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/efi.h> 13 #include <linux/kernel.h> 14 #include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */ 15 #include <asm/efi.h> 16 17 #include "efistub.h" 18 19 bool efi_nochunk; 20 bool efi_nokaslr; 21 bool efi_noinitrd; 22 int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT; 23 bool efi_novamap; 24 25 static bool efi_nosoftreserve; 26 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA); 27 28 bool __pure __efi_soft_reserve_enabled(void) 29 { 30 return !efi_nosoftreserve; 31 } 32 33 void efi_char16_puts(efi_char16_t *str) 34 { 35 efi_call_proto(efi_table_attr(efi_system_table, con_out), 36 output_string, str); 37 } 38 39 static 40 u32 utf8_to_utf32(const u8 **s8) 41 { 42 u32 c32; 43 u8 c0, cx; 44 size_t clen, i; 45 46 c0 = cx = *(*s8)++; 47 /* 48 * The position of the most-significant 0 bit gives us the length of 49 * a multi-octet encoding. 50 */ 51 for (clen = 0; cx & 0x80; ++clen) 52 cx <<= 1; 53 /* 54 * If the 0 bit is in position 8, this is a valid single-octet 55 * encoding. If the 0 bit is in position 7 or positions 1-3, the 56 * encoding is invalid. 57 * In either case, we just return the first octet. 58 */ 59 if (clen < 2 || clen > 4) 60 return c0; 61 /* Get the bits from the first octet. */ 62 c32 = cx >> clen--; 63 for (i = 0; i < clen; ++i) { 64 /* Trailing octets must have 10 in most significant bits. */ 65 cx = (*s8)[i] ^ 0x80; 66 if (cx & 0xc0) 67 return c0; 68 c32 = (c32 << 6) | cx; 69 } 70 /* 71 * Check for validity: 72 * - The character must be in the Unicode range. 73 * - It must not be a surrogate. 74 * - It must be encoded using the correct number of octets. 75 */ 76 if (c32 > 0x10ffff || 77 (c32 & 0xf800) == 0xd800 || 78 clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000)) 79 return c0; 80 *s8 += clen; 81 return c32; 82 } 83 84 void efi_puts(const char *str) 85 { 86 efi_char16_t buf[128]; 87 size_t pos = 0, lim = ARRAY_SIZE(buf); 88 const u8 *s8 = (const u8 *)str; 89 u32 c32; 90 91 while (*s8) { 92 if (*s8 == '\n') 93 buf[pos++] = L'\r'; 94 c32 = utf8_to_utf32(&s8); 95 if (c32 < 0x10000) { 96 /* Characters in plane 0 use a single word. */ 97 buf[pos++] = c32; 98 } else { 99 /* 100 * Characters in other planes encode into a surrogate 101 * pair. 102 */ 103 buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10); 104 buf[pos++] = 0xdc00 + (c32 & 0x3ff); 105 } 106 if (*s8 == '\0' || pos >= lim - 2) { 107 buf[pos] = L'\0'; 108 efi_char16_puts(buf); 109 pos = 0; 110 } 111 } 112 } 113 114 int efi_printk(const char *fmt, ...) 115 { 116 char printf_buf[256]; 117 va_list args; 118 int printed; 119 int loglevel = printk_get_level(fmt); 120 121 switch (loglevel) { 122 case '0' ... '9': 123 loglevel -= '0'; 124 break; 125 default: 126 /* 127 * Use loglevel -1 for cases where we just want to print to 128 * the screen. 129 */ 130 loglevel = -1; 131 break; 132 } 133 134 if (loglevel >= efi_loglevel) 135 return 0; 136 137 if (loglevel >= 0) 138 efi_puts("EFI stub: "); 139 140 fmt = printk_skip_level(fmt); 141 142 va_start(args, fmt); 143 printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args); 144 va_end(args); 145 146 efi_puts(printf_buf); 147 if (printed >= sizeof(printf_buf)) { 148 efi_puts("[Message truncated]\n"); 149 return -1; 150 } 151 152 return printed; 153 } 154 155 /* 156 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi= 157 * option, e.g. efi=nochunk. 158 * 159 * It should be noted that efi= is parsed in two very different 160 * environments, first in the early boot environment of the EFI boot 161 * stub, and subsequently during the kernel boot. 162 */ 163 efi_status_t efi_parse_options(char const *cmdline) 164 { 165 size_t len = strlen(cmdline) + 1; 166 efi_status_t status; 167 char *str, *buf; 168 169 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); 170 if (status != EFI_SUCCESS) 171 return status; 172 173 str = skip_spaces(memcpy(buf, cmdline, len)); 174 175 while (*str) { 176 char *param, *val; 177 178 str = next_arg(str, ¶m, &val); 179 180 if (!strcmp(param, "nokaslr")) { 181 efi_nokaslr = true; 182 } else if (!strcmp(param, "quiet")) { 183 efi_loglevel = CONSOLE_LOGLEVEL_QUIET; 184 } else if (!strcmp(param, "noinitrd")) { 185 efi_noinitrd = true; 186 } else if (!strcmp(param, "efi") && val) { 187 efi_nochunk = parse_option_str(val, "nochunk"); 188 efi_novamap = parse_option_str(val, "novamap"); 189 190 efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && 191 parse_option_str(val, "nosoftreserve"); 192 193 if (parse_option_str(val, "disable_early_pci_dma")) 194 efi_disable_pci_dma = true; 195 if (parse_option_str(val, "no_disable_early_pci_dma")) 196 efi_disable_pci_dma = false; 197 if (parse_option_str(val, "debug")) 198 efi_loglevel = CONSOLE_LOGLEVEL_DEBUG; 199 } else if (!strcmp(param, "video") && 200 val && strstarts(val, "efifb:")) { 201 efi_parse_option_graphics(val + strlen("efifb:")); 202 } 203 } 204 efi_bs_call(free_pool, buf); 205 return EFI_SUCCESS; 206 } 207 208 /* 209 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. 210 */ 211 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) 212 { 213 unsigned int c; 214 215 while (n--) { 216 c = *src++; 217 if (n && c >= 0xd800 && c <= 0xdbff && 218 *src >= 0xdc00 && *src <= 0xdfff) { 219 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff); 220 src++; 221 n--; 222 } 223 if (c >= 0xd800 && c <= 0xdfff) 224 c = 0xfffd; /* Unmatched surrogate */ 225 if (c < 0x80) { 226 *dst++ = c; 227 continue; 228 } 229 if (c < 0x800) { 230 *dst++ = 0xc0 + (c >> 6); 231 goto t1; 232 } 233 if (c < 0x10000) { 234 *dst++ = 0xe0 + (c >> 12); 235 goto t2; 236 } 237 *dst++ = 0xf0 + (c >> 18); 238 *dst++ = 0x80 + ((c >> 12) & 0x3f); 239 t2: 240 *dst++ = 0x80 + ((c >> 6) & 0x3f); 241 t1: 242 *dst++ = 0x80 + (c & 0x3f); 243 } 244 245 return dst; 246 } 247 248 /* 249 * Convert the unicode UEFI command line to ASCII to pass to kernel. 250 * Size of memory allocated return in *cmd_line_len. 251 * Returns NULL on error. 252 */ 253 char *efi_convert_cmdline(efi_loaded_image_t *image, 254 int *cmd_line_len, unsigned long max_addr) 255 { 256 const u16 *s2; 257 u8 *s1 = NULL; 258 unsigned long cmdline_addr = 0; 259 int load_options_chars = efi_table_attr(image, load_options_size) / 2; 260 const u16 *options = efi_table_attr(image, load_options); 261 int options_bytes = 0; /* UTF-8 bytes */ 262 int options_chars = 0; /* UTF-16 chars */ 263 efi_status_t status; 264 u16 zero = 0; 265 266 if (options) { 267 s2 = options; 268 while (options_chars < load_options_chars) { 269 u16 c = *s2++; 270 271 if (c == L'\0' || c == L'\n') 272 break; 273 /* 274 * Get the number of UTF-8 bytes corresponding to a 275 * UTF-16 character. 276 * The first part handles everything in the BMP. 277 */ 278 options_bytes += 1 + (c >= 0x80) + (c >= 0x800); 279 options_chars++; 280 /* 281 * Add one more byte for valid surrogate pairs. Invalid 282 * surrogates will be replaced with 0xfffd and take up 283 * only 3 bytes. 284 */ 285 if ((c & 0xfc00) == 0xd800) { 286 /* 287 * If the very last word is a high surrogate, 288 * we must ignore it since we can't access the 289 * low surrogate. 290 */ 291 if (options_chars == load_options_chars) { 292 options_bytes -= 3; 293 options_chars--; 294 break; 295 } else if ((*s2 & 0xfc00) == 0xdc00) { 296 options_bytes++; 297 options_chars++; 298 s2++; 299 } 300 } 301 } 302 } 303 304 if (!options_chars) { 305 /* No command line options, so return empty string*/ 306 options = &zero; 307 } 308 309 options_bytes++; /* NUL termination */ 310 311 status = efi_allocate_pages(options_bytes, &cmdline_addr, max_addr); 312 if (status != EFI_SUCCESS) 313 return NULL; 314 315 s1 = (u8 *)cmdline_addr; 316 s2 = (const u16 *)options; 317 318 s1 = efi_utf16_to_utf8(s1, s2, options_chars); 319 *s1 = '\0'; 320 321 *cmd_line_len = options_bytes; 322 return (char *)cmdline_addr; 323 } 324 325 /* 326 * Handle calling ExitBootServices according to the requirements set out by the 327 * spec. Obtains the current memory map, and returns that info after calling 328 * ExitBootServices. The client must specify a function to perform any 329 * processing of the memory map data prior to ExitBootServices. A client 330 * specific structure may be passed to the function via priv. The client 331 * function may be called multiple times. 332 */ 333 efi_status_t efi_exit_boot_services(void *handle, 334 struct efi_boot_memmap *map, 335 void *priv, 336 efi_exit_boot_map_processing priv_func) 337 { 338 efi_status_t status; 339 340 status = efi_get_memory_map(map); 341 342 if (status != EFI_SUCCESS) 343 goto fail; 344 345 status = priv_func(map, priv); 346 if (status != EFI_SUCCESS) 347 goto free_map; 348 349 if (efi_disable_pci_dma) 350 efi_pci_disable_bridge_busmaster(); 351 352 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 353 354 if (status == EFI_INVALID_PARAMETER) { 355 /* 356 * The memory map changed between efi_get_memory_map() and 357 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4: 358 * EFI_BOOT_SERVICES.ExitBootServices we need to get the 359 * updated map, and try again. The spec implies one retry 360 * should be sufficent, which is confirmed against the EDK2 361 * implementation. Per the spec, we can only invoke 362 * get_memory_map() and exit_boot_services() - we cannot alloc 363 * so efi_get_memory_map() cannot be used, and we must reuse 364 * the buffer. For all practical purposes, the headroom in the 365 * buffer should account for any changes in the map so the call 366 * to get_memory_map() is expected to succeed here. 367 */ 368 *map->map_size = *map->buff_size; 369 status = efi_bs_call(get_memory_map, 370 map->map_size, 371 *map->map, 372 map->key_ptr, 373 map->desc_size, 374 map->desc_ver); 375 376 /* exit_boot_services() was called, thus cannot free */ 377 if (status != EFI_SUCCESS) 378 goto fail; 379 380 status = priv_func(map, priv); 381 /* exit_boot_services() was called, thus cannot free */ 382 if (status != EFI_SUCCESS) 383 goto fail; 384 385 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 386 } 387 388 /* exit_boot_services() was called, thus cannot free */ 389 if (status != EFI_SUCCESS) 390 goto fail; 391 392 return EFI_SUCCESS; 393 394 free_map: 395 efi_bs_call(free_pool, *map->map); 396 fail: 397 return status; 398 } 399 400 void *get_efi_config_table(efi_guid_t guid) 401 { 402 unsigned long tables = efi_table_attr(efi_system_table, tables); 403 int nr_tables = efi_table_attr(efi_system_table, nr_tables); 404 int i; 405 406 for (i = 0; i < nr_tables; i++) { 407 efi_config_table_t *t = (void *)tables; 408 409 if (efi_guidcmp(t->guid, guid) == 0) 410 return efi_table_attr(t, table); 411 412 tables += efi_is_native() ? sizeof(efi_config_table_t) 413 : sizeof(efi_config_table_32_t); 414 } 415 return NULL; 416 } 417 418 /* 419 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way 420 * for the firmware or bootloader to expose the initrd data directly to the stub 421 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is 422 * very easy to implement. It is a simple Linux initrd specific conduit between 423 * kernel and firmware, allowing us to put the EFI stub (being part of the 424 * kernel) in charge of where and when to load the initrd, while leaving it up 425 * to the firmware to decide whether it needs to expose its filesystem hierarchy 426 * via EFI protocols. 427 */ 428 static const struct { 429 struct efi_vendor_dev_path vendor; 430 struct efi_generic_dev_path end; 431 } __packed initrd_dev_path = { 432 { 433 { 434 EFI_DEV_MEDIA, 435 EFI_DEV_MEDIA_VENDOR, 436 sizeof(struct efi_vendor_dev_path), 437 }, 438 LINUX_EFI_INITRD_MEDIA_GUID 439 }, { 440 EFI_DEV_END_PATH, 441 EFI_DEV_END_ENTIRE, 442 sizeof(struct efi_generic_dev_path) 443 } 444 }; 445 446 /** 447 * efi_load_initrd_dev_path - load the initrd from the Linux initrd device path 448 * @load_addr: pointer to store the address where the initrd was loaded 449 * @load_size: pointer to store the size of the loaded initrd 450 * @max: upper limit for the initrd memory allocation 451 * @return: %EFI_SUCCESS if the initrd was loaded successfully, in which 452 * case @load_addr and @load_size are assigned accordingly 453 * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd 454 * device path 455 * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL 456 * %EFI_OUT_OF_RESOURCES if memory allocation failed 457 * %EFI_LOAD_ERROR in all other cases 458 */ 459 static 460 efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, 461 unsigned long *load_size, 462 unsigned long max) 463 { 464 efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; 465 efi_device_path_protocol_t *dp; 466 efi_load_file2_protocol_t *lf2; 467 unsigned long initrd_addr; 468 unsigned long initrd_size; 469 efi_handle_t handle; 470 efi_status_t status; 471 472 dp = (efi_device_path_protocol_t *)&initrd_dev_path; 473 status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle); 474 if (status != EFI_SUCCESS) 475 return status; 476 477 status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, 478 (void **)&lf2); 479 if (status != EFI_SUCCESS) 480 return status; 481 482 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); 483 if (status != EFI_BUFFER_TOO_SMALL) 484 return EFI_LOAD_ERROR; 485 486 status = efi_allocate_pages(initrd_size, &initrd_addr, max); 487 if (status != EFI_SUCCESS) 488 return status; 489 490 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, 491 (void *)initrd_addr); 492 if (status != EFI_SUCCESS) { 493 efi_free(initrd_size, initrd_addr); 494 return EFI_LOAD_ERROR; 495 } 496 497 *load_addr = initrd_addr; 498 *load_size = initrd_size; 499 return EFI_SUCCESS; 500 } 501 502 static 503 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image, 504 unsigned long *load_addr, 505 unsigned long *load_size, 506 unsigned long soft_limit, 507 unsigned long hard_limit) 508 { 509 if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) || 510 (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) { 511 *load_addr = *load_size = 0; 512 return EFI_SUCCESS; 513 } 514 515 return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, 516 soft_limit, hard_limit, 517 load_addr, load_size); 518 } 519 520 efi_status_t efi_load_initrd(efi_loaded_image_t *image, 521 unsigned long *load_addr, 522 unsigned long *load_size, 523 unsigned long soft_limit, 524 unsigned long hard_limit) 525 { 526 efi_status_t status; 527 528 if (!load_addr || !load_size) 529 return EFI_INVALID_PARAMETER; 530 531 status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit); 532 if (status == EFI_SUCCESS) { 533 efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n"); 534 } else if (status == EFI_NOT_FOUND) { 535 status = efi_load_initrd_cmdline(image, load_addr, load_size, 536 soft_limit, hard_limit); 537 if (status == EFI_SUCCESS && *load_size > 0) 538 efi_info("Loaded initrd from command line option\n"); 539 } 540 541 return status; 542 } 543 544 efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key) 545 { 546 efi_event_t events[2], timer; 547 unsigned long index; 548 efi_simple_text_input_protocol_t *con_in; 549 efi_status_t status; 550 551 con_in = efi_table_attr(efi_system_table, con_in); 552 if (!con_in) 553 return EFI_UNSUPPORTED; 554 efi_set_event_at(events, 0, efi_table_attr(con_in, wait_for_key)); 555 556 status = efi_bs_call(create_event, EFI_EVT_TIMER, 0, NULL, NULL, &timer); 557 if (status != EFI_SUCCESS) 558 return status; 559 560 status = efi_bs_call(set_timer, timer, EfiTimerRelative, 561 EFI_100NSEC_PER_USEC * usec); 562 if (status != EFI_SUCCESS) 563 return status; 564 efi_set_event_at(events, 1, timer); 565 566 status = efi_bs_call(wait_for_event, 2, events, &index); 567 if (status == EFI_SUCCESS) { 568 if (index == 0) 569 status = efi_call_proto(con_in, read_keystroke, key); 570 else 571 status = EFI_TIMEOUT; 572 } 573 574 efi_bs_call(close_event, timer); 575 576 return status; 577 } 578