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 <linux/spinlock.h>
9#include <asm-generic/mm_hooks.h>
10
11static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
12{
13}
14
15/* on PA-RISC, we actually have enough contexts to justify an allocator
16 * for them.  prumpf */
17
18extern unsigned long alloc_sid(void);
19extern void free_sid(unsigned long);
20
21static inline int
22init_new_context(struct task_struct *tsk, struct mm_struct *mm)
23{
24	BUG_ON(atomic_read(&mm->mm_users) != 1);
25
26	mm->context = alloc_sid();
27	return 0;
28}
29
30static inline void
31destroy_context(struct mm_struct *mm)
32{
33	free_sid(mm->context);
34	mm->context = 0;
35}
36
37static inline unsigned long __space_to_prot(mm_context_t context)
38{
39#if SPACEID_SHIFT == 0
40	return context << 1;
41#else
42	return context >> (SPACEID_SHIFT - 1);
43#endif
44}
45
46static inline void load_context(mm_context_t context)
47{
48	mtsp(context, 3);
49	mtctl(__space_to_prot(context), 8);
50}
51
52static inline void switch_mm_irqs_off(struct mm_struct *prev,
53		struct mm_struct *next, struct task_struct *tsk)
54{
55	if (prev != next) {
56#ifdef CONFIG_TLB_PTLOCK
57		/* put physical address of page_table_lock in cr28 (tr4)
58		   for TLB faults */
59		spinlock_t *pgd_lock = &next->page_table_lock;
60		mtctl(__pa(__ldcw_align(&pgd_lock->rlock.raw_lock)), 28);
61#endif
62		mtctl(__pa(next->pgd), 25);
63		load_context(next->context);
64	}
65}
66
67static inline void switch_mm(struct mm_struct *prev,
68		struct mm_struct *next, struct task_struct *tsk)
69{
70	unsigned long flags;
71
72	if (prev == next)
73		return;
74
75	local_irq_save(flags);
76	switch_mm_irqs_off(prev, next, tsk);
77	local_irq_restore(flags);
78}
79#define switch_mm_irqs_off switch_mm_irqs_off
80
81#define deactivate_mm(tsk,mm)	do { } while (0)
82
83static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
84{
85	/*
86	 * Activate_mm is our one chance to allocate a space id
87	 * for a new mm created in the exec path. There's also
88	 * some lazy tlb stuff, which is currently dead code, but
89	 * we only allocate a space id if one hasn't been allocated
90	 * already, so we should be OK.
91	 */
92
93	BUG_ON(next == &init_mm); /* Should never happen */
94
95	if (next->context == 0)
96	    next->context = alloc_sid();
97
98	switch_mm(prev,next,current);
99}
100#endif
101