1 /*
2  *  S390 version
3  *
4  *  Derived from "include/asm-i386/mmu_context.h"
5  */
6 
7 #ifndef __S390_MMU_CONTEXT_H
8 #define __S390_MMU_CONTEXT_H
9 
10 #include <asm/pgalloc.h>
11 #include <asm/uaccess.h>
12 #include <asm/tlbflush.h>
13 #include <asm/ctl_reg.h>
14 
15 static inline int init_new_context(struct task_struct *tsk,
16 				   struct mm_struct *mm)
17 {
18 	atomic_set(&mm->context.attach_count, 0);
19 	mm->context.flush_mm = 0;
20 	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
21 #ifdef CONFIG_64BIT
22 	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
23 #endif
24 	mm->context.has_pgste = 0;
25 	mm->context.asce_limit = STACK_TOP_MAX;
26 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
27 	return 0;
28 }
29 
30 #define destroy_context(mm)             do { } while (0)
31 
32 #ifndef CONFIG_64BIT
33 #define LCTL_OPCODE "lctl"
34 #else
35 #define LCTL_OPCODE "lctlg"
36 #endif
37 
38 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
39 {
40 	pgd_t *pgd = mm->pgd;
41 
42 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
43 	if (s390_user_mode != HOME_SPACE_MODE) {
44 		/* Load primary space page table origin. */
45 		asm volatile(LCTL_OPCODE" 1,1,%0\n"
46 			     : : "m" (S390_lowcore.user_asce) );
47 	} else
48 		/* Load home space page table origin. */
49 		asm volatile(LCTL_OPCODE" 13,13,%0"
50 			     : : "m" (S390_lowcore.user_asce) );
51 	set_fs(current->thread.mm_segment);
52 }
53 
54 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
55 			     struct task_struct *tsk)
56 {
57 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
58 	update_mm(next, tsk);
59 	atomic_dec(&prev->context.attach_count);
60 	WARN_ON(atomic_read(&prev->context.attach_count) < 0);
61 	atomic_inc(&next->context.attach_count);
62 	/* Check for TLBs not flushed yet */
63 	__tlb_flush_mm_lazy(next);
64 }
65 
66 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
67 #define deactivate_mm(tsk,mm)	do { } while (0)
68 
69 static inline void activate_mm(struct mm_struct *prev,
70                                struct mm_struct *next)
71 {
72         switch_mm(prev, next, current);
73 }
74 
75 static inline void arch_dup_mmap(struct mm_struct *oldmm,
76 				 struct mm_struct *mm)
77 {
78 #ifdef CONFIG_64BIT
79 	if (oldmm->context.asce_limit < mm->context.asce_limit)
80 		crst_table_downgrade(mm, oldmm->context.asce_limit);
81 #endif
82 }
83 
84 static inline void arch_exit_mmap(struct mm_struct *mm)
85 {
86 }
87 
88 #endif /* __S390_MMU_CONTEXT_H */
89