1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Functions for working with the Flattened Device Tree data format 4 * 5 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp 6 * benh@kernel.crashing.org 7 */ 8 9 #define pr_fmt(fmt) "OF: fdt: " fmt 10 11 #include <linux/acpi.h> 12 #include <linux/crash_dump.h> 13 #include <linux/crc32.h> 14 #include <linux/kernel.h> 15 #include <linux/initrd.h> 16 #include <linux/memblock.h> 17 #include <linux/mutex.h> 18 #include <linux/of.h> 19 #include <linux/of_fdt.h> 20 #include <linux/sizes.h> 21 #include <linux/string.h> 22 #include <linux/errno.h> 23 #include <linux/slab.h> 24 #include <linux/libfdt.h> 25 #include <linux/debugfs.h> 26 #include <linux/serial_core.h> 27 #include <linux/sysfs.h> 28 #include <linux/random.h> 29 30 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 31 #include <asm/page.h> 32 33 #include "of_private.h" 34 35 /* 36 * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by 37 * cmd_wrap_S_dtb in scripts/Makefile.dtbs 38 */ 39 extern uint8_t __dtb_empty_root_begin[]; 40 extern uint8_t __dtb_empty_root_end[]; 41 42 /* 43 * of_fdt_limit_memory - limit the number of regions in the /memory node 44 * @limit: maximum entries 45 * 46 * Adjust the flattened device tree to have at most 'limit' number of 47 * memory entries in the /memory node. This function may be called 48 * any time after initial_boot_param is set. 49 */ 50 void __init of_fdt_limit_memory(int limit) 51 { 52 int memory; 53 int len; 54 const void *val; 55 int cell_size = sizeof(uint32_t)*(dt_root_addr_cells + dt_root_size_cells); 56 57 memory = fdt_path_offset(initial_boot_params, "/memory"); 58 if (memory > 0) { 59 val = fdt_getprop(initial_boot_params, memory, "reg", &len); 60 if (len > limit*cell_size) { 61 len = limit*cell_size; 62 pr_debug("Limiting number of entries to %d\n", limit); 63 fdt_setprop(initial_boot_params, memory, "reg", val, 64 len); 65 } 66 } 67 } 68 69 bool of_fdt_device_is_available(const void *blob, unsigned long node) 70 { 71 const char *status = fdt_getprop(blob, node, "status", NULL); 72 73 if (!status) 74 return true; 75 76 if (!strcmp(status, "ok") || !strcmp(status, "okay")) 77 return true; 78 79 return false; 80 } 81 82 static void *unflatten_dt_alloc(void **mem, unsigned long size, 83 unsigned long align) 84 { 85 void *res; 86 87 *mem = PTR_ALIGN(*mem, align); 88 res = *mem; 89 *mem += size; 90 91 return res; 92 } 93 94 static void populate_properties(const void *blob, 95 int offset, 96 void **mem, 97 struct device_node *np, 98 const char *nodename, 99 bool dryrun) 100 { 101 struct property *pp, **pprev = NULL; 102 int cur; 103 bool has_name = false; 104 105 pprev = &np->properties; 106 for (cur = fdt_first_property_offset(blob, offset); 107 cur >= 0; 108 cur = fdt_next_property_offset(blob, cur)) { 109 const __be32 *val; 110 const char *pname; 111 u32 sz; 112 113 val = fdt_getprop_by_offset(blob, cur, &pname, &sz); 114 if (!val) { 115 pr_warn("Cannot locate property at 0x%x\n", cur); 116 continue; 117 } 118 119 if (!pname) { 120 pr_warn("Cannot find property name at 0x%x\n", cur); 121 continue; 122 } 123 124 if (!strcmp(pname, "name")) 125 has_name = true; 126 127 pp = unflatten_dt_alloc(mem, sizeof(struct property), 128 __alignof__(struct property)); 129 if (dryrun) 130 continue; 131 132 /* We accept flattened tree phandles either in 133 * ePAPR-style "phandle" properties, or the 134 * legacy "linux,phandle" properties. If both 135 * appear and have different values, things 136 * will get weird. Don't do that. 137 */ 138 if (!strcmp(pname, "phandle") || 139 !strcmp(pname, "linux,phandle")) { 140 if (!np->phandle) 141 np->phandle = be32_to_cpup(val); 142 } 143 144 /* And we process the "ibm,phandle" property 145 * used in pSeries dynamic device tree 146 * stuff 147 */ 148 if (!strcmp(pname, "ibm,phandle")) 149 np->phandle = be32_to_cpup(val); 150 151 pp->name = (char *)pname; 152 pp->length = sz; 153 pp->value = (__be32 *)val; 154 *pprev = pp; 155 pprev = &pp->next; 156 } 157 158 /* With version 0x10 we may not have the name property, 159 * recreate it here from the unit name if absent 160 */ 161 if (!has_name) { 162 const char *p = nodename, *ps = p, *pa = NULL; 163 int len; 164 165 while (*p) { 166 if ((*p) == '@') 167 pa = p; 168 else if ((*p) == '/') 169 ps = p + 1; 170 p++; 171 } 172 173 if (pa < ps) 174 pa = p; 175 len = (pa - ps) + 1; 176 pp = unflatten_dt_alloc(mem, sizeof(struct property) + len, 177 __alignof__(struct property)); 178 if (!dryrun) { 179 pp->name = "name"; 180 pp->length = len; 181 pp->value = pp + 1; 182 *pprev = pp; 183 memcpy(pp->value, ps, len - 1); 184 ((char *)pp->value)[len - 1] = 0; 185 pr_debug("fixed up name for %s -> %s\n", 186 nodename, (char *)pp->value); 187 } 188 } 189 } 190 191 static int populate_node(const void *blob, 192 int offset, 193 void **mem, 194 struct device_node *dad, 195 struct device_node **pnp, 196 bool dryrun) 197 { 198 struct device_node *np; 199 const char *pathp; 200 int len; 201 202 pathp = fdt_get_name(blob, offset, &len); 203 if (!pathp) { 204 *pnp = NULL; 205 return len; 206 } 207 208 len++; 209 210 np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len, 211 __alignof__(struct device_node)); 212 if (!dryrun) { 213 char *fn; 214 of_node_init(np); 215 np->full_name = fn = ((char *)np) + sizeof(*np); 216 217 memcpy(fn, pathp, len); 218 219 if (dad != NULL) { 220 np->parent = dad; 221 np->sibling = dad->child; 222 dad->child = np; 223 } 224 } 225 226 populate_properties(blob, offset, mem, np, pathp, dryrun); 227 if (!dryrun) { 228 np->name = of_get_property(np, "name", NULL); 229 if (!np->name) 230 np->name = "<NULL>"; 231 } 232 233 *pnp = np; 234 return 0; 235 } 236 237 static void reverse_nodes(struct device_node *parent) 238 { 239 struct device_node *child, *next; 240 241 /* In-depth first */ 242 child = parent->child; 243 while (child) { 244 reverse_nodes(child); 245 246 child = child->sibling; 247 } 248 249 /* Reverse the nodes in the child list */ 250 child = parent->child; 251 parent->child = NULL; 252 while (child) { 253 next = child->sibling; 254 255 child->sibling = parent->child; 256 parent->child = child; 257 child = next; 258 } 259 } 260 261 /** 262 * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree 263 * @blob: The parent device tree blob 264 * @mem: Memory chunk to use for allocating device nodes and properties 265 * @dad: Parent struct device_node 266 * @nodepp: The device_node tree created by the call 267 * 268 * Return: The size of unflattened device tree or error code 269 */ 270 static int unflatten_dt_nodes(const void *blob, 271 void *mem, 272 struct device_node *dad, 273 struct device_node **nodepp) 274 { 275 struct device_node *root; 276 int offset = 0, depth = 0, initial_depth = 0; 277 #define FDT_MAX_DEPTH 64 278 struct device_node *nps[FDT_MAX_DEPTH]; 279 void *base = mem; 280 bool dryrun = !base; 281 int ret; 282 283 if (nodepp) 284 *nodepp = NULL; 285 286 /* 287 * We're unflattening device sub-tree if @dad is valid. There are 288 * possibly multiple nodes in the first level of depth. We need 289 * set @depth to 1 to make fdt_next_node() happy as it bails 290 * immediately when negative @depth is found. Otherwise, the device 291 * nodes except the first one won't be unflattened successfully. 292 */ 293 if (dad) 294 depth = initial_depth = 1; 295 296 root = dad; 297 nps[depth] = dad; 298 299 for (offset = 0; 300 offset >= 0 && depth >= initial_depth; 301 offset = fdt_next_node(blob, offset, &depth)) { 302 if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1)) 303 continue; 304 305 if (!IS_ENABLED(CONFIG_OF_KOBJ) && 306 !of_fdt_device_is_available(blob, offset)) 307 continue; 308 309 ret = populate_node(blob, offset, &mem, nps[depth], 310 &nps[depth+1], dryrun); 311 if (ret < 0) 312 return ret; 313 314 if (!dryrun && nodepp && !*nodepp) 315 *nodepp = nps[depth+1]; 316 if (!dryrun && !root) 317 root = nps[depth+1]; 318 } 319 320 if (offset < 0 && offset != -FDT_ERR_NOTFOUND) { 321 pr_err("Error %d processing FDT\n", offset); 322 return -EINVAL; 323 } 324 325 /* 326 * Reverse the child list. Some drivers assumes node order matches .dts 327 * node order 328 */ 329 if (!dryrun) 330 reverse_nodes(root); 331 332 return mem - base; 333 } 334 335 /** 336 * __unflatten_device_tree - create tree of device_nodes from flat blob 337 * @blob: The blob to expand 338 * @dad: Parent device node 339 * @mynodes: The device_node tree created by the call 340 * @dt_alloc: An allocator that provides a virtual address to memory 341 * for the resulting tree 342 * @detached: if true set OF_DETACHED on @mynodes 343 * 344 * unflattens a device-tree, creating the tree of struct device_node. It also 345 * fills the "name" and "type" pointers of the nodes so the normal device-tree 346 * walking functions can be used. 347 * 348 * Return: NULL on failure or the memory chunk containing the unflattened 349 * device tree on success. 350 */ 351 void *__unflatten_device_tree(const void *blob, 352 struct device_node *dad, 353 struct device_node **mynodes, 354 void *(*dt_alloc)(u64 size, u64 align), 355 bool detached) 356 { 357 int size; 358 void *mem; 359 int ret; 360 361 if (mynodes) 362 *mynodes = NULL; 363 364 pr_debug(" -> unflatten_device_tree()\n"); 365 366 if (!blob) { 367 pr_debug("No device tree pointer\n"); 368 return NULL; 369 } 370 371 pr_debug("Unflattening device tree:\n"); 372 pr_debug("magic: %08x\n", fdt_magic(blob)); 373 pr_debug("size: %08x\n", fdt_totalsize(blob)); 374 pr_debug("version: %08x\n", fdt_version(blob)); 375 376 if (fdt_check_header(blob)) { 377 pr_err("Invalid device tree blob header\n"); 378 return NULL; 379 } 380 381 /* First pass, scan for size */ 382 size = unflatten_dt_nodes(blob, NULL, dad, NULL); 383 if (size <= 0) 384 return NULL; 385 386 size = ALIGN(size, 4); 387 pr_debug(" size is %d, allocating...\n", size); 388 389 /* Allocate memory for the expanded device tree */ 390 mem = dt_alloc(size + 4, __alignof__(struct device_node)); 391 if (!mem) 392 return NULL; 393 394 memset(mem, 0, size); 395 396 *(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef); 397 398 pr_debug(" unflattening %p...\n", mem); 399 400 /* Second pass, do actual unflattening */ 401 ret = unflatten_dt_nodes(blob, mem, dad, mynodes); 402 403 if (be32_to_cpup(mem + size) != 0xdeadbeef) 404 pr_warn("End of tree marker overwritten: %08x\n", 405 be32_to_cpup(mem + size)); 406 407 if (ret <= 0) 408 return NULL; 409 410 if (detached && mynodes && *mynodes) { 411 of_node_set_flag(*mynodes, OF_DETACHED); 412 pr_debug("unflattened tree is detached\n"); 413 } 414 415 pr_debug(" <- unflatten_device_tree()\n"); 416 return mem; 417 } 418 419 static void *kernel_tree_alloc(u64 size, u64 align) 420 { 421 return kzalloc(size, GFP_KERNEL); 422 } 423 424 static DEFINE_MUTEX(of_fdt_unflatten_mutex); 425 426 /** 427 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob 428 * @blob: Flat device tree blob 429 * @dad: Parent device node 430 * @mynodes: The device tree created by the call 431 * 432 * unflattens the device-tree passed by the firmware, creating the 433 * tree of struct device_node. It also fills the "name" and "type" 434 * pointers of the nodes so the normal device-tree walking functions 435 * can be used. 436 * 437 * Return: NULL on failure or the memory chunk containing the unflattened 438 * device tree on success. 439 */ 440 void *of_fdt_unflatten_tree(const unsigned long *blob, 441 struct device_node *dad, 442 struct device_node **mynodes) 443 { 444 void *mem; 445 446 mutex_lock(&of_fdt_unflatten_mutex); 447 mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc, 448 true); 449 mutex_unlock(&of_fdt_unflatten_mutex); 450 451 return mem; 452 } 453 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); 454 455 /* Everything below here references initial_boot_params directly. */ 456 int __initdata dt_root_addr_cells; 457 int __initdata dt_root_size_cells; 458 459 void *initial_boot_params __ro_after_init; 460 461 #ifdef CONFIG_OF_EARLY_FLATTREE 462 463 static u32 of_fdt_crc32; 464 465 /* 466 * fdt_reserve_elfcorehdr() - reserves memory for elf core header 467 * 468 * This function reserves the memory occupied by an elf core header 469 * described in the device tree. This region contains all the 470 * information about primary kernel's core image and is used by a dump 471 * capture kernel to access the system memory on primary kernel. 472 */ 473 static void __init fdt_reserve_elfcorehdr(void) 474 { 475 if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size) 476 return; 477 478 if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) { 479 pr_warn("elfcorehdr is overlapped\n"); 480 return; 481 } 482 483 memblock_reserve(elfcorehdr_addr, elfcorehdr_size); 484 485 pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n", 486 elfcorehdr_size >> 10, elfcorehdr_addr); 487 } 488 489 /** 490 * early_init_fdt_scan_reserved_mem() - create reserved memory regions 491 * 492 * This function grabs memory from early allocator for device exclusive use 493 * defined in device tree structures. It should be called by arch specific code 494 * once the early allocator (i.e. memblock) has been fully activated. 495 */ 496 void __init early_init_fdt_scan_reserved_mem(void) 497 { 498 int n; 499 u64 base, size; 500 501 if (!initial_boot_params) 502 return; 503 504 fdt_scan_reserved_mem(); 505 fdt_reserve_elfcorehdr(); 506 507 /* Process header /memreserve/ fields */ 508 for (n = 0; ; n++) { 509 fdt_get_mem_rsv(initial_boot_params, n, &base, &size); 510 if (!size) 511 break; 512 memblock_reserve(base, size); 513 } 514 515 fdt_init_reserved_mem(); 516 } 517 518 /** 519 * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob 520 */ 521 void __init early_init_fdt_reserve_self(void) 522 { 523 if (!initial_boot_params) 524 return; 525 526 /* Reserve the dtb region */ 527 memblock_reserve(__pa(initial_boot_params), 528 fdt_totalsize(initial_boot_params)); 529 } 530 531 /** 532 * of_scan_flat_dt - scan flattened tree blob and call callback on each. 533 * @it: callback function 534 * @data: context data pointer 535 * 536 * This function is used to scan the flattened device-tree, it is 537 * used to extract the memory information at boot before we can 538 * unflatten the tree 539 */ 540 int __init of_scan_flat_dt(int (*it)(unsigned long node, 541 const char *uname, int depth, 542 void *data), 543 void *data) 544 { 545 const void *blob = initial_boot_params; 546 const char *pathp; 547 int offset, rc = 0, depth = -1; 548 549 if (!blob) 550 return 0; 551 552 for (offset = fdt_next_node(blob, -1, &depth); 553 offset >= 0 && depth >= 0 && !rc; 554 offset = fdt_next_node(blob, offset, &depth)) { 555 556 pathp = fdt_get_name(blob, offset, NULL); 557 rc = it(offset, pathp, depth, data); 558 } 559 return rc; 560 } 561 562 /** 563 * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each. 564 * @parent: parent node 565 * @it: callback function 566 * @data: context data pointer 567 * 568 * This function is used to scan sub-nodes of a node. 569 */ 570 int __init of_scan_flat_dt_subnodes(unsigned long parent, 571 int (*it)(unsigned long node, 572 const char *uname, 573 void *data), 574 void *data) 575 { 576 const void *blob = initial_boot_params; 577 int node; 578 579 fdt_for_each_subnode(node, blob, parent) { 580 const char *pathp; 581 int rc; 582 583 pathp = fdt_get_name(blob, node, NULL); 584 rc = it(node, pathp, data); 585 if (rc) 586 return rc; 587 } 588 return 0; 589 } 590 591 /** 592 * of_get_flat_dt_subnode_by_name - get the subnode by given name 593 * 594 * @node: the parent node 595 * @uname: the name of subnode 596 * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none 597 */ 598 599 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname) 600 { 601 return fdt_subnode_offset(initial_boot_params, node, uname); 602 } 603 604 /* 605 * of_get_flat_dt_root - find the root node in the flat blob 606 */ 607 unsigned long __init of_get_flat_dt_root(void) 608 { 609 return 0; 610 } 611 612 /* 613 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr 614 * 615 * This function can be used within scan_flattened_dt callback to get 616 * access to properties 617 */ 618 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name, 619 int *size) 620 { 621 return fdt_getprop(initial_boot_params, node, name, size); 622 } 623 624 /** 625 * of_fdt_is_compatible - Return true if given node from the given blob has 626 * compat in its compatible list 627 * @blob: A device tree blob 628 * @node: node to test 629 * @compat: compatible string to compare with compatible list. 630 * 631 * Return: a non-zero value on match with smaller values returned for more 632 * specific compatible values. 633 */ 634 static int of_fdt_is_compatible(const void *blob, 635 unsigned long node, const char *compat) 636 { 637 const char *cp; 638 int cplen; 639 unsigned long l, score = 0; 640 641 cp = fdt_getprop(blob, node, "compatible", &cplen); 642 if (cp == NULL) 643 return 0; 644 while (cplen > 0) { 645 score++; 646 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) 647 return score; 648 l = strlen(cp) + 1; 649 cp += l; 650 cplen -= l; 651 } 652 653 return 0; 654 } 655 656 /** 657 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list 658 * @node: node to test 659 * @compat: compatible string to compare with compatible list. 660 */ 661 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat) 662 { 663 return of_fdt_is_compatible(initial_boot_params, node, compat); 664 } 665 666 /* 667 * of_flat_dt_match - Return true if node matches a list of compatible values 668 */ 669 static int __init of_flat_dt_match(unsigned long node, const char *const *compat) 670 { 671 unsigned int tmp, score = 0; 672 673 if (!compat) 674 return 0; 675 676 while (*compat) { 677 tmp = of_fdt_is_compatible(initial_boot_params, node, *compat); 678 if (tmp && (score == 0 || (tmp < score))) 679 score = tmp; 680 compat++; 681 } 682 683 return score; 684 } 685 686 /* 687 * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle 688 */ 689 uint32_t __init of_get_flat_dt_phandle(unsigned long node) 690 { 691 return fdt_get_phandle(initial_boot_params, node); 692 } 693 694 const char * __init of_flat_dt_get_machine_name(void) 695 { 696 const char *name; 697 unsigned long dt_root = of_get_flat_dt_root(); 698 699 name = of_get_flat_dt_prop(dt_root, "model", NULL); 700 if (!name) 701 name = of_get_flat_dt_prop(dt_root, "compatible", NULL); 702 return name; 703 } 704 705 /** 706 * of_flat_dt_match_machine - Iterate match tables to find matching machine. 707 * 708 * @default_match: A machine specific ptr to return in case of no match. 709 * @get_next_compat: callback function to return next compatible match table. 710 * 711 * Iterate through machine match tables to find the best match for the machine 712 * compatible string in the FDT. 713 */ 714 const void * __init of_flat_dt_match_machine(const void *default_match, 715 const void * (*get_next_compat)(const char * const**)) 716 { 717 const void *data = NULL; 718 const void *best_data = default_match; 719 const char *const *compat; 720 unsigned long dt_root; 721 unsigned int best_score = ~1, score = 0; 722 723 dt_root = of_get_flat_dt_root(); 724 while ((data = get_next_compat(&compat))) { 725 score = of_flat_dt_match(dt_root, compat); 726 if (score > 0 && score < best_score) { 727 best_data = data; 728 best_score = score; 729 } 730 } 731 if (!best_data) { 732 const char *prop; 733 int size; 734 735 pr_err("\n unrecognized device tree list:\n[ "); 736 737 prop = of_get_flat_dt_prop(dt_root, "compatible", &size); 738 if (prop) { 739 while (size > 0) { 740 printk("'%s' ", prop); 741 size -= strlen(prop) + 1; 742 prop += strlen(prop) + 1; 743 } 744 } 745 printk("]\n\n"); 746 return NULL; 747 } 748 749 pr_info("Machine model: %s\n", of_flat_dt_get_machine_name()); 750 751 return best_data; 752 } 753 754 static void __early_init_dt_declare_initrd(unsigned long start, 755 unsigned long end) 756 { 757 /* 758 * __va() is not yet available this early on some platforms. In that 759 * case, the platform uses phys_initrd_start/phys_initrd_size instead 760 * and does the VA conversion itself. 761 */ 762 if (!IS_ENABLED(CONFIG_ARM64) && 763 !(IS_ENABLED(CONFIG_RISCV) && IS_ENABLED(CONFIG_64BIT))) { 764 initrd_start = (unsigned long)__va(start); 765 initrd_end = (unsigned long)__va(end); 766 initrd_below_start_ok = 1; 767 } 768 } 769 770 /** 771 * early_init_dt_check_for_initrd - Decode initrd location from flat tree 772 * @node: reference to node containing initrd location ('chosen') 773 */ 774 static void __init early_init_dt_check_for_initrd(unsigned long node) 775 { 776 u64 start, end; 777 int len; 778 const __be32 *prop; 779 780 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) 781 return; 782 783 pr_debug("Looking for initrd properties... "); 784 785 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len); 786 if (!prop) 787 return; 788 start = of_read_number(prop, len/4); 789 790 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len); 791 if (!prop) 792 return; 793 end = of_read_number(prop, len/4); 794 if (start > end) 795 return; 796 797 __early_init_dt_declare_initrd(start, end); 798 phys_initrd_start = start; 799 phys_initrd_size = end - start; 800 801 pr_debug("initrd_start=0x%llx initrd_end=0x%llx\n", start, end); 802 } 803 804 /** 805 * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat 806 * tree 807 * @node: reference to node containing elfcorehdr location ('chosen') 808 */ 809 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node) 810 { 811 const __be32 *prop; 812 int len; 813 814 if (!IS_ENABLED(CONFIG_CRASH_DUMP)) 815 return; 816 817 pr_debug("Looking for elfcorehdr property... "); 818 819 prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len); 820 if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells))) 821 return; 822 823 elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop); 824 elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop); 825 826 pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n", 827 elfcorehdr_addr, elfcorehdr_size); 828 } 829 830 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND; 831 832 /* 833 * The main usage of linux,usable-memory-range is for crash dump kernel. 834 * Originally, the number of usable-memory regions is one. Now there may 835 * be two regions, low region and high region. 836 * To make compatibility with existing user-space and older kdump, the low 837 * region is always the last range of linux,usable-memory-range if exist. 838 */ 839 #define MAX_USABLE_RANGES 2 840 841 /** 842 * early_init_dt_check_for_usable_mem_range - Decode usable memory range 843 * location from flat tree 844 */ 845 void __init early_init_dt_check_for_usable_mem_range(void) 846 { 847 struct memblock_region rgn[MAX_USABLE_RANGES] = {0}; 848 const __be32 *prop, *endp; 849 int len, i; 850 unsigned long node = chosen_node_offset; 851 852 if ((long)node < 0) 853 return; 854 855 pr_debug("Looking for usable-memory-range property... "); 856 857 prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len); 858 if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells))) 859 return; 860 861 endp = prop + (len / sizeof(__be32)); 862 for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) { 863 rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop); 864 rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop); 865 866 pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n", 867 i, &rgn[i].base, &rgn[i].size); 868 } 869 870 memblock_cap_memory_range(rgn[0].base, rgn[0].size); 871 for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++) 872 memblock_add(rgn[i].base, rgn[i].size); 873 } 874 875 #ifdef CONFIG_SERIAL_EARLYCON 876 877 int __init early_init_dt_scan_chosen_stdout(void) 878 { 879 int offset; 880 const char *p, *q, *options = NULL; 881 int l; 882 const struct earlycon_id *match; 883 const void *fdt = initial_boot_params; 884 int ret; 885 886 offset = fdt_path_offset(fdt, "/chosen"); 887 if (offset < 0) 888 offset = fdt_path_offset(fdt, "/chosen@0"); 889 if (offset < 0) 890 return -ENOENT; 891 892 p = fdt_getprop(fdt, offset, "stdout-path", &l); 893 if (!p) 894 p = fdt_getprop(fdt, offset, "linux,stdout-path", &l); 895 if (!p || !l) 896 return -ENOENT; 897 898 q = strchrnul(p, ':'); 899 if (*q != '\0') 900 options = q + 1; 901 l = q - p; 902 903 /* Get the node specified by stdout-path */ 904 offset = fdt_path_offset_namelen(fdt, p, l); 905 if (offset < 0) { 906 pr_warn("earlycon: stdout-path %.*s not found\n", l, p); 907 return 0; 908 } 909 910 for (match = __earlycon_table; match < __earlycon_table_end; match++) { 911 if (!match->compatible[0]) 912 continue; 913 914 if (fdt_node_check_compatible(fdt, offset, match->compatible)) 915 continue; 916 917 ret = of_setup_earlycon(match, offset, options); 918 if (!ret || ret == -EALREADY) 919 return 0; 920 } 921 return -ENODEV; 922 } 923 #endif 924 925 /* 926 * early_init_dt_scan_root - fetch the top level address and size cells 927 */ 928 int __init early_init_dt_scan_root(void) 929 { 930 const __be32 *prop; 931 const void *fdt = initial_boot_params; 932 int node = fdt_path_offset(fdt, "/"); 933 934 if (node < 0) 935 return -ENODEV; 936 937 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT; 938 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT; 939 940 prop = of_get_flat_dt_prop(node, "#size-cells", NULL); 941 if (prop) 942 dt_root_size_cells = be32_to_cpup(prop); 943 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells); 944 945 prop = of_get_flat_dt_prop(node, "#address-cells", NULL); 946 if (prop) 947 dt_root_addr_cells = be32_to_cpup(prop); 948 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells); 949 950 return 0; 951 } 952 953 u64 __init dt_mem_next_cell(int s, const __be32 **cellp) 954 { 955 const __be32 *p = *cellp; 956 957 *cellp = p + s; 958 return of_read_number(p, s); 959 } 960 961 /* 962 * early_init_dt_scan_memory - Look for and parse memory nodes 963 */ 964 int __init early_init_dt_scan_memory(void) 965 { 966 int node, found_memory = 0; 967 const void *fdt = initial_boot_params; 968 969 fdt_for_each_subnode(node, fdt, 0) { 970 const char *type = of_get_flat_dt_prop(node, "device_type", NULL); 971 const __be32 *reg, *endp; 972 int l; 973 bool hotpluggable; 974 975 /* We are scanning "memory" nodes only */ 976 if (type == NULL || strcmp(type, "memory") != 0) 977 continue; 978 979 if (!of_fdt_device_is_available(fdt, node)) 980 continue; 981 982 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l); 983 if (reg == NULL) 984 reg = of_get_flat_dt_prop(node, "reg", &l); 985 if (reg == NULL) 986 continue; 987 988 endp = reg + (l / sizeof(__be32)); 989 hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL); 990 991 pr_debug("memory scan node %s, reg size %d,\n", 992 fdt_get_name(fdt, node, NULL), l); 993 994 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { 995 u64 base, size; 996 997 base = dt_mem_next_cell(dt_root_addr_cells, ®); 998 size = dt_mem_next_cell(dt_root_size_cells, ®); 999 1000 if (size == 0) 1001 continue; 1002 pr_debug(" - %llx, %llx\n", base, size); 1003 1004 early_init_dt_add_memory_arch(base, size); 1005 1006 found_memory = 1; 1007 1008 if (!hotpluggable) 1009 continue; 1010 1011 if (memblock_mark_hotplug(base, size)) 1012 pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n", 1013 base, base + size); 1014 } 1015 } 1016 return found_memory; 1017 } 1018 1019 int __init early_init_dt_scan_chosen(char *cmdline) 1020 { 1021 int l, node; 1022 const char *p; 1023 const void *rng_seed; 1024 const void *fdt = initial_boot_params; 1025 1026 node = fdt_path_offset(fdt, "/chosen"); 1027 if (node < 0) 1028 node = fdt_path_offset(fdt, "/chosen@0"); 1029 if (node < 0) 1030 /* Handle the cmdline config options even if no /chosen node */ 1031 goto handle_cmdline; 1032 1033 chosen_node_offset = node; 1034 1035 early_init_dt_check_for_initrd(node); 1036 early_init_dt_check_for_elfcorehdr(node); 1037 1038 rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); 1039 if (rng_seed && l > 0) { 1040 add_bootloader_randomness(rng_seed, l); 1041 1042 /* try to clear seed so it won't be found. */ 1043 fdt_nop_property(initial_boot_params, node, "rng-seed"); 1044 1045 /* update CRC check value */ 1046 of_fdt_crc32 = crc32_be(~0, initial_boot_params, 1047 fdt_totalsize(initial_boot_params)); 1048 } 1049 1050 /* Retrieve command line */ 1051 p = of_get_flat_dt_prop(node, "bootargs", &l); 1052 if (p != NULL && l > 0) 1053 strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE)); 1054 1055 handle_cmdline: 1056 /* 1057 * CONFIG_CMDLINE is meant to be a default in case nothing else 1058 * managed to set the command line, unless CONFIG_CMDLINE_FORCE 1059 * is set in which case we override whatever was found earlier. 1060 */ 1061 #ifdef CONFIG_CMDLINE 1062 #if defined(CONFIG_CMDLINE_EXTEND) 1063 strlcat(cmdline, " ", COMMAND_LINE_SIZE); 1064 strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1065 #elif defined(CONFIG_CMDLINE_FORCE) 1066 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1067 #else 1068 /* No arguments from boot loader, use kernel's cmdl*/ 1069 if (!((char *)cmdline)[0]) 1070 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1071 #endif 1072 #endif /* CONFIG_CMDLINE */ 1073 1074 pr_debug("Command line is: %s\n", (char *)cmdline); 1075 1076 return 0; 1077 } 1078 1079 #ifndef MIN_MEMBLOCK_ADDR 1080 #define MIN_MEMBLOCK_ADDR __pa(PAGE_OFFSET) 1081 #endif 1082 #ifndef MAX_MEMBLOCK_ADDR 1083 #define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0) 1084 #endif 1085 1086 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size) 1087 { 1088 const u64 phys_offset = MIN_MEMBLOCK_ADDR; 1089 1090 if (size < PAGE_SIZE - (base & ~PAGE_MASK)) { 1091 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1092 base, base + size); 1093 return; 1094 } 1095 1096 if (!PAGE_ALIGNED(base)) { 1097 size -= PAGE_SIZE - (base & ~PAGE_MASK); 1098 base = PAGE_ALIGN(base); 1099 } 1100 size &= PAGE_MASK; 1101 1102 if (base > MAX_MEMBLOCK_ADDR) { 1103 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1104 base, base + size); 1105 return; 1106 } 1107 1108 if (base + size - 1 > MAX_MEMBLOCK_ADDR) { 1109 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n", 1110 ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size); 1111 size = MAX_MEMBLOCK_ADDR - base + 1; 1112 } 1113 1114 if (base + size < phys_offset) { 1115 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1116 base, base + size); 1117 return; 1118 } 1119 if (base < phys_offset) { 1120 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n", 1121 base, phys_offset); 1122 size -= phys_offset - base; 1123 base = phys_offset; 1124 } 1125 memblock_add(base, size); 1126 } 1127 1128 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align) 1129 { 1130 void *ptr = memblock_alloc(size, align); 1131 1132 if (!ptr) 1133 panic("%s: Failed to allocate %llu bytes align=0x%llx\n", 1134 __func__, size, align); 1135 1136 return ptr; 1137 } 1138 1139 bool __init early_init_dt_verify(void *params) 1140 { 1141 if (!params) 1142 return false; 1143 1144 /* check device tree validity */ 1145 if (fdt_check_header(params)) 1146 return false; 1147 1148 /* Setup flat device-tree pointer */ 1149 initial_boot_params = params; 1150 of_fdt_crc32 = crc32_be(~0, initial_boot_params, 1151 fdt_totalsize(initial_boot_params)); 1152 1153 /* Initialize {size,address}-cells info */ 1154 early_init_dt_scan_root(); 1155 1156 return true; 1157 } 1158 1159 1160 void __init early_init_dt_scan_nodes(void) 1161 { 1162 int rc; 1163 1164 /* Retrieve various information from the /chosen node */ 1165 rc = early_init_dt_scan_chosen(boot_command_line); 1166 if (rc) 1167 pr_warn("No chosen node found, continuing without\n"); 1168 1169 /* Setup memory, calling early_init_dt_add_memory_arch */ 1170 early_init_dt_scan_memory(); 1171 1172 /* Handle linux,usable-memory-range property */ 1173 early_init_dt_check_for_usable_mem_range(); 1174 } 1175 1176 bool __init early_init_dt_scan(void *params) 1177 { 1178 bool status; 1179 1180 status = early_init_dt_verify(params); 1181 if (!status) 1182 return false; 1183 1184 early_init_dt_scan_nodes(); 1185 return true; 1186 } 1187 1188 static void *__init copy_device_tree(void *fdt) 1189 { 1190 int size; 1191 void *dt; 1192 1193 size = fdt_totalsize(fdt); 1194 dt = early_init_dt_alloc_memory_arch(size, 1195 roundup_pow_of_two(FDT_V17_SIZE)); 1196 1197 if (dt) 1198 memcpy(dt, fdt, size); 1199 1200 return dt; 1201 } 1202 1203 /** 1204 * unflatten_device_tree - create tree of device_nodes from flat blob 1205 * 1206 * unflattens the device-tree passed by the firmware, creating the 1207 * tree of struct device_node. It also fills the "name" and "type" 1208 * pointers of the nodes so the normal device-tree walking functions 1209 * can be used. 1210 */ 1211 void __init unflatten_device_tree(void) 1212 { 1213 void *fdt = initial_boot_params; 1214 1215 /* Don't use the bootloader provided DTB if ACPI is enabled */ 1216 if (!acpi_disabled) 1217 fdt = NULL; 1218 1219 /* 1220 * Populate an empty root node when ACPI is enabled or bootloader 1221 * doesn't provide one. 1222 */ 1223 if (!fdt) { 1224 fdt = (void *) __dtb_empty_root_begin; 1225 /* fdt_totalsize() will be used for copy size */ 1226 if (fdt_totalsize(fdt) > 1227 __dtb_empty_root_end - __dtb_empty_root_begin) { 1228 pr_err("invalid size in dtb_empty_root\n"); 1229 return; 1230 } 1231 of_fdt_crc32 = crc32_be(~0, fdt, fdt_totalsize(fdt)); 1232 fdt = copy_device_tree(fdt); 1233 } 1234 1235 __unflatten_device_tree(fdt, NULL, &of_root, 1236 early_init_dt_alloc_memory_arch, false); 1237 1238 /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ 1239 of_alias_scan(early_init_dt_alloc_memory_arch); 1240 1241 unittest_unflatten_overlay_base(); 1242 } 1243 1244 /** 1245 * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob 1246 * 1247 * Copies and unflattens the device-tree passed by the firmware, creating the 1248 * tree of struct device_node. It also fills the "name" and "type" 1249 * pointers of the nodes so the normal device-tree walking functions 1250 * can be used. This should only be used when the FDT memory has not been 1251 * reserved such is the case when the FDT is built-in to the kernel init 1252 * section. If the FDT memory is reserved already then unflatten_device_tree 1253 * should be used instead. 1254 */ 1255 void __init unflatten_and_copy_device_tree(void) 1256 { 1257 if (initial_boot_params) 1258 initial_boot_params = copy_device_tree(initial_boot_params); 1259 1260 unflatten_device_tree(); 1261 } 1262 1263 #ifdef CONFIG_SYSFS 1264 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj, 1265 struct bin_attribute *bin_attr, 1266 char *buf, loff_t off, size_t count) 1267 { 1268 memcpy(buf, initial_boot_params + off, count); 1269 return count; 1270 } 1271 1272 static int __init of_fdt_raw_init(void) 1273 { 1274 static struct bin_attribute of_fdt_raw_attr = 1275 __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0); 1276 1277 if (!initial_boot_params) 1278 return 0; 1279 1280 if (of_fdt_crc32 != crc32_be(~0, initial_boot_params, 1281 fdt_totalsize(initial_boot_params))) { 1282 pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n"); 1283 return 0; 1284 } 1285 of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params); 1286 return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr); 1287 } 1288 late_initcall(of_fdt_raw_init); 1289 #endif 1290 1291 #endif /* CONFIG_OF_EARLY_FLATTREE */ 1292