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 struct dentry *cma_debugfs_root;
 25
 26static int cma_debugfs_get(void *data, u64 *val)
 27{
 28	unsigned long *p = data;
 29
 30	*val = *p;
 31
 32	return 0;
 33}
 34DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 35
 36static 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}
 49DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
 50
 51static 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}
 71DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
 72
 73static 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
 80static 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
 94static 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
124static 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}
131DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
132
133static 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, GFP_KERNEL);
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
156static 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}
163DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
164
165static 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", S_IWUSR, tmp, cma,
176				&cma_alloc_fops);
177
178	debugfs_create_file("free", S_IWUSR, tmp, cma,
179				&cma_free_fops);
180
181	debugfs_create_file("base_pfn", S_IRUGO, tmp,
182				&cma->base_pfn, &cma_debugfs_fops);
183	debugfs_create_file("count", S_IRUGO, tmp,
184				&cma->count, &cma_debugfs_fops);
185	debugfs_create_file("order_per_bit", S_IRUGO, tmp,
186				&cma->order_per_bit, &cma_debugfs_fops);
187	debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
188	debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
189
190	u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
191	debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
192}
193
194static int __init cma_debugfs_init(void)
195{
196	int i;
197
198	cma_debugfs_root = debugfs_create_dir("cma", NULL);
199	if (!cma_debugfs_root)
200		return -ENOMEM;
201
202	for (i = 0; i < cma_area_count; i++)
203		cma_debugfs_add_one(&cma_areas[i], i);
204
205	return 0;
206}
207late_initcall(cma_debugfs_init);