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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __PARISC_MMU_CONTEXT_H
3#define __PARISC_MMU_CONTEXT_H
4
5#include <linux/mm.h>
6#include <linux/sched.h>
7#include <linux/atomic.h>
8#include <asm-generic/mm_hooks.h>
9
10static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
11{
12}
13
14/* on PA-RISC, we actually have enough contexts to justify an allocator
15 * for them. prumpf */
16
17extern unsigned long alloc_sid(void);
18extern void free_sid(unsigned long);
19
20static inline int
21init_new_context(struct task_struct *tsk, struct mm_struct *mm)
22{
23 BUG_ON(atomic_read(&mm->mm_users) != 1);
24
25 mm->context = alloc_sid();
26 return 0;
27}
28
29static inline void
30destroy_context(struct mm_struct *mm)
31{
32 free_sid(mm->context);
33 mm->context = 0;
34}
35
36static inline unsigned long __space_to_prot(mm_context_t context)
37{
38#if SPACEID_SHIFT == 0
39 return context << 1;
40#else
41 return context >> (SPACEID_SHIFT - 1);
42#endif
43}
44
45static inline void load_context(mm_context_t context)
46{
47 mtsp(context, 3);
48 mtctl(__space_to_prot(context), 8);
49}
50
51static inline void switch_mm_irqs_off(struct mm_struct *prev,
52 struct mm_struct *next, struct task_struct *tsk)
53{
54 if (prev != next) {
55 mtctl(__pa(next->pgd), 25);
56 load_context(next->context);
57 }
58}
59
60static inline void switch_mm(struct mm_struct *prev,
61 struct mm_struct *next, struct task_struct *tsk)
62{
63 unsigned long flags;
64
65 if (prev == next)
66 return;
67
68 local_irq_save(flags);
69 switch_mm_irqs_off(prev, next, tsk);
70 local_irq_restore(flags);
71}
72#define switch_mm_irqs_off switch_mm_irqs_off
73
74#define deactivate_mm(tsk,mm) do { } while (0)
75
76static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
77{
78 /*
79 * Activate_mm is our one chance to allocate a space id
80 * for a new mm created in the exec path. There's also
81 * some lazy tlb stuff, which is currently dead code, but
82 * we only allocate a space id if one hasn't been allocated
83 * already, so we should be OK.
84 */
85
86 BUG_ON(next == &init_mm); /* Should never happen */
87
88 if (next->context == 0)
89 next->context = alloc_sid();
90
91 switch_mm(prev,next,current);
92}
93#endif