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	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}
47DEFINE_DEBUGFS_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
48
49static 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}
69DEFINE_DEBUGFS_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
70
71static 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
78static 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
92static 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
122static 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}
129DEFINE_DEBUGFS_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
130
131static 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
154static 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}
161DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
162
163static 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
185static 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}
197late_initcall(cma_debugfs_init);
198