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
18struct cma_mem {
19 struct hlist_node node;
20 struct page *p;
21 unsigned long n;
22};
23
24static int cma_debugfs_get(void *data, u64 *val)
25{
26 unsigned long *p = data;
27
28 *val = *p;
29
30 return 0;
31}
32DEFINE_DEBUGFS_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
33
34static int cma_used_get(void *data, u64 *val)
35{
36 struct cma *cma = data;
37
38 spin_lock_irq(lock: &cma->lock);
39 *val = cma->count - cma->available_count;
40 spin_unlock_irq(lock: &cma->lock);
41
42 return 0;
43}
44DEFINE_DEBUGFS_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
45
46static int cma_maxchunk_get(void *data, u64 *val)
47{
48 struct cma *cma = data;
49 struct cma_memrange *cmr;
50 unsigned long maxchunk = 0;
51 unsigned long start, end;
52 unsigned long bitmap_maxno;
53 int r;
54
55 spin_lock_irq(lock: &cma->lock);
56 for (r = 0; r < cma->nranges; r++) {
57 cmr = &cma->ranges[r];
58 bitmap_maxno = cma_bitmap_maxno(cma, cmr);
59 for_each_clear_bitrange(start, end, cmr->bitmap, bitmap_maxno)
60 maxchunk = max(end - start, maxchunk);
61 }
62 spin_unlock_irq(lock: &cma->lock);
63 *val = (u64)maxchunk << cma->order_per_bit;
64
65 return 0;
66}
67DEFINE_DEBUGFS_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
68
69static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
70{
71 spin_lock(lock: &cma->mem_head_lock);
72 hlist_add_head(n: &mem->node, h: &cma->mem_head);
73 spin_unlock(lock: &cma->mem_head_lock);
74}
75
76static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
77{
78 struct cma_mem *mem = NULL;
79
80 spin_lock(lock: &cma->mem_head_lock);
81 if (!hlist_empty(h: &cma->mem_head)) {
82 mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
83 hlist_del_init(n: &mem->node);
84 }
85 spin_unlock(lock: &cma->mem_head_lock);
86
87 return mem;
88}
89
90static int cma_free_mem(struct cma *cma, int count)
91{
92 struct cma_mem *mem = NULL;
93
94 while (count) {
95 mem = cma_get_entry_from_list(cma);
96 if (mem == NULL)
97 return 0;
98
99 if (mem->n <= count) {
100 cma_release(cma, pages: mem->p, count: mem->n);
101 count -= mem->n;
102 kfree(objp: mem);
103 } else if (cma->order_per_bit == 0) {
104 cma_release(cma, pages: mem->p, count);
105 mem->p += count;
106 mem->n -= count;
107 count = 0;
108 cma_add_to_cma_mem_list(cma, mem);
109 } else {
110 pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
111 cma_add_to_cma_mem_list(cma, mem);
112 break;
113 }
114 }
115
116 return 0;
117
118}
119
120static int cma_free_write(void *data, u64 val)
121{
122 int pages = val;
123 struct cma *cma = data;
124
125 return cma_free_mem(cma, count: pages);
126}
127DEFINE_DEBUGFS_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
128
129static int cma_alloc_mem(struct cma *cma, int count)
130{
131 struct cma_mem *mem;
132 struct page *p;
133
134 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
135 if (!mem)
136 return -ENOMEM;
137
138 p = cma_alloc(cma, count, align: 0, no_warn: false);
139 if (!p) {
140 kfree(objp: mem);
141 return -ENOMEM;
142 }
143
144 mem->p = p;
145 mem->n = count;
146
147 cma_add_to_cma_mem_list(cma, mem);
148
149 return 0;
150}
151
152static int cma_alloc_write(void *data, u64 val)
153{
154 int pages = val;
155 struct cma *cma = data;
156
157 return cma_alloc_mem(cma, count: pages);
158}
159DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
160
161static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry)
162{
163 struct dentry *tmp, *dir, *rangedir;
164 int r;
165 char rdirname[12];
166 struct cma_memrange *cmr;
167
168 tmp = debugfs_create_dir(name: cma->name, parent: root_dentry);
169
170 debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
171 debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
172 debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops);
173 debugfs_create_file("order_per_bit", 0444, tmp,
174 &cma->order_per_bit, &cma_debugfs_fops);
175 debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops);
176 debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops);
177
178 rangedir = debugfs_create_dir(name: "ranges", parent: tmp);
179 for (r = 0; r < cma->nranges; r++) {
180 cmr = &cma->ranges[r];
181 snprintf(buf: rdirname, size: sizeof(rdirname), fmt: "%d", r);
182 dir = debugfs_create_dir(name: rdirname, parent: rangedir);
183 debugfs_create_file("base_pfn", 0444, dir,
184 &cmr->base_pfn, &cma_debugfs_fops);
185 cmr->dfs_bitmap.array = (u32 *)cmr->bitmap;
186 cmr->dfs_bitmap.n_elements =
187 DIV_ROUND_UP(cma_bitmap_maxno(cma, cmr),
188 BITS_PER_BYTE * sizeof(u32));
189 debugfs_create_u32_array(name: "bitmap", mode: 0444, parent: dir,
190 array: &cmr->dfs_bitmap);
191 }
192
193 /*
194 * Backward compatible symlinks to range 0 for base_pfn and bitmap.
195 */
196 debugfs_create_symlink(name: "base_pfn", parent: tmp, dest: "ranges/0/base_pfn");
197 debugfs_create_symlink(name: "bitmap", parent: tmp, dest: "ranges/0/bitmap");
198}
199
200static int __init cma_debugfs_init(void)
201{
202 struct dentry *cma_debugfs_root;
203 int i;
204
205 cma_debugfs_root = debugfs_create_dir(name: "cma", NULL);
206
207 for (i = 0; i < cma_area_count; i++)
208 cma_debugfs_add_one(cma: &cma_areas[i], root_dentry: cma_debugfs_root);
209
210 return 0;
211}
212late_initcall(cma_debugfs_init);
213

source code of linux/mm/cma_debug.c