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 <asm/efi.h> 15 16 #include "efistub.h" 17 18 bool efi_nochunk; 19 bool efi_nokaslr; 20 bool efi_noinitrd; 21 bool efi_quiet; 22 bool efi_novamap; 23 24 static bool efi_nosoftreserve; 25 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA); 26 27 bool __pure __efi_soft_reserve_enabled(void) 28 { 29 return !efi_nosoftreserve; 30 } 31 32 void efi_char16_puts(efi_char16_t *str) 33 { 34 efi_call_proto(efi_table_attr(efi_system_table, con_out), 35 output_string, str); 36 } 37 38 void efi_puts(const char *str) 39 { 40 efi_char16_t buf[128]; 41 size_t pos = 0, lim = ARRAY_SIZE(buf); 42 43 while (*str) { 44 if (*str == '\n') 45 buf[pos++] = L'\r'; 46 /* Cast to unsigned char to avoid sign-extension */ 47 buf[pos++] = (unsigned char)(*str++); 48 if (*str == '\0' || pos >= lim - 2) { 49 buf[pos] = L'\0'; 50 efi_char16_puts(buf); 51 pos = 0; 52 } 53 } 54 } 55 56 int efi_printk(const char *fmt, ...) 57 { 58 char printf_buf[256]; 59 va_list args; 60 int printed; 61 62 va_start(args, fmt); 63 printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args); 64 va_end(args); 65 66 efi_puts(printf_buf); 67 if (printed >= sizeof(printf_buf)) { 68 efi_puts("[Message truncated]\n"); 69 return -1; 70 } 71 72 return printed; 73 } 74 75 /* 76 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi= 77 * option, e.g. efi=nochunk. 78 * 79 * It should be noted that efi= is parsed in two very different 80 * environments, first in the early boot environment of the EFI boot 81 * stub, and subsequently during the kernel boot. 82 */ 83 efi_status_t efi_parse_options(char const *cmdline) 84 { 85 size_t len = strlen(cmdline) + 1; 86 efi_status_t status; 87 char *str, *buf; 88 89 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); 90 if (status != EFI_SUCCESS) 91 return status; 92 93 str = skip_spaces(memcpy(buf, cmdline, len)); 94 95 while (*str) { 96 char *param, *val; 97 98 str = next_arg(str, ¶m, &val); 99 100 if (!strcmp(param, "nokaslr")) { 101 efi_nokaslr = true; 102 } else if (!strcmp(param, "quiet")) { 103 efi_quiet = true; 104 } else if (!strcmp(param, "noinitrd")) { 105 efi_noinitrd = true; 106 } else if (!strcmp(param, "efi") && val) { 107 efi_nochunk = parse_option_str(val, "nochunk"); 108 efi_novamap = parse_option_str(val, "novamap"); 109 110 efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && 111 parse_option_str(val, "nosoftreserve"); 112 113 if (parse_option_str(val, "disable_early_pci_dma")) 114 efi_disable_pci_dma = true; 115 if (parse_option_str(val, "no_disable_early_pci_dma")) 116 efi_disable_pci_dma = false; 117 } else if (!strcmp(param, "video") && 118 val && strstarts(val, "efifb:")) { 119 efi_parse_option_graphics(val + strlen("efifb:")); 120 } 121 } 122 efi_bs_call(free_pool, buf); 123 return EFI_SUCCESS; 124 } 125 126 /* 127 * Get the number of UTF-8 bytes corresponding to an UTF-16 character. 128 * This overestimates for surrogates, but that is okay. 129 */ 130 static int efi_utf8_bytes(u16 c) 131 { 132 return 1 + (c >= 0x80) + (c >= 0x800); 133 } 134 135 /* 136 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. 137 */ 138 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) 139 { 140 unsigned int c; 141 142 while (n--) { 143 c = *src++; 144 if (n && c >= 0xd800 && c <= 0xdbff && 145 *src >= 0xdc00 && *src <= 0xdfff) { 146 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff); 147 src++; 148 n--; 149 } 150 if (c >= 0xd800 && c <= 0xdfff) 151 c = 0xfffd; /* Unmatched surrogate */ 152 if (c < 0x80) { 153 *dst++ = c; 154 continue; 155 } 156 if (c < 0x800) { 157 *dst++ = 0xc0 + (c >> 6); 158 goto t1; 159 } 160 if (c < 0x10000) { 161 *dst++ = 0xe0 + (c >> 12); 162 goto t2; 163 } 164 *dst++ = 0xf0 + (c >> 18); 165 *dst++ = 0x80 + ((c >> 12) & 0x3f); 166 t2: 167 *dst++ = 0x80 + ((c >> 6) & 0x3f); 168 t1: 169 *dst++ = 0x80 + (c & 0x3f); 170 } 171 172 return dst; 173 } 174 175 /* 176 * Convert the unicode UEFI command line to ASCII to pass to kernel. 177 * Size of memory allocated return in *cmd_line_len. 178 * Returns NULL on error. 179 */ 180 char *efi_convert_cmdline(efi_loaded_image_t *image, 181 int *cmd_line_len, unsigned long max_addr) 182 { 183 const u16 *s2; 184 u8 *s1 = NULL; 185 unsigned long cmdline_addr = 0; 186 int load_options_chars = efi_table_attr(image, load_options_size) / 2; 187 const u16 *options = efi_table_attr(image, load_options); 188 int options_bytes = 0; /* UTF-8 bytes */ 189 int options_chars = 0; /* UTF-16 chars */ 190 efi_status_t status; 191 u16 zero = 0; 192 193 if (options) { 194 s2 = options; 195 while (*s2 && *s2 != '\n' 196 && options_chars < load_options_chars) { 197 options_bytes += efi_utf8_bytes(*s2++); 198 options_chars++; 199 } 200 } 201 202 if (!options_chars) { 203 /* No command line options, so return empty string*/ 204 options = &zero; 205 } 206 207 options_bytes++; /* NUL termination */ 208 209 status = efi_allocate_pages(options_bytes, &cmdline_addr, max_addr); 210 if (status != EFI_SUCCESS) 211 return NULL; 212 213 s1 = (u8 *)cmdline_addr; 214 s2 = (const u16 *)options; 215 216 s1 = efi_utf16_to_utf8(s1, s2, options_chars); 217 *s1 = '\0'; 218 219 *cmd_line_len = options_bytes; 220 return (char *)cmdline_addr; 221 } 222 223 /* 224 * Handle calling ExitBootServices according to the requirements set out by the 225 * spec. Obtains the current memory map, and returns that info after calling 226 * ExitBootServices. The client must specify a function to perform any 227 * processing of the memory map data prior to ExitBootServices. A client 228 * specific structure may be passed to the function via priv. The client 229 * function may be called multiple times. 230 */ 231 efi_status_t efi_exit_boot_services(void *handle, 232 struct efi_boot_memmap *map, 233 void *priv, 234 efi_exit_boot_map_processing priv_func) 235 { 236 efi_status_t status; 237 238 status = efi_get_memory_map(map); 239 240 if (status != EFI_SUCCESS) 241 goto fail; 242 243 status = priv_func(map, priv); 244 if (status != EFI_SUCCESS) 245 goto free_map; 246 247 if (efi_disable_pci_dma) 248 efi_pci_disable_bridge_busmaster(); 249 250 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 251 252 if (status == EFI_INVALID_PARAMETER) { 253 /* 254 * The memory map changed between efi_get_memory_map() and 255 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4: 256 * EFI_BOOT_SERVICES.ExitBootServices we need to get the 257 * updated map, and try again. The spec implies one retry 258 * should be sufficent, which is confirmed against the EDK2 259 * implementation. Per the spec, we can only invoke 260 * get_memory_map() and exit_boot_services() - we cannot alloc 261 * so efi_get_memory_map() cannot be used, and we must reuse 262 * the buffer. For all practical purposes, the headroom in the 263 * buffer should account for any changes in the map so the call 264 * to get_memory_map() is expected to succeed here. 265 */ 266 *map->map_size = *map->buff_size; 267 status = efi_bs_call(get_memory_map, 268 map->map_size, 269 *map->map, 270 map->key_ptr, 271 map->desc_size, 272 map->desc_ver); 273 274 /* exit_boot_services() was called, thus cannot free */ 275 if (status != EFI_SUCCESS) 276 goto fail; 277 278 status = priv_func(map, priv); 279 /* exit_boot_services() was called, thus cannot free */ 280 if (status != EFI_SUCCESS) 281 goto fail; 282 283 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 284 } 285 286 /* exit_boot_services() was called, thus cannot free */ 287 if (status != EFI_SUCCESS) 288 goto fail; 289 290 return EFI_SUCCESS; 291 292 free_map: 293 efi_bs_call(free_pool, *map->map); 294 fail: 295 return status; 296 } 297 298 void *get_efi_config_table(efi_guid_t guid) 299 { 300 unsigned long tables = efi_table_attr(efi_system_table, tables); 301 int nr_tables = efi_table_attr(efi_system_table, nr_tables); 302 int i; 303 304 for (i = 0; i < nr_tables; i++) { 305 efi_config_table_t *t = (void *)tables; 306 307 if (efi_guidcmp(t->guid, guid) == 0) 308 return efi_table_attr(t, table); 309 310 tables += efi_is_native() ? sizeof(efi_config_table_t) 311 : sizeof(efi_config_table_32_t); 312 } 313 return NULL; 314 } 315 316 /* 317 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way 318 * for the firmware or bootloader to expose the initrd data directly to the stub 319 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is 320 * very easy to implement. It is a simple Linux initrd specific conduit between 321 * kernel and firmware, allowing us to put the EFI stub (being part of the 322 * kernel) in charge of where and when to load the initrd, while leaving it up 323 * to the firmware to decide whether it needs to expose its filesystem hierarchy 324 * via EFI protocols. 325 */ 326 static const struct { 327 struct efi_vendor_dev_path vendor; 328 struct efi_generic_dev_path end; 329 } __packed initrd_dev_path = { 330 { 331 { 332 EFI_DEV_MEDIA, 333 EFI_DEV_MEDIA_VENDOR, 334 sizeof(struct efi_vendor_dev_path), 335 }, 336 LINUX_EFI_INITRD_MEDIA_GUID 337 }, { 338 EFI_DEV_END_PATH, 339 EFI_DEV_END_ENTIRE, 340 sizeof(struct efi_generic_dev_path) 341 } 342 }; 343 344 /** 345 * efi_load_initrd_dev_path - load the initrd from the Linux initrd device path 346 * @load_addr: pointer to store the address where the initrd was loaded 347 * @load_size: pointer to store the size of the loaded initrd 348 * @max: upper limit for the initrd memory allocation 349 * @return: %EFI_SUCCESS if the initrd was loaded successfully, in which 350 * case @load_addr and @load_size are assigned accordingly 351 * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd 352 * device path 353 * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL 354 * %EFI_OUT_OF_RESOURCES if memory allocation failed 355 * %EFI_LOAD_ERROR in all other cases 356 */ 357 static 358 efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, 359 unsigned long *load_size, 360 unsigned long max) 361 { 362 efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; 363 efi_device_path_protocol_t *dp; 364 efi_load_file2_protocol_t *lf2; 365 unsigned long initrd_addr; 366 unsigned long initrd_size; 367 efi_handle_t handle; 368 efi_status_t status; 369 370 dp = (efi_device_path_protocol_t *)&initrd_dev_path; 371 status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle); 372 if (status != EFI_SUCCESS) 373 return status; 374 375 status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, 376 (void **)&lf2); 377 if (status != EFI_SUCCESS) 378 return status; 379 380 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); 381 if (status != EFI_BUFFER_TOO_SMALL) 382 return EFI_LOAD_ERROR; 383 384 status = efi_allocate_pages(initrd_size, &initrd_addr, max); 385 if (status != EFI_SUCCESS) 386 return status; 387 388 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, 389 (void *)initrd_addr); 390 if (status != EFI_SUCCESS) { 391 efi_free(initrd_size, initrd_addr); 392 return EFI_LOAD_ERROR; 393 } 394 395 *load_addr = initrd_addr; 396 *load_size = initrd_size; 397 return EFI_SUCCESS; 398 } 399 400 static 401 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image, 402 unsigned long *load_addr, 403 unsigned long *load_size, 404 unsigned long soft_limit, 405 unsigned long hard_limit) 406 { 407 if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) || 408 (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) { 409 *load_addr = *load_size = 0; 410 return EFI_SUCCESS; 411 } 412 413 return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, 414 soft_limit, hard_limit, 415 load_addr, load_size); 416 } 417 418 efi_status_t efi_load_initrd(efi_loaded_image_t *image, 419 unsigned long *load_addr, 420 unsigned long *load_size, 421 unsigned long soft_limit, 422 unsigned long hard_limit) 423 { 424 efi_status_t status; 425 426 if (!load_addr || !load_size) 427 return EFI_INVALID_PARAMETER; 428 429 status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit); 430 if (status == EFI_SUCCESS) { 431 efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n"); 432 } else if (status == EFI_NOT_FOUND) { 433 status = efi_load_initrd_cmdline(image, load_addr, load_size, 434 soft_limit, hard_limit); 435 if (status == EFI_SUCCESS && *load_size > 0) 436 efi_info("Loaded initrd from command line option\n"); 437 } 438 439 return status; 440 } 441