pool.c 7.7 KB

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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. static struct gen_pool *atomic_pool_dma __ro_after_init;
  16. static unsigned long pool_size_dma;
  17. static struct gen_pool *atomic_pool_dma32 __ro_after_init;
  18. static unsigned long pool_size_dma32;
  19. static struct gen_pool *atomic_pool_kernel __ro_after_init;
  20. static unsigned long pool_size_kernel;
  21. /* Size can be defined by the coherent_pool command line */
  22. static size_t atomic_pool_size;
  23. /* Dynamic background expansion when the atomic pool is near capacity */
  24. static struct work_struct atomic_pool_work;
  25. static int __init early_coherent_pool(char *p)
  26. {
  27. atomic_pool_size = memparse(p, &p);
  28. return 0;
  29. }
  30. early_param("coherent_pool", early_coherent_pool);
  31. static void __init dma_atomic_pool_debugfs_init(void)
  32. {
  33. struct dentry *root;
  34. root = debugfs_create_dir("dma_pools", NULL);
  35. if (IS_ERR_OR_NULL(root))
  36. return;
  37. debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
  38. debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
  39. debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
  40. }
  41. static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
  42. {
  43. if (gfp & __GFP_DMA)
  44. pool_size_dma += size;
  45. else if (gfp & __GFP_DMA32)
  46. pool_size_dma32 += size;
  47. else
  48. pool_size_kernel += size;
  49. }
  50. static bool cma_in_zone(gfp_t gfp)
  51. {
  52. unsigned long size;
  53. phys_addr_t end;
  54. struct cma *cma;
  55. cma = dev_get_cma_area(NULL);
  56. if (!cma)
  57. return false;
  58. size = cma_get_size(cma);
  59. if (!size)
  60. return false;
  61. /* CMA can't cross zone boundaries, see cma_activate_area() */
  62. end = cma_get_base(cma) + size - 1;
  63. if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
  64. return end <= DMA_BIT_MASK(zone_dma_bits);
  65. if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32) && !zone_dma32_are_empty())
  66. return end <= DMA_BIT_MASK(32);
  67. return true;
  68. }
  69. static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
  70. gfp_t gfp)
  71. {
  72. unsigned int order;
  73. struct page *page = NULL;
  74. void *addr;
  75. int ret = -ENOMEM;
  76. /* Cannot allocate larger than MAX_ORDER-1 */
  77. order = min(get_order(pool_size), MAX_ORDER-1);
  78. do {
  79. pool_size = 1 << (PAGE_SHIFT + order);
  80. if (cma_in_zone(gfp))
  81. page = dma_alloc_from_contiguous(NULL, 1 << order,
  82. order, false);
  83. if (!page)
  84. page = alloc_pages(gfp, order);
  85. } while (!page && order-- > 0);
  86. if (!page)
  87. goto out;
  88. arch_dma_prep_coherent(page, pool_size);
  89. #ifdef CONFIG_DMA_DIRECT_REMAP
  90. addr = dma_common_contiguous_remap(page, pool_size,
  91. pgprot_dmacoherent(PAGE_KERNEL),
  92. __builtin_return_address(0));
  93. if (!addr)
  94. goto free_page;
  95. #else
  96. addr = page_to_virt(page);
  97. #endif
  98. /*
  99. * Memory in the atomic DMA pools must be unencrypted, the pools do not
  100. * shrink so no re-encryption occurs in dma_direct_free().
  101. */
  102. ret = set_memory_decrypted((unsigned long)page_to_virt(page),
  103. 1 << order);
  104. if (ret)
  105. goto remove_mapping;
  106. ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
  107. pool_size, NUMA_NO_NODE);
  108. if (ret)
  109. goto encrypt_mapping;
  110. dma_atomic_pool_size_add(gfp, pool_size);
  111. return 0;
  112. encrypt_mapping:
  113. ret = set_memory_encrypted((unsigned long)page_to_virt(page),
  114. 1 << order);
  115. if (WARN_ON_ONCE(ret)) {
  116. /* Decrypt succeeded but encrypt failed, purposely leak */
  117. goto out;
  118. }
  119. remove_mapping:
  120. #ifdef CONFIG_DMA_DIRECT_REMAP
  121. dma_common_free_remap(addr, pool_size);
  122. #endif
  123. free_page: __maybe_unused
  124. __free_pages(page, order);
  125. out:
  126. return ret;
  127. }
  128. static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
  129. {
  130. if (pool && gen_pool_avail(pool) < atomic_pool_size)
  131. atomic_pool_expand(pool, gen_pool_size(pool), gfp);
  132. }
  133. static void atomic_pool_work_fn(struct work_struct *work)
  134. {
  135. if (IS_ENABLED(CONFIG_ZONE_DMA))
  136. atomic_pool_resize(atomic_pool_dma,
  137. GFP_KERNEL | GFP_DMA);
  138. if (IS_ENABLED(CONFIG_ZONE_DMA32) && !zone_dma32_are_empty())
  139. atomic_pool_resize(atomic_pool_dma32,
  140. GFP_KERNEL | GFP_DMA32);
  141. atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
  142. }
  143. static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
  144. gfp_t gfp)
  145. {
  146. struct gen_pool *pool;
  147. int ret;
  148. pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
  149. if (!pool)
  150. return NULL;
  151. gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
  152. ret = atomic_pool_expand(pool, pool_size, gfp);
  153. if (ret) {
  154. gen_pool_destroy(pool);
  155. pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
  156. pool_size >> 10, &gfp);
  157. return NULL;
  158. }
  159. pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
  160. gen_pool_size(pool) >> 10, &gfp);
  161. return pool;
  162. }
  163. static int __init dma_atomic_pool_init(void)
  164. {
  165. int ret = 0;
  166. /*
  167. * If coherent_pool was not used on the command line, default the pool
  168. * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
  169. */
  170. if (!atomic_pool_size) {
  171. unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
  172. pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
  173. atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
  174. }
  175. INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
  176. atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
  177. GFP_KERNEL);
  178. if (!atomic_pool_kernel)
  179. ret = -ENOMEM;
  180. if (has_managed_dma()) {
  181. atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
  182. GFP_KERNEL | GFP_DMA);
  183. if (!atomic_pool_dma)
  184. ret = -ENOMEM;
  185. }
  186. if (IS_ENABLED(CONFIG_ZONE_DMA32) && !zone_dma32_are_empty()) {
  187. atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
  188. GFP_KERNEL | GFP_DMA32);
  189. if (!atomic_pool_dma32)
  190. ret = -ENOMEM;
  191. }
  192. dma_atomic_pool_debugfs_init();
  193. return ret;
  194. }
  195. postcore_initcall(dma_atomic_pool_init);
  196. static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
  197. {
  198. if (prev == NULL) {
  199. if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32) && !zone_dma32_are_empty())
  200. return atomic_pool_dma32;
  201. if (atomic_pool_dma && (gfp & GFP_DMA))
  202. return atomic_pool_dma;
  203. return atomic_pool_kernel;
  204. }
  205. if (prev == atomic_pool_kernel)
  206. return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
  207. if (prev == atomic_pool_dma32)
  208. return atomic_pool_dma;
  209. return NULL;
  210. }
  211. static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
  212. struct gen_pool *pool, void **cpu_addr,
  213. bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
  214. {
  215. unsigned long addr;
  216. phys_addr_t phys;
  217. addr = gen_pool_alloc(pool, size);
  218. if (!addr)
  219. return NULL;
  220. phys = gen_pool_virt_to_phys(pool, addr);
  221. if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
  222. gen_pool_free(pool, addr, size);
  223. return NULL;
  224. }
  225. if (gen_pool_avail(pool) < atomic_pool_size)
  226. schedule_work(&atomic_pool_work);
  227. *cpu_addr = (void *)addr;
  228. memset(*cpu_addr, 0, size);
  229. return pfn_to_page(__phys_to_pfn(phys));
  230. }
  231. struct page *dma_alloc_from_pool(struct device *dev, size_t size,
  232. void **cpu_addr, gfp_t gfp,
  233. bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
  234. {
  235. struct gen_pool *pool = NULL;
  236. struct page *page;
  237. while ((pool = dma_guess_pool(pool, gfp))) {
  238. page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
  239. phys_addr_ok);
  240. if (page)
  241. return page;
  242. }
  243. WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
  244. return NULL;
  245. }
  246. bool dma_free_from_pool(struct device *dev, void *start, size_t size)
  247. {
  248. struct gen_pool *pool = NULL;
  249. while ((pool = dma_guess_pool(pool, 0))) {
  250. if (!gen_pool_has_addr(pool, (unsigned long)start, size))
  251. continue;
  252. gen_pool_free(pool, (unsigned long)start, size);
  253. return true;
  254. }
  255. return false;
  256. }