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 */ 222 223 efi_status_t allocate_new_fdt_and_exit_boot(void *handle, 224 unsigned long *new_fdt_addr, 225 char *cmdline_ptr, 226 unsigned long fdt_addr, 227 unsigned long fdt_size) 228 { 229 unsigned long desc_size; 230 u32 desc_ver; 231 efi_status_t status; 232 struct exit_boot_struct priv; 233 234 if (!efi_novamap) { 235 status = efi_alloc_virtmap(&priv.runtime_map, &desc_size, 236 &desc_ver); 237 if (status != EFI_SUCCESS) { 238 efi_err("Unable to retrieve UEFI memory map.\n"); 239 return status; 240 } 241 } 242 243 efi_info("Exiting boot services...\n"); 244 245 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX); 246 if (status != EFI_SUCCESS) { 247 efi_err("Unable to allocate memory for new device tree.\n"); 248 goto fail; 249 } 250 251 status = update_fdt((void *)fdt_addr, fdt_size, 252 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr); 253 254 if (status != EFI_SUCCESS) { 255 efi_err("Unable to construct new device tree.\n"); 256 goto fail_free_new_fdt; 257 } 258 259 priv.new_fdt_addr = (void *)*new_fdt_addr; 260 261 status = efi_exit_boot_services(handle, &priv, exit_boot_func); 262 263 if (status == EFI_SUCCESS) { 264 efi_set_virtual_address_map_t *svam; 265 266 if (efi_novamap) 267 return EFI_SUCCESS; 268 269 /* Install the new virtual address map */ 270 svam = efi_system_table->runtime->set_virtual_address_map; 271 status = svam(priv.runtime_entry_count * desc_size, desc_size, 272 desc_ver, priv.runtime_map); 273 274 /* 275 * We are beyond the point of no return here, so if the call to 276 * SetVirtualAddressMap() failed, we need to signal that to the 277 * incoming kernel but proceed normally otherwise. 278 */ 279 if (status != EFI_SUCCESS) { 280 efi_memory_desc_t *p; 281 int l; 282 283 /* 284 * Set the virtual address field of all 285 * EFI_MEMORY_RUNTIME entries to 0. This will signal 286 * the incoming kernel that no virtual translation has 287 * been installed. 288 */ 289 for (l = 0; l < priv.boot_memmap->map_size; 290 l += priv.boot_memmap->desc_size) { 291 p = (void *)priv.boot_memmap->map + l; 292 293 if (p->attribute & EFI_MEMORY_RUNTIME) 294 p->virt_addr = 0; 295 } 296 } 297 return EFI_SUCCESS; 298 } 299 300 efi_err("Exit boot services failed.\n"); 301 302 fail_free_new_fdt: 303 efi_free(MAX_FDT_SIZE, *new_fdt_addr); 304 305 fail: 306 efi_bs_call(free_pool, priv.runtime_map); 307 308 return EFI_LOAD_ERROR; 309 } 310 311 void *get_fdt(unsigned long *fdt_size) 312 { 313 void *fdt; 314 315 fdt = get_efi_config_table(DEVICE_TREE_GUID); 316 317 if (!fdt) 318 return NULL; 319 320 if (fdt_check_header(fdt) != 0) { 321 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 322 return NULL; 323 } 324 *fdt_size = fdt_totalsize(fdt); 325 return fdt; 326 } 327