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);