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 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 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) && !efi_nokaslr) { 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 } 149 } 150 151 /* Shrink the FDT back to its minimum size: */ 152 fdt_pack(fdt); 153 154 return EFI_SUCCESS; 155 156 fdt_set_fail: 157 if (status == -FDT_ERR_NOSPACE) 158 return EFI_BUFFER_TOO_SMALL; 159 160 return EFI_LOAD_ERROR; 161 } 162 163 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) 164 { 165 int node = fdt_path_offset(fdt, "/chosen"); 166 u64 fdt_val64; 167 u32 fdt_val32; 168 int err; 169 170 if (node < 0) 171 return EFI_LOAD_ERROR; 172 173 fdt_val64 = cpu_to_fdt64((unsigned long)map->map); 174 175 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); 176 if (err) 177 return EFI_LOAD_ERROR; 178 179 fdt_val32 = cpu_to_fdt32(map->map_size); 180 181 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); 182 if (err) 183 return EFI_LOAD_ERROR; 184 185 fdt_val32 = cpu_to_fdt32(map->desc_size); 186 187 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); 188 if (err) 189 return EFI_LOAD_ERROR; 190 191 fdt_val32 = cpu_to_fdt32(map->desc_ver); 192 193 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); 194 if (err) 195 return EFI_LOAD_ERROR; 196 197 return EFI_SUCCESS; 198 } 199 200 struct exit_boot_struct { 201 struct efi_boot_memmap *boot_memmap; 202 efi_memory_desc_t *runtime_map; 203 int runtime_entry_count; 204 void *new_fdt_addr; 205 }; 206 207 static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv) 208 { 209 struct exit_boot_struct *p = priv; 210 211 p->boot_memmap = map; 212 213 /* 214 * Update the memory map with virtual addresses. The function will also 215 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 216 * entries so that we can pass it straight to SetVirtualAddressMap() 217 */ 218 efi_get_virtmap(map->map, map->map_size, map->desc_size, 219 p->runtime_map, &p->runtime_entry_count); 220 221 return update_fdt_memmap(p->new_fdt_addr, map); 222 } 223 224 #ifndef MAX_FDT_SIZE 225 # define MAX_FDT_SIZE SZ_2M 226 #endif 227 228 /* 229 * Allocate memory for a new FDT, then add EFI, commandline, and 230 * initrd related fields to the FDT. This routine increases the 231 * FDT allocation size until the allocated memory is large 232 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 233 * which are fixed at 4K bytes, so in most cases the first 234 * allocation should succeed. 235 * EFI boot services are exited at the end of this function. 236 * There must be no allocations between the get_memory_map() 237 * call and the exit_boot_services() call, so the exiting of 238 * boot services is very tightly tied to the creation of the FDT 239 * with the final memory map in it. 240 */ 241 242 efi_status_t allocate_new_fdt_and_exit_boot(void *handle, 243 unsigned long *new_fdt_addr, 244 u64 initrd_addr, u64 initrd_size, 245 char *cmdline_ptr, 246 unsigned long fdt_addr, 247 unsigned long fdt_size) 248 { 249 unsigned long desc_size; 250 u32 desc_ver; 251 efi_status_t status; 252 struct exit_boot_struct priv; 253 254 if (!efi_novamap) { 255 status = efi_alloc_virtmap(&priv.runtime_map, &desc_size, 256 &desc_ver); 257 if (status != EFI_SUCCESS) { 258 efi_err("Unable to retrieve UEFI memory map.\n"); 259 return status; 260 } 261 } 262 263 efi_info("Exiting boot services...\n"); 264 265 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX); 266 if (status != EFI_SUCCESS) { 267 efi_err("Unable to allocate memory for new device tree.\n"); 268 goto fail; 269 } 270 271 status = update_fdt((void *)fdt_addr, fdt_size, 272 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr, 273 initrd_addr, initrd_size); 274 275 if (status != EFI_SUCCESS) { 276 efi_err("Unable to construct new device tree.\n"); 277 goto fail_free_new_fdt; 278 } 279 280 priv.new_fdt_addr = (void *)*new_fdt_addr; 281 282 status = efi_exit_boot_services(handle, &priv, exit_boot_func); 283 284 if (status == EFI_SUCCESS) { 285 efi_set_virtual_address_map_t *svam; 286 287 if (efi_novamap) 288 return EFI_SUCCESS; 289 290 /* Install the new virtual address map */ 291 svam = efi_system_table->runtime->set_virtual_address_map; 292 status = svam(priv.runtime_entry_count * desc_size, desc_size, 293 desc_ver, priv.runtime_map); 294 295 /* 296 * We are beyond the point of no return here, so if the call to 297 * SetVirtualAddressMap() failed, we need to signal that to the 298 * incoming kernel but proceed normally otherwise. 299 */ 300 if (status != EFI_SUCCESS) { 301 efi_memory_desc_t *p; 302 int l; 303 304 /* 305 * Set the virtual address field of all 306 * EFI_MEMORY_RUNTIME entries to 0. This will signal 307 * the incoming kernel that no virtual translation has 308 * been installed. 309 */ 310 for (l = 0; l < priv.boot_memmap->map_size; 311 l += priv.boot_memmap->desc_size) { 312 p = (void *)priv.boot_memmap->map + l; 313 314 if (p->attribute & EFI_MEMORY_RUNTIME) 315 p->virt_addr = 0; 316 } 317 } 318 return EFI_SUCCESS; 319 } 320 321 efi_err("Exit boot services failed.\n"); 322 323 fail_free_new_fdt: 324 efi_free(MAX_FDT_SIZE, *new_fdt_addr); 325 326 fail: 327 efi_bs_call(free_pool, priv.runtime_map); 328 329 return EFI_LOAD_ERROR; 330 } 331 332 void *get_fdt(unsigned long *fdt_size) 333 { 334 void *fdt; 335 336 fdt = get_efi_config_table(DEVICE_TREE_GUID); 337 338 if (!fdt) 339 return NULL; 340 341 if (fdt_check_header(fdt) != 0) { 342 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 343 return NULL; 344 } 345 *fdt_size = fdt_totalsize(fdt); 346 return fdt; 347 } 348