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 return EFI_SUCCESS; 151 152fdt_set_fail: 153 if (status == -FDT_ERR_NOSPACE) 154 return EFI_BUFFER_TOO_SMALL; 155 156 return EFI_LOAD_ERROR; 157} 158 159#ifndef EFI_FDT_ALIGN 160#define EFI_FDT_ALIGN EFI_PAGE_SIZE 161#endif 162 163/* 164 * Allocate memory for a new FDT, then add EFI, commandline, and 165 * initrd related fields to the FDT. This routine increases the 166 * FDT allocation size until the allocated memory is large 167 * enough. EFI allocations are in EFI_PAGE_SIZE granules, 168 * which are fixed at 4K bytes, so in most cases the first 169 * allocation should succeed. 170 * EFI boot services are exited at the end of this function. 171 * There must be no allocations between the get_memory_map() 172 * call and the exit_boot_services() call, so the exiting of 173 * boot services is very tightly tied to the creation of the FDT 174 * with the final memory map in it. 175 */ 176 177efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 178 void *handle, 179 unsigned long *new_fdt_addr, 180 unsigned long max_addr, 181 u64 initrd_addr, u64 initrd_size, 182 char *cmdline_ptr, 183 unsigned long fdt_addr, 184 unsigned long fdt_size) 185{ 186 unsigned long map_size, desc_size; 187 u32 desc_ver; 188 unsigned long mmap_key; 189 efi_memory_desc_t *memory_map, *runtime_map; 190 unsigned long new_fdt_size; 191 efi_status_t status; 192 int runtime_entry_count = 0; 193 194 /* 195 * Get a copy of the current memory map that we will use to prepare 196 * the input for SetVirtualAddressMap(). We don't have to worry about 197 * subsequent allocations adding entries, since they could not affect 198 * the number of EFI_MEMORY_RUNTIME regions. 199 */ 200 status = efi_get_memory_map(sys_table, &runtime_map, &map_size, 201 &desc_size, &desc_ver, &mmap_key); 202 if (status != EFI_SUCCESS) { 203 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n"); 204 return status; 205 } 206 207 pr_efi(sys_table, 208 "Exiting boot services and installing virtual address map...\n"); 209 210 /* 211 * Estimate size of new FDT, and allocate memory for it. We 212 * will allocate a bigger buffer if this ends up being too 213 * small, so a rough guess is OK here. 214 */ 215 new_fdt_size = fdt_size + EFI_PAGE_SIZE; 216 while (1) { 217 status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN, 218 new_fdt_addr, max_addr); 219 if (status != EFI_SUCCESS) { 220 pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n"); 221 goto fail; 222 } 223 224 /* 225 * Now that we have done our final memory allocation (and free) 226 * we can get the memory map key needed for 227 * exit_boot_services(). 228 */ 229 status = efi_get_memory_map(sys_table, &memory_map, &map_size, 230 &desc_size, &desc_ver, &mmap_key); 231 if (status != EFI_SUCCESS) 232 goto fail_free_new_fdt; 233 234 status = update_fdt(sys_table, 235 (void *)fdt_addr, fdt_size, 236 (void *)*new_fdt_addr, new_fdt_size, 237 cmdline_ptr, initrd_addr, initrd_size, 238 memory_map, map_size, desc_size, desc_ver); 239 240 /* Succeeding the first time is the expected case. */ 241 if (status == EFI_SUCCESS) 242 break; 243 244 if (status == EFI_BUFFER_TOO_SMALL) { 245 /* 246 * We need to allocate more space for the new 247 * device tree, so free existing buffer that is 248 * too small. Also free memory map, as we will need 249 * to get new one that reflects the free/alloc we do 250 * on the device tree buffer. 251 */ 252 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 253 sys_table->boottime->free_pool(memory_map); 254 new_fdt_size += EFI_PAGE_SIZE; 255 } else { 256 pr_efi_err(sys_table, "Unable to constuct new device tree.\n"); 257 goto fail_free_mmap; 258 } 259 } 260 261 /* 262 * Update the memory map with virtual addresses. The function will also 263 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME 264 * entries so that we can pass it straight into SetVirtualAddressMap() 265 */ 266 efi_get_virtmap(memory_map, map_size, desc_size, runtime_map, 267 &runtime_entry_count); 268 269 /* Now we are ready to exit_boot_services.*/ 270 status = sys_table->boottime->exit_boot_services(handle, mmap_key); 271 272 if (status == EFI_SUCCESS) { 273 efi_set_virtual_address_map_t *svam; 274 275 /* Install the new virtual address map */ 276 svam = sys_table->runtime->set_virtual_address_map; 277 status = svam(runtime_entry_count * desc_size, desc_size, 278 desc_ver, runtime_map); 279 280 /* 281 * We are beyond the point of no return here, so if the call to 282 * SetVirtualAddressMap() failed, we need to signal that to the 283 * incoming kernel but proceed normally otherwise. 284 */ 285 if (status != EFI_SUCCESS) { 286 int l; 287 288 /* 289 * Set the virtual address field of all 290 * EFI_MEMORY_RUNTIME entries to 0. This will signal 291 * the incoming kernel that no virtual translation has 292 * been installed. 293 */ 294 for (l = 0; l < map_size; l += desc_size) { 295 efi_memory_desc_t *p = (void *)memory_map + l; 296 297 if (p->attribute & EFI_MEMORY_RUNTIME) 298 p->virt_addr = 0; 299 } 300 } 301 return EFI_SUCCESS; 302 } 303 304 pr_efi_err(sys_table, "Exit boot services failed.\n"); 305 306fail_free_mmap: 307 sys_table->boottime->free_pool(memory_map); 308 309fail_free_new_fdt: 310 efi_free(sys_table, new_fdt_size, *new_fdt_addr); 311 312fail: 313 sys_table->boottime->free_pool(runtime_map); 314 return EFI_LOAD_ERROR; 315} 316 317void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size) 318{ 319 efi_guid_t fdt_guid = DEVICE_TREE_GUID; 320 efi_config_table_t *tables; 321 void *fdt; 322 int i; 323 324 tables = (efi_config_table_t *) sys_table->tables; 325 fdt = NULL; 326 327 for (i = 0; i < sys_table->nr_tables; i++) 328 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) { 329 fdt = (void *) tables[i].table; 330 if (fdt_check_header(fdt) != 0) { 331 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n"); 332 return NULL; 333 } 334 *fdt_size = fdt_totalsize(fdt); 335 break; 336 } 337 338 return fdt; 339} 340