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
16 static struct gen_pool *atomic_pool_dma __ro_after_init;
17 static unsigned long pool_size_dma;
18 static struct gen_pool *atomic_pool_dma32 __ro_after_init;
19 static unsigned long pool_size_dma32;
20 static struct gen_pool *atomic_pool_kernel __ro_after_init;
21 static unsigned long pool_size_kernel;
22
23 /* Size can be defined by the coherent_pool command line */
24 static size_t atomic_pool_size;
25
26 /* Dynamic background expansion when the atomic pool is near capacity */
27 static struct work_struct atomic_pool_work;
28
early_coherent_pool(char * p)29 static int __init early_coherent_pool(char *p)
30 {
31 atomic_pool_size = memparse(p, &p);
32 return 0;
33 }
34 early_param("coherent_pool", early_coherent_pool);
35
dma_atomic_pool_debugfs_init(void)36 static void __init dma_atomic_pool_debugfs_init(void)
37 {
38 struct dentry *root;
39
40 root = debugfs_create_dir("dma_pools", NULL);
41 if (IS_ERR_OR_NULL(root))
42 return;
43
44 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
45 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
46 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
47 }
48
dma_atomic_pool_size_add(gfp_t gfp,size_t size)49 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
50 {
51 if (gfp & __GFP_DMA)
52 pool_size_dma += size;
53 else if (gfp & __GFP_DMA32)
54 pool_size_dma32 += size;
55 else
56 pool_size_kernel += size;
57 }
58
cma_in_zone(gfp_t gfp)59 static bool cma_in_zone(gfp_t gfp)
60 {
61 unsigned long size;
62 phys_addr_t end;
63 struct cma *cma;
64
65 cma = dev_get_cma_area(NULL);
66 if (!cma)
67 return false;
68
69 size = cma_get_size(cma);
70 if (!size)
71 return false;
72
73 /* CMA can't cross zone boundaries, see cma_activate_area() */
74 end = cma_get_base(cma) + size - 1;
75 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
76 return end <= DMA_BIT_MASK(zone_dma_bits);
77 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
78 return end <= DMA_BIT_MASK(32);
79 return true;
80 }
81
atomic_pool_expand(struct gen_pool * pool,size_t pool_size,gfp_t gfp)82 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
83 gfp_t gfp)
84 {
85 unsigned int order;
86 struct page *page = NULL;
87 void *addr;
88 int ret = -ENOMEM;
89
90 /* Cannot allocate larger than MAX_ORDER-1 */
91 order = min(get_order(pool_size), MAX_ORDER-1);
92
93 do {
94 pool_size = 1 << (PAGE_SHIFT + order);
95 if (cma_in_zone(gfp))
96 page = dma_alloc_from_contiguous(NULL, 1 << order,
97 order, false);
98 if (!page)
99 page = alloc_pages(gfp, order);
100 } while (!page && order-- > 0);
101 if (!page)
102 goto out;
103
104 arch_dma_prep_coherent(page, pool_size);
105
106 #ifdef CONFIG_DMA_DIRECT_REMAP
107 addr = dma_common_contiguous_remap(page, pool_size,
108 pgprot_dmacoherent(PAGE_KERNEL),
109 __builtin_return_address(0));
110 if (!addr)
111 goto free_page;
112 #else
113 addr = page_to_virt(page);
114 #endif
115 /*
116 * Memory in the atomic DMA pools must be unencrypted, the pools do not
117 * shrink so no re-encryption occurs in dma_direct_free().
118 */
119 ret = set_memory_decrypted((unsigned long)page_to_virt(page),
120 1 << order);
121 if (ret)
122 goto remove_mapping;
123 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
124 pool_size, NUMA_NO_NODE);
125 if (ret)
126 goto encrypt_mapping;
127
128 dma_atomic_pool_size_add(gfp, pool_size);
129 return 0;
130
131 encrypt_mapping:
132 ret = set_memory_encrypted((unsigned long)page_to_virt(page),
133 1 << order);
134 if (WARN_ON_ONCE(ret)) {
135 /* Decrypt succeeded but encrypt failed, purposely leak */
136 goto out;
137 }
138 remove_mapping:
139 #ifdef CONFIG_DMA_DIRECT_REMAP
140 dma_common_free_remap(addr, pool_size);
141 #endif
142 free_page: __maybe_unused
143 __free_pages(page, order);
144 out:
145 return ret;
146 }
147
atomic_pool_resize(struct gen_pool * pool,gfp_t gfp)148 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
149 {
150 if (pool && gen_pool_avail(pool) < atomic_pool_size)
151 atomic_pool_expand(pool, gen_pool_size(pool), gfp);
152 }
153
atomic_pool_work_fn(struct work_struct * work)154 static void atomic_pool_work_fn(struct work_struct *work)
155 {
156 if (IS_ENABLED(CONFIG_ZONE_DMA))
157 atomic_pool_resize(atomic_pool_dma,
158 GFP_KERNEL | GFP_DMA);
159 if (IS_ENABLED(CONFIG_ZONE_DMA32))
160 atomic_pool_resize(atomic_pool_dma32,
161 GFP_KERNEL | GFP_DMA32);
162 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
163 }
164
__dma_atomic_pool_init(size_t pool_size,gfp_t gfp)165 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
166 gfp_t gfp)
167 {
168 struct gen_pool *pool;
169 int ret;
170
171 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
172 if (!pool)
173 return NULL;
174
175 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
176
177 ret = atomic_pool_expand(pool, pool_size, gfp);
178 if (ret) {
179 gen_pool_destroy(pool);
180 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
181 pool_size >> 10, &gfp);
182 return NULL;
183 }
184
185 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
186 gen_pool_size(pool) >> 10, &gfp);
187 return pool;
188 }
189
dma_atomic_pool_init(void)190 static int __init dma_atomic_pool_init(void)
191 {
192 int ret = 0;
193
194 /*
195 * If coherent_pool was not used on the command line, default the pool
196 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
197 */
198 if (!atomic_pool_size) {
199 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
200 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
201 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
202 }
203 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
204
205 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
206 GFP_KERNEL);
207 if (!atomic_pool_kernel)
208 ret = -ENOMEM;
209 if (has_managed_dma()) {
210 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
211 GFP_KERNEL | GFP_DMA);
212 if (!atomic_pool_dma)
213 ret = -ENOMEM;
214 }
215 if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
216 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
217 GFP_KERNEL | GFP_DMA32);
218 if (!atomic_pool_dma32)
219 ret = -ENOMEM;
220 }
221
222 dma_atomic_pool_debugfs_init();
223 return ret;
224 }
225 postcore_initcall(dma_atomic_pool_init);
226
dma_guess_pool(struct gen_pool * prev,gfp_t gfp)227 static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
228 {
229 if (prev == NULL) {
230 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
231 return atomic_pool_dma32;
232 if (atomic_pool_dma && (gfp & GFP_DMA))
233 return atomic_pool_dma;
234 return atomic_pool_kernel;
235 }
236 if (prev == atomic_pool_kernel)
237 return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
238 if (prev == atomic_pool_dma32)
239 return atomic_pool_dma;
240 return NULL;
241 }
242
__dma_alloc_from_pool(struct device * dev,size_t size,struct gen_pool * pool,void ** cpu_addr,bool (* phys_addr_ok)(struct device *,phys_addr_t,size_t))243 static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
244 struct gen_pool *pool, void **cpu_addr,
245 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
246 {
247 unsigned long addr;
248 phys_addr_t phys;
249
250 addr = gen_pool_alloc(pool, size);
251 if (!addr)
252 return NULL;
253
254 phys = gen_pool_virt_to_phys(pool, addr);
255 if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
256 gen_pool_free(pool, addr, size);
257 return NULL;
258 }
259
260 if (gen_pool_avail(pool) < atomic_pool_size)
261 schedule_work(&atomic_pool_work);
262
263 *cpu_addr = (void *)addr;
264 memset(*cpu_addr, 0, size);
265 return pfn_to_page(__phys_to_pfn(phys));
266 }
267
dma_alloc_from_pool(struct device * dev,size_t size,void ** cpu_addr,gfp_t gfp,bool (* phys_addr_ok)(struct device *,phys_addr_t,size_t))268 struct page *dma_alloc_from_pool(struct device *dev, size_t size,
269 void **cpu_addr, gfp_t gfp,
270 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
271 {
272 struct gen_pool *pool = NULL;
273 struct page *page;
274
275 while ((pool = dma_guess_pool(pool, gfp))) {
276 page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
277 phys_addr_ok);
278 if (page)
279 return page;
280 }
281
282 WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
283 return NULL;
284 }
285
dma_free_from_pool(struct device * dev,void * start,size_t size)286 bool dma_free_from_pool(struct device *dev, void *start, size_t size)
287 {
288 struct gen_pool *pool = NULL;
289
290 while ((pool = dma_guess_pool(pool, 0))) {
291 if (!gen_pool_has_addr(pool, (unsigned long)start, size))
292 continue;
293 gen_pool_free(pool, (unsigned long)start, size);
294 return true;
295 }
296
297 return false;
298 }
299