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_SIMPLE_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 | mutex_lock(&cma->lock); |
40 | /* pages counter is smaller than sizeof(int) */ |
41 | used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma)); |
42 | mutex_unlock(&cma->lock); |
43 | *val = (u64)used << cma->order_per_bit; |
44 | |
45 | return 0; |
46 | } |
47 | DEFINE_SIMPLE_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 | mutex_lock(&cma->lock); |
57 | for (;;) { |
58 | start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end); |
59 | if (start >= cma->count) |
60 | break; |
61 | end = find_next_bit(cma->bitmap, bitmap_maxno, start); |
62 | maxchunk = max(end - start, maxchunk); |
63 | } |
64 | mutex_unlock(&cma->lock); |
65 | *val = (u64)maxchunk << cma->order_per_bit; |
66 | |
67 | return 0; |
68 | } |
69 | DEFINE_SIMPLE_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_SIMPLE_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_SIMPLE_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 | char name[16]; |
167 | int u32s; |
168 | |
169 | scnprintf(name, sizeof(name), "cma-%s" , cma->name); |
170 | |
171 | tmp = debugfs_create_dir(name, root_dentry); |
172 | |
173 | debugfs_create_file("alloc" , 0200, tmp, cma, &cma_alloc_fops); |
174 | debugfs_create_file("free" , 0200, tmp, cma, &cma_free_fops); |
175 | debugfs_create_file("base_pfn" , 0444, tmp, |
176 | &cma->base_pfn, &cma_debugfs_fops); |
177 | debugfs_create_file("count" , 0444, tmp, &cma->count, &cma_debugfs_fops); |
178 | debugfs_create_file("order_per_bit" , 0444, tmp, |
179 | &cma->order_per_bit, &cma_debugfs_fops); |
180 | debugfs_create_file("used" , 0444, tmp, cma, &cma_used_fops); |
181 | debugfs_create_file("maxchunk" , 0444, tmp, cma, &cma_maxchunk_fops); |
182 | |
183 | u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32)); |
184 | debugfs_create_u32_array("bitmap" , 0444, tmp, (u32 *)cma->bitmap, u32s); |
185 | } |
186 | |
187 | static int __init cma_debugfs_init(void) |
188 | { |
189 | struct dentry *cma_debugfs_root; |
190 | int i; |
191 | |
192 | cma_debugfs_root = debugfs_create_dir("cma" , NULL); |
193 | |
194 | for (i = 0; i < cma_area_count; i++) |
195 | cma_debugfs_add_one(&cma_areas[i], cma_debugfs_root); |
196 | |
197 | return 0; |
198 | } |
199 | late_initcall(cma_debugfs_init); |
200 | |