1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * FDT related 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 2013 Linaro Limited; author Roy Franz 8 */ 9 10 #include <linux/efi.h> 11 #include <linux/libfdt.h> 12 #include <asm/efi.h> 13 14 #include "efistub.h" 15 16 #define EFI_DT_ADDR_CELLS_DEFAULT 2 17 #define EFI_DT_SIZE_CELLS_DEFAULT 2 18 19 static void fdt_update_cell_size(void *fdt) 20 { 21 int offset; 22 23 offset = fdt_path_offset(fdt, "/"); 24 /* Set the #address-cells and #size-cells values for an empty tree */ 25 26 fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT); 27 fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT); 28 } 29 30 static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size, 31 void *fdt, int new_fdt_size, char *cmdline_ptr, 32 u64 initrd_addr, u64 initrd_size) 33 { 34 int node, num_rsv; 35 int status; 36 u32 fdt_val32; 37 u64 fdt_val64; 38 39 /* Do some checks on provided FDT, if it exists: */ 40 if (orig_fdt) { 41 if (fdt_check_header(orig_fdt)) { 42 pr_efi_err("Device Tree header not valid!\n"); 43 return EFI_LOAD_ERROR; 44 } 45 /* 46 * We don't get the size of the FDT if we get if from a 47 * configuration table: 48 */ 49 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) { 50 pr_efi_err("Truncated device tree! foo!\n"); 51 return EFI_LOAD_ERROR; 52 } 53 } 54 55 if (orig_fdt) { 56 status = fdt_open_into(orig_fdt, fdt, new_fdt_size); 57 } else { 58 status = fdt_create_empty_tree(fdt, new_fdt_size); 59 if (status == 0) { 60 /* 61 * Any failure from the following function is 62 * non-critical: 63 */ 64 fdt_update_cell_size(fdt); 65 } 66 } 67 68 if (status != 0) 69 goto fdt_set_fail; 70 71 /* 72 * Delete all memory reserve map entries. When booting via UEFI, 73 * kernel will use the UEFI memory map to find reserved regions. 74 */ 75 num_rsv = fdt_num_mem_rsv(fdt); 76 while (num_rsv-- > 0) 77 fdt_del_mem_rsv(fdt, num_rsv); 78 79 node = fdt_subnode_offset(fdt, 0, "chosen"); 80 if (node < 0) { 81 node = fdt_add_subnode(fdt, 0, "chosen"); 82 if (node < 0) { 83 /* 'node' is an error code when negative: */ 84 status = node; 85 goto fdt_set_fail; 86 } 87 } 88 89 if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) { 90 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, 91 strlen(cmdline_ptr) + 1); 92 if (status) 93 goto fdt_set_fail; 94 } 95 96 /* Set initrd address/end in device tree, if present */ 97 if (initrd_size != 0) { 98 u64 initrd_image_end; 99 u64 initrd_image_start = cpu_to_fdt64(initrd_addr); 100 101 status = fdt_setprop_var(fdt, node, "linux,initrd-start", initrd_image_start); 102 if (status) 103 goto fdt_set_fail; 104 105 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size); 106 status = fdt_setprop_var(fdt, node, "linux,initrd-end", initrd_image_end); 107 if (status) 108 goto fdt_set_fail; 109 } 110 111 /* Add FDT entries for EFI runtime services in chosen node. */ 112 node = fdt_subnode_offset(fdt, 0, "chosen"); 113 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table()); 114 115 status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64); 116 if (status) 117 goto fdt_set_fail; 118 119 fdt_val64 = U64_MAX; /* placeholder */ 120 121 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); 122 if (status) 123 goto fdt_set_fail; 124 125 fdt_val32 = U32_MAX; /* placeholder */ 126 127 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); 128 if (status) 129 goto fdt_set_fail; 130 131 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); 132 if (status) 133 goto fdt_set_fail; 134 135 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); 136 if (status) 137 goto fdt_set_fail; 138 139 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 140 efi_status_t efi_status; 141 142 efi_status = efi_get_random_bytes(sizeof(fdt_val64), 143 (u8 *)&fdt_val64); 144 if (efi_status == EFI_SUCCESS) { 145 status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64); 146 if (status) 147 goto fdt_set_fail; 148 } else if (efi_status != EFI_NOT_FOUND) { 149 return efi_status; 150 } 151 } 152 153 /* Shrink the FDT back to its minimum size: */ 154 fdt_pack(fdt); 155 156 return EFI_SUCCESS; 157 158 fdt_set_fail: 159 if (status == -FDT_ERR_NOSPACE) 160 return EFI_BUFFER_TOO_SMALL; 161 162 return EFI_LOAD_ERROR; 163 } 164 165 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) 166 { 167 int node = fdt_path_offset(fdt, "/chosen"); 168 u64 fdt_val64; 169 u32 fdt_val32; 170 int err; 171 172 if (node < 0) 173 return EFI_LOAD_ERROR; 174 175 fdt_val64 = cpu_to_fdt64((unsigned long)*map->map); 176 177 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); 178 if (err) 179 return EFI_LOAD_ERROR; 180 181 fdt_val32 = cpu_to_fdt32(*map->map_size); 182 183 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); 184 if (err) 185 return EFI_LOAD_ERROR; 186 187 fdt_val32 = cpu_to_fdt32(*map->desc_size); 188 189 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); 190 if (err) 191 return EFI_LOAD_ERROR; 192 193 fdt_val32 = cpu_to_fdt32(*map->desc_ver); 194 195 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); 196 if (err) 197 return EFI_LOAD_ERROR; 198 199 return EFI_SUCCESS; 200 } 201 202 #ifndef EFI_FDT_ALIGN 203 # define EFI_FDT_ALIGN EFI_PAGE_SIZE 204 #endif 205 206 struct exit_boot_struct { 207 efi_memory_desc_t *runtime_map; 208 int *runtime_entry_count; 209 void *new_fdt_addr; 210 }; 211 212 static efi_status_t exit_boot_func(struct efi_boot_memmap *map, 213 void *priv) 214 { 215 struct exit_boot_struct *p = priv; 216 /* 217 * Update the memory map with virtual addresses. The function will also 218 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 219 * entries so that we can pass it straight to SetVirtualAddressMap() 220 */ 221 efi_get_virtmap(*map->map, *map->map_size, *map->desc_size, 222 p->runtime_map, p->runtime_entry_count); 223 224 return update_fdt_memmap(p->new_fdt_addr, map); 225 } 226 227 #ifndef MAX_FDT_SIZE 228 # define MAX_FDT_SIZE SZ_2M 229 #endif 230 231 /* 232 * Allocate memory for a new FDT, then add EFI, commandline, and 233 * initrd related fields to the FDT. This routine increases the 234 * FDT allocation size until the allocated memory is large 235 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 236 * which are fixed at 4K bytes, so in most cases the first 237 * allocation should succeed. 238 * EFI boot services are exited at the end of this function. 239 * There must be no allocations between the get_memory_map() 240 * call and the exit_boot_services() call, so the exiting of 241 * boot services is very tightly tied to the creation of the FDT 242 * with the final memory map in it. 243 */ 244 245 efi_status_t allocate_new_fdt_and_exit_boot(void *handle, 246 unsigned long *new_fdt_addr, 247 unsigned long max_addr, 248 u64 initrd_addr, u64 initrd_size, 249 char *cmdline_ptr, 250 unsigned long fdt_addr, 251 unsigned long fdt_size) 252 { 253 unsigned long map_size, desc_size, buff_size; 254 u32 desc_ver; 255 unsigned long mmap_key; 256 efi_memory_desc_t *memory_map, *runtime_map; 257 efi_status_t status; 258 int runtime_entry_count; 259 struct efi_boot_memmap map; 260 struct exit_boot_struct priv; 261 262 map.map = &runtime_map; 263 map.map_size = &map_size; 264 map.desc_size = &desc_size; 265 map.desc_ver = &desc_ver; 266 map.key_ptr = &mmap_key; 267 map.buff_size = &buff_size; 268 269 /* 270 * Get a copy of the current memory map that we will use to prepare 271 * the input for SetVirtualAddressMap(). We don't have to worry about 272 * subsequent allocations adding entries, since they could not affect 273 * the number of EFI_MEMORY_RUNTIME regions. 274 */ 275 status = efi_get_memory_map(&map); 276 if (status != EFI_SUCCESS) { 277 pr_efi_err("Unable to retrieve UEFI memory map.\n"); 278 return status; 279 } 280 281 pr_efi("Exiting boot services and installing virtual address map...\n"); 282 283 map.map = &memory_map; 284 status = efi_high_alloc(MAX_FDT_SIZE, EFI_FDT_ALIGN, 285 new_fdt_addr, max_addr); 286 if (status != EFI_SUCCESS) { 287 pr_efi_err("Unable to allocate memory for new device tree.\n"); 288 goto fail; 289 } 290 291 /* 292 * Now that we have done our final memory allocation (and free) 293 * we can get the memory map key needed for exit_boot_services(). 294 */ 295 status = efi_get_memory_map(&map); 296 if (status != EFI_SUCCESS) 297 goto fail_free_new_fdt; 298 299 status = update_fdt((void *)fdt_addr, fdt_size, 300 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr, 301 initrd_addr, initrd_size); 302 303 if (status != EFI_SUCCESS) { 304 pr_efi_err("Unable to construct new device tree.\n"); 305 goto fail_free_new_fdt; 306 } 307 308 runtime_entry_count = 0; 309 priv.runtime_map = runtime_map; 310 priv.runtime_entry_count = &runtime_entry_count; 311 priv.new_fdt_addr = (void *)*new_fdt_addr; 312 313 status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func); 314 315 if (status == EFI_SUCCESS) { 316 efi_set_virtual_address_map_t *svam; 317 318 if (novamap()) 319 return EFI_SUCCESS; 320 321 /* Install the new virtual address map */ 322 svam = efi_system_table()->runtime->set_virtual_address_map; 323 status = svam(runtime_entry_count * desc_size, desc_size, 324 desc_ver, runtime_map); 325 326 /* 327 * We are beyond the point of no return here, so if the call to 328 * SetVirtualAddressMap() failed, we need to signal that to the 329 * incoming kernel but proceed normally otherwise. 330 */ 331 if (status != EFI_SUCCESS) { 332 int l; 333 334 /* 335 * Set the virtual address field of all 336 * EFI_MEMORY_RUNTIME entries to 0. This will signal 337 * the incoming kernel that no virtual translation has 338 * been installed. 339 */ 340 for (l = 0; l < map_size; l += desc_size) { 341 efi_memory_desc_t *p = (void *)memory_map + l; 342 343 if (p->attribute & EFI_MEMORY_RUNTIME) 344 p->virt_addr = 0; 345 } 346 } 347 return EFI_SUCCESS; 348 } 349 350 pr_efi_err("Exit boot services failed.\n"); 351 352 fail_free_new_fdt: 353 efi_free(MAX_FDT_SIZE, *new_fdt_addr); 354 355 fail: 356 efi_system_table()->boottime->free_pool(runtime_map); 357 358 return EFI_LOAD_ERROR; 359 } 360 361 void *get_fdt(unsigned long *fdt_size) 362 { 363 void *fdt; 364 365 fdt = get_efi_config_table(DEVICE_TREE_GUID); 366 367 if (!fdt) 368 return NULL; 369 370 if (fdt_check_header(fdt) != 0) { 371 pr_efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 372 return NULL; 373 } 374 *fdt_size = fdt_totalsize(fdt); 375 return fdt; 376 } 377