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 	mm->context.compat_mm = test_thread_flag(TIF_31BIT);
29 #ifdef CONFIG_PGSTE
30 	mm->context.alloc_pgste = page_table_allocate_pgste ||
31 		test_thread_flag(TIF_PGSTE) ||
32 		(current->mm && current->mm->context.alloc_pgste);
33 	mm->context.has_pgste = 0;
34 	mm->context.uses_skeys = 0;
35 	mm->context.uses_cmm = 0;
36 	mm->context.allow_gmap_hpage_1m = 0;
37 #endif
38 	switch (mm->context.asce_limit) {
39 	case _REGION2_SIZE:
40 		/*
41 		 * forked 3-level task, fall through to set new asce with new
42 		 * mm->pgd
43 		 */
44 	case 0:
45 		/* context created by exec, set asce limit to 4TB */
46 		mm->context.asce_limit = STACK_TOP_MAX;
47 		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
48 				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
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 	}
65 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
66 	return 0;
67 }
68 
69 #define destroy_context(mm)             do { } while (0)
70 
71 static inline void set_user_asce(struct mm_struct *mm)
72 {
73 	S390_lowcore.user_asce = mm->context.asce;
74 	__ctl_load(S390_lowcore.user_asce, 1, 1);
75 	clear_cpu_flag(CIF_ASCE_PRIMARY);
76 }
77 
78 static inline void clear_user_asce(void)
79 {
80 	S390_lowcore.user_asce = S390_lowcore.kernel_asce;
81 	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
82 	set_cpu_flag(CIF_ASCE_PRIMARY);
83 }
84 
85 mm_segment_t enable_sacf_uaccess(void);
86 void disable_sacf_uaccess(mm_segment_t old_fs);
87 
88 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
89 			     struct task_struct *tsk)
90 {
91 	int cpu = smp_processor_id();
92 
93 	S390_lowcore.user_asce = next->context.asce;
94 	cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
95 	/* Clear previous user-ASCE from CR1 and CR7 */
96 	if (!test_cpu_flag(CIF_ASCE_PRIMARY)) {
97 		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
98 		set_cpu_flag(CIF_ASCE_PRIMARY);
99 	}
100 	if (test_cpu_flag(CIF_ASCE_SECONDARY)) {
101 		__ctl_load(S390_lowcore.vdso_asce, 7, 7);
102 		clear_cpu_flag(CIF_ASCE_SECONDARY);
103 	}
104 	if (prev != next)
105 		cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
106 }
107 
108 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
109 static inline void finish_arch_post_lock_switch(void)
110 {
111 	struct task_struct *tsk = current;
112 	struct mm_struct *mm = tsk->mm;
113 
114 	if (mm) {
115 		preempt_disable();
116 		while (atomic_read(&mm->context.flush_count))
117 			cpu_relax();
118 		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
119 		__tlb_flush_mm_lazy(mm);
120 		preempt_enable();
121 	}
122 	set_fs(current->thread.mm_segment);
123 }
124 
125 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
126 #define deactivate_mm(tsk,mm)	do { } while (0)
127 
128 static inline void activate_mm(struct mm_struct *prev,
129                                struct mm_struct *next)
130 {
131 	switch_mm(prev, next, current);
132 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
133 	set_user_asce(next);
134 }
135 
136 #endif /* __S390_MMU_CONTEXT_H */
137