cma_debug.c

  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(&cma->lock);
 39	*val = cma->count - cma->available_count;
 40	spin_unlock_irq(&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(&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(&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(&cma->mem_head_lock);
 72	hlist_add_head(&mem->node, &cma->mem_head);
 73	spin_unlock(&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(&cma->mem_head_lock);
 81	if (!hlist_empty(&cma->mem_head)) {
 82		mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
 83		hlist_del_init(&mem->node);
 84	}
 85	spin_unlock(&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, mem->p, mem->n);
101			count -= mem->n;
102			kfree(mem);
103		} else if (cma->order_per_bit == 0) {
104			cma_release(cma, 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, 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, 0, false);
139	if (!p) {
140		kfree(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, 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(cma->name, 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("ranges", tmp);
179	for (r = 0; r < cma->nranges; r++) {
180		cmr = &cma->ranges[r];
181		snprintf(rdirname, sizeof(rdirname), "%d", r);
182		dir = debugfs_create_dir(rdirname, 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("bitmap", 0444, dir,
190				&cmr->dfs_bitmap);
191	}
192
193	/*
194	 * Backward compatible symlinks to range 0 for base_pfn and bitmap.
195	 */
196	debugfs_create_symlink("base_pfn", tmp, "ranges/0/base_pfn");
197	debugfs_create_symlink("bitmap", tmp, "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("cma", NULL);
206
207	for (i = 0; i < cma_area_count; i++)
208		cma_debugfs_add_one(&cma_areas[i], cma_debugfs_root);
209
210	return 0;
211}
212late_initcall(cma_debugfs_init);