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 { 33 int node, num_rsv; 34 int status; 35 u32 fdt_val32; 36 u64 fdt_val64; 37 38 /* Do some checks on provided FDT, if it exists: */ 39 if (orig_fdt) { 40 if (fdt_check_header(orig_fdt)) { 41 efi_err("Device Tree header not valid!\n"); 42 return EFI_LOAD_ERROR; 43 } 44 /* 45 * We don't get the size of the FDT if we get if from a 46 * configuration table: 47 */ 48 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) { 49 efi_err("Truncated device tree! foo!\n"); 50 return EFI_LOAD_ERROR; 51 } 52 } 53 54 if (orig_fdt) { 55 status = fdt_open_into(orig_fdt, fdt, new_fdt_size); 56 } else { 57 status = fdt_create_empty_tree(fdt, new_fdt_size); 58 if (status == 0) { 59 /* 60 * Any failure from the following function is 61 * non-critical: 62 */ 63 fdt_update_cell_size(fdt); 64 } 65 } 66 67 if (status != 0) 68 goto fdt_set_fail; 69 70 /* 71 * Delete all memory reserve map entries. When booting via UEFI, 72 * kernel will use the UEFI memory map to find reserved regions. 73 */ 74 num_rsv = fdt_num_mem_rsv(fdt); 75 while (num_rsv-- > 0) 76 fdt_del_mem_rsv(fdt, num_rsv); 77 78 node = fdt_subnode_offset(fdt, 0, "chosen"); 79 if (node < 0) { 80 node = fdt_add_subnode(fdt, 0, "chosen"); 81 if (node < 0) { 82 /* 'node' is an error code when negative: */ 83 status = node; 84 goto fdt_set_fail; 85 } 86 } 87 88 if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) { 89 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, 90 strlen(cmdline_ptr) + 1); 91 if (status) 92 goto fdt_set_fail; 93 } 94 95 /* Add FDT entries for EFI runtime services in chosen node. */ 96 node = fdt_subnode_offset(fdt, 0, "chosen"); 97 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table); 98 99 status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64); 100 if (status) 101 goto fdt_set_fail; 102 103 fdt_val64 = U64_MAX; /* placeholder */ 104 105 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); 106 if (status) 107 goto fdt_set_fail; 108 109 fdt_val32 = U32_MAX; /* placeholder */ 110 111 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); 112 if (status) 113 goto fdt_set_fail; 114 115 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); 116 if (status) 117 goto fdt_set_fail; 118 119 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); 120 if (status) 121 goto fdt_set_fail; 122 123 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) { 124 efi_status_t efi_status; 125 126 efi_status = efi_get_random_bytes(sizeof(fdt_val64), 127 (u8 *)&fdt_val64); 128 if (efi_status == EFI_SUCCESS) { 129 status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64); 130 if (status) 131 goto fdt_set_fail; 132 } 133 } 134 135 /* Shrink the FDT back to its minimum size: */ 136 fdt_pack(fdt); 137 138 return EFI_SUCCESS; 139 140 fdt_set_fail: 141 if (status == -FDT_ERR_NOSPACE) 142 return EFI_BUFFER_TOO_SMALL; 143 144 return EFI_LOAD_ERROR; 145 } 146 147 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) 148 { 149 int node = fdt_path_offset(fdt, "/chosen"); 150 u64 fdt_val64; 151 u32 fdt_val32; 152 int err; 153 154 if (node < 0) 155 return EFI_LOAD_ERROR; 156 157 fdt_val64 = cpu_to_fdt64((unsigned long)map->map); 158 159 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); 160 if (err) 161 return EFI_LOAD_ERROR; 162 163 fdt_val32 = cpu_to_fdt32(map->map_size); 164 165 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); 166 if (err) 167 return EFI_LOAD_ERROR; 168 169 fdt_val32 = cpu_to_fdt32(map->desc_size); 170 171 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); 172 if (err) 173 return EFI_LOAD_ERROR; 174 175 fdt_val32 = cpu_to_fdt32(map->desc_ver); 176 177 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); 178 if (err) 179 return EFI_LOAD_ERROR; 180 181 return EFI_SUCCESS; 182 } 183 184 struct exit_boot_struct { 185 struct efi_boot_memmap *boot_memmap; 186 efi_memory_desc_t *runtime_map; 187 int runtime_entry_count; 188 void *new_fdt_addr; 189 }; 190 191 static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv) 192 { 193 struct exit_boot_struct *p = priv; 194 195 p->boot_memmap = map; 196 197 /* 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 update_fdt_memmap(p->new_fdt_addr, map); 206 } 207 208 #ifndef MAX_FDT_SIZE 209 # define MAX_FDT_SIZE SZ_2M 210 #endif 211 212 /* 213 * Allocate memory for a new FDT, then add EFI and commandline related fields 214 * to the FDT. This routine increases the FDT allocation size until the 215 * allocated memory is large enough. EFI allocations are in EFI_PAGE_SIZE 216 * granules, which are fixed at 4K bytes, so in most cases the first allocation 217 * should succeed. EFI boot services are exited at the end of this function. 218 * There must be no allocations between the get_memory_map() call and the 219 * exit_boot_services() call, so the exiting of boot services is very tightly 220 * tied to the creation of the FDT with the final memory map in it. 221 */ 222 static 223 efi_status_t allocate_new_fdt_and_exit_boot(void *handle, 224 efi_loaded_image_t *image, 225 unsigned long *new_fdt_addr, 226 char *cmdline_ptr) 227 { 228 unsigned long desc_size; 229 u32 desc_ver; 230 efi_status_t status; 231 struct exit_boot_struct priv; 232 unsigned long fdt_addr = 0; 233 unsigned long fdt_size = 0; 234 235 if (!efi_novamap) { 236 status = efi_alloc_virtmap(&priv.runtime_map, &desc_size, 237 &desc_ver); 238 if (status != EFI_SUCCESS) { 239 efi_err("Unable to retrieve UEFI memory map.\n"); 240 return status; 241 } 242 } 243 244 /* 245 * Unauthenticated device tree data is a security hazard, so ignore 246 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure 247 * boot is enabled if we can't determine its state. 248 */ 249 if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) || 250 efi_get_secureboot() != efi_secureboot_mode_disabled) { 251 if (strstr(cmdline_ptr, "dtb=")) 252 efi_err("Ignoring DTB from command line.\n"); 253 } else { 254 status = efi_load_dtb(image, &fdt_addr, &fdt_size); 255 256 if (status != EFI_SUCCESS && status != EFI_NOT_READY) { 257 efi_err("Failed to load device tree!\n"); 258 goto fail; 259 } 260 } 261 262 if (fdt_addr) { 263 efi_info("Using DTB from command line\n"); 264 } else { 265 /* Look for a device tree configuration table entry. */ 266 fdt_addr = (uintptr_t)get_fdt(&fdt_size); 267 if (fdt_addr) 268 efi_info("Using DTB from configuration table\n"); 269 } 270 271 if (!fdt_addr) 272 efi_info("Generating empty DTB\n"); 273 274 efi_info("Exiting boot services...\n"); 275 276 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX); 277 if (status != EFI_SUCCESS) { 278 efi_err("Unable to allocate memory for new device tree.\n"); 279 goto fail; 280 } 281 282 status = update_fdt((void *)fdt_addr, fdt_size, 283 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr); 284 285 if (status != EFI_SUCCESS) { 286 efi_err("Unable to construct new device tree.\n"); 287 goto fail_free_new_fdt; 288 } 289 290 priv.new_fdt_addr = (void *)*new_fdt_addr; 291 292 status = efi_exit_boot_services(handle, &priv, exit_boot_func); 293 294 if (status == EFI_SUCCESS) { 295 efi_set_virtual_address_map_t *svam; 296 297 if (efi_novamap) 298 return EFI_SUCCESS; 299 300 /* Install the new virtual address map */ 301 svam = efi_system_table->runtime->set_virtual_address_map; 302 status = svam(priv.runtime_entry_count * desc_size, desc_size, 303 desc_ver, priv.runtime_map); 304 305 /* 306 * We are beyond the point of no return here, so if the call to 307 * SetVirtualAddressMap() failed, we need to signal that to the 308 * incoming kernel but proceed normally otherwise. 309 */ 310 if (status != EFI_SUCCESS) { 311 efi_memory_desc_t *p; 312 int l; 313 314 /* 315 * Set the virtual address field of all 316 * EFI_MEMORY_RUNTIME entries to U64_MAX. This will 317 * signal the incoming kernel that no virtual 318 * translation has been installed. 319 */ 320 for (l = 0; l < priv.boot_memmap->map_size; 321 l += priv.boot_memmap->desc_size) { 322 p = (void *)priv.boot_memmap->map + l; 323 324 if (p->attribute & EFI_MEMORY_RUNTIME) 325 p->virt_addr = U64_MAX; 326 } 327 } 328 return EFI_SUCCESS; 329 } 330 331 efi_err("Exit boot services failed.\n"); 332 333 fail_free_new_fdt: 334 efi_free(MAX_FDT_SIZE, *new_fdt_addr); 335 336 fail: 337 efi_free(fdt_size, fdt_addr); 338 339 efi_bs_call(free_pool, priv.runtime_map); 340 341 return EFI_LOAD_ERROR; 342 } 343 344 efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image, 345 unsigned long kernel_addr, char *cmdline_ptr) 346 { 347 unsigned long fdt_addr; 348 efi_status_t status; 349 350 status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr, 351 cmdline_ptr); 352 if (status != EFI_SUCCESS) { 353 efi_err("Failed to update FDT and exit boot services\n"); 354 return status; 355 } 356 357 if (IS_ENABLED(CONFIG_ARM)) 358 efi_handle_post_ebs_state(); 359 360 efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr)); 361 /* not reached */ 362 } 363 364 void *get_fdt(unsigned long *fdt_size) 365 { 366 void *fdt; 367 368 fdt = get_efi_config_table(DEVICE_TREE_GUID); 369 370 if (!fdt) 371 return NULL; 372 373 if (fdt_check_header(fdt) != 0) { 374 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 375 return NULL; 376 } 377 *fdt_size = fdt_totalsize(fdt); 378 return fdt; 379 } 380