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
18static 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
58static 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
74static 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
90static 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