1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DMABUF System heap exporter 4 * 5 * Copyright (C) 2011 Google, Inc. 6 * Copyright (C) 2019, 2020 Linaro Ltd. 7 * 8 * Portions based off of Andrew Davis' SRAM heap: 9 * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ 10 * Andrew F. Davis <afd@ti.com> 11 */ 12 13 #include <linux/dma-buf.h> 14 #include <linux/dma-mapping.h> 15 #include <linux/dma-heap.h> 16 #include <linux/err.h> 17 #include <linux/highmem.h> 18 #include <linux/mm.h> 19 #include <linux/module.h> 20 #include <linux/scatterlist.h> 21 #include <linux/slab.h> 22 #include <linux/vmalloc.h> 23 24 static struct dma_heap *sys_heap; 25 26 struct system_heap_buffer { 27 struct dma_heap *heap; 28 struct list_head attachments; 29 struct mutex lock; 30 unsigned long len; 31 struct sg_table sg_table; 32 int vmap_cnt; 33 void *vaddr; 34 }; 35 36 struct dma_heap_attachment { 37 struct device *dev; 38 struct sg_table *table; 39 struct list_head list; 40 bool mapped; 41 }; 42 43 #define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO) 44 #define HIGH_ORDER_GFP (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \ 45 | __GFP_NORETRY) & ~__GFP_RECLAIM) \ 46 | __GFP_COMP) 47 static gfp_t order_flags[] = {HIGH_ORDER_GFP, HIGH_ORDER_GFP, LOW_ORDER_GFP}; 48 /* 49 * The selection of the orders used for allocation (1MB, 64K, 4K) is designed 50 * to match with the sizes often found in IOMMUs. Using order 4 pages instead 51 * of order 0 pages can significantly improve the performance of many IOMMUs 52 * by reducing TLB pressure and time spent updating page tables. 53 */ 54 static const unsigned int orders[] = {8, 4, 0}; 55 #define NUM_ORDERS ARRAY_SIZE(orders) 56 57 static struct sg_table *dup_sg_table(struct sg_table *table) 58 { 59 struct sg_table *new_table; 60 int ret, i; 61 struct scatterlist *sg, *new_sg; 62 63 new_table = kzalloc(sizeof(*new_table), GFP_KERNEL); 64 if (!new_table) 65 return ERR_PTR(-ENOMEM); 66 67 ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL); 68 if (ret) { 69 kfree(new_table); 70 return ERR_PTR(-ENOMEM); 71 } 72 73 new_sg = new_table->sgl; 74 for_each_sgtable_sg(table, sg, i) { 75 sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset); 76 new_sg = sg_next(new_sg); 77 } 78 79 return new_table; 80 } 81 82 static int system_heap_attach(struct dma_buf *dmabuf, 83 struct dma_buf_attachment *attachment) 84 { 85 struct system_heap_buffer *buffer = dmabuf->priv; 86 struct dma_heap_attachment *a; 87 struct sg_table *table; 88 89 a = kzalloc(sizeof(*a), GFP_KERNEL); 90 if (!a) 91 return -ENOMEM; 92 93 table = dup_sg_table(&buffer->sg_table); 94 if (IS_ERR(table)) { 95 kfree(a); 96 return -ENOMEM; 97 } 98 99 a->table = table; 100 a->dev = attachment->dev; 101 INIT_LIST_HEAD(&a->list); 102 a->mapped = false; 103 104 attachment->priv = a; 105 106 mutex_lock(&buffer->lock); 107 list_add(&a->list, &buffer->attachments); 108 mutex_unlock(&buffer->lock); 109 110 return 0; 111 } 112 113 static void system_heap_detach(struct dma_buf *dmabuf, 114 struct dma_buf_attachment *attachment) 115 { 116 struct system_heap_buffer *buffer = dmabuf->priv; 117 struct dma_heap_attachment *a = attachment->priv; 118 119 mutex_lock(&buffer->lock); 120 list_del(&a->list); 121 mutex_unlock(&buffer->lock); 122 123 sg_free_table(a->table); 124 kfree(a->table); 125 kfree(a); 126 } 127 128 static struct sg_table *system_heap_map_dma_buf(struct dma_buf_attachment *attachment, 129 enum dma_data_direction direction) 130 { 131 struct dma_heap_attachment *a = attachment->priv; 132 struct sg_table *table = a->table; 133 int ret; 134 135 ret = dma_map_sgtable(attachment->dev, table, direction, 0); 136 if (ret) 137 return ERR_PTR(ret); 138 139 a->mapped = true; 140 return table; 141 } 142 143 static void system_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, 144 struct sg_table *table, 145 enum dma_data_direction direction) 146 { 147 struct dma_heap_attachment *a = attachment->priv; 148 149 a->mapped = false; 150 dma_unmap_sgtable(attachment->dev, table, direction, 0); 151 } 152 153 static int system_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, 154 enum dma_data_direction direction) 155 { 156 struct system_heap_buffer *buffer = dmabuf->priv; 157 struct dma_heap_attachment *a; 158 159 mutex_lock(&buffer->lock); 160 161 if (buffer->vmap_cnt) 162 invalidate_kernel_vmap_range(buffer->vaddr, buffer->len); 163 164 list_for_each_entry(a, &buffer->attachments, list) { 165 if (!a->mapped) 166 continue; 167 dma_sync_sgtable_for_cpu(a->dev, a->table, direction); 168 } 169 mutex_unlock(&buffer->lock); 170 171 return 0; 172 } 173 174 static int system_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, 175 enum dma_data_direction direction) 176 { 177 struct system_heap_buffer *buffer = dmabuf->priv; 178 struct dma_heap_attachment *a; 179 180 mutex_lock(&buffer->lock); 181 182 if (buffer->vmap_cnt) 183 flush_kernel_vmap_range(buffer->vaddr, buffer->len); 184 185 list_for_each_entry(a, &buffer->attachments, list) { 186 if (!a->mapped) 187 continue; 188 dma_sync_sgtable_for_device(a->dev, a->table, direction); 189 } 190 mutex_unlock(&buffer->lock); 191 192 return 0; 193 } 194 195 static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) 196 { 197 struct system_heap_buffer *buffer = dmabuf->priv; 198 struct sg_table *table = &buffer->sg_table; 199 unsigned long addr = vma->vm_start; 200 struct sg_page_iter piter; 201 int ret; 202 203 for_each_sgtable_page(table, &piter, vma->vm_pgoff) { 204 struct page *page = sg_page_iter_page(&piter); 205 206 ret = remap_pfn_range(vma, addr, page_to_pfn(page), PAGE_SIZE, 207 vma->vm_page_prot); 208 if (ret) 209 return ret; 210 addr += PAGE_SIZE; 211 if (addr >= vma->vm_end) 212 return 0; 213 } 214 return 0; 215 } 216 217 static void *system_heap_do_vmap(struct system_heap_buffer *buffer) 218 { 219 struct sg_table *table = &buffer->sg_table; 220 int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE; 221 struct page **pages = vmalloc(sizeof(struct page *) * npages); 222 struct page **tmp = pages; 223 struct sg_page_iter piter; 224 void *vaddr; 225 226 if (!pages) 227 return ERR_PTR(-ENOMEM); 228 229 for_each_sgtable_page(table, &piter, 0) { 230 WARN_ON(tmp - pages >= npages); 231 *tmp++ = sg_page_iter_page(&piter); 232 } 233 234 vaddr = vmap(pages, npages, VM_MAP, PAGE_KERNEL); 235 vfree(pages); 236 237 if (!vaddr) 238 return ERR_PTR(-ENOMEM); 239 240 return vaddr; 241 } 242 243 static int system_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) 244 { 245 struct system_heap_buffer *buffer = dmabuf->priv; 246 void *vaddr; 247 int ret = 0; 248 249 mutex_lock(&buffer->lock); 250 if (buffer->vmap_cnt) { 251 buffer->vmap_cnt++; 252 iosys_map_set_vaddr(map, buffer->vaddr); 253 goto out; 254 } 255 256 vaddr = system_heap_do_vmap(buffer); 257 if (IS_ERR(vaddr)) { 258 ret = PTR_ERR(vaddr); 259 goto out; 260 } 261 262 buffer->vaddr = vaddr; 263 buffer->vmap_cnt++; 264 iosys_map_set_vaddr(map, buffer->vaddr); 265 out: 266 mutex_unlock(&buffer->lock); 267 268 return ret; 269 } 270 271 static void system_heap_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) 272 { 273 struct system_heap_buffer *buffer = dmabuf->priv; 274 275 mutex_lock(&buffer->lock); 276 if (!--buffer->vmap_cnt) { 277 vunmap(buffer->vaddr); 278 buffer->vaddr = NULL; 279 } 280 mutex_unlock(&buffer->lock); 281 iosys_map_clear(map); 282 } 283 284 static void system_heap_dma_buf_release(struct dma_buf *dmabuf) 285 { 286 struct system_heap_buffer *buffer = dmabuf->priv; 287 struct sg_table *table; 288 struct scatterlist *sg; 289 int i; 290 291 table = &buffer->sg_table; 292 for_each_sgtable_sg(table, sg, i) { 293 struct page *page = sg_page(sg); 294 295 __free_pages(page, compound_order(page)); 296 } 297 sg_free_table(table); 298 kfree(buffer); 299 } 300 301 static const struct dma_buf_ops system_heap_buf_ops = { 302 .attach = system_heap_attach, 303 .detach = system_heap_detach, 304 .map_dma_buf = system_heap_map_dma_buf, 305 .unmap_dma_buf = system_heap_unmap_dma_buf, 306 .begin_cpu_access = system_heap_dma_buf_begin_cpu_access, 307 .end_cpu_access = system_heap_dma_buf_end_cpu_access, 308 .mmap = system_heap_mmap, 309 .vmap = system_heap_vmap, 310 .vunmap = system_heap_vunmap, 311 .release = system_heap_dma_buf_release, 312 }; 313 314 static struct page *alloc_largest_available(unsigned long size, 315 unsigned int max_order) 316 { 317 struct page *page; 318 int i; 319 320 for (i = 0; i < NUM_ORDERS; i++) { 321 if (size < (PAGE_SIZE << orders[i])) 322 continue; 323 if (max_order < orders[i]) 324 continue; 325 326 page = alloc_pages(order_flags[i], orders[i]); 327 if (!page) 328 continue; 329 return page; 330 } 331 return NULL; 332 } 333 334 static struct dma_buf *system_heap_allocate(struct dma_heap *heap, 335 unsigned long len, 336 u32 fd_flags, 337 u64 heap_flags) 338 { 339 struct system_heap_buffer *buffer; 340 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 341 unsigned long size_remaining = len; 342 unsigned int max_order = orders[0]; 343 struct dma_buf *dmabuf; 344 struct sg_table *table; 345 struct scatterlist *sg; 346 struct list_head pages; 347 struct page *page, *tmp_page; 348 int i, ret = -ENOMEM; 349 350 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); 351 if (!buffer) 352 return ERR_PTR(-ENOMEM); 353 354 INIT_LIST_HEAD(&buffer->attachments); 355 mutex_init(&buffer->lock); 356 buffer->heap = heap; 357 buffer->len = len; 358 359 INIT_LIST_HEAD(&pages); 360 i = 0; 361 while (size_remaining > 0) { 362 /* 363 * Avoid trying to allocate memory if the process 364 * has been killed by SIGKILL 365 */ 366 if (fatal_signal_pending(current)) { 367 ret = -EINTR; 368 goto free_buffer; 369 } 370 371 page = alloc_largest_available(size_remaining, max_order); 372 if (!page) 373 goto free_buffer; 374 375 list_add_tail(&page->lru, &pages); 376 size_remaining -= page_size(page); 377 max_order = compound_order(page); 378 i++; 379 } 380 381 table = &buffer->sg_table; 382 if (sg_alloc_table(table, i, GFP_KERNEL)) 383 goto free_buffer; 384 385 sg = table->sgl; 386 list_for_each_entry_safe(page, tmp_page, &pages, lru) { 387 sg_set_page(sg, page, page_size(page), 0); 388 sg = sg_next(sg); 389 list_del(&page->lru); 390 } 391 392 /* create the dmabuf */ 393 exp_info.exp_name = dma_heap_get_name(heap); 394 exp_info.ops = &system_heap_buf_ops; 395 exp_info.size = buffer->len; 396 exp_info.flags = fd_flags; 397 exp_info.priv = buffer; 398 dmabuf = dma_buf_export(&exp_info); 399 if (IS_ERR(dmabuf)) { 400 ret = PTR_ERR(dmabuf); 401 goto free_pages; 402 } 403 return dmabuf; 404 405 free_pages: 406 for_each_sgtable_sg(table, sg, i) { 407 struct page *p = sg_page(sg); 408 409 __free_pages(p, compound_order(p)); 410 } 411 sg_free_table(table); 412 free_buffer: 413 list_for_each_entry_safe(page, tmp_page, &pages, lru) 414 __free_pages(page, compound_order(page)); 415 kfree(buffer); 416 417 return ERR_PTR(ret); 418 } 419 420 static const struct dma_heap_ops system_heap_ops = { 421 .allocate = system_heap_allocate, 422 }; 423 424 static int system_heap_create(void) 425 { 426 struct dma_heap_export_info exp_info; 427 428 exp_info.name = "system"; 429 exp_info.ops = &system_heap_ops; 430 exp_info.priv = NULL; 431 432 sys_heap = dma_heap_add(&exp_info); 433 if (IS_ERR(sys_heap)) 434 return PTR_ERR(sys_heap); 435 436 return 0; 437 } 438 module_init(system_heap_create); 439