summaryrefslogtreecommitdiffstats
path: root/kernel/dma/pool.c
blob: 6bc74a2d51273e3d32c841844f8f0f8f2eac079d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2012 ARM Ltd.
 * Copyright (C) 2020 Google LLC
 */
#include <linux/debugfs.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/init.h>
#include <linux/genalloc.h>
#include <linux/set_memory.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

static struct gen_pool *atomic_pool_dma __ro_after_init;
static unsigned long pool_size_dma;
static struct gen_pool *atomic_pool_dma32 __ro_after_init;
static unsigned long pool_size_dma32;
static struct gen_pool *atomic_pool_kernel __ro_after_init;
static unsigned long pool_size_kernel;

/* Size can be defined by the coherent_pool command line */
static size_t atomic_pool_size;

/* Dynamic background expansion when the atomic pool is near capacity */
static struct work_struct atomic_pool_work;

static int __init early_coherent_pool(char *p)
{
	atomic_pool_size = memparse(p, &p);
	return 0;
}
early_param("coherent_pool", early_coherent_pool);

static void __init dma_atomic_pool_debugfs_init(void)
{
	struct dentry *root;

	root = debugfs_create_dir("dma_pools", NULL);
	if (IS_ERR_OR_NULL(root))
		return;

	debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
	debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
	debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
}

static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
{
	if (gfp & __GFP_DMA)
		pool_size_dma += size;
	else if (gfp & __GFP_DMA32)
		pool_size_dma32 += size;
	else
		pool_size_kernel += size;
}

static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
			      gfp_t gfp)
{
	unsigned int order;
	struct page *page;
	void *addr;
	int ret = -ENOMEM;

	/* Cannot allocate larger than MAX_ORDER-1 */
	order = min(get_order(pool_size), MAX_ORDER-1);

	do {
		pool_size = 1 << (PAGE_SHIFT + order);
		page = alloc_pages(gfp, order);
	} while (!page && order-- > 0);
	if (!page)
		goto out;

	arch_dma_prep_coherent(page, pool_size);

#ifdef CONFIG_DMA_DIRECT_REMAP
	addr = dma_common_contiguous_remap(page, pool_size,
					   pgprot_dmacoherent(PAGE_KERNEL),
					   __builtin_return_address(0));
	if (!addr)
		goto free_page;
#else
	addr = page_to_virt(page);
#endif
	/*
	 * Memory in the atomic DMA pools must be unencrypted, the pools do not
	 * shrink so no re-encryption occurs in dma_direct_free_pages().
	 */
	ret = set_memory_decrypted((unsigned long)page_to_virt(page),
				   1 << order);
	if (ret)
		goto remove_mapping;
	ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
				pool_size, NUMA_NO_NODE);
	if (ret)
		goto encrypt_mapping;

	dma_atomic_pool_size_add(gfp, pool_size);
	return 0;

encrypt_mapping:
	ret = set_memory_encrypted((unsigned long)page_to_virt(page),
				   1 << order);
	if (WARN_ON_ONCE(ret)) {
		/* Decrypt succeeded but encrypt failed, purposely leak */
		goto out;
	}
remove_mapping:
#ifdef CONFIG_DMA_DIRECT_REMAP
	dma_common_free_remap(addr, pool_size);
#endif
free_page: __maybe_unused
	__free_pages(page, order);
out:
	return ret;
}

static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
{
	if (pool && gen_pool_avail(pool) < atomic_pool_size)
		atomic_pool_expand(pool, gen_pool_size(pool), gfp);
}

static void atomic_pool_work_fn(struct work_struct *work)
{
	if (IS_ENABLED(CONFIG_ZONE_DMA))
		atomic_pool_resize(atomic_pool_dma,
				   GFP_KERNEL | GFP_DMA);
	if (IS_ENABLED(CONFIG_ZONE_DMA32))
		atomic_pool_resize(atomic_pool_dma32,
				   GFP_KERNEL | GFP_DMA32);
	atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
}

static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
						      gfp_t gfp)
{
	struct gen_pool *pool;
	int ret;

	pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
	if (!pool)
		return NULL;

	gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);

	ret = atomic_pool_expand(pool, pool_size, gfp);
	if (ret) {
		gen_pool_destroy(pool);
		pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
		       pool_size >> 10, &gfp);
		return NULL;
	}

	pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
		gen_pool_size(pool) >> 10, &gfp);
	return pool;
}

static int __init dma_atomic_pool_init(void)
{
	int ret = 0;

	/*
	 * If coherent_pool was not used on the command line, default the pool
	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
	 */
	if (!atomic_pool_size) {
		unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
		pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
		atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
	}
	INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);

	atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
						    GFP_KERNEL);
	if (!atomic_pool_kernel)
		ret = -ENOMEM;
	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
		atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
						GFP_KERNEL | GFP_DMA);
		if (!atomic_pool_dma)
			ret = -ENOMEM;
	}
	if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
		atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
						GFP_KERNEL | GFP_DMA32);
		if (!atomic_pool_dma32)
			ret = -ENOMEM;
	}

	dma_atomic_pool_debugfs_init();
	return ret;
}
postcore_initcall(dma_atomic_pool_init);

static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev)
{
	u64 phys_mask;
	gfp_t gfp;

	gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
					  &phys_mask);
	if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)
		return atomic_pool_dma;
	if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)
		return atomic_pool_dma32;
	return atomic_pool_kernel;
}

static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool)
{
	if (bad_pool == atomic_pool_kernel)
		return atomic_pool_dma32 ? : atomic_pool_dma;

	if (bad_pool == atomic_pool_dma32)
		return atomic_pool_dma;

	return NULL;
}

static inline struct gen_pool *dma_guess_pool(struct device *dev,
					      struct gen_pool *bad_pool)
{
	if (bad_pool)
		return dma_get_safer_pool(bad_pool);

	return dma_guess_pool_from_device(dev);
}

void *dma_alloc_from_pool(struct device *dev, size_t size,
			  struct page **ret_page, gfp_t flags)
{
	struct gen_pool *pool = NULL;
	unsigned long val = 0;
	void *ptr = NULL;
	phys_addr_t phys;

	while (1) {
		pool = dma_guess_pool(dev, pool);
		if (!pool) {
			WARN(1, "Failed to get suitable pool for %s\n",
			     dev_name(dev));
			break;
		}

		val = gen_pool_alloc(pool, size);
		if (!val)
			continue;

		phys = gen_pool_virt_to_phys(pool, val);
		if (dma_coherent_ok(dev, phys, size))
			break;

		gen_pool_free(pool, val, size);
		val = 0;
	}


	if (val) {
		*ret_page = pfn_to_page(__phys_to_pfn(phys));
		ptr = (void *)val;
		memset(ptr, 0, size);

		if (gen_pool_avail(pool) < atomic_pool_size)
			schedule_work(&atomic_pool_work);
	}

	return ptr;
}

bool dma_free_from_pool(struct device *dev, void *start, size_t size)
{
	struct gen_pool *pool = NULL;

	while (1) {
		pool = dma_guess_pool(dev, pool);
		if (!pool)
			return false;

		if (gen_pool_has_addr(pool, (unsigned long)start, size)) {
			gen_pool_free(pool, (unsigned long)start, size);
			return true;
		}
	}
}