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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
| // SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 Google LLC
* Author: Quentin Perret <qperret@google.com>
*/
#include <asm/kvm_hyp.h>
#include <nvhe/gfp.h>
u64 __hyp_vmemmap;
/*
* Example buddy-tree for a 4-pages physically contiguous pool:
*
* o : Page 3
* /
* o-o : Page 2
* /
* / o : Page 1
* / /
* o---o-o : Page 0
* Order 2 1 0
*
* Example of requests on this zon:
* __find_buddy(pool, page 0, order 0) => page 1
* __find_buddy(pool, page 0, order 1) => page 2
* __find_buddy(pool, page 1, order 0) => page 0
* __find_buddy(pool, page 2, order 0) => page 3
*/
static struct hyp_page *__find_buddy(struct hyp_pool *pool, struct hyp_page *p,
unsigned int order)
{
phys_addr_t addr = hyp_page_to_phys(p);
addr ^= (PAGE_SIZE << order);
if (addr < pool->range_start || addr >= pool->range_end)
return NULL;
return hyp_phys_to_page(addr);
}
static void __hyp_attach_page(struct hyp_pool *pool,
struct hyp_page *p)
{
unsigned int order = p->order;
struct hyp_page *buddy;
p->order = HYP_NO_ORDER;
for (; order < HYP_MAX_ORDER; order++) {
/* Nothing to do if the buddy isn't in a free-list */
buddy = __find_buddy(pool, p, order);
if (!buddy || list_empty(&buddy->node) || buddy->order != order)
break;
/* Otherwise, coalesce the buddies and go one level up */
list_del_init(&buddy->node);
buddy->order = HYP_NO_ORDER;
p = (p < buddy) ? p : buddy;
}
p->order = order;
list_add_tail(&p->node, &pool->free_area[order]);
}
void hyp_put_page(void *addr)
{
struct hyp_page *p = hyp_virt_to_page(addr);
struct hyp_pool *pool = hyp_page_to_pool(p);
hyp_spin_lock(&pool->lock);
if (!p->refcount)
hyp_panic();
p->refcount--;
if (!p->refcount)
__hyp_attach_page(pool, p);
hyp_spin_unlock(&pool->lock);
}
void hyp_get_page(void *addr)
{
struct hyp_page *p = hyp_virt_to_page(addr);
struct hyp_pool *pool = hyp_page_to_pool(p);
hyp_spin_lock(&pool->lock);
p->refcount++;
hyp_spin_unlock(&pool->lock);
}
/* Extract a page from the buddy tree, at a specific order */
static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool,
struct hyp_page *p,
unsigned int order)
{
struct hyp_page *buddy;
if (p->order == HYP_NO_ORDER || p->order < order)
return NULL;
list_del_init(&p->node);
/* Split the page in two until reaching the requested order */
while (p->order > order) {
p->order--;
buddy = __find_buddy(pool, p, p->order);
buddy->order = p->order;
list_add_tail(&buddy->node, &pool->free_area[buddy->order]);
}
p->refcount = 1;
return p;
}
static void clear_hyp_page(struct hyp_page *p)
{
unsigned long i;
for (i = 0; i < (1 << p->order); i++)
clear_page(hyp_page_to_virt(p) + (i << PAGE_SHIFT));
}
static void *__hyp_alloc_pages(struct hyp_pool *pool, gfp_t mask,
unsigned int order)
{
unsigned int i = order;
struct hyp_page *p;
/* Look for a high-enough-order page */
while (i <= HYP_MAX_ORDER && list_empty(&pool->free_area[i]))
i++;
if (i > HYP_MAX_ORDER)
return NULL;
/* Extract it from the tree at the right order */
p = list_first_entry(&pool->free_area[i], struct hyp_page, node);
p = __hyp_extract_page(pool, p, order);
if (mask & HYP_GFP_ZERO)
clear_hyp_page(p);
return p;
}
void *hyp_alloc_pages(struct hyp_pool *pool, gfp_t mask, unsigned int order)
{
struct hyp_page *p;
hyp_spin_lock(&pool->lock);
p = __hyp_alloc_pages(pool, mask, order);
hyp_spin_unlock(&pool->lock);
return p ? hyp_page_to_virt(p) : NULL;
}
/* hyp_vmemmap must be backed beforehand */
int hyp_pool_init(struct hyp_pool *pool, phys_addr_t phys,
unsigned int nr_pages, unsigned int used_pages)
{
struct hyp_page *p;
int i;
if (phys % PAGE_SIZE)
return -EINVAL;
hyp_spin_lock_init(&pool->lock);
for (i = 0; i <= HYP_MAX_ORDER; i++)
INIT_LIST_HEAD(&pool->free_area[i]);
pool->range_start = phys;
pool->range_end = phys + (nr_pages << PAGE_SHIFT);
/* Init the vmemmap portion */
p = hyp_phys_to_page(phys);
memset(p, 0, sizeof(*p) * nr_pages);
for (i = 0; i < nr_pages; i++, p++) {
p->pool = pool;
INIT_LIST_HEAD(&p->node);
}
/* Attach the unused pages to the buddy tree */
p = hyp_phys_to_page(phys + (used_pages << PAGE_SHIFT));
for (i = used_pages; i < nr_pages; i++, p++)
__hyp_attach_page(pool, p);
return 0;
}
|