1 /*
2  *  include/asm-s390/mmu_context.h
3  *
4  *  S390 version
5  *
6  *  Derived from "include/asm-i386/mmu_context.h"
7  */
8 
9 #ifndef __S390_MMU_CONTEXT_H
10 #define __S390_MMU_CONTEXT_H
11 
12 #include <asm/pgalloc.h>
13 #include <asm/uaccess.h>
14 #include <asm-generic/mm_hooks.h>
15 
16 static inline int init_new_context(struct task_struct *tsk,
17 				   struct mm_struct *mm)
18 {
19 	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
20 #ifdef CONFIG_64BIT
21 	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
22 #endif
23 	if (current->mm->context.alloc_pgste) {
24 		/*
25 		 * alloc_pgste indicates, that any NEW context will be created
26 		 * with extended page tables. The old context is unchanged. The
27 		 * page table allocation and the page table operations will
28 		 * look at has_pgste to distinguish normal and extended page
29 		 * tables. The only way to create extended page tables is to
30 		 * set alloc_pgste and then create a new context (e.g. dup_mm).
31 		 * The page table allocation is called after init_new_context
32 		 * and if has_pgste is set, it will create extended page
33 		 * tables.
34 		 */
35 		mm->context.noexec = 0;
36 		mm->context.has_pgste = 1;
37 		mm->context.alloc_pgste = 1;
38 	} else {
39 		mm->context.noexec = (user_mode == SECONDARY_SPACE_MODE);
40 		mm->context.has_pgste = 0;
41 		mm->context.alloc_pgste = 0;
42 	}
43 	mm->context.asce_limit = STACK_TOP_MAX;
44 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
45 	return 0;
46 }
47 
48 #define destroy_context(mm)             do { } while (0)
49 
50 #ifndef __s390x__
51 #define LCTL_OPCODE "lctl"
52 #else
53 #define LCTL_OPCODE "lctlg"
54 #endif
55 
56 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
57 {
58 	pgd_t *pgd = mm->pgd;
59 
60 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
61 	if (user_mode != HOME_SPACE_MODE) {
62 		/* Load primary space page table origin. */
63 		pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
64 		S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
65 		asm volatile(LCTL_OPCODE" 1,1,%0\n"
66 			     : : "m" (S390_lowcore.user_exec_asce) );
67 	} else
68 		/* Load home space page table origin. */
69 		asm volatile(LCTL_OPCODE" 13,13,%0"
70 			     : : "m" (S390_lowcore.user_asce) );
71 	set_fs(current->thread.mm_segment);
72 }
73 
74 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
75 			     struct task_struct *tsk)
76 {
77 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
78 	update_mm(next, tsk);
79 }
80 
81 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
82 #define deactivate_mm(tsk,mm)	do { } while (0)
83 
84 static inline void activate_mm(struct mm_struct *prev,
85                                struct mm_struct *next)
86 {
87         switch_mm(prev, next, current);
88 }
89 
90 #endif /* __S390_MMU_CONTEXT_H */
91