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 <linux/efi.h> 11 #include <asm/efi.h> 12 13 #include "efistub.h" 14 15 static bool efi_nochunk; 16 static bool efi_nokaslr; 17 static bool efi_noinitrd; 18 static bool efi_quiet; 19 static bool efi_novamap; 20 static bool efi_nosoftreserve; 21 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA); 22 23 bool __pure nochunk(void) 24 { 25 return efi_nochunk; 26 } 27 bool __pure nokaslr(void) 28 { 29 return efi_nokaslr; 30 } 31 bool __pure noinitrd(void) 32 { 33 return efi_noinitrd; 34 } 35 bool __pure is_quiet(void) 36 { 37 return efi_quiet; 38 } 39 bool __pure novamap(void) 40 { 41 return efi_novamap; 42 } 43 bool __pure __efi_soft_reserve_enabled(void) 44 { 45 return !efi_nosoftreserve; 46 } 47 48 void efi_printk(char *str) 49 { 50 char *s8; 51 52 for (s8 = str; *s8; s8++) { 53 efi_char16_t ch[2] = { 0 }; 54 55 ch[0] = *s8; 56 if (*s8 == '\n') { 57 efi_char16_t nl[2] = { '\r', 0 }; 58 efi_char16_printk(nl); 59 } 60 61 efi_char16_printk(ch); 62 } 63 } 64 65 /* 66 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi= 67 * option, e.g. efi=nochunk. 68 * 69 * It should be noted that efi= is parsed in two very different 70 * environments, first in the early boot environment of the EFI boot 71 * stub, and subsequently during the kernel boot. 72 */ 73 efi_status_t efi_parse_options(char const *cmdline) 74 { 75 size_t len = strlen(cmdline) + 1; 76 efi_status_t status; 77 char *str, *buf; 78 79 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); 80 if (status != EFI_SUCCESS) 81 return status; 82 83 str = skip_spaces(memcpy(buf, cmdline, len)); 84 85 while (*str) { 86 char *param, *val; 87 88 str = next_arg(str, ¶m, &val); 89 90 if (!strcmp(param, "nokaslr")) { 91 efi_nokaslr = true; 92 } else if (!strcmp(param, "quiet")) { 93 efi_quiet = true; 94 } else if (!strcmp(param, "noinitrd")) { 95 efi_noinitrd = true; 96 } else if (!strcmp(param, "efi") && val) { 97 efi_nochunk = parse_option_str(val, "nochunk"); 98 efi_novamap = parse_option_str(val, "novamap"); 99 100 efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && 101 parse_option_str(val, "nosoftreserve"); 102 103 if (parse_option_str(val, "disable_early_pci_dma")) 104 efi_disable_pci_dma = true; 105 if (parse_option_str(val, "no_disable_early_pci_dma")) 106 efi_disable_pci_dma = false; 107 } else if (!strcmp(param, "video") && 108 val && strstarts(val, "efifb:")) { 109 efi_parse_option_graphics(val + strlen("efifb:")); 110 } 111 } 112 efi_bs_call(free_pool, buf); 113 return EFI_SUCCESS; 114 } 115 116 /* 117 * Get the number of UTF-8 bytes corresponding to an UTF-16 character. 118 * This overestimates for surrogates, but that is okay. 119 */ 120 static int efi_utf8_bytes(u16 c) 121 { 122 return 1 + (c >= 0x80) + (c >= 0x800); 123 } 124 125 /* 126 * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. 127 */ 128 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) 129 { 130 unsigned int c; 131 132 while (n--) { 133 c = *src++; 134 if (n && c >= 0xd800 && c <= 0xdbff && 135 *src >= 0xdc00 && *src <= 0xdfff) { 136 c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff); 137 src++; 138 n--; 139 } 140 if (c >= 0xd800 && c <= 0xdfff) 141 c = 0xfffd; /* Unmatched surrogate */ 142 if (c < 0x80) { 143 *dst++ = c; 144 continue; 145 } 146 if (c < 0x800) { 147 *dst++ = 0xc0 + (c >> 6); 148 goto t1; 149 } 150 if (c < 0x10000) { 151 *dst++ = 0xe0 + (c >> 12); 152 goto t2; 153 } 154 *dst++ = 0xf0 + (c >> 18); 155 *dst++ = 0x80 + ((c >> 12) & 0x3f); 156 t2: 157 *dst++ = 0x80 + ((c >> 6) & 0x3f); 158 t1: 159 *dst++ = 0x80 + (c & 0x3f); 160 } 161 162 return dst; 163 } 164 165 /* 166 * Convert the unicode UEFI command line to ASCII to pass to kernel. 167 * Size of memory allocated return in *cmd_line_len. 168 * Returns NULL on error. 169 */ 170 char *efi_convert_cmdline(efi_loaded_image_t *image, 171 int *cmd_line_len, unsigned long max_addr) 172 { 173 const u16 *s2; 174 u8 *s1 = NULL; 175 unsigned long cmdline_addr = 0; 176 int load_options_chars = efi_table_attr(image, load_options_size) / 2; 177 const u16 *options = efi_table_attr(image, load_options); 178 int options_bytes = 0; /* UTF-8 bytes */ 179 int options_chars = 0; /* UTF-16 chars */ 180 efi_status_t status; 181 u16 zero = 0; 182 183 if (options) { 184 s2 = options; 185 while (*s2 && *s2 != '\n' 186 && options_chars < load_options_chars) { 187 options_bytes += efi_utf8_bytes(*s2++); 188 options_chars++; 189 } 190 } 191 192 if (!options_chars) { 193 /* No command line options, so return empty string*/ 194 options = &zero; 195 } 196 197 options_bytes++; /* NUL termination */ 198 199 status = efi_allocate_pages(options_bytes, &cmdline_addr, max_addr); 200 if (status != EFI_SUCCESS) 201 return NULL; 202 203 s1 = (u8 *)cmdline_addr; 204 s2 = (const u16 *)options; 205 206 s1 = efi_utf16_to_utf8(s1, s2, options_chars); 207 *s1 = '\0'; 208 209 *cmd_line_len = options_bytes; 210 return (char *)cmdline_addr; 211 } 212 213 /* 214 * Handle calling ExitBootServices according to the requirements set out by the 215 * spec. Obtains the current memory map, and returns that info after calling 216 * ExitBootServices. The client must specify a function to perform any 217 * processing of the memory map data prior to ExitBootServices. A client 218 * specific structure may be passed to the function via priv. The client 219 * function may be called multiple times. 220 */ 221 efi_status_t efi_exit_boot_services(void *handle, 222 struct efi_boot_memmap *map, 223 void *priv, 224 efi_exit_boot_map_processing priv_func) 225 { 226 efi_status_t status; 227 228 status = efi_get_memory_map(map); 229 230 if (status != EFI_SUCCESS) 231 goto fail; 232 233 status = priv_func(map, priv); 234 if (status != EFI_SUCCESS) 235 goto free_map; 236 237 if (efi_disable_pci_dma) 238 efi_pci_disable_bridge_busmaster(); 239 240 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 241 242 if (status == EFI_INVALID_PARAMETER) { 243 /* 244 * The memory map changed between efi_get_memory_map() and 245 * exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4: 246 * EFI_BOOT_SERVICES.ExitBootServices we need to get the 247 * updated map, and try again. The spec implies one retry 248 * should be sufficent, which is confirmed against the EDK2 249 * implementation. Per the spec, we can only invoke 250 * get_memory_map() and exit_boot_services() - we cannot alloc 251 * so efi_get_memory_map() cannot be used, and we must reuse 252 * the buffer. For all practical purposes, the headroom in the 253 * buffer should account for any changes in the map so the call 254 * to get_memory_map() is expected to succeed here. 255 */ 256 *map->map_size = *map->buff_size; 257 status = efi_bs_call(get_memory_map, 258 map->map_size, 259 *map->map, 260 map->key_ptr, 261 map->desc_size, 262 map->desc_ver); 263 264 /* exit_boot_services() was called, thus cannot free */ 265 if (status != EFI_SUCCESS) 266 goto fail; 267 268 status = priv_func(map, priv); 269 /* exit_boot_services() was called, thus cannot free */ 270 if (status != EFI_SUCCESS) 271 goto fail; 272 273 status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); 274 } 275 276 /* exit_boot_services() was called, thus cannot free */ 277 if (status != EFI_SUCCESS) 278 goto fail; 279 280 return EFI_SUCCESS; 281 282 free_map: 283 efi_bs_call(free_pool, *map->map); 284 fail: 285 return status; 286 } 287 288 void *get_efi_config_table(efi_guid_t guid) 289 { 290 unsigned long tables = efi_table_attr(efi_system_table, tables); 291 int nr_tables = efi_table_attr(efi_system_table, nr_tables); 292 int i; 293 294 for (i = 0; i < nr_tables; i++) { 295 efi_config_table_t *t = (void *)tables; 296 297 if (efi_guidcmp(t->guid, guid) == 0) 298 return efi_table_attr(t, table); 299 300 tables += efi_is_native() ? sizeof(efi_config_table_t) 301 : sizeof(efi_config_table_32_t); 302 } 303 return NULL; 304 } 305 306 void efi_char16_printk(efi_char16_t *str) 307 { 308 efi_call_proto(efi_table_attr(efi_system_table, con_out), 309 output_string, str); 310 } 311 312 /* 313 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way 314 * for the firmware or bootloader to expose the initrd data directly to the stub 315 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is 316 * very easy to implement. It is a simple Linux initrd specific conduit between 317 * kernel and firmware, allowing us to put the EFI stub (being part of the 318 * kernel) in charge of where and when to load the initrd, while leaving it up 319 * to the firmware to decide whether it needs to expose its filesystem hierarchy 320 * via EFI protocols. 321 */ 322 static const struct { 323 struct efi_vendor_dev_path vendor; 324 struct efi_generic_dev_path end; 325 } __packed initrd_dev_path = { 326 { 327 { 328 EFI_DEV_MEDIA, 329 EFI_DEV_MEDIA_VENDOR, 330 sizeof(struct efi_vendor_dev_path), 331 }, 332 LINUX_EFI_INITRD_MEDIA_GUID 333 }, { 334 EFI_DEV_END_PATH, 335 EFI_DEV_END_ENTIRE, 336 sizeof(struct efi_generic_dev_path) 337 } 338 }; 339 340 /** 341 * efi_load_initrd_dev_path - load the initrd from the Linux initrd device path 342 * @load_addr: pointer to store the address where the initrd was loaded 343 * @load_size: pointer to store the size of the loaded initrd 344 * @max: upper limit for the initrd memory allocation 345 * @return: %EFI_SUCCESS if the initrd was loaded successfully, in which 346 * case @load_addr and @load_size are assigned accordingly 347 * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd 348 * device path 349 * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL 350 * %EFI_OUT_OF_RESOURCES if memory allocation failed 351 * %EFI_LOAD_ERROR in all other cases 352 */ 353 efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, 354 unsigned long *load_size, 355 unsigned long max) 356 { 357 efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; 358 efi_device_path_protocol_t *dp; 359 efi_load_file2_protocol_t *lf2; 360 unsigned long initrd_addr; 361 unsigned long initrd_size; 362 efi_handle_t handle; 363 efi_status_t status; 364 365 if (!load_addr || !load_size) 366 return EFI_INVALID_PARAMETER; 367 368 dp = (efi_device_path_protocol_t *)&initrd_dev_path; 369 status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle); 370 if (status != EFI_SUCCESS) 371 return status; 372 373 status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, 374 (void **)&lf2); 375 if (status != EFI_SUCCESS) 376 return status; 377 378 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); 379 if (status != EFI_BUFFER_TOO_SMALL) 380 return EFI_LOAD_ERROR; 381 382 status = efi_allocate_pages(initrd_size, &initrd_addr, max); 383 if (status != EFI_SUCCESS) 384 return status; 385 386 status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, 387 (void *)initrd_addr); 388 if (status != EFI_SUCCESS) { 389 efi_free(initrd_size, initrd_addr); 390 return EFI_LOAD_ERROR; 391 } 392 393 *load_addr = initrd_addr; 394 *load_size = initrd_size; 395 return EFI_SUCCESS; 396 } 397