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