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 void efi_puts(const char *str) 40 { 41 efi_char16_t buf[128]; 42 size_t pos = 0, lim = ARRAY_SIZE(buf); 43 44 while (*str) { 45 if (*str == '\n') 46 buf[pos++] = L'\r'; 47 /* Cast to unsigned char to avoid sign-extension */ 48 buf[pos++] = (unsigned char)(*str++); 49 if (*str == '\0' || pos >= lim - 2) { 50 buf[pos] = L'\0'; 51 efi_char16_puts(buf); 52 pos = 0; 53 } 54 } 55 } 56 57 int efi_printk(const char *fmt, ...) 58 { 59 char printf_buf[256]; 60 va_list args; 61 int printed; 62 int loglevel = printk_get_level(fmt); 63 64 switch (loglevel) { 65 case '0' ... '9': 66 loglevel -= '0'; 67 break; 68 default: 69 /* 70 * Use loglevel -1 for cases where we just want to print to 71 * the screen. 72 */ 73 loglevel = -1; 74 break; 75 } 76 77 if (loglevel >= efi_loglevel) 78 return 0; 79 80 if (loglevel >= 0) 81 efi_puts("EFI stub: "); 82 83 fmt = printk_skip_level(fmt); 84 85 va_start(args, fmt); 86 printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args); 87 va_end(args); 88 89 efi_puts(printf_buf); 90 if (printed >= sizeof(printf_buf)) { 91 efi_puts("[Message truncated]\n"); 92 return -1; 93 } 94 95 return printed; 96 } 97 98 /* 99 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi= 100 * option, e.g. efi=nochunk. 101 * 102 * It should be noted that efi= is parsed in two very different 103 * environments, first in the early boot environment of the EFI boot 104 * stub, and subsequently during the kernel boot. 105 */ 106 efi_status_t efi_parse_options(char const *cmdline) 107 { 108 size_t len = strlen(cmdline) + 1; 109 efi_status_t status; 110 char *str, *buf; 111 112 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); 113 if (status != EFI_SUCCESS) 114 return status; 115 116 str = skip_spaces(memcpy(buf, cmdline, len)); 117 118 while (*str) { 119 char *param, *val; 120 121 str = next_arg(str, ¶m, &val); 122 123 if (!strcmp(param, "nokaslr")) { 124 efi_nokaslr = true; 125 } else if (!strcmp(param, "quiet")) { 126 efi_loglevel = CONSOLE_LOGLEVEL_QUIET; 127 } else if (!strcmp(param, "noinitrd")) { 128 efi_noinitrd = true; 129 } else if (!strcmp(param, "efi") && val) { 130 efi_nochunk = parse_option_str(val, "nochunk"); 131 efi_novamap = parse_option_str(val, "novamap"); 132 133 efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && 134 parse_option_str(val, "nosoftreserve"); 135 136 if (parse_option_str(val, "disable_early_pci_dma")) 137 efi_disable_pci_dma = true; 138 if (parse_option_str(val, "no_disable_early_pci_dma")) 139 efi_disable_pci_dma = false; 140 if (parse_option_str(val, "debug")) 141 efi_loglevel = CONSOLE_LOGLEVEL_DEBUG; 142 } else if (!strcmp(param, "video") && 143 val && strstarts(val, "efifb:")) { 144 efi_parse_option_graphics(val + strlen("efifb:")); 145 } 146 } 147 efi_bs_call(free_pool, buf); 148 return EFI_SUCCESS; 149 } 150 151 /* 152 * Get the number of UTF-8 bytes corresponding to an UTF-16 character. 153 * This overestimates for surrogates, but that is okay. 154 */ 155 static int efi_utf8_bytes(u16 c) 156 { 157 return 1 + (c >= 0x80) + (c >= 0x800); 158 } 159 160 /* 161 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. 162 */ 163 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) 164 { 165 unsigned int c; 166 167 while (n--) { 168 c = *src++; 169 if (n && c >= 0xd800 && c <= 0xdbff && 170 *src >= 0xdc00 && *src <= 0xdfff) { 171 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff); 172 src++; 173 n--; 174 } 175 if (c >= 0xd800 && c <= 0xdfff) 176 c = 0xfffd; /* Unmatched surrogate */ 177 if (c < 0x80) { 178 *dst++ = c; 179 continue; 180 } 181 if (c < 0x800) { 182 *dst++ = 0xc0 + (c >> 6); 183 goto t1; 184 } 185 if (c < 0x10000) { 186 *dst++ = 0xe0 + (c >> 12); 187 goto t2; 188 } 189 *dst++ = 0xf0 + (c >> 18); 190 *dst++ = 0x80 + ((c >> 12) & 0x3f); 191 t2: 192 *dst++ = 0x80 + ((c >> 6) & 0x3f); 193 t1: 194 *dst++ = 0x80 + (c & 0x3f); 195 } 196 197 return dst; 198 } 199 200 /* 201 * Convert the unicode UEFI command line to ASCII to pass to kernel. 202 * Size of memory allocated return in *cmd_line_len. 203 * Returns NULL on error. 204 */ 205 char *efi_convert_cmdline(efi_loaded_image_t *image, 206 int *cmd_line_len, unsigned long max_addr) 207 { 208 const u16 *s2; 209 u8 *s1 = NULL; 210 unsigned long cmdline_addr = 0; 211 int load_options_chars = efi_table_attr(image, load_options_size) / 2; 212 const u16 *options = efi_table_attr(image, load_options); 213 int options_bytes = 0; /* UTF-8 bytes */ 214 int options_chars = 0; /* UTF-16 chars */ 215 efi_status_t status; 216 u16 zero = 0; 217 218 if (options) { 219 s2 = options; 220 while (*s2 && *s2 != '\n' 221 && options_chars < load_options_chars) { 222 options_bytes += efi_utf8_bytes(*s2++); 223 options_chars++; 224 } 225 } 226 227 if (!options_chars) { 228 /* No command line options, so return empty string*/ 229 options = &zero; 230 } 231 232 options_bytes++; /* NUL termination */ 233 234 status = efi_allocate_pages(options_bytes, &cmdline_addr, max_addr); 235 if (status != EFI_SUCCESS) 236 return NULL; 237 238 s1 = (u8 *)cmdline_addr; 239 s2 = (const u16 *)options; 240 241 s1 = efi_utf16_to_utf8(s1, s2, options_chars); 242 *s1 = '\0'; 243 244 *cmd_line_len = options_bytes; 245 return (char *)cmdline_addr; 246 } 247 248 /* 249 * Handle calling ExitBootServices according to the requirements set out by the 250 * spec. Obtains the current memory map, and returns that info after calling 251 * ExitBootServices. The client must specify a function to perform any 252 * processing of the memory map data prior to ExitBootServices. A client 253 * specific structure may be passed to the function via priv. The client 254 * function may be called multiple times. 255 */ 256 efi_status_t efi_exit_boot_services(void *handle, 257 struct efi_boot_memmap *map, 258 void *priv, 259 efi_exit_boot_map_processing priv_func) 260 { 261 efi_status_t status; 262 263 status = efi_get_memory_map(map); 264 265 if (status != EFI_SUCCESS) 266 goto fail; 267 268 status = priv_func(map, priv); 269 if (status != EFI_SUCCESS) 270 goto free_map; 271 272 if (efi_disable_pci_dma) 273 efi_pci_disable_bridge_busmaster(); 274 275 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 276 277 if (status == EFI_INVALID_PARAMETER) { 278 /* 279 * The memory map changed between efi_get_memory_map() and 280 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4: 281 * EFI_BOOT_SERVICES.ExitBootServices we need to get the 282 * updated map, and try again. The spec implies one retry 283 * should be sufficent, which is confirmed against the EDK2 284 * implementation. Per the spec, we can only invoke 285 * get_memory_map() and exit_boot_services() - we cannot alloc 286 * so efi_get_memory_map() cannot be used, and we must reuse 287 * the buffer. For all practical purposes, the headroom in the 288 * buffer should account for any changes in the map so the call 289 * to get_memory_map() is expected to succeed here. 290 */ 291 *map->map_size = *map->buff_size; 292 status = efi_bs_call(get_memory_map, 293 map->map_size, 294 *map->map, 295 map->key_ptr, 296 map->desc_size, 297 map->desc_ver); 298 299 /* exit_boot_services() was called, thus cannot free */ 300 if (status != EFI_SUCCESS) 301 goto fail; 302 303 status = priv_func(map, priv); 304 /* exit_boot_services() was called, thus cannot free */ 305 if (status != EFI_SUCCESS) 306 goto fail; 307 308 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 309 } 310 311 /* exit_boot_services() was called, thus cannot free */ 312 if (status != EFI_SUCCESS) 313 goto fail; 314 315 return EFI_SUCCESS; 316 317 free_map: 318 efi_bs_call(free_pool, *map->map); 319 fail: 320 return status; 321 } 322 323 void *get_efi_config_table(efi_guid_t guid) 324 { 325 unsigned long tables = efi_table_attr(efi_system_table, tables); 326 int nr_tables = efi_table_attr(efi_system_table, nr_tables); 327 int i; 328 329 for (i = 0; i < nr_tables; i++) { 330 efi_config_table_t *t = (void *)tables; 331 332 if (efi_guidcmp(t->guid, guid) == 0) 333 return efi_table_attr(t, table); 334 335 tables += efi_is_native() ? sizeof(efi_config_table_t) 336 : sizeof(efi_config_table_32_t); 337 } 338 return NULL; 339 } 340 341 /* 342 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way 343 * for the firmware or bootloader to expose the initrd data directly to the stub 344 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is 345 * very easy to implement. It is a simple Linux initrd specific conduit between 346 * kernel and firmware, allowing us to put the EFI stub (being part of the 347 * kernel) in charge of where and when to load the initrd, while leaving it up 348 * to the firmware to decide whether it needs to expose its filesystem hierarchy 349 * via EFI protocols. 350 */ 351 static const struct { 352 struct efi_vendor_dev_path vendor; 353 struct efi_generic_dev_path end; 354 } __packed initrd_dev_path = { 355 { 356 { 357 EFI_DEV_MEDIA, 358 EFI_DEV_MEDIA_VENDOR, 359 sizeof(struct efi_vendor_dev_path), 360 }, 361 LINUX_EFI_INITRD_MEDIA_GUID 362 }, { 363 EFI_DEV_END_PATH, 364 EFI_DEV_END_ENTIRE, 365 sizeof(struct efi_generic_dev_path) 366 } 367 }; 368 369 /** 370 * efi_load_initrd_dev_path - load the initrd from the Linux initrd device path 371 * @load_addr: pointer to store the address where the initrd was loaded 372 * @load_size: pointer to store the size of the loaded initrd 373 * @max: upper limit for the initrd memory allocation 374 * @return: %EFI_SUCCESS if the initrd was loaded successfully, in which 375 * case @load_addr and @load_size are assigned accordingly 376 * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd 377 * device path 378 * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL 379 * %EFI_OUT_OF_RESOURCES if memory allocation failed 380 * %EFI_LOAD_ERROR in all other cases 381 */ 382 static 383 efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, 384 unsigned long *load_size, 385 unsigned long max) 386 { 387 efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; 388 efi_device_path_protocol_t *dp; 389 efi_load_file2_protocol_t *lf2; 390 unsigned long initrd_addr; 391 unsigned long initrd_size; 392 efi_handle_t handle; 393 efi_status_t status; 394 395 dp = (efi_device_path_protocol_t *)&initrd_dev_path; 396 status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle); 397 if (status != EFI_SUCCESS) 398 return status; 399 400 status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, 401 (void **)&lf2); 402 if (status != EFI_SUCCESS) 403 return status; 404 405 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); 406 if (status != EFI_BUFFER_TOO_SMALL) 407 return EFI_LOAD_ERROR; 408 409 status = efi_allocate_pages(initrd_size, &initrd_addr, max); 410 if (status != EFI_SUCCESS) 411 return status; 412 413 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, 414 (void *)initrd_addr); 415 if (status != EFI_SUCCESS) { 416 efi_free(initrd_size, initrd_addr); 417 return EFI_LOAD_ERROR; 418 } 419 420 *load_addr = initrd_addr; 421 *load_size = initrd_size; 422 return EFI_SUCCESS; 423 } 424 425 static 426 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image, 427 unsigned long *load_addr, 428 unsigned long *load_size, 429 unsigned long soft_limit, 430 unsigned long hard_limit) 431 { 432 if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) || 433 (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) { 434 *load_addr = *load_size = 0; 435 return EFI_SUCCESS; 436 } 437 438 return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, 439 soft_limit, hard_limit, 440 load_addr, load_size); 441 } 442 443 efi_status_t efi_load_initrd(efi_loaded_image_t *image, 444 unsigned long *load_addr, 445 unsigned long *load_size, 446 unsigned long soft_limit, 447 unsigned long hard_limit) 448 { 449 efi_status_t status; 450 451 if (!load_addr || !load_size) 452 return EFI_INVALID_PARAMETER; 453 454 status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit); 455 if (status == EFI_SUCCESS) { 456 efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n"); 457 } else if (status == EFI_NOT_FOUND) { 458 status = efi_load_initrd_cmdline(image, load_addr, load_size, 459 soft_limit, hard_limit); 460 if (status == EFI_SUCCESS && *load_size > 0) 461 efi_info("Loaded initrd from command line option\n"); 462 } 463 464 return status; 465 } 466