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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 * Copyright (C) 2020 Google LLC
5 */
6#include <linux/cma.h>
7#include <linux/debugfs.h>
8#include <linux/dma-map-ops.h>
9#include <linux/dma-direct.h>
10#include <linux/init.h>
11#include <linux/genalloc.h>
12#include <linux/set_memory.h>
13#include <linux/slab.h>
14#include <linux/workqueue.h>
15#include <linux/cc_platform.h>
16
17struct dma_gen_pool {
18 bool cc_shared;
19 struct gen_pool *pool;
20};
21
22static struct dma_gen_pool atomic_pool_dma __ro_after_init;
23static unsigned long pool_size_dma;
24static struct dma_gen_pool atomic_pool_dma32 __ro_after_init;
25static unsigned long pool_size_dma32;
26static struct dma_gen_pool atomic_pool_kernel __ro_after_init;
27static unsigned long pool_size_kernel;
28
29/* Size can be defined by the coherent_pool command line */
30static size_t atomic_pool_size;
31
32/* Dynamic background expansion when the atomic pool is near capacity */
33static struct work_struct atomic_pool_work;
34
35static int __init early_coherent_pool(char *p)
36{
37 atomic_pool_size = memparse(p, &p);
38 return 0;
39}
40early_param("coherent_pool", early_coherent_pool);
41
42static void __init dma_atomic_pool_debugfs_init(void)
43{
44 struct dentry *root;
45
46 root = debugfs_create_dir("dma_pools", NULL);
47 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
48 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
49 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
50}
51
52static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
53{
54 if (gfp & __GFP_DMA)
55 pool_size_dma += size;
56 else if (gfp & __GFP_DMA32)
57 pool_size_dma32 += size;
58 else
59 pool_size_kernel += size;
60}
61
62static bool cma_in_zone(gfp_t gfp)
63{
64 unsigned long size;
65 phys_addr_t end;
66 struct cma *cma;
67
68 cma = dev_get_cma_area(NULL);
69 if (!cma)
70 return false;
71
72 size = cma_get_size(cma);
73 if (!size)
74 return false;
75
76 /* CMA can't cross zone boundaries, see cma_activate_area() */
77 end = cma_get_base(cma) + size - 1;
78 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
79 return end <= zone_dma_limit;
80 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
81 return end <= max(DMA_BIT_MASK(32), zone_dma_limit);
82 return true;
83}
84
85static int atomic_pool_expand(struct dma_gen_pool *dma_pool, size_t pool_size,
86 gfp_t gfp)
87{
88 unsigned int order;
89 struct page *page = NULL;
90 bool leak_pages = false;
91 void *addr;
92 int ret = -ENOMEM;
93 pgprot_t prot __maybe_unused;
94
95 /* Cannot allocate larger than MAX_PAGE_ORDER */
96 order = min(get_order(pool_size), MAX_PAGE_ORDER);
97
98 do {
99 pool_size = 1 << (PAGE_SHIFT + order);
100 if (cma_in_zone(gfp))
101 page = dma_alloc_from_contiguous(NULL, 1 << order,
102 order, false);
103 if (!page)
104 page = alloc_pages(gfp | __GFP_NOWARN, order);
105 } while (!page && order-- > 0);
106 if (!page)
107 goto out;
108
109 arch_dma_prep_coherent(page, pool_size);
110
111#ifdef CONFIG_DMA_DIRECT_REMAP
112 if (dma_pool->cc_shared)
113 prot = pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL));
114 else
115 prot = pgprot_dmacoherent(PAGE_KERNEL);
116
117 addr = dma_common_contiguous_remap(page, pool_size, prot,
118 __builtin_return_address(0));
119 if (!addr)
120 goto free_page;
121#else
122 addr = page_to_virt(page);
123#endif
124 /*
125 * Memory in the atomic DMA pools must be unencrypted, the pools do not
126 * shrink so no re-encryption occurs in dma_direct_free().
127 */
128 if (dma_pool->cc_shared) {
129 ret = set_memory_decrypted((unsigned long)page_to_virt(page),
130 1 << order);
131 if (ret) {
132 leak_pages = true;
133 goto remove_mapping;
134 }
135 }
136
137 ret = gen_pool_add_virt(dma_pool->pool, (unsigned long)addr,
138 page_to_phys(page), pool_size, NUMA_NO_NODE);
139 if (ret)
140 goto encrypt_mapping;
141
142 dma_atomic_pool_size_add(gfp, pool_size);
143 return 0;
144
145encrypt_mapping:
146 if (dma_pool->cc_shared &&
147 set_memory_encrypted((unsigned long)page_to_virt(page), 1 << order))
148 leak_pages = true;
149
150remove_mapping:
151#ifdef CONFIG_DMA_DIRECT_REMAP
152 dma_common_free_remap(addr, pool_size);
153free_page:
154#endif
155 if (!leak_pages)
156 __free_pages(page, order);
157out:
158 return ret;
159}
160
161static void atomic_pool_resize(struct dma_gen_pool *dma_pool, gfp_t gfp)
162{
163 if (dma_pool->pool && gen_pool_avail(dma_pool->pool) < atomic_pool_size)
164 atomic_pool_expand(dma_pool, gen_pool_size(dma_pool->pool), gfp);
165}
166
167static void atomic_pool_work_fn(struct work_struct *work)
168{
169 if (IS_ENABLED(CONFIG_ZONE_DMA))
170 atomic_pool_resize(&atomic_pool_dma,
171 GFP_KERNEL | GFP_DMA);
172 if (IS_ENABLED(CONFIG_ZONE_DMA32))
173 atomic_pool_resize(&atomic_pool_dma32,
174 GFP_KERNEL | GFP_DMA32);
175 atomic_pool_resize(&atomic_pool_kernel, GFP_KERNEL);
176}
177
178static __init struct dma_gen_pool *__dma_atomic_pool_init(struct dma_gen_pool *dma_pool,
179 size_t pool_size, gfp_t gfp)
180{
181 int ret;
182
183 dma_pool->pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
184 if (!dma_pool->pool)
185 return NULL;
186
187 gen_pool_set_algo(dma_pool->pool, gen_pool_first_fit_order_align, NULL);
188
189 /* if platform is using memory encryption atomic pools are by default shared. */
190 if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
191 dma_pool->cc_shared = true;
192 else
193 dma_pool->cc_shared = false;
194
195 ret = atomic_pool_expand(dma_pool, pool_size, gfp);
196 if (ret) {
197 gen_pool_destroy(dma_pool->pool);
198 dma_pool->pool = NULL;
199 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
200 pool_size >> 10, &gfp);
201 return NULL;
202 }
203
204 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
205 gen_pool_size(dma_pool->pool) >> 10, &gfp);
206 return dma_pool;
207}
208
209#ifdef CONFIG_ZONE_DMA32
210#define has_managed_dma32 has_managed_zone(ZONE_DMA32)
211#else
212#define has_managed_dma32 false
213#endif
214
215static int __init dma_atomic_pool_init(void)
216{
217 int ret = 0;
218
219 /*
220 * If coherent_pool was not used on the command line, default the pool
221 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_PAGE_ORDER.
222 */
223 if (!atomic_pool_size) {
224 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
225 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
226 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
227 }
228 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
229
230 /* All memory might be in the DMA zone(s) to begin with */
231 if (has_managed_zone(ZONE_NORMAL)) {
232 __dma_atomic_pool_init(&atomic_pool_kernel, atomic_pool_size, GFP_KERNEL);
233 if (!atomic_pool_kernel.pool)
234 ret = -ENOMEM;
235 }
236
237 if (has_managed_dma()) {
238 __dma_atomic_pool_init(&atomic_pool_dma, atomic_pool_size,
239 GFP_KERNEL | GFP_DMA);
240 if (!atomic_pool_dma.pool)
241 ret = -ENOMEM;
242 }
243
244 if (has_managed_dma32) {
245 __dma_atomic_pool_init(&atomic_pool_dma32, atomic_pool_size,
246 GFP_KERNEL | GFP_DMA32);
247 if (!atomic_pool_dma32.pool)
248 ret = -ENOMEM;
249 }
250
251 dma_atomic_pool_debugfs_init();
252 return ret;
253}
254postcore_initcall(dma_atomic_pool_init);
255
256static inline struct dma_gen_pool *__dma_guess_pool(struct dma_gen_pool *first,
257 struct dma_gen_pool *second, struct dma_gen_pool *third)
258{
259 if (first->pool)
260 return first;
261 if (second && second->pool)
262 return second;
263 if (third && third->pool)
264 return third;
265 return NULL;
266}
267
268static inline struct dma_gen_pool *dma_guess_pool(struct dma_gen_pool *prev,
269 gfp_t gfp)
270{
271 if (!prev) {
272 if (gfp & GFP_DMA)
273 return __dma_guess_pool(&atomic_pool_dma,
274 &atomic_pool_dma32,
275 &atomic_pool_kernel);
276
277 if (gfp & GFP_DMA32)
278 return __dma_guess_pool(&atomic_pool_dma32,
279 &atomic_pool_dma,
280 &atomic_pool_kernel);
281
282 return __dma_guess_pool(&atomic_pool_kernel,
283 &atomic_pool_dma32,
284 &atomic_pool_dma);
285 }
286
287 if (prev == &atomic_pool_kernel)
288 return __dma_guess_pool(&atomic_pool_dma32,
289 &atomic_pool_dma, NULL);
290
291 if (prev == &atomic_pool_dma32)
292 return __dma_guess_pool(&atomic_pool_dma, NULL, NULL);
293
294 return NULL;
295}
296
297static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
298 struct gen_pool *pool, void **cpu_addr,
299 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
300{
301 unsigned long addr;
302 phys_addr_t phys;
303
304 addr = gen_pool_alloc(pool, size);
305 if (!addr)
306 return NULL;
307
308 phys = gen_pool_virt_to_phys(pool, addr);
309 if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
310 gen_pool_free(pool, addr, size);
311 return NULL;
312 }
313
314 if (gen_pool_avail(pool) < atomic_pool_size)
315 schedule_work(&atomic_pool_work);
316
317 *cpu_addr = (void *)addr;
318 memset(*cpu_addr, 0, size);
319 return pfn_to_page(__phys_to_pfn(phys));
320}
321
322struct page *dma_alloc_from_pool(struct device *dev, size_t size,
323 void **cpu_addr, gfp_t gfp, unsigned long attrs,
324 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
325{
326 struct dma_gen_pool *dma_pool = NULL;
327 struct page *page;
328 bool pool_found = false;
329
330 while ((dma_pool = dma_guess_pool(dma_pool, gfp))) {
331
332 if (dma_pool->cc_shared != !!(attrs & __DMA_ATTR_ALLOC_CC_SHARED))
333 continue;
334
335 pool_found = true;
336 page = __dma_alloc_from_pool(dev, size, dma_pool->pool, cpu_addr,
337 phys_addr_ok);
338 if (page)
339 return page;
340 }
341
342 if (pool_found)
343 WARN(!(gfp & __GFP_NOWARN), "DMA pool exhausted for %s\n", dev_name(dev));
344 else
345 WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
346 return NULL;
347}
348
349bool dma_free_from_pool(struct device *dev, void *start, size_t size)
350{
351 struct dma_gen_pool *dma_pool = NULL;
352
353 while ((dma_pool = dma_guess_pool(dma_pool, 0))) {
354
355 if (!gen_pool_has_addr(dma_pool->pool, (unsigned long)start, size))
356 continue;
357
358 gen_pool_free(dma_pool->pool, (unsigned long)start, size);
359 return true;
360 }
361
362 return false;
363}
364
365struct dma_pool_phys_match {
366 phys_addr_t phys;
367 size_t size;
368 unsigned long addr;
369 bool found;
370};
371
372static void dma_pool_find_phys(struct gen_pool *pool, struct gen_pool_chunk *chunk,
373 void *data)
374{
375 struct dma_pool_phys_match *match = data;
376 phys_addr_t end = match->phys + match->size - 1;
377 phys_addr_t chunk_end;
378
379 if (match->found)
380 return;
381
382 chunk_end = chunk->phys_addr + (chunk->end_addr - chunk->start_addr);
383 if (match->phys < chunk->phys_addr || end > chunk_end)
384 return;
385
386 match->addr = chunk->start_addr + (match->phys - chunk->phys_addr);
387 match->found = true;
388}
389
390static bool dma_free_from_pool_phys(struct dma_gen_pool *dma_pool, phys_addr_t phys,
391 size_t size)
392{
393 struct dma_pool_phys_match match = {
394 .phys = phys,
395 .size = size,
396 };
397
398 gen_pool_for_each_chunk(dma_pool->pool, dma_pool_find_phys, &match);
399 if (!match.found)
400 return false;
401
402 gen_pool_free(dma_pool->pool, match.addr, size);
403 return true;
404}
405
406/*
407 * FIXME: We could avoid this by storing the remapped virtual address in
408 * struct page and using that for lookup.
409 */
410bool dma_free_from_pool_page(struct device *dev, struct page *page, size_t size)
411{
412 struct dma_gen_pool *dma_pool = NULL;
413 phys_addr_t phys = page_to_phys(page);
414
415 if (!IS_ENABLED(CONFIG_DMA_DIRECT_REMAP))
416 return dma_free_from_pool(dev, page_address(page), size);
417
418 while ((dma_pool = dma_guess_pool(dma_pool, 0))) {
419 if (dma_free_from_pool_phys(dma_pool, phys, size))
420 return true;
421 }
422
423 return false;
424}