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