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