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 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 efi_memory_desc_t *memory_map, 24 unsigned long map_size, unsigned long desc_size, 25 u32 desc_ver) 26 { 27 int node, num_rsv; 28 int status; 29 u32 fdt_val32; 30 u64 fdt_val64; 31 32 /* Do some checks on provided FDT, if it exists*/ 33 if (orig_fdt) { 34 if (fdt_check_header(orig_fdt)) { 35 pr_efi_err(sys_table, "Device Tree header not valid!\n"); 36 return EFI_LOAD_ERROR; 37 } 38 /* 39 * We don't get the size of the FDT if we get if from a 40 * configuration table. 41 */ 42 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) { 43 pr_efi_err(sys_table, "Truncated device tree! foo!\n"); 44 return EFI_LOAD_ERROR; 45 } 46 } 47 48 if (orig_fdt) 49 status = fdt_open_into(orig_fdt, fdt, new_fdt_size); 50 else 51 status = fdt_create_empty_tree(fdt, new_fdt_size); 52 53 if (status != 0) 54 goto fdt_set_fail; 55 56 /* 57 * Delete all memory reserve map entries. When booting via UEFI, 58 * kernel will use the UEFI memory map to find reserved regions. 59 */ 60 num_rsv = fdt_num_mem_rsv(fdt); 61 while (num_rsv-- > 0) 62 fdt_del_mem_rsv(fdt, num_rsv); 63 64 node = fdt_subnode_offset(fdt, 0, "chosen"); 65 if (node < 0) { 66 node = fdt_add_subnode(fdt, 0, "chosen"); 67 if (node < 0) { 68 status = node; /* node is error code when negative */ 69 goto fdt_set_fail; 70 } 71 } 72 73 if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) { 74 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, 75 strlen(cmdline_ptr) + 1); 76 if (status) 77 goto fdt_set_fail; 78 } 79 80 /* Set initrd address/end in device tree, if present */ 81 if (initrd_size != 0) { 82 u64 initrd_image_end; 83 u64 initrd_image_start = cpu_to_fdt64(initrd_addr); 84 85 status = fdt_setprop(fdt, node, "linux,initrd-start", 86 &initrd_image_start, sizeof(u64)); 87 if (status) 88 goto fdt_set_fail; 89 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size); 90 status = fdt_setprop(fdt, node, "linux,initrd-end", 91 &initrd_image_end, sizeof(u64)); 92 if (status) 93 goto fdt_set_fail; 94 } 95 96 /* Add FDT entries for EFI runtime services in chosen node. */ 97 node = fdt_subnode_offset(fdt, 0, "chosen"); 98 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table); 99 status = fdt_setprop(fdt, node, "linux,uefi-system-table", 100 &fdt_val64, sizeof(fdt_val64)); 101 if (status) 102 goto fdt_set_fail; 103 104 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map); 105 status = fdt_setprop(fdt, node, "linux,uefi-mmap-start", 106 &fdt_val64, sizeof(fdt_val64)); 107 if (status) 108 goto fdt_set_fail; 109 110 fdt_val32 = cpu_to_fdt32(map_size); 111 status = fdt_setprop(fdt, node, "linux,uefi-mmap-size", 112 &fdt_val32, sizeof(fdt_val32)); 113 if (status) 114 goto fdt_set_fail; 115 116 fdt_val32 = cpu_to_fdt32(desc_size); 117 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size", 118 &fdt_val32, sizeof(fdt_val32)); 119 if (status) 120 goto fdt_set_fail; 121 122 fdt_val32 = cpu_to_fdt32(desc_ver); 123 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver", 124 &fdt_val32, sizeof(fdt_val32)); 125 if (status) 126 goto fdt_set_fail; 127 128 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 129 efi_status_t efi_status; 130 131 efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64), 132 (u8 *)&fdt_val64); 133 if (efi_status == EFI_SUCCESS) { 134 status = fdt_setprop(fdt, node, "kaslr-seed", 135 &fdt_val64, sizeof(fdt_val64)); 136 if (status) 137 goto fdt_set_fail; 138 } else if (efi_status != EFI_NOT_FOUND) { 139 return efi_status; 140 } 141 } 142 return EFI_SUCCESS; 143 144 fdt_set_fail: 145 if (status == -FDT_ERR_NOSPACE) 146 return EFI_BUFFER_TOO_SMALL; 147 148 return EFI_LOAD_ERROR; 149 } 150 151 #ifndef EFI_FDT_ALIGN 152 #define EFI_FDT_ALIGN EFI_PAGE_SIZE 153 #endif 154 155 /* 156 * Allocate memory for a new FDT, then add EFI, commandline, and 157 * initrd related fields to the FDT. This routine increases the 158 * FDT allocation size until the allocated memory is large 159 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 160 * which are fixed at 4K bytes, so in most cases the first 161 * allocation should succeed. 162 * EFI boot services are exited at the end of this function. 163 * There must be no allocations between the get_memory_map() 164 * call and the exit_boot_services() call, so the exiting of 165 * boot services is very tightly tied to the creation of the FDT 166 * with the final memory map in it. 167 */ 168 169 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 170 void *handle, 171 unsigned long *new_fdt_addr, 172 unsigned long max_addr, 173 u64 initrd_addr, u64 initrd_size, 174 char *cmdline_ptr, 175 unsigned long fdt_addr, 176 unsigned long fdt_size) 177 { 178 unsigned long map_size, desc_size; 179 u32 desc_ver; 180 unsigned long mmap_key; 181 efi_memory_desc_t *memory_map, *runtime_map; 182 unsigned long new_fdt_size; 183 efi_status_t status; 184 int runtime_entry_count = 0; 185 186 /* 187 * Get a copy of the current memory map that we will use to prepare 188 * the input for SetVirtualAddressMap(). We don't have to worry about 189 * subsequent allocations adding entries, since they could not affect 190 * the number of EFI_MEMORY_RUNTIME regions. 191 */ 192 status = efi_get_memory_map(sys_table, &runtime_map, &map_size, 193 &desc_size, &desc_ver, &mmap_key); 194 if (status != EFI_SUCCESS) { 195 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n"); 196 return status; 197 } 198 199 pr_efi(sys_table, 200 "Exiting boot services and installing virtual address map...\n"); 201 202 /* 203 * Estimate size of new FDT, and allocate memory for it. We 204 * will allocate a bigger buffer if this ends up being too 205 * small, so a rough guess is OK here. 206 */ 207 new_fdt_size = fdt_size + EFI_PAGE_SIZE; 208 while (1) { 209 status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN, 210 new_fdt_addr, max_addr); 211 if (status != EFI_SUCCESS) { 212 pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n"); 213 goto fail; 214 } 215 216 /* 217 * Now that we have done our final memory allocation (and free) 218 * we can get the memory map key needed for 219 * exit_boot_services(). 220 */ 221 status = efi_get_memory_map(sys_table, &memory_map, &map_size, 222 &desc_size, &desc_ver, &mmap_key); 223 if (status != EFI_SUCCESS) 224 goto fail_free_new_fdt; 225 226 status = update_fdt(sys_table, 227 (void *)fdt_addr, fdt_size, 228 (void *)*new_fdt_addr, new_fdt_size, 229 cmdline_ptr, initrd_addr, initrd_size, 230 memory_map, map_size, desc_size, desc_ver); 231 232 /* Succeeding the first time is the expected case. */ 233 if (status == EFI_SUCCESS) 234 break; 235 236 if (status == EFI_BUFFER_TOO_SMALL) { 237 /* 238 * We need to allocate more space for the new 239 * device tree, so free existing buffer that is 240 * too small. Also free memory map, as we will need 241 * to get new one that reflects the free/alloc we do 242 * on the device tree buffer. 243 */ 244 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 245 sys_table->boottime->free_pool(memory_map); 246 new_fdt_size += EFI_PAGE_SIZE; 247 } else { 248 pr_efi_err(sys_table, "Unable to construct new device tree.\n"); 249 goto fail_free_mmap; 250 } 251 } 252 253 /* 254 * Update the memory map with virtual addresses. The function will also 255 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 256 * entries so that we can pass it straight into SetVirtualAddressMap() 257 */ 258 efi_get_virtmap(memory_map, map_size, desc_size, runtime_map, 259 &runtime_entry_count); 260 261 /* Now we are ready to exit_boot_services.*/ 262 status = sys_table->boottime->exit_boot_services(handle, mmap_key); 263 264 if (status == EFI_SUCCESS) { 265 efi_set_virtual_address_map_t *svam; 266 267 /* Install the new virtual address map */ 268 svam = sys_table->runtime->set_virtual_address_map; 269 status = svam(runtime_entry_count * desc_size, desc_size, 270 desc_ver, runtime_map); 271 272 /* 273 * We are beyond the point of no return here, so if the call to 274 * SetVirtualAddressMap() failed, we need to signal that to the 275 * incoming kernel but proceed normally otherwise. 276 */ 277 if (status != EFI_SUCCESS) { 278 int l; 279 280 /* 281 * Set the virtual address field of all 282 * EFI_MEMORY_RUNTIME entries to 0. This will signal 283 * the incoming kernel that no virtual translation has 284 * been installed. 285 */ 286 for (l = 0; l < map_size; l += desc_size) { 287 efi_memory_desc_t *p = (void *)memory_map + l; 288 289 if (p->attribute & EFI_MEMORY_RUNTIME) 290 p->virt_addr = 0; 291 } 292 } 293 return EFI_SUCCESS; 294 } 295 296 pr_efi_err(sys_table, "Exit boot services failed.\n"); 297 298 fail_free_mmap: 299 sys_table->boottime->free_pool(memory_map); 300 301 fail_free_new_fdt: 302 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 303 304 fail: 305 sys_table->boottime->free_pool(runtime_map); 306 return EFI_LOAD_ERROR; 307 } 308 309 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size) 310 { 311 efi_guid_t fdt_guid = DEVICE_TREE_GUID; 312 efi_config_table_t *tables; 313 void *fdt; 314 int i; 315 316 tables = (efi_config_table_t *) sys_table->tables; 317 fdt = NULL; 318 319 for (i = 0; i < sys_table->nr_tables; i++) 320 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) { 321 fdt = (void *) tables[i].table; 322 if (fdt_check_header(fdt) != 0) { 323 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 324 return NULL; 325 } 326 *fdt_size = fdt_totalsize(fdt); 327 break; 328 } 329 330 return fdt; 331 } 332