summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/mmu_context_hash64.c
blob: 178876aef40f8d6dd5d69b650e986225e0ddfb70 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
 *  MMU context allocation for 64-bit kernels.
 *
 *  Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/slab.h>

#include <asm/mmu_context.h>
#include <asm/pgalloc.h>

#include "icswx.h"

static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDA(mmu_context_ida);

int __init_new_context(void)
{
	int index;
	int err;

again:
	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
		return -ENOMEM;

	spin_lock(&mmu_context_lock);
	err = ida_get_new_above(&mmu_context_ida, 1, &index);
	spin_unlock(&mmu_context_lock);

	if (err == -EAGAIN)
		goto again;
	else if (err)
		return err;

	if (index > MAX_USER_CONTEXT) {
		spin_lock(&mmu_context_lock);
		ida_remove(&mmu_context_ida, index);
		spin_unlock(&mmu_context_lock);
		return -ENOMEM;
	}

	return index;
}
EXPORT_SYMBOL_GPL(__init_new_context);

int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
	int index;

	index = __init_new_context();
	if (index < 0)
		return index;

	/* The old code would re-promote on fork, we don't do that
	 * when using slices as it could cause problem promoting slices
	 * that have been forced down to 4K
	 */
	if (slice_mm_new_context(mm))
		slice_set_user_psize(mm, mmu_virtual_psize);
	subpage_prot_init_new_context(mm);
	mm->context.id = index;
#ifdef CONFIG_PPC_ICSWX
	mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
	if (!mm->context.cop_lockp) {
		__destroy_context(index);
		subpage_prot_free(mm);
		mm->context.id = MMU_NO_CONTEXT;
		return -ENOMEM;
	}
	spin_lock_init(mm->context.cop_lockp);
#endif /* CONFIG_PPC_ICSWX */

#ifdef CONFIG_PPC_64K_PAGES
	mm->context.pte_frag = NULL;
#endif
	return 0;
}

void __destroy_context(int context_id)
{
	spin_lock(&mmu_context_lock);
	ida_remove(&mmu_context_ida, context_id);
	spin_unlock(&mmu_context_lock);
}
EXPORT_SYMBOL_GPL(__destroy_context);

#ifdef CONFIG_PPC_64K_PAGES
static void destroy_pagetable_page(struct mm_struct *mm)
{
	int count;
	void *pte_frag;
	struct page *page;

	pte_frag = mm->context.pte_frag;
	if (!pte_frag)
		return;

	page = virt_to_page(pte_frag);
	/* drop all the pending references */
	count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
	/* We allow PTE_FRAG_NR fragments from a PTE page */
	count = atomic_sub_return(PTE_FRAG_NR - count, &page->_count);
	if (!count) {
		pgtable_page_dtor(page);
		free_hot_cold_page(page, 0);
	}
}

#else
static inline void destroy_pagetable_page(struct mm_struct *mm)
{
	return;
}
#endif


void destroy_context(struct mm_struct *mm)
{

#ifdef CONFIG_PPC_ICSWX
	drop_cop(mm->context.acop, mm);
	kfree(mm->context.cop_lockp);
	mm->context.cop_lockp = NULL;
#endif /* CONFIG_PPC_ICSWX */

	destroy_pagetable_page(mm);
	__destroy_context(mm->context.id);
	subpage_prot_free(mm);
	mm->context.id = MMU_NO_CONTEXT;
}
OpenPOWER on IntegriCloud