1 /* 2 * FDT related Helper functions used by the EFI stub on multiple 3 * architectures. This should be #included by the EFI stub 4 * implementation files. 5 * 6 * Copyright 2013 Linaro Limited; author Roy Franz 7 * 8 * This file is part of the Linux kernel, and is made available 9 * under the terms of the GNU General Public License version 2. 10 * 11 */ 12 13 #include <linux/efi.h> 14 #include <linux/libfdt.h> 15 #include <asm/efi.h> 16 17 #include "efistub.h" 18 19 #define EFI_DT_ADDR_CELLS_DEFAULT 2 20 #define EFI_DT_SIZE_CELLS_DEFAULT 2 21 22 static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt) 23 { 24 int offset; 25 26 offset = fdt_path_offset(fdt, "/"); 27 /* Set the #address-cells and #size-cells values for an empty tree */ 28 29 fdt_setprop_u32(fdt, offset, "#address-cells", 30 EFI_DT_ADDR_CELLS_DEFAULT); 31 32 fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT); 33 } 34 35 static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt, 36 unsigned long orig_fdt_size, 37 void *fdt, int new_fdt_size, char *cmdline_ptr, 38 u64 initrd_addr, u64 initrd_size) 39 { 40 int node, num_rsv; 41 int status; 42 u32 fdt_val32; 43 u64 fdt_val64; 44 45 /* Do some checks on provided FDT, if it exists*/ 46 if (orig_fdt) { 47 if (fdt_check_header(orig_fdt)) { 48 pr_efi_err(sys_table, "Device Tree header not valid!\n"); 49 return EFI_LOAD_ERROR; 50 } 51 /* 52 * We don't get the size of the FDT if we get if from a 53 * configuration table. 54 */ 55 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) { 56 pr_efi_err(sys_table, "Truncated device tree! foo!\n"); 57 return EFI_LOAD_ERROR; 58 } 59 } 60 61 if (orig_fdt) { 62 status = fdt_open_into(orig_fdt, fdt, new_fdt_size); 63 } else { 64 status = fdt_create_empty_tree(fdt, new_fdt_size); 65 if (status == 0) { 66 /* 67 * Any failure from the following function is non 68 * critical 69 */ 70 fdt_update_cell_size(sys_table, fdt); 71 } 72 } 73 74 if (status != 0) 75 goto fdt_set_fail; 76 77 /* 78 * Delete all memory reserve map entries. When booting via UEFI, 79 * kernel will use the UEFI memory map to find reserved regions. 80 */ 81 num_rsv = fdt_num_mem_rsv(fdt); 82 while (num_rsv-- > 0) 83 fdt_del_mem_rsv(fdt, num_rsv); 84 85 node = fdt_subnode_offset(fdt, 0, "chosen"); 86 if (node < 0) { 87 node = fdt_add_subnode(fdt, 0, "chosen"); 88 if (node < 0) { 89 status = node; /* node is error code when negative */ 90 goto fdt_set_fail; 91 } 92 } 93 94 if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) { 95 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, 96 strlen(cmdline_ptr) + 1); 97 if (status) 98 goto fdt_set_fail; 99 } 100 101 /* Set initrd address/end in device tree, if present */ 102 if (initrd_size != 0) { 103 u64 initrd_image_end; 104 u64 initrd_image_start = cpu_to_fdt64(initrd_addr); 105 106 status = fdt_setprop(fdt, node, "linux,initrd-start", 107 &initrd_image_start, sizeof(u64)); 108 if (status) 109 goto fdt_set_fail; 110 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size); 111 status = fdt_setprop(fdt, node, "linux,initrd-end", 112 &initrd_image_end, sizeof(u64)); 113 if (status) 114 goto fdt_set_fail; 115 } 116 117 /* Add FDT entries for EFI runtime services in chosen node. */ 118 node = fdt_subnode_offset(fdt, 0, "chosen"); 119 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table); 120 status = fdt_setprop(fdt, node, "linux,uefi-system-table", 121 &fdt_val64, sizeof(fdt_val64)); 122 if (status) 123 goto fdt_set_fail; 124 125 fdt_val64 = U64_MAX; /* placeholder */ 126 status = fdt_setprop(fdt, node, "linux,uefi-mmap-start", 127 &fdt_val64, sizeof(fdt_val64)); 128 if (status) 129 goto fdt_set_fail; 130 131 fdt_val32 = U32_MAX; /* placeholder */ 132 status = fdt_setprop(fdt, node, "linux,uefi-mmap-size", 133 &fdt_val32, sizeof(fdt_val32)); 134 if (status) 135 goto fdt_set_fail; 136 137 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size", 138 &fdt_val32, sizeof(fdt_val32)); 139 if (status) 140 goto fdt_set_fail; 141 142 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver", 143 &fdt_val32, sizeof(fdt_val32)); 144 if (status) 145 goto fdt_set_fail; 146 147 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 148 efi_status_t efi_status; 149 150 efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64), 151 (u8 *)&fdt_val64); 152 if (efi_status == EFI_SUCCESS) { 153 status = fdt_setprop(fdt, node, "kaslr-seed", 154 &fdt_val64, sizeof(fdt_val64)); 155 if (status) 156 goto fdt_set_fail; 157 } else if (efi_status != EFI_NOT_FOUND) { 158 return efi_status; 159 } 160 } 161 return EFI_SUCCESS; 162 163 fdt_set_fail: 164 if (status == -FDT_ERR_NOSPACE) 165 return EFI_BUFFER_TOO_SMALL; 166 167 return EFI_LOAD_ERROR; 168 } 169 170 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) 171 { 172 int node = fdt_path_offset(fdt, "/chosen"); 173 u64 fdt_val64; 174 u32 fdt_val32; 175 int err; 176 177 if (node < 0) 178 return EFI_LOAD_ERROR; 179 180 fdt_val64 = cpu_to_fdt64((unsigned long)*map->map); 181 err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start", 182 &fdt_val64, sizeof(fdt_val64)); 183 if (err) 184 return EFI_LOAD_ERROR; 185 186 fdt_val32 = cpu_to_fdt32(*map->map_size); 187 err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size", 188 &fdt_val32, sizeof(fdt_val32)); 189 if (err) 190 return EFI_LOAD_ERROR; 191 192 fdt_val32 = cpu_to_fdt32(*map->desc_size); 193 err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-size", 194 &fdt_val32, sizeof(fdt_val32)); 195 if (err) 196 return EFI_LOAD_ERROR; 197 198 fdt_val32 = cpu_to_fdt32(*map->desc_ver); 199 err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-ver", 200 &fdt_val32, sizeof(fdt_val32)); 201 if (err) 202 return EFI_LOAD_ERROR; 203 204 return EFI_SUCCESS; 205 } 206 207 #ifndef EFI_FDT_ALIGN 208 #define EFI_FDT_ALIGN EFI_PAGE_SIZE 209 #endif 210 211 struct exit_boot_struct { 212 efi_memory_desc_t *runtime_map; 213 int *runtime_entry_count; 214 void *new_fdt_addr; 215 }; 216 217 static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg, 218 struct efi_boot_memmap *map, 219 void *priv) 220 { 221 struct exit_boot_struct *p = priv; 222 /* 223 * Update the memory map with virtual addresses. The function will also 224 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 225 * entries so that we can pass it straight to SetVirtualAddressMap() 226 */ 227 efi_get_virtmap(*map->map, *map->map_size, *map->desc_size, 228 p->runtime_map, p->runtime_entry_count); 229 230 return update_fdt_memmap(p->new_fdt_addr, map); 231 } 232 233 #ifndef MAX_FDT_SIZE 234 #define MAX_FDT_SIZE SZ_2M 235 #endif 236 237 /* 238 * Allocate memory for a new FDT, then add EFI, commandline, and 239 * initrd related fields to the FDT. This routine increases the 240 * FDT allocation size until the allocated memory is large 241 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 242 * which are fixed at 4K bytes, so in most cases the first 243 * allocation should succeed. 244 * EFI boot services are exited at the end of this function. 245 * There must be no allocations between the get_memory_map() 246 * call and the exit_boot_services() call, so the exiting of 247 * boot services is very tightly tied to the creation of the FDT 248 * with the final memory map in it. 249 */ 250 251 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 252 void *handle, 253 unsigned long *new_fdt_addr, 254 unsigned long max_addr, 255 u64 initrd_addr, u64 initrd_size, 256 char *cmdline_ptr, 257 unsigned long fdt_addr, 258 unsigned long fdt_size) 259 { 260 unsigned long map_size, desc_size, buff_size; 261 u32 desc_ver; 262 unsigned long mmap_key; 263 efi_memory_desc_t *memory_map, *runtime_map; 264 efi_status_t status; 265 int runtime_entry_count = 0; 266 struct efi_boot_memmap map; 267 struct exit_boot_struct priv; 268 269 map.map = &runtime_map; 270 map.map_size = &map_size; 271 map.desc_size = &desc_size; 272 map.desc_ver = &desc_ver; 273 map.key_ptr = &mmap_key; 274 map.buff_size = &buff_size; 275 276 /* 277 * Get a copy of the current memory map that we will use to prepare 278 * the input for SetVirtualAddressMap(). We don't have to worry about 279 * subsequent allocations adding entries, since they could not affect 280 * the number of EFI_MEMORY_RUNTIME regions. 281 */ 282 status = efi_get_memory_map(sys_table, &map); 283 if (status != EFI_SUCCESS) { 284 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n"); 285 return status; 286 } 287 288 pr_efi(sys_table, 289 "Exiting boot services and installing virtual address map...\n"); 290 291 map.map = &memory_map; 292 status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN, 293 new_fdt_addr, max_addr); 294 if (status != EFI_SUCCESS) { 295 pr_efi_err(sys_table, 296 "Unable to allocate memory for new device tree.\n"); 297 goto fail; 298 } 299 300 /* 301 * Now that we have done our final memory allocation (and free) 302 * we can get the memory map key needed for exit_boot_services(). 303 */ 304 status = efi_get_memory_map(sys_table, &map); 305 if (status != EFI_SUCCESS) 306 goto fail_free_new_fdt; 307 308 status = update_fdt(sys_table, (void *)fdt_addr, fdt_size, 309 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr, 310 initrd_addr, initrd_size); 311 312 if (status != EFI_SUCCESS) { 313 pr_efi_err(sys_table, "Unable to construct new device tree.\n"); 314 goto fail_free_new_fdt; 315 } 316 317 priv.runtime_map = runtime_map; 318 priv.runtime_entry_count = &runtime_entry_count; 319 priv.new_fdt_addr = (void *)*new_fdt_addr; 320 status = efi_exit_boot_services(sys_table, handle, &map, &priv, 321 exit_boot_func); 322 323 if (status == EFI_SUCCESS) { 324 efi_set_virtual_address_map_t *svam; 325 326 /* Install the new virtual address map */ 327 svam = sys_table->runtime->set_virtual_address_map; 328 status = svam(runtime_entry_count * desc_size, desc_size, 329 desc_ver, runtime_map); 330 331 /* 332 * We are beyond the point of no return here, so if the call to 333 * SetVirtualAddressMap() failed, we need to signal that to the 334 * incoming kernel but proceed normally otherwise. 335 */ 336 if (status != EFI_SUCCESS) { 337 int l; 338 339 /* 340 * Set the virtual address field of all 341 * EFI_MEMORY_RUNTIME entries to 0. This will signal 342 * the incoming kernel that no virtual translation has 343 * been installed. 344 */ 345 for (l = 0; l < map_size; l += desc_size) { 346 efi_memory_desc_t *p = (void *)memory_map + l; 347 348 if (p->attribute & EFI_MEMORY_RUNTIME) 349 p->virt_addr = 0; 350 } 351 } 352 return EFI_SUCCESS; 353 } 354 355 pr_efi_err(sys_table, "Exit boot services failed.\n"); 356 357 fail_free_new_fdt: 358 efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr); 359 360 fail: 361 sys_table->boottime->free_pool(runtime_map); 362 return EFI_LOAD_ERROR; 363 } 364 365 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size) 366 { 367 efi_guid_t fdt_guid = DEVICE_TREE_GUID; 368 efi_config_table_t *tables; 369 void *fdt; 370 int i; 371 372 tables = (efi_config_table_t *) sys_table->tables; 373 fdt = NULL; 374 375 for (i = 0; i < sys_table->nr_tables; i++) 376 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) { 377 fdt = (void *) tables[i].table; 378 if (fdt_check_header(fdt) != 0) { 379 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 380 return NULL; 381 } 382 *fdt_size = fdt_totalsize(fdt); 383 break; 384 } 385 386 return fdt; 387 } 388