1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Helper functions used by the EFI stub on multiple 4 * architectures. This should be #included by the EFI stub 5 * implementation files. 6 * 7 * Copyright 2011 Intel Corporation; author Matt Fleming 8 */ 9 10 #include <stdarg.h> 11 12 #include <linux/ctype.h> 13 #include <linux/efi.h> 14 #include <linux/kernel.h> 15 #include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */ 16 #include <asm/efi.h> 17 #include <asm/setup.h> 18 19 #include "efistub.h" 20 21 bool efi_nochunk; 22 bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE); 23 bool efi_noinitrd; 24 int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT; 25 bool efi_novamap; 26 27 static bool efi_nosoftreserve; 28 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA); 29 30 bool __pure __efi_soft_reserve_enabled(void) 31 { 32 return !efi_nosoftreserve; 33 } 34 35 /** 36 * efi_char16_puts() - Write a UCS-2 encoded string to the console 37 * @str: UCS-2 encoded string 38 */ 39 void efi_char16_puts(efi_char16_t *str) 40 { 41 efi_call_proto(efi_table_attr(efi_system_table, con_out), 42 output_string, str); 43 } 44 45 static 46 u32 utf8_to_utf32(const u8 **s8) 47 { 48 u32 c32; 49 u8 c0, cx; 50 size_t clen, i; 51 52 c0 = cx = *(*s8)++; 53 /* 54 * The position of the most-significant 0 bit gives us the length of 55 * a multi-octet encoding. 56 */ 57 for (clen = 0; cx & 0x80; ++clen) 58 cx <<= 1; 59 /* 60 * If the 0 bit is in position 8, this is a valid single-octet 61 * encoding. If the 0 bit is in position 7 or positions 1-3, the 62 * encoding is invalid. 63 * In either case, we just return the first octet. 64 */ 65 if (clen < 2 || clen > 4) 66 return c0; 67 /* Get the bits from the first octet. */ 68 c32 = cx >> clen--; 69 for (i = 0; i < clen; ++i) { 70 /* Trailing octets must have 10 in most significant bits. */ 71 cx = (*s8)[i] ^ 0x80; 72 if (cx & 0xc0) 73 return c0; 74 c32 = (c32 << 6) | cx; 75 } 76 /* 77 * Check for validity: 78 * - The character must be in the Unicode range. 79 * - It must not be a surrogate. 80 * - It must be encoded using the correct number of octets. 81 */ 82 if (c32 > 0x10ffff || 83 (c32 & 0xf800) == 0xd800 || 84 clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000)) 85 return c0; 86 *s8 += clen; 87 return c32; 88 } 89 90 /** 91 * efi_puts() - Write a UTF-8 encoded string to the console 92 * @str: UTF-8 encoded string 93 */ 94 void efi_puts(const char *str) 95 { 96 efi_char16_t buf[128]; 97 size_t pos = 0, lim = ARRAY_SIZE(buf); 98 const u8 *s8 = (const u8 *)str; 99 u32 c32; 100 101 while (*s8) { 102 if (*s8 == '\n') 103 buf[pos++] = L'\r'; 104 c32 = utf8_to_utf32(&s8); 105 if (c32 < 0x10000) { 106 /* Characters in plane 0 use a single word. */ 107 buf[pos++] = c32; 108 } else { 109 /* 110 * Characters in other planes encode into a surrogate 111 * pair. 112 */ 113 buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10); 114 buf[pos++] = 0xdc00 + (c32 & 0x3ff); 115 } 116 if (*s8 == '\0' || pos >= lim - 2) { 117 buf[pos] = L'\0'; 118 efi_char16_puts(buf); 119 pos = 0; 120 } 121 } 122 } 123 124 /** 125 * efi_printk() - Print a kernel message 126 * @fmt: format string 127 * 128 * The first letter of the format string is used to determine the logging level 129 * of the message. If the level is less then the current EFI logging level, the 130 * message is suppressed. The message will be truncated to 255 bytes. 131 * 132 * Return: number of printed characters 133 */ 134 int efi_printk(const char *fmt, ...) 135 { 136 char printf_buf[256]; 137 va_list args; 138 int printed; 139 int loglevel = printk_get_level(fmt); 140 141 switch (loglevel) { 142 case '0' ... '9': 143 loglevel -= '0'; 144 break; 145 default: 146 /* 147 * Use loglevel -1 for cases where we just want to print to 148 * the screen. 149 */ 150 loglevel = -1; 151 break; 152 } 153 154 if (loglevel >= efi_loglevel) 155 return 0; 156 157 if (loglevel >= 0) 158 efi_puts("EFI stub: "); 159 160 fmt = printk_skip_level(fmt); 161 162 va_start(args, fmt); 163 printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args); 164 va_end(args); 165 166 efi_puts(printf_buf); 167 if (printed >= sizeof(printf_buf)) { 168 efi_puts("[Message truncated]\n"); 169 return -1; 170 } 171 172 return printed; 173 } 174 175 /** 176 * efi_parse_options() - Parse EFI command line options 177 * @cmdline: kernel command line 178 * 179 * Parse the ASCII string @cmdline for EFI options, denoted by the efi= 180 * option, e.g. efi=nochunk. 181 * 182 * It should be noted that efi= is parsed in two very different 183 * environments, first in the early boot environment of the EFI boot 184 * stub, and subsequently during the kernel boot. 185 * 186 * Return: status code 187 */ 188 efi_status_t efi_parse_options(char const *cmdline) 189 { 190 size_t len; 191 efi_status_t status; 192 char *str, *buf; 193 194 if (!cmdline) 195 return EFI_SUCCESS; 196 197 len = strnlen(cmdline, COMMAND_LINE_SIZE - 1) + 1; 198 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); 199 if (status != EFI_SUCCESS) 200 return status; 201 202 memcpy(buf, cmdline, len - 1); 203 buf[len - 1] = '\0'; 204 str = skip_spaces(buf); 205 206 while (*str) { 207 char *param, *val; 208 209 str = next_arg(str, ¶m, &val); 210 if (!val && !strcmp(param, "--")) 211 break; 212 213 if (!strcmp(param, "nokaslr")) { 214 efi_nokaslr = true; 215 } else if (!strcmp(param, "quiet")) { 216 efi_loglevel = CONSOLE_LOGLEVEL_QUIET; 217 } else if (!strcmp(param, "noinitrd")) { 218 efi_noinitrd = true; 219 } else if (!strcmp(param, "efi") && val) { 220 efi_nochunk = parse_option_str(val, "nochunk"); 221 efi_novamap = parse_option_str(val, "novamap"); 222 223 efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && 224 parse_option_str(val, "nosoftreserve"); 225 226 if (parse_option_str(val, "disable_early_pci_dma")) 227 efi_disable_pci_dma = true; 228 if (parse_option_str(val, "no_disable_early_pci_dma")) 229 efi_disable_pci_dma = false; 230 if (parse_option_str(val, "debug")) 231 efi_loglevel = CONSOLE_LOGLEVEL_DEBUG; 232 } else if (!strcmp(param, "video") && 233 val && strstarts(val, "efifb:")) { 234 efi_parse_option_graphics(val + strlen("efifb:")); 235 } 236 } 237 efi_bs_call(free_pool, buf); 238 return EFI_SUCCESS; 239 } 240 241 /* 242 * The EFI_LOAD_OPTION descriptor has the following layout: 243 * u32 Attributes; 244 * u16 FilePathListLength; 245 * u16 Description[]; 246 * efi_device_path_protocol_t FilePathList[]; 247 * u8 OptionalData[]; 248 * 249 * This function validates and unpacks the variable-size data fields. 250 */ 251 static 252 bool efi_load_option_unpack(efi_load_option_unpacked_t *dest, 253 const efi_load_option_t *src, size_t size) 254 { 255 const void *pos; 256 u16 c; 257 efi_device_path_protocol_t header; 258 const efi_char16_t *description; 259 const efi_device_path_protocol_t *file_path_list; 260 261 if (size < offsetof(efi_load_option_t, variable_data)) 262 return false; 263 pos = src->variable_data; 264 size -= offsetof(efi_load_option_t, variable_data); 265 266 if ((src->attributes & ~EFI_LOAD_OPTION_MASK) != 0) 267 return false; 268 269 /* Scan description. */ 270 description = pos; 271 do { 272 if (size < sizeof(c)) 273 return false; 274 c = *(const u16 *)pos; 275 pos += sizeof(c); 276 size -= sizeof(c); 277 } while (c != L'\0'); 278 279 /* Scan file_path_list. */ 280 file_path_list = pos; 281 do { 282 if (size < sizeof(header)) 283 return false; 284 header = *(const efi_device_path_protocol_t *)pos; 285 if (header.length < sizeof(header)) 286 return false; 287 if (size < header.length) 288 return false; 289 pos += header.length; 290 size -= header.length; 291 } while ((header.type != EFI_DEV_END_PATH && header.type != EFI_DEV_END_PATH2) || 292 (header.sub_type != EFI_DEV_END_ENTIRE)); 293 if (pos != (const void *)file_path_list + src->file_path_list_length) 294 return false; 295 296 dest->attributes = src->attributes; 297 dest->file_path_list_length = src->file_path_list_length; 298 dest->description = description; 299 dest->file_path_list = file_path_list; 300 dest->optional_data_size = size; 301 dest->optional_data = size ? pos : NULL; 302 303 return true; 304 } 305 306 /* 307 * At least some versions of Dell firmware pass the entire contents of the 308 * Boot#### variable, i.e. the EFI_LOAD_OPTION descriptor, rather than just the 309 * OptionalData field. 310 * 311 * Detect this case and extract OptionalData. 312 */ 313 void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_size) 314 { 315 const efi_load_option_t *load_option = *load_options; 316 efi_load_option_unpacked_t load_option_unpacked; 317 318 if (!IS_ENABLED(CONFIG_X86)) 319 return; 320 if (!load_option) 321 return; 322 if (*load_options_size < sizeof(*load_option)) 323 return; 324 if ((load_option->attributes & ~EFI_LOAD_OPTION_BOOT_MASK) != 0) 325 return; 326 327 if (!efi_load_option_unpack(&load_option_unpacked, load_option, *load_options_size)) 328 return; 329 330 efi_warn_once(FW_BUG "LoadOptions is an EFI_LOAD_OPTION descriptor\n"); 331 efi_warn_once(FW_BUG "Using OptionalData as a workaround\n"); 332 333 *load_options = load_option_unpacked.optional_data; 334 *load_options_size = load_option_unpacked.optional_data_size; 335 } 336 337 /* 338 * Convert the unicode UEFI command line to ASCII to pass to kernel. 339 * Size of memory allocated return in *cmd_line_len. 340 * Returns NULL on error. 341 */ 342 char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len) 343 { 344 const u16 *s2; 345 unsigned long cmdline_addr = 0; 346 int options_chars = efi_table_attr(image, load_options_size); 347 const u16 *options = efi_table_attr(image, load_options); 348 int options_bytes = 0, safe_options_bytes = 0; /* UTF-8 bytes */ 349 bool in_quote = false; 350 efi_status_t status; 351 352 efi_apply_loadoptions_quirk((const void **)&options, &options_chars); 353 options_chars /= sizeof(*options); 354 355 if (options) { 356 s2 = options; 357 while (options_bytes < COMMAND_LINE_SIZE && options_chars--) { 358 u16 c = *s2++; 359 360 if (c < 0x80) { 361 if (c == L'\0' || c == L'\n') 362 break; 363 if (c == L'"') 364 in_quote = !in_quote; 365 else if (!in_quote && isspace((char)c)) 366 safe_options_bytes = options_bytes; 367 368 options_bytes++; 369 continue; 370 } 371 372 /* 373 * Get the number of UTF-8 bytes corresponding to a 374 * UTF-16 character. 375 * The first part handles everything in the BMP. 376 */ 377 options_bytes += 2 + (c >= 0x800); 378 /* 379 * Add one more byte for valid surrogate pairs. Invalid 380 * surrogates will be replaced with 0xfffd and take up 381 * only 3 bytes. 382 */ 383 if ((c & 0xfc00) == 0xd800) { 384 /* 385 * If the very last word is a high surrogate, 386 * we must ignore it since we can't access the 387 * low surrogate. 388 */ 389 if (!options_chars) { 390 options_bytes -= 3; 391 } else if ((*s2 & 0xfc00) == 0xdc00) { 392 options_bytes++; 393 options_chars--; 394 s2++; 395 } 396 } 397 } 398 if (options_bytes >= COMMAND_LINE_SIZE) { 399 options_bytes = safe_options_bytes; 400 efi_err("Command line is too long: truncated to %d bytes\n", 401 options_bytes); 402 } 403 } 404 405 options_bytes++; /* NUL termination */ 406 407 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, options_bytes, 408 (void **)&cmdline_addr); 409 if (status != EFI_SUCCESS) 410 return NULL; 411 412 snprintf((char *)cmdline_addr, options_bytes, "%.*ls", 413 options_bytes - 1, options); 414 415 *cmd_line_len = options_bytes; 416 return (char *)cmdline_addr; 417 } 418 419 /** 420 * efi_exit_boot_services() - Exit boot services 421 * @handle: handle of the exiting image 422 * @map: pointer to receive the memory map 423 * @priv: argument to be passed to @priv_func 424 * @priv_func: function to process the memory map before exiting boot services 425 * 426 * Handle calling ExitBootServices according to the requirements set out by the 427 * spec. Obtains the current memory map, and returns that info after calling 428 * ExitBootServices. The client must specify a function to perform any 429 * processing of the memory map data prior to ExitBootServices. A client 430 * specific structure may be passed to the function via priv. The client 431 * function may be called multiple times. 432 * 433 * Return: status code 434 */ 435 efi_status_t efi_exit_boot_services(void *handle, 436 struct efi_boot_memmap *map, 437 void *priv, 438 efi_exit_boot_map_processing priv_func) 439 { 440 efi_status_t status; 441 442 status = efi_get_memory_map(map); 443 444 if (status != EFI_SUCCESS) 445 goto fail; 446 447 status = priv_func(map, priv); 448 if (status != EFI_SUCCESS) 449 goto free_map; 450 451 if (efi_disable_pci_dma) 452 efi_pci_disable_bridge_busmaster(); 453 454 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 455 456 if (status == EFI_INVALID_PARAMETER) { 457 /* 458 * The memory map changed between efi_get_memory_map() and 459 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4: 460 * EFI_BOOT_SERVICES.ExitBootServices we need to get the 461 * updated map, and try again. The spec implies one retry 462 * should be sufficent, which is confirmed against the EDK2 463 * implementation. Per the spec, we can only invoke 464 * get_memory_map() and exit_boot_services() - we cannot alloc 465 * so efi_get_memory_map() cannot be used, and we must reuse 466 * the buffer. For all practical purposes, the headroom in the 467 * buffer should account for any changes in the map so the call 468 * to get_memory_map() is expected to succeed here. 469 */ 470 *map->map_size = *map->buff_size; 471 status = efi_bs_call(get_memory_map, 472 map->map_size, 473 *map->map, 474 map->key_ptr, 475 map->desc_size, 476 map->desc_ver); 477 478 /* exit_boot_services() was called, thus cannot free */ 479 if (status != EFI_SUCCESS) 480 goto fail; 481 482 status = priv_func(map, priv); 483 /* exit_boot_services() was called, thus cannot free */ 484 if (status != EFI_SUCCESS) 485 goto fail; 486 487 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 488 } 489 490 /* exit_boot_services() was called, thus cannot free */ 491 if (status != EFI_SUCCESS) 492 goto fail; 493 494 return EFI_SUCCESS; 495 496 free_map: 497 efi_bs_call(free_pool, *map->map); 498 fail: 499 return status; 500 } 501 502 /** 503 * get_efi_config_table() - retrieve UEFI configuration table 504 * @guid: GUID of the configuration table to be retrieved 505 * Return: pointer to the configuration table or NULL 506 */ 507 void *get_efi_config_table(efi_guid_t guid) 508 { 509 unsigned long tables = efi_table_attr(efi_system_table, tables); 510 int nr_tables = efi_table_attr(efi_system_table, nr_tables); 511 int i; 512 513 for (i = 0; i < nr_tables; i++) { 514 efi_config_table_t *t = (void *)tables; 515 516 if (efi_guidcmp(t->guid, guid) == 0) 517 return efi_table_attr(t, table); 518 519 tables += efi_is_native() ? sizeof(efi_config_table_t) 520 : sizeof(efi_config_table_32_t); 521 } 522 return NULL; 523 } 524 525 /* 526 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way 527 * for the firmware or bootloader to expose the initrd data directly to the stub 528 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is 529 * very easy to implement. It is a simple Linux initrd specific conduit between 530 * kernel and firmware, allowing us to put the EFI stub (being part of the 531 * kernel) in charge of where and when to load the initrd, while leaving it up 532 * to the firmware to decide whether it needs to expose its filesystem hierarchy 533 * via EFI protocols. 534 */ 535 static const struct { 536 struct efi_vendor_dev_path vendor; 537 struct efi_generic_dev_path end; 538 } __packed initrd_dev_path = { 539 { 540 { 541 EFI_DEV_MEDIA, 542 EFI_DEV_MEDIA_VENDOR, 543 sizeof(struct efi_vendor_dev_path), 544 }, 545 LINUX_EFI_INITRD_MEDIA_GUID 546 }, { 547 EFI_DEV_END_PATH, 548 EFI_DEV_END_ENTIRE, 549 sizeof(struct efi_generic_dev_path) 550 } 551 }; 552 553 /** 554 * efi_load_initrd_dev_path() - load the initrd from the Linux initrd device path 555 * @load_addr: pointer to store the address where the initrd was loaded 556 * @load_size: pointer to store the size of the loaded initrd 557 * @max: upper limit for the initrd memory allocation 558 * 559 * Return: 560 * * %EFI_SUCCESS if the initrd was loaded successfully, in which 561 * case @load_addr and @load_size are assigned accordingly 562 * * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd device path 563 * * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL 564 * * %EFI_OUT_OF_RESOURCES if memory allocation failed 565 * * %EFI_LOAD_ERROR in all other cases 566 */ 567 static 568 efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, 569 unsigned long *load_size, 570 unsigned long max) 571 { 572 efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; 573 efi_device_path_protocol_t *dp; 574 efi_load_file2_protocol_t *lf2; 575 unsigned long initrd_addr; 576 unsigned long initrd_size; 577 efi_handle_t handle; 578 efi_status_t status; 579 580 dp = (efi_device_path_protocol_t *)&initrd_dev_path; 581 status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle); 582 if (status != EFI_SUCCESS) 583 return status; 584 585 status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, 586 (void **)&lf2); 587 if (status != EFI_SUCCESS) 588 return status; 589 590 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); 591 if (status != EFI_BUFFER_TOO_SMALL) 592 return EFI_LOAD_ERROR; 593 594 status = efi_allocate_pages(initrd_size, &initrd_addr, max); 595 if (status != EFI_SUCCESS) 596 return status; 597 598 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, 599 (void *)initrd_addr); 600 if (status != EFI_SUCCESS) { 601 efi_free(initrd_size, initrd_addr); 602 return EFI_LOAD_ERROR; 603 } 604 605 *load_addr = initrd_addr; 606 *load_size = initrd_size; 607 return EFI_SUCCESS; 608 } 609 610 static 611 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image, 612 unsigned long *load_addr, 613 unsigned long *load_size, 614 unsigned long soft_limit, 615 unsigned long hard_limit) 616 { 617 if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) || 618 (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) { 619 *load_addr = *load_size = 0; 620 return EFI_SUCCESS; 621 } 622 623 return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, 624 soft_limit, hard_limit, 625 load_addr, load_size); 626 } 627 628 /** 629 * efi_load_initrd() - Load initial RAM disk 630 * @image: EFI loaded image protocol 631 * @load_addr: pointer to loaded initrd 632 * @load_size: size of loaded initrd 633 * @soft_limit: preferred address for loading the initrd 634 * @hard_limit: upper limit address for loading the initrd 635 * 636 * Return: status code 637 */ 638 efi_status_t efi_load_initrd(efi_loaded_image_t *image, 639 unsigned long *load_addr, 640 unsigned long *load_size, 641 unsigned long soft_limit, 642 unsigned long hard_limit) 643 { 644 efi_status_t status; 645 646 if (!load_addr || !load_size) 647 return EFI_INVALID_PARAMETER; 648 649 status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit); 650 if (status == EFI_SUCCESS) { 651 efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n"); 652 } else if (status == EFI_NOT_FOUND) { 653 status = efi_load_initrd_cmdline(image, load_addr, load_size, 654 soft_limit, hard_limit); 655 if (status == EFI_SUCCESS && *load_size > 0) 656 efi_info("Loaded initrd from command line option\n"); 657 } 658 659 return status; 660 } 661 662 /** 663 * efi_wait_for_key() - Wait for key stroke 664 * @usec: number of microseconds to wait for key stroke 665 * @key: key entered 666 * 667 * Wait for up to @usec microseconds for a key stroke. 668 * 669 * Return: status code, EFI_SUCCESS if key received 670 */ 671 efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key) 672 { 673 efi_event_t events[2], timer; 674 unsigned long index; 675 efi_simple_text_input_protocol_t *con_in; 676 efi_status_t status; 677 678 con_in = efi_table_attr(efi_system_table, con_in); 679 if (!con_in) 680 return EFI_UNSUPPORTED; 681 efi_set_event_at(events, 0, efi_table_attr(con_in, wait_for_key)); 682 683 status = efi_bs_call(create_event, EFI_EVT_TIMER, 0, NULL, NULL, &timer); 684 if (status != EFI_SUCCESS) 685 return status; 686 687 status = efi_bs_call(set_timer, timer, EfiTimerRelative, 688 EFI_100NSEC_PER_USEC * usec); 689 if (status != EFI_SUCCESS) 690 return status; 691 efi_set_event_at(events, 1, timer); 692 693 status = efi_bs_call(wait_for_event, 2, events, &index); 694 if (status == EFI_SUCCESS) { 695 if (index == 0) 696 status = efi_call_proto(con_in, read_keystroke, key); 697 else 698 status = EFI_TIMEOUT; 699 } 700 701 efi_bs_call(close_event, timer); 702 703 return status; 704 } 705