mm);
127                 preempt_enable();
128         }
129         set_fs(current->thread.mm_segment);
130 }
131
132 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
133 #define deactivate_mm(tsk,mm)   do { } while (0)
134
135 static inline void activate_mm(struct mm_struct *prev,
136                                struct mm_struct *next)
137 {
138         switch_mm(prev, next, current);
139         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
140         set_user_asce(next);
141 }
142
143 #endif /* __S390_MMU_CONTEXT_H */