1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * CMA DebugFS Interface
4 *
5 * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
6 */
7
8
9 #include <linux/debugfs.h>
10 #include <linux/cma.h>
11 #include <linux/list.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/mm_types.h>
15
16 #include "cma.h"
17
18 struct cma_mem {
19 struct hlist_node node;
20 struct page *p;
21 unsigned long n;
22 };
23
24 static struct dentry *cma_debugfs_root;
25
cma_debugfs_get(void * data,u64 * val)26 static int cma_debugfs_get(void *data, u64 *val)
27 {
28 unsigned long *p = data;
29
30 *val = *p;
31
32 return 0;
33 }
34 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
35
cma_used_get(void * data,u64 * val)36 static int cma_used_get(void *data, u64 *val)
37 {
38 struct cma *cma = data;
39 unsigned long used;
40
41 mutex_lock(&cma->lock);
42 /* pages counter is smaller than sizeof(int) */
43 used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma));
44 mutex_unlock(&cma->lock);
45 *val = (u64)used << cma->order_per_bit;
46
47 return 0;
48 }
49 DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
50
cma_maxchunk_get(void * data,u64 * val)51 static int cma_maxchunk_get(void *data, u64 *val)
52 {
53 struct cma *cma = data;
54 unsigned long maxchunk = 0;
55 unsigned long start, end = 0;
56 unsigned long bitmap_maxno = cma_bitmap_maxno(cma);
57
58 mutex_lock(&cma->lock);
59 for (;;) {
60 start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
61 if (start >= cma->count)
62 break;
63 end = find_next_bit(cma->bitmap, bitmap_maxno, start);
64 maxchunk = max(end - start, maxchunk);
65 }
66 mutex_unlock(&cma->lock);
67 *val = (u64)maxchunk << cma->order_per_bit;
68
69 return 0;
70 }
71 DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
72
cma_add_to_cma_mem_list(struct cma * cma,struct cma_mem * mem)73 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
74 {
75 spin_lock(&cma->mem_head_lock);
76 hlist_add_head(&mem->node, &cma->mem_head);
77 spin_unlock(&cma->mem_head_lock);
78 }
79
cma_get_entry_from_list(struct cma * cma)80 static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
81 {
82 struct cma_mem *mem = NULL;
83
84 spin_lock(&cma->mem_head_lock);
85 if (!hlist_empty(&cma->mem_head)) {
86 mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
87 hlist_del_init(&mem->node);
88 }
89 spin_unlock(&cma->mem_head_lock);
90
91 return mem;
92 }
93
cma_free_mem(struct cma * cma,int count)94 static int cma_free_mem(struct cma *cma, int count)
95 {
96 struct cma_mem *mem = NULL;
97
98 while (count) {
99 mem = cma_get_entry_from_list(cma);
100 if (mem == NULL)
101 return 0;
102
103 if (mem->n <= count) {
104 cma_release(cma, mem->p, mem->n);
105 count -= mem->n;
106 kfree(mem);
107 } else if (cma->order_per_bit == 0) {
108 cma_release(cma, mem->p, count);
109 mem->p += count;
110 mem->n -= count;
111 count = 0;
112 cma_add_to_cma_mem_list(cma, mem);
113 } else {
114 pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
115 cma_add_to_cma_mem_list(cma, mem);
116 break;
117 }
118 }
119
120 return 0;
121
122 }
123
cma_free_write(void * data,u64 val)124 static int cma_free_write(void *data, u64 val)
125 {
126 int pages = val;
127 struct cma *cma = data;
128
129 return cma_free_mem(cma, pages);
130 }
131 DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
132
cma_alloc_mem(struct cma * cma,int count)133 static int cma_alloc_mem(struct cma *cma, int count)
134 {
135 struct cma_mem *mem;
136 struct page *p;
137
138 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
139 if (!mem)
140 return -ENOMEM;
141
142 p = cma_alloc(cma, count, 0, false);
143 if (!p) {
144 kfree(mem);
145 return -ENOMEM;
146 }
147
148 mem->p = p;
149 mem->n = count;
150
151 cma_add_to_cma_mem_list(cma, mem);
152
153 return 0;
154 }
155
cma_alloc_write(void * data,u64 val)156 static int cma_alloc_write(void *data, u64 val)
157 {
158 int pages = val;
159 struct cma *cma = data;
160
161 return cma_alloc_mem(cma, pages);
162 }
163 DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
164
cma_debugfs_add_one(struct cma * cma,int idx)165 static void cma_debugfs_add_one(struct cma *cma, int idx)
166 {
167 struct dentry *tmp;
168 char name[16];
169 int u32s;
170
171 scnprintf(name, sizeof(name), "cma-%s", cma->name);
172
173 tmp = debugfs_create_dir(name, cma_debugfs_root);
174
175 debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
176 debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
177 debugfs_create_file("base_pfn", 0444, tmp,
178 &cma->base_pfn, &cma_debugfs_fops);
179 debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops);
180 debugfs_create_file("order_per_bit", 0444, tmp,
181 &cma->order_per_bit, &cma_debugfs_fops);
182 debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops);
183 debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops);
184
185 u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
186 debugfs_create_u32_array("bitmap", 0444, tmp, (u32 *)cma->bitmap, u32s);
187 }
188
cma_debugfs_init(void)189 static int __init cma_debugfs_init(void)
190 {
191 int i;
192
193 cma_debugfs_root = debugfs_create_dir("cma", NULL);
194 if (!cma_debugfs_root)
195 return -ENOMEM;
196
197 for (i = 0; i < cma_area_count; i++)
198 cma_debugfs_add_one(&cma_areas[i], i);
199
200 return 0;
201 }
202 late_initcall(cma_debugfs_init);
203
