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 19efi_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, prev, 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 any memory nodes present. We must delete nodes which 58 * early_init_dt_scan_memory may try to use. 59 */ 60 prev = 0; 61 for (;;) { 62 const char *type; 63 int len; 64 65 node = fdt_next_node(fdt, prev, NULL); 66 if (node < 0) 67 break; 68 69 type = fdt_getprop(fdt, node, "device_type", &len); 70 if (type && strncmp(type, "memory", len) == 0) { 71 fdt_del_node(fdt, node); 72 continue; 73 } 74 75 prev = node; 76 } 77 78 /* 79 * Delete all memory reserve map entries. When booting via UEFI, 80 * kernel will use the UEFI memory map to find reserved regions. 81 */ 82 num_rsv = fdt_num_mem_rsv(fdt); 83 while (num_rsv-- > 0) 84 fdt_del_mem_rsv(fdt, num_rsv); 85 86 node = fdt_subnode_offset(fdt, 0, "chosen"); 87 if (node < 0) { 88 node = fdt_add_subnode(fdt, 0, "chosen"); 89 if (node < 0) { 90 status = node; /* node is error code when negative */ 91 goto fdt_set_fail; 92 } 93 } 94 95 if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) { 96 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, 97 strlen(cmdline_ptr) + 1); 98 if (status) 99 goto fdt_set_fail; 100 } 101 102 /* Set initrd address/end in device tree, if present */ 103 if (initrd_size != 0) { 104 u64 initrd_image_end; 105 u64 initrd_image_start = cpu_to_fdt64(initrd_addr); 106 107 status = fdt_setprop(fdt, node, "linux,initrd-start", 108 &initrd_image_start, sizeof(u64)); 109 if (status) 110 goto fdt_set_fail; 111 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size); 112 status = fdt_setprop(fdt, node, "linux,initrd-end", 113 &initrd_image_end, sizeof(u64)); 114 if (status) 115 goto fdt_set_fail; 116 } 117 118 /* Add FDT entries for EFI runtime services in chosen node. */ 119 node = fdt_subnode_offset(fdt, 0, "chosen"); 120 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table); 121 status = fdt_setprop(fdt, node, "linux,uefi-system-table", 122 &fdt_val64, sizeof(fdt_val64)); 123 if (status) 124 goto fdt_set_fail; 125 126 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map); 127 status = fdt_setprop(fdt, node, "linux,uefi-mmap-start", 128 &fdt_val64, sizeof(fdt_val64)); 129 if (status) 130 goto fdt_set_fail; 131 132 fdt_val32 = cpu_to_fdt32(map_size); 133 status = fdt_setprop(fdt, node, "linux,uefi-mmap-size", 134 &fdt_val32, sizeof(fdt_val32)); 135 if (status) 136 goto fdt_set_fail; 137 138 fdt_val32 = cpu_to_fdt32(desc_size); 139 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size", 140 &fdt_val32, sizeof(fdt_val32)); 141 if (status) 142 goto fdt_set_fail; 143 144 fdt_val32 = cpu_to_fdt32(desc_ver); 145 status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver", 146 &fdt_val32, sizeof(fdt_val32)); 147 if (status) 148 goto fdt_set_fail; 149 150 /* 151 * Add kernel version banner so stub/kernel match can be 152 * verified. 153 */ 154 status = fdt_setprop_string(fdt, node, "linux,uefi-stub-kern-ver", 155 linux_banner); 156 if (status) 157 goto fdt_set_fail; 158 159 return EFI_SUCCESS; 160 161fdt_set_fail: 162 if (status == -FDT_ERR_NOSPACE) 163 return EFI_BUFFER_TOO_SMALL; 164 165 return EFI_LOAD_ERROR; 166} 167 168#ifndef EFI_FDT_ALIGN 169#define EFI_FDT_ALIGN EFI_PAGE_SIZE 170#endif 171 172/* 173 * Allocate memory for a new FDT, then add EFI, commandline, and 174 * initrd related fields to the FDT. This routine increases the 175 * FDT allocation size until the allocated memory is large 176 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 177 * which are fixed at 4K bytes, so in most cases the first 178 * allocation should succeed. 179 * EFI boot services are exited at the end of this function. 180 * There must be no allocations between the get_memory_map() 181 * call and the exit_boot_services() call, so the exiting of 182 * boot services is very tightly tied to the creation of the FDT 183 * with the final memory map in it. 184 */ 185 186efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 187 void *handle, 188 unsigned long *new_fdt_addr, 189 unsigned long max_addr, 190 u64 initrd_addr, u64 initrd_size, 191 char *cmdline_ptr, 192 unsigned long fdt_addr, 193 unsigned long fdt_size) 194{ 195 unsigned long map_size, desc_size; 196 u32 desc_ver; 197 unsigned long mmap_key; 198 efi_memory_desc_t *memory_map, *runtime_map; 199 unsigned long new_fdt_size; 200 efi_status_t status; 201 int runtime_entry_count = 0; 202 203 /* 204 * Get a copy of the current memory map that we will use to prepare 205 * the input for SetVirtualAddressMap(). We don't have to worry about 206 * subsequent allocations adding entries, since they could not affect 207 * the number of EFI_MEMORY_RUNTIME regions. 208 */ 209 status = efi_get_memory_map(sys_table, &runtime_map, &map_size, 210 &desc_size, &desc_ver, &mmap_key); 211 if (status != EFI_SUCCESS) { 212 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n"); 213 return status; 214 } 215 216 pr_efi(sys_table, 217 "Exiting boot services and installing virtual address map...\n"); 218 219 /* 220 * Estimate size of new FDT, and allocate memory for it. We 221 * will allocate a bigger buffer if this ends up being too 222 * small, so a rough guess is OK here. 223 */ 224 new_fdt_size = fdt_size + EFI_PAGE_SIZE; 225 while (1) { 226 status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN, 227 new_fdt_addr, max_addr); 228 if (status != EFI_SUCCESS) { 229 pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n"); 230 goto fail; 231 } 232 233 /* 234 * Now that we have done our final memory allocation (and free) 235 * we can get the memory map key needed for 236 * exit_boot_services(). 237 */ 238 status = efi_get_memory_map(sys_table, &memory_map, &map_size, 239 &desc_size, &desc_ver, &mmap_key); 240 if (status != EFI_SUCCESS) 241 goto fail_free_new_fdt; 242 243 status = update_fdt(sys_table, 244 (void *)fdt_addr, fdt_size, 245 (void *)*new_fdt_addr, new_fdt_size, 246 cmdline_ptr, initrd_addr, initrd_size, 247 memory_map, map_size, desc_size, desc_ver); 248 249 /* Succeeding the first time is the expected case. */ 250 if (status == EFI_SUCCESS) 251 break; 252 253 if (status == EFI_BUFFER_TOO_SMALL) { 254 /* 255 * We need to allocate more space for the new 256 * device tree, so free existing buffer that is 257 * too small. Also free memory map, as we will need 258 * to get new one that reflects the free/alloc we do 259 * on the device tree buffer. 260 */ 261 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 262 sys_table->boottime->free_pool(memory_map); 263 new_fdt_size += EFI_PAGE_SIZE; 264 } else { 265 pr_efi_err(sys_table, "Unable to constuct new device tree.\n"); 266 goto fail_free_mmap; 267 } 268 } 269 270 /* 271 * Update the memory map with virtual addresses. The function will also 272 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 273 * entries so that we can pass it straight into SetVirtualAddressMap() 274 */ 275 efi_get_virtmap(memory_map, map_size, desc_size, runtime_map, 276 &runtime_entry_count); 277 278 /* Now we are ready to exit_boot_services.*/ 279 status = sys_table->boottime->exit_boot_services(handle, mmap_key); 280 281 if (status == EFI_SUCCESS) { 282 efi_set_virtual_address_map_t *svam; 283 284 /* Install the new virtual address map */ 285 svam = sys_table->runtime->set_virtual_address_map; 286 status = svam(runtime_entry_count * desc_size, desc_size, 287 desc_ver, runtime_map); 288 289 /* 290 * We are beyond the point of no return here, so if the call to 291 * SetVirtualAddressMap() failed, we need to signal that to the 292 * incoming kernel but proceed normally otherwise. 293 */ 294 if (status != EFI_SUCCESS) { 295 int l; 296 297 /* 298 * Set the virtual address field of all 299 * EFI_MEMORY_RUNTIME entries to 0. This will signal 300 * the incoming kernel that no virtual translation has 301 * been installed. 302 */ 303 for (l = 0; l < map_size; l += desc_size) { 304 efi_memory_desc_t *p = (void *)memory_map + l; 305 306 if (p->attribute & EFI_MEMORY_RUNTIME) 307 p->virt_addr = 0; 308 } 309 } 310 return EFI_SUCCESS; 311 } 312 313 pr_efi_err(sys_table, "Exit boot services failed.\n"); 314 315fail_free_mmap: 316 sys_table->boottime->free_pool(memory_map); 317 318fail_free_new_fdt: 319 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 320 321fail: 322 sys_table->boottime->free_pool(runtime_map); 323 return EFI_LOAD_ERROR; 324} 325 326void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size) 327{ 328 efi_guid_t fdt_guid = DEVICE_TREE_GUID; 329 efi_config_table_t *tables; 330 void *fdt; 331 int i; 332 333 tables = (efi_config_table_t *) sys_table->tables; 334 fdt = NULL; 335 336 for (i = 0; i < sys_table->nr_tables; i++) 337 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) { 338 fdt = (void *) tables[i].table; 339 if (fdt_check_header(fdt) != 0) { 340 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 341 return NULL; 342 } 343 *fdt_size = fdt_totalsize(fdt); 344 break; 345 } 346 347 return fdt; 348} 349