1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/init.h> 4 #include <linux/errno.h> 5 #include <linux/mm.h> 6 #include <linux/mman.h> 7 #include <linux/slab.h> 8 #include <linux/vmalloc.h> 9 #include <linux/io_uring.h> 10 #include <linux/io_uring_types.h> 11 #include <asm/shmparam.h> 12 13 #include "memmap.h" 14 #include "kbuf.h" 15 #include "rsrc.h" 16 #include "zcrx.h" 17 18 static bool io_mem_alloc_compound(struct page **pages, int nr_pages, 19 size_t size, gfp_t gfp, 20 struct user_struct *user) 21 { 22 unsigned long nr_compound, extra; 23 struct page *page; 24 int i, order; 25 26 order = get_order(size); 27 if (order > MAX_PAGE_ORDER) 28 return false; 29 else if (order) 30 gfp |= __GFP_COMP; 31 32 /* 33 * get_order() rounds a non power of two size up, so the allocation 34 * can hold more pages than the region exposes. Account those too, 35 * and leave the compound allocation alone if they do not fit. 36 */ 37 nr_compound = 1UL << order; 38 extra = nr_compound - nr_pages; 39 if (extra && user && __io_account_mem(user, extra)) 40 return false; 41 42 page = alloc_pages(gfp, order); 43 if (!page) { 44 if (extra && user) 45 __io_unaccount_mem(user, extra); 46 return false; 47 } 48 49 for (i = 0; i < nr_pages; i++) 50 pages[i] = page + i; 51 52 return true; 53 } 54 55 struct page **io_pin_pages(unsigned long uaddr, unsigned long len, int *npages) 56 { 57 unsigned long start, end, nr_pages; 58 struct page **pages; 59 int ret; 60 61 if (check_add_overflow(uaddr, len, &end)) 62 return ERR_PTR(-EOVERFLOW); 63 if (check_add_overflow(end, PAGE_SIZE - 1, &end)) 64 return ERR_PTR(-EOVERFLOW); 65 66 end = end >> PAGE_SHIFT; 67 start = uaddr >> PAGE_SHIFT; 68 nr_pages = end - start; 69 if (WARN_ON_ONCE(!nr_pages)) 70 return ERR_PTR(-EINVAL); 71 if (nr_pages > INT_MAX / sizeof(struct page *)) 72 return ERR_PTR(-EOVERFLOW); 73 74 pages = kvmalloc_objs(struct page *, nr_pages, GFP_KERNEL_ACCOUNT); 75 if (!pages) 76 return ERR_PTR(-ENOMEM); 77 78 ret = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM, 79 pages); 80 /* success, mapped all pages */ 81 if (ret == nr_pages) { 82 *npages = nr_pages; 83 return pages; 84 } 85 86 /* partial map, or didn't map anything */ 87 if (ret >= 0) { 88 /* if we did partial map, release any pages we did get */ 89 if (ret) 90 unpin_user_pages(pages, ret); 91 ret = -EFAULT; 92 } 93 kvfree(pages); 94 return ERR_PTR(ret); 95 } 96 97 enum { 98 /* memory was vmap'ed for the kernel, freeing the region vunmap's it */ 99 IO_REGION_F_VMAP = 1, 100 /* memory is provided by user and pinned by the kernel */ 101 IO_REGION_F_USER_PROVIDED = 2, 102 /* only the first page in the array is ref'ed */ 103 IO_REGION_F_SINGLE_REF = 4, 104 }; 105 106 void io_free_region(struct user_struct *user, struct io_mapped_region *mr) 107 { 108 if (mr->pages) { 109 long nr_refs = mr->nr_pages; 110 111 if (mr->flags & IO_REGION_F_SINGLE_REF) 112 nr_refs = 1; 113 114 if (mr->flags & IO_REGION_F_USER_PROVIDED) 115 unpin_user_pages(mr->pages, nr_refs); 116 else 117 release_pages(mr->pages, nr_refs); 118 119 kvfree(mr->pages); 120 } 121 if ((mr->flags & IO_REGION_F_VMAP) && mr->ptr) 122 vunmap(mr->ptr); 123 if (mr->nr_pages && user) { 124 unsigned long nr_accounted = mr->nr_pages; 125 126 /* a compound region was accounted for the whole allocation */ 127 if (mr->flags & IO_REGION_F_SINGLE_REF) 128 nr_accounted = 1UL << get_order(io_region_size(mr)); 129 130 __io_unaccount_mem(user, nr_accounted); 131 } 132 133 memset(mr, 0, sizeof(*mr)); 134 } 135 136 static int io_region_init_ptr(struct io_mapped_region *mr) 137 { 138 struct io_imu_folio_data ifd; 139 void *ptr; 140 141 if (io_check_coalesce_buffer(mr->pages, mr->nr_pages, &ifd)) { 142 if (ifd.nr_folios == 1 && !PageHighMem(mr->pages[0])) { 143 mr->ptr = page_address(mr->pages[0]); 144 return 0; 145 } 146 } 147 ptr = vmap(mr->pages, mr->nr_pages, VM_MAP, PAGE_KERNEL); 148 if (!ptr) 149 return -ENOMEM; 150 151 mr->ptr = ptr; 152 mr->flags |= IO_REGION_F_VMAP; 153 return 0; 154 } 155 156 static int io_region_pin_pages(struct io_mapped_region *mr, 157 struct io_uring_region_desc *reg) 158 { 159 size_t size = io_region_size(mr); 160 struct page **pages; 161 int nr_pages; 162 163 pages = io_pin_pages(reg->user_addr, size, &nr_pages); 164 if (IS_ERR(pages)) 165 return PTR_ERR(pages); 166 if (WARN_ON_ONCE(nr_pages != mr->nr_pages)) 167 return -EFAULT; 168 169 mr->pages = pages; 170 mr->flags |= IO_REGION_F_USER_PROVIDED; 171 return 0; 172 } 173 174 static int io_region_allocate_pages(struct io_mapped_region *mr, 175 struct io_uring_region_desc *reg, 176 unsigned long mmap_offset, 177 struct user_struct *user) 178 { 179 gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN; 180 size_t size = io_region_size(mr); 181 unsigned long nr_allocated; 182 struct page **pages; 183 184 pages = kvmalloc_objs(*pages, mr->nr_pages, gfp); 185 if (!pages) 186 return -ENOMEM; 187 188 if (io_mem_alloc_compound(pages, mr->nr_pages, size, gfp, user)) { 189 mr->flags |= IO_REGION_F_SINGLE_REF; 190 goto done; 191 } 192 193 nr_allocated = alloc_pages_bulk_node(gfp, NUMA_NO_NODE, 194 mr->nr_pages, pages); 195 if (nr_allocated != mr->nr_pages) { 196 if (nr_allocated) 197 release_pages(pages, nr_allocated); 198 kvfree(pages); 199 return -ENOMEM; 200 } 201 done: 202 reg->mmap_offset = mmap_offset; 203 mr->pages = pages; 204 return 0; 205 } 206 207 int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, 208 struct io_uring_region_desc *reg, 209 unsigned long mmap_offset) 210 { 211 int nr_pages, ret; 212 u64 end; 213 214 if (WARN_ON_ONCE(mr->pages || mr->ptr || mr->nr_pages)) 215 return -EFAULT; 216 if (memchr_inv(®->__resv, 0, sizeof(reg->__resv))) 217 return -EINVAL; 218 if (reg->flags & ~IORING_MEM_REGION_TYPE_USER) 219 return -EINVAL; 220 /* user_addr should be set IFF it's a user memory backed region */ 221 if ((reg->flags & IORING_MEM_REGION_TYPE_USER) != !!reg->user_addr) 222 return -EFAULT; 223 if (!reg->size || reg->mmap_offset || reg->id) 224 return -EINVAL; 225 if ((reg->size >> PAGE_SHIFT) > INT_MAX) 226 return -E2BIG; 227 if ((reg->user_addr | reg->size) & ~PAGE_MASK) 228 return -EINVAL; 229 if (check_add_overflow(reg->user_addr, reg->size, &end)) 230 return -EOVERFLOW; 231 232 nr_pages = reg->size >> PAGE_SHIFT; 233 if (ctx->user) { 234 ret = __io_account_mem(ctx->user, nr_pages); 235 if (ret) 236 return ret; 237 } 238 mr->nr_pages = nr_pages; 239 240 if (reg->flags & IORING_MEM_REGION_TYPE_USER) 241 ret = io_region_pin_pages(mr, reg); 242 else 243 ret = io_region_allocate_pages(mr, reg, mmap_offset, ctx->user); 244 if (ret) 245 goto out_free; 246 247 ret = io_region_init_ptr(mr); 248 if (ret) 249 goto out_free; 250 return 0; 251 out_free: 252 io_free_region(ctx->user, mr); 253 return ret; 254 } 255 256 static struct io_mapped_region *io_mmap_get_region(struct io_ring_ctx *ctx, 257 loff_t pgoff) 258 { 259 loff_t offset = pgoff << PAGE_SHIFT; 260 unsigned int id; 261 262 263 switch (offset & IORING_OFF_MMAP_MASK) { 264 case IORING_OFF_SQ_RING: 265 case IORING_OFF_CQ_RING: 266 return &ctx->ring_region; 267 case IORING_OFF_SQES: 268 return &ctx->sq_region; 269 case IORING_OFF_PBUF_RING: 270 id = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT; 271 return io_pbuf_get_region(ctx, id); 272 case IORING_MAP_OFF_PARAM_REGION: 273 return &ctx->param_region; 274 case IORING_MAP_OFF_ZCRX_REGION: 275 id = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_ZCRX_SHIFT; 276 return io_zcrx_get_region(ctx, id); 277 } 278 return NULL; 279 } 280 281 static void *io_region_validate_mmap(struct io_ring_ctx *ctx, 282 struct io_mapped_region *mr) 283 { 284 lockdep_assert_held(&ctx->mmap_lock); 285 286 if (!io_region_is_set(mr)) 287 return ERR_PTR(-EINVAL); 288 if (mr->flags & IO_REGION_F_USER_PROVIDED) 289 return ERR_PTR(-EINVAL); 290 291 return io_region_get_ptr(mr); 292 } 293 294 static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff) 295 { 296 struct io_ring_ctx *ctx = file->private_data; 297 struct io_mapped_region *region; 298 299 region = io_mmap_get_region(ctx, pgoff); 300 if (!region) 301 return ERR_PTR(-EINVAL); 302 return io_region_validate_mmap(ctx, region); 303 } 304 305 #ifdef CONFIG_MMU 306 307 static int io_region_mmap(struct io_ring_ctx *ctx, 308 struct io_mapped_region *mr, 309 struct vm_area_struct *vma, 310 unsigned max_pages) 311 { 312 unsigned long nr_pages = min(mr->nr_pages, max_pages); 313 314 vm_flags_set(vma, VM_DONTEXPAND); 315 return vm_insert_pages(vma, vma->vm_start, mr->pages, &nr_pages); 316 } 317 318 __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma) 319 { 320 struct io_ring_ctx *ctx = file->private_data; 321 size_t sz = vma->vm_end - vma->vm_start; 322 long offset = vma->vm_pgoff << PAGE_SHIFT; 323 unsigned int page_limit = UINT_MAX; 324 struct io_mapped_region *region; 325 void *ptr; 326 327 guard(mutex)(&ctx->mmap_lock); 328 329 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff); 330 if (IS_ERR(ptr)) 331 return PTR_ERR(ptr); 332 333 switch (offset & IORING_OFF_MMAP_MASK) { 334 case IORING_OFF_SQ_RING: 335 case IORING_OFF_CQ_RING: 336 page_limit = (sz + PAGE_SIZE - 1) >> PAGE_SHIFT; 337 break; 338 } 339 340 region = io_mmap_get_region(ctx, vma->vm_pgoff); 341 return io_region_mmap(ctx, region, vma, page_limit); 342 } 343 344 unsigned long io_uring_get_unmapped_area(struct file *filp, unsigned long addr, 345 unsigned long len, unsigned long pgoff, 346 unsigned long flags) 347 { 348 struct io_ring_ctx *ctx = filp->private_data; 349 void *ptr; 350 351 /* 352 * Do not allow to map to user-provided address to avoid breaking the 353 * aliasing rules. Userspace is not able to guess the offset address of 354 * kernel kmalloc()ed memory area. 355 */ 356 if (addr) 357 return -EINVAL; 358 359 guard(mutex)(&ctx->mmap_lock); 360 361 ptr = io_uring_validate_mmap_request(filp, pgoff); 362 if (IS_ERR(ptr)) 363 return PTR_ERR(ptr); 364 365 /* 366 * Some architectures have strong cache aliasing requirements. 367 * For such architectures we need a coherent mapping which aliases 368 * kernel memory *and* userspace memory. To achieve that: 369 * - use a NULL file pointer to reference physical memory, and 370 * - use the kernel virtual address of the shared io_uring context 371 * (instead of the userspace-provided address, which has to be 0UL 372 * anyway). 373 * - use the same pgoff which the get_unmapped_area() uses to 374 * calculate the page colouring. 375 * For architectures without such aliasing requirements, the 376 * architecture will return any suitable mapping because addr is 0. 377 */ 378 filp = NULL; 379 flags |= MAP_SHARED; 380 pgoff = 0; /* has been translated to ptr above */ 381 #ifdef SHM_COLOUR 382 addr = (uintptr_t) ptr; 383 pgoff = addr >> PAGE_SHIFT; 384 #else 385 addr = 0UL; 386 #endif 387 return mm_get_unmapped_area(filp, addr, len, pgoff, flags); 388 } 389 390 #else /* !CONFIG_MMU */ 391 392 /* 393 * Drop the pages that were initially referenced and added in 394 * io_uring_mmap(). We cannot have had a mremap() as that isn't supported, 395 * hence the vma should be identical to the one we initially referenced and 396 * mapped, and partial unmaps and splitting isn't possible on a file backed 397 * mapping. 398 */ 399 static void io_uring_nommu_vm_close(struct vm_area_struct *vma) 400 { 401 unsigned long index; 402 403 for (index = vma->vm_start; index < vma->vm_end; index += PAGE_SIZE) 404 put_page(virt_to_page((void *) index)); 405 } 406 407 static const struct vm_operations_struct io_uring_nommu_vm_ops = { 408 .close = io_uring_nommu_vm_close, 409 }; 410 411 int io_uring_mmap(struct file *file, struct vm_area_struct *vma) 412 { 413 struct io_ring_ctx *ctx = file->private_data; 414 struct io_mapped_region *region; 415 unsigned long i; 416 417 if (!is_nommu_shared_mapping(vma->vm_flags)) 418 return -EINVAL; 419 420 guard(mutex)(&ctx->mmap_lock); 421 region = io_mmap_get_region(ctx, vma->vm_pgoff); 422 if (!region || !io_region_is_set(region)) 423 return -EINVAL; 424 425 if ((vma->vm_end - vma->vm_start) != 426 (unsigned long) region->nr_pages << PAGE_SHIFT) 427 return -EINVAL; 428 429 /* 430 * Pin the pages so io_free_region()'s release_pages() does not 431 * drop the last reference while this VMA exists. delete_vma() 432 * in mm/nommu.c calls vma_close() which runs ->close above. 433 */ 434 for (i = 0; i < region->nr_pages; i++) 435 get_page(region->pages[i]); 436 437 vma->vm_ops = &io_uring_nommu_vm_ops; 438 return 0; 439 } 440 441 unsigned int io_uring_nommu_mmap_capabilities(struct file *file) 442 { 443 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; 444 } 445 446 unsigned long io_uring_get_unmapped_area(struct file *file, unsigned long addr, 447 unsigned long len, unsigned long pgoff, 448 unsigned long flags) 449 { 450 struct io_ring_ctx *ctx = file->private_data; 451 void *ptr; 452 453 guard(mutex)(&ctx->mmap_lock); 454 455 ptr = io_uring_validate_mmap_request(file, pgoff); 456 if (IS_ERR(ptr)) 457 return PTR_ERR(ptr); 458 459 return (unsigned long) ptr; 460 } 461 462 #endif /* !CONFIG_MMU */ 463