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/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 	atomic_set(&mm->context.attach_count, 0);
22 	mm->context.flush_mm = 0;
23 	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
24 #ifdef CONFIG_64BIT
25 	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
26 #endif
27 	if (current->mm && current->mm->context.alloc_pgste) {
28 		/*
29 		 * alloc_pgste indicates, that any NEW context will be created
30 		 * with extended page tables. The old context is unchanged. The
31 		 * page table allocation and the page table operations will
32 		 * look at has_pgste to distinguish normal and extended page
33 		 * tables. The only way to create extended page tables is to
34 		 * set alloc_pgste and then create a new context (e.g. dup_mm).
35 		 * The page table allocation is called after init_new_context
36 		 * and if has_pgste is set, it will create extended page
37 		 * tables.
38 		 */
39 		mm->context.has_pgste = 1;
40 		mm->context.alloc_pgste = 1;
41 	} else {
42 		mm->context.has_pgste = 0;
43 		mm->context.alloc_pgste = 0;
44 	}
45 	mm->context.asce_limit = STACK_TOP_MAX;
46 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
47 	return 0;
48 }
49 
50 #define destroy_context(mm)             do { } while (0)
51 
52 #ifndef __s390x__
53 #define LCTL_OPCODE "lctl"
54 #else
55 #define LCTL_OPCODE "lctlg"
56 #endif
57 
58 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
59 {
60 	pgd_t *pgd = mm->pgd;
61 
62 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
63 	if (user_mode != HOME_SPACE_MODE) {
64 		/* Load primary space page table origin. */
65 		asm volatile(LCTL_OPCODE" 1,1,%0\n"
66 			     : : "m" (S390_lowcore.user_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 	atomic_dec(&prev->context.attach_count);
80 	WARN_ON(atomic_read(&prev->context.attach_count) < 0);
81 	atomic_inc(&next->context.attach_count);
82 	/* Check for TLBs not flushed yet */
83 	if (next->context.flush_mm)
84 		__tlb_flush_mm(next);
85 }
86 
87 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
88 #define deactivate_mm(tsk,mm)	do { } while (0)
89 
90 static inline void activate_mm(struct mm_struct *prev,
91                                struct mm_struct *next)
92 {
93         switch_mm(prev, next, current);
94 }
95 
96 #endif /* __S390_MMU_CONTEXT_H */
97