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 #define MAX_FILENAME_SIZE 256 16 17 /* 18 * Some firmware implementations have problems reading files in one go. 19 * A read chunk size of 1MB seems to work for most platforms. 20 * 21 * Unfortunately, reading files in chunks triggers *other* bugs on some 22 * platforms, so we provide a way to disable this workaround, which can 23 * be done by passing "efi=nochunk" on the EFI boot stub command line. 24 * 25 * If you experience issues with initrd images being corrupt it's worth 26 * trying efi=nochunk, but chunking is enabled by default on x86 because 27 * there are far more machines that require the workaround than those that 28 * break with it enabled. 29 */ 30 #define EFI_READ_CHUNK_SIZE SZ_1M 31 32 struct finfo { 33 efi_file_info_t info; 34 efi_char16_t filename[MAX_FILENAME_SIZE]; 35 }; 36 efi_open_file(efi_file_protocol_t * volume,struct finfo * fi,efi_file_protocol_t ** handle,unsigned long * file_size)37 static efi_status_t efi_open_file(efi_file_protocol_t *volume, 38 struct finfo *fi, 39 efi_file_protocol_t **handle, 40 unsigned long *file_size) 41 { 42 efi_guid_t info_guid = EFI_FILE_INFO_ID; 43 efi_file_protocol_t *fh; 44 unsigned long info_sz; 45 efi_status_t status; 46 efi_char16_t *c; 47 48 /* Replace UNIX dir separators with EFI standard ones */ 49 for (c = fi->filename; *c != L'\0'; c++) { 50 if (*c == L'/') 51 *c = L'\\'; 52 } 53 54 status = efi_call_proto(volume, open, &fh, fi->filename, 55 EFI_FILE_MODE_READ, 0); 56 if (status != EFI_SUCCESS) { 57 efi_err("Failed to open file: %ls\n", fi->filename); 58 return status; 59 } 60 61 info_sz = sizeof(struct finfo); 62 status = efi_call_proto(fh, get_info, &info_guid, &info_sz, fi); 63 if (status != EFI_SUCCESS) { 64 efi_err("Failed to get file info\n"); 65 efi_call_proto(fh, close); 66 return status; 67 } 68 69 *handle = fh; 70 *file_size = fi->info.file_size; 71 return EFI_SUCCESS; 72 } 73 efi_open_volume(efi_loaded_image_t * image,efi_file_protocol_t ** fh)74 static efi_status_t efi_open_volume(efi_loaded_image_t *image, 75 efi_file_protocol_t **fh) 76 { 77 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID; 78 efi_simple_file_system_protocol_t *io; 79 efi_status_t status; 80 81 status = efi_bs_call(handle_protocol, efi_table_attr(image, device_handle), 82 &fs_proto, (void **)&io); 83 if (status != EFI_SUCCESS) { 84 efi_err("Failed to handle fs_proto\n"); 85 return status; 86 } 87 88 status = efi_call_proto(io, open_volume, fh); 89 if (status != EFI_SUCCESS) 90 efi_err("Failed to open volume\n"); 91 92 return status; 93 } 94 find_file_option(const efi_char16_t * cmdline,int cmdline_len,const efi_char16_t * prefix,int prefix_size,efi_char16_t * result,int result_len)95 static int find_file_option(const efi_char16_t *cmdline, int cmdline_len, 96 const efi_char16_t *prefix, int prefix_size, 97 efi_char16_t *result, int result_len) 98 { 99 int prefix_len = prefix_size / 2; 100 bool found = false; 101 int i; 102 103 for (i = prefix_len; i < cmdline_len; i++) { 104 if (!memcmp(&cmdline[i - prefix_len], prefix, prefix_size)) { 105 found = true; 106 break; 107 } 108 } 109 110 if (!found) 111 return 0; 112 113 /* Skip any leading slashes */ 114 while (i < cmdline_len && (cmdline[i] == L'/' || cmdline[i] == L'\\')) 115 i++; 116 117 while (--result_len > 0 && i < cmdline_len) { 118 efi_char16_t c = cmdline[i++]; 119 120 if (c == L'\0' || c == L'\n' || c == L' ') 121 break; 122 *result++ = c; 123 } 124 *result = L'\0'; 125 return i; 126 } 127 efi_open_device_path(efi_file_protocol_t ** volume,struct finfo * fi)128 static efi_status_t efi_open_device_path(efi_file_protocol_t **volume, 129 struct finfo *fi) 130 { 131 efi_guid_t text_to_dp_guid = EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL_GUID; 132 static efi_device_path_from_text_protocol_t *text_to_dp = NULL; 133 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID; 134 efi_device_path_protocol_t *initrd_dp; 135 efi_simple_file_system_protocol_t *io; 136 struct efi_file_path_dev_path *fpath; 137 efi_handle_t handle; 138 efi_status_t status; 139 140 /* See if the text to device path protocol exists */ 141 if (!text_to_dp && 142 efi_bs_call(locate_protocol, &text_to_dp_guid, NULL, 143 (void **)&text_to_dp) != EFI_SUCCESS) 144 return EFI_UNSUPPORTED; 145 146 147 /* Convert the filename wide string into a device path */ 148 initrd_dp = efi_fn_call(text_to_dp, convert_text_to_device_path, 149 fi->filename); 150 151 /* Check whether the device path in question implements simple FS */ 152 if ((efi_bs_call(locate_device_path, &fs_proto, &initrd_dp, &handle) ?: 153 efi_bs_call(handle_protocol, handle, &fs_proto, (void **)&io)) 154 != EFI_SUCCESS) 155 return EFI_NOT_FOUND; 156 157 /* Check whether the remaining device path is a file device path */ 158 if (initrd_dp->type != EFI_DEV_MEDIA || 159 initrd_dp->sub_type != EFI_DEV_MEDIA_FILE) { 160 efi_warn("Unexpected device path node type: (%x, %x)\n", 161 initrd_dp->type, initrd_dp->sub_type); 162 return EFI_LOAD_ERROR; 163 } 164 165 /* Copy the remaining file path into the fi structure */ 166 fpath = (struct efi_file_path_dev_path *)initrd_dp; 167 memcpy(fi->filename, fpath->filename, 168 min(sizeof(fi->filename), 169 fpath->header.length - sizeof(fpath->header))); 170 171 status = efi_call_proto(io, open_volume, volume); 172 if (status != EFI_SUCCESS) 173 efi_err("Failed to open volume\n"); 174 175 return status; 176 } 177 178 /* 179 * Check the cmdline for a LILO-style file= arguments. 180 * 181 * We only support loading a file from the same filesystem as 182 * the kernel image. 183 */ handle_cmdline_files(efi_loaded_image_t * image,const efi_char16_t * optstr,int optstr_size,unsigned long soft_limit,unsigned long hard_limit,unsigned long * load_addr,unsigned long * load_size)184 efi_status_t handle_cmdline_files(efi_loaded_image_t *image, 185 const efi_char16_t *optstr, 186 int optstr_size, 187 unsigned long soft_limit, 188 unsigned long hard_limit, 189 unsigned long *load_addr, 190 unsigned long *load_size) 191 { 192 const efi_char16_t *cmdline = efi_table_attr(image, load_options); 193 u32 cmdline_len = efi_table_attr(image, load_options_size); 194 unsigned long efi_chunk_size = ULONG_MAX; 195 efi_file_protocol_t *volume = NULL; 196 efi_file_protocol_t *file; 197 unsigned long alloc_addr; 198 unsigned long alloc_size; 199 efi_status_t status; 200 int offset; 201 202 if (!load_addr || !load_size) 203 return EFI_INVALID_PARAMETER; 204 205 efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len); 206 cmdline_len /= sizeof(*cmdline); 207 208 if (IS_ENABLED(CONFIG_X86) && !efi_nochunk) 209 efi_chunk_size = EFI_READ_CHUNK_SIZE; 210 211 alloc_addr = alloc_size = 0; 212 do { 213 struct finfo fi; 214 unsigned long size; 215 void *addr; 216 217 offset = find_file_option(cmdline, cmdline_len, 218 optstr, optstr_size, 219 fi.filename, ARRAY_SIZE(fi.filename)); 220 221 if (!offset) 222 break; 223 224 cmdline += offset; 225 cmdline_len -= offset; 226 227 status = efi_open_device_path(&volume, &fi); 228 if (status == EFI_UNSUPPORTED || status == EFI_NOT_FOUND) 229 /* try the volume that holds the kernel itself */ 230 status = efi_open_volume(image, &volume); 231 232 if (status != EFI_SUCCESS) 233 goto err_free_alloc; 234 235 status = efi_open_file(volume, &fi, &file, &size); 236 if (status != EFI_SUCCESS) 237 goto err_close_volume; 238 239 /* 240 * Check whether the existing allocation can contain the next 241 * file. This condition will also trigger naturally during the 242 * first (and typically only) iteration of the loop, given that 243 * alloc_size == 0 in that case. 244 */ 245 if (round_up(alloc_size + size, EFI_ALLOC_ALIGN) > 246 round_up(alloc_size, EFI_ALLOC_ALIGN)) { 247 unsigned long old_addr = alloc_addr; 248 249 status = EFI_OUT_OF_RESOURCES; 250 if (soft_limit < hard_limit) 251 status = efi_allocate_pages(alloc_size + size, 252 &alloc_addr, 253 soft_limit); 254 if (status == EFI_OUT_OF_RESOURCES) 255 status = efi_allocate_pages(alloc_size + size, 256 &alloc_addr, 257 hard_limit); 258 if (status != EFI_SUCCESS) { 259 efi_err("Failed to allocate memory for files\n"); 260 goto err_close_file; 261 } 262 263 if (old_addr != 0) { 264 /* 265 * This is not the first time we've gone 266 * around this loop, and so we are loading 267 * multiple files that need to be concatenated 268 * and returned in a single buffer. 269 */ 270 memcpy((void *)alloc_addr, (void *)old_addr, alloc_size); 271 efi_free(alloc_size, old_addr); 272 } 273 } 274 275 addr = (void *)alloc_addr + alloc_size; 276 alloc_size += size; 277 278 while (size) { 279 unsigned long chunksize = min(size, efi_chunk_size); 280 281 status = efi_call_proto(file, read, &chunksize, addr); 282 if (status != EFI_SUCCESS) { 283 efi_err("Failed to read file\n"); 284 goto err_close_file; 285 } 286 addr += chunksize; 287 size -= chunksize; 288 } 289 efi_call_proto(file, close); 290 efi_call_proto(volume, close); 291 } while (offset > 0); 292 293 *load_addr = alloc_addr; 294 *load_size = alloc_size; 295 296 if (*load_size == 0) 297 return EFI_NOT_READY; 298 return EFI_SUCCESS; 299 300 err_close_file: 301 efi_call_proto(file, close); 302 303 err_close_volume: 304 efi_call_proto(volume, close); 305 306 err_free_alloc: 307 efi_free(alloc_size, alloc_addr); 308 return status; 309 } 310