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 phys_addr_t initial_boot_params_pa __ro_after_init; 461 462 #ifdef CONFIG_OF_EARLY_FLATTREE 463 464 static u32 of_fdt_crc32; 465 466 /* 467 * fdt_reserve_elfcorehdr() - reserves memory for elf core header 468 * 469 * This function reserves the memory occupied by an elf core header 470 * described in the device tree. This region contains all the 471 * information about primary kernel's core image and is used by a dump 472 * capture kernel to access the system memory on primary kernel. 473 */ 474 static void __init fdt_reserve_elfcorehdr(void) 475 { 476 if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size) 477 return; 478 479 if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) { 480 pr_warn("elfcorehdr is overlapped\n"); 481 return; 482 } 483 484 memblock_reserve(elfcorehdr_addr, elfcorehdr_size); 485 486 pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n", 487 elfcorehdr_size >> 10, elfcorehdr_addr); 488 } 489 490 /** 491 * early_init_fdt_scan_reserved_mem() - create reserved memory regions 492 * 493 * This function grabs memory from early allocator for device exclusive use 494 * defined in device tree structures. It should be called by arch specific code 495 * once the early allocator (i.e. memblock) has been fully activated. 496 */ 497 void __init early_init_fdt_scan_reserved_mem(void) 498 { 499 int n; 500 u64 base, size; 501 502 if (!initial_boot_params) 503 return; 504 505 fdt_scan_reserved_mem(); 506 fdt_reserve_elfcorehdr(); 507 508 /* Process header /memreserve/ fields */ 509 for (n = 0; ; n++) { 510 fdt_get_mem_rsv(initial_boot_params, n, &base, &size); 511 if (!size) 512 break; 513 memblock_reserve(base, size); 514 } 515 } 516 517 /** 518 * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob 519 */ 520 void __init early_init_fdt_reserve_self(void) 521 { 522 if (!initial_boot_params) 523 return; 524 525 /* Reserve the dtb region */ 526 memblock_reserve(__pa(initial_boot_params), 527 fdt_totalsize(initial_boot_params)); 528 } 529 530 /** 531 * of_scan_flat_dt - scan flattened tree blob and call callback on each. 532 * @it: callback function 533 * @data: context data pointer 534 * 535 * This function is used to scan the flattened device-tree, it is 536 * used to extract the memory information at boot before we can 537 * unflatten the tree 538 */ 539 int __init of_scan_flat_dt(int (*it)(unsigned long node, 540 const char *uname, int depth, 541 void *data), 542 void *data) 543 { 544 const void *blob = initial_boot_params; 545 const char *pathp; 546 int offset, rc = 0, depth = -1; 547 548 if (!blob) 549 return 0; 550 551 for (offset = fdt_next_node(blob, -1, &depth); 552 offset >= 0 && depth >= 0 && !rc; 553 offset = fdt_next_node(blob, offset, &depth)) { 554 555 pathp = fdt_get_name(blob, offset, NULL); 556 rc = it(offset, pathp, depth, data); 557 } 558 return rc; 559 } 560 561 /** 562 * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each. 563 * @parent: parent node 564 * @it: callback function 565 * @data: context data pointer 566 * 567 * This function is used to scan sub-nodes of a node. 568 */ 569 int __init of_scan_flat_dt_subnodes(unsigned long parent, 570 int (*it)(unsigned long node, 571 const char *uname, 572 void *data), 573 void *data) 574 { 575 const void *blob = initial_boot_params; 576 int node; 577 578 fdt_for_each_subnode(node, blob, parent) { 579 const char *pathp; 580 int rc; 581 582 pathp = fdt_get_name(blob, node, NULL); 583 rc = it(node, pathp, data); 584 if (rc) 585 return rc; 586 } 587 return 0; 588 } 589 590 /** 591 * of_get_flat_dt_subnode_by_name - get the subnode by given name 592 * 593 * @node: the parent node 594 * @uname: the name of subnode 595 * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none 596 */ 597 598 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname) 599 { 600 return fdt_subnode_offset(initial_boot_params, node, uname); 601 } 602 603 /* 604 * of_get_flat_dt_root - find the root node in the flat blob 605 */ 606 unsigned long __init of_get_flat_dt_root(void) 607 { 608 return 0; 609 } 610 611 /* 612 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr 613 * 614 * This function can be used within scan_flattened_dt callback to get 615 * access to properties 616 */ 617 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name, 618 int *size) 619 { 620 return fdt_getprop(initial_boot_params, node, name, size); 621 } 622 623 /** 624 * of_fdt_is_compatible - Return true if given node from the given blob has 625 * compat in its compatible list 626 * @blob: A device tree blob 627 * @node: node to test 628 * @compat: compatible string to compare with compatible list. 629 * 630 * Return: a non-zero value on match with smaller values returned for more 631 * specific compatible values. 632 */ 633 static int of_fdt_is_compatible(const void *blob, 634 unsigned long node, const char *compat) 635 { 636 const char *cp; 637 int cplen; 638 unsigned long l, score = 0; 639 640 cp = fdt_getprop(blob, node, "compatible", &cplen); 641 if (cp == NULL) 642 return 0; 643 while (cplen > 0) { 644 score++; 645 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) 646 return score; 647 l = strlen(cp) + 1; 648 cp += l; 649 cplen -= l; 650 } 651 652 return 0; 653 } 654 655 /** 656 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list 657 * @node: node to test 658 * @compat: compatible string to compare with compatible list. 659 */ 660 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat) 661 { 662 return of_fdt_is_compatible(initial_boot_params, node, compat); 663 } 664 665 /* 666 * of_flat_dt_match - Return true if node matches a list of compatible values 667 */ 668 static int __init of_flat_dt_match(unsigned long node, const char *const *compat) 669 { 670 unsigned int tmp, score = 0; 671 672 if (!compat) 673 return 0; 674 675 while (*compat) { 676 tmp = of_fdt_is_compatible(initial_boot_params, node, *compat); 677 if (tmp && (score == 0 || (tmp < score))) 678 score = tmp; 679 compat++; 680 } 681 682 return score; 683 } 684 685 /* 686 * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle 687 */ 688 uint32_t __init of_get_flat_dt_phandle(unsigned long node) 689 { 690 return fdt_get_phandle(initial_boot_params, node); 691 } 692 693 const char * __init of_flat_dt_get_machine_name(void) 694 { 695 const char *name; 696 unsigned long dt_root = of_get_flat_dt_root(); 697 698 name = of_get_flat_dt_prop(dt_root, "model", NULL); 699 if (!name) 700 name = of_get_flat_dt_prop(dt_root, "compatible", NULL); 701 return name; 702 } 703 704 /** 705 * of_flat_dt_match_machine - Iterate match tables to find matching machine. 706 * 707 * @default_match: A machine specific ptr to return in case of no match. 708 * @get_next_compat: callback function to return next compatible match table. 709 * 710 * Iterate through machine match tables to find the best match for the machine 711 * compatible string in the FDT. 712 */ 713 const void * __init of_flat_dt_match_machine(const void *default_match, 714 const void * (*get_next_compat)(const char * const**)) 715 { 716 const void *data = NULL; 717 const void *best_data = default_match; 718 const char *const *compat; 719 unsigned long dt_root; 720 unsigned int best_score = ~1, score = 0; 721 722 dt_root = of_get_flat_dt_root(); 723 while ((data = get_next_compat(&compat))) { 724 score = of_flat_dt_match(dt_root, compat); 725 if (score > 0 && score < best_score) { 726 best_data = data; 727 best_score = score; 728 } 729 } 730 if (!best_data) { 731 const char *prop; 732 int size; 733 734 pr_err("\n unrecognized device tree list:\n[ "); 735 736 prop = of_get_flat_dt_prop(dt_root, "compatible", &size); 737 if (prop) { 738 while (size > 0) { 739 printk("'%s' ", prop); 740 size -= strlen(prop) + 1; 741 prop += strlen(prop) + 1; 742 } 743 } 744 printk("]\n\n"); 745 return NULL; 746 } 747 748 pr_info("Machine model: %s\n", of_flat_dt_get_machine_name()); 749 750 return best_data; 751 } 752 753 static void __early_init_dt_declare_initrd(unsigned long start, 754 unsigned long end) 755 { 756 /* 757 * __va() is not yet available this early on some platforms. In that 758 * case, the platform uses phys_initrd_start/phys_initrd_size instead 759 * and does the VA conversion itself. 760 */ 761 if (!IS_ENABLED(CONFIG_ARM64) && 762 !(IS_ENABLED(CONFIG_RISCV) && IS_ENABLED(CONFIG_64BIT))) { 763 initrd_start = (unsigned long)__va(start); 764 initrd_end = (unsigned long)__va(end); 765 initrd_below_start_ok = 1; 766 } 767 } 768 769 /** 770 * early_init_dt_check_for_initrd - Decode initrd location from flat tree 771 * @node: reference to node containing initrd location ('chosen') 772 */ 773 static void __init early_init_dt_check_for_initrd(unsigned long node) 774 { 775 u64 start, end; 776 int len; 777 const __be32 *prop; 778 779 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) 780 return; 781 782 pr_debug("Looking for initrd properties... "); 783 784 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len); 785 if (!prop) 786 return; 787 start = of_read_number(prop, len/4); 788 789 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len); 790 if (!prop) 791 return; 792 end = of_read_number(prop, len/4); 793 if (start > end) 794 return; 795 796 __early_init_dt_declare_initrd(start, end); 797 phys_initrd_start = start; 798 phys_initrd_size = end - start; 799 800 pr_debug("initrd_start=0x%llx initrd_end=0x%llx\n", start, end); 801 } 802 803 /** 804 * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat 805 * tree 806 * @node: reference to node containing elfcorehdr location ('chosen') 807 */ 808 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node) 809 { 810 const __be32 *prop; 811 int len; 812 813 if (!IS_ENABLED(CONFIG_CRASH_DUMP)) 814 return; 815 816 pr_debug("Looking for elfcorehdr property... "); 817 818 prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len); 819 if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells))) 820 return; 821 822 elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop); 823 elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop); 824 825 pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n", 826 elfcorehdr_addr, elfcorehdr_size); 827 } 828 829 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND; 830 831 /* 832 * The main usage of linux,usable-memory-range is for crash dump kernel. 833 * Originally, the number of usable-memory regions is one. Now there may 834 * be two regions, low region and high region. 835 * To make compatibility with existing user-space and older kdump, the low 836 * region is always the last range of linux,usable-memory-range if exist. 837 */ 838 #define MAX_USABLE_RANGES 2 839 840 /** 841 * early_init_dt_check_for_usable_mem_range - Decode usable memory range 842 * location from flat tree 843 */ 844 void __init early_init_dt_check_for_usable_mem_range(void) 845 { 846 struct memblock_region rgn[MAX_USABLE_RANGES] = {0}; 847 const __be32 *prop, *endp; 848 int len, i; 849 unsigned long node = chosen_node_offset; 850 851 if ((long)node < 0) 852 return; 853 854 pr_debug("Looking for usable-memory-range property... "); 855 856 prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len); 857 if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells))) 858 return; 859 860 endp = prop + (len / sizeof(__be32)); 861 for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) { 862 rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop); 863 rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop); 864 865 pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n", 866 i, &rgn[i].base, &rgn[i].size); 867 } 868 869 memblock_cap_memory_range(rgn[0].base, rgn[0].size); 870 for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++) 871 memblock_add(rgn[i].base, rgn[i].size); 872 } 873 874 #ifdef CONFIG_SERIAL_EARLYCON 875 876 int __init early_init_dt_scan_chosen_stdout(void) 877 { 878 int offset; 879 const char *p, *q, *options = NULL; 880 int l; 881 const struct earlycon_id *match; 882 const void *fdt = initial_boot_params; 883 int ret; 884 885 offset = fdt_path_offset(fdt, "/chosen"); 886 if (offset < 0) 887 offset = fdt_path_offset(fdt, "/chosen@0"); 888 if (offset < 0) 889 return -ENOENT; 890 891 p = fdt_getprop(fdt, offset, "stdout-path", &l); 892 if (!p) 893 p = fdt_getprop(fdt, offset, "linux,stdout-path", &l); 894 if (!p || !l) 895 return -ENOENT; 896 897 q = strchrnul(p, ':'); 898 if (*q != '\0') 899 options = q + 1; 900 l = q - p; 901 902 /* Get the node specified by stdout-path */ 903 offset = fdt_path_offset_namelen(fdt, p, l); 904 if (offset < 0) { 905 pr_warn("earlycon: stdout-path %.*s not found\n", l, p); 906 return 0; 907 } 908 909 for (match = __earlycon_table; match < __earlycon_table_end; match++) { 910 if (!match->compatible[0]) 911 continue; 912 913 if (fdt_node_check_compatible(fdt, offset, match->compatible)) 914 continue; 915 916 ret = of_setup_earlycon(match, offset, options); 917 if (!ret || ret == -EALREADY) 918 return 0; 919 } 920 return -ENODEV; 921 } 922 #endif 923 924 /* 925 * early_init_dt_scan_root - fetch the top level address and size cells 926 */ 927 int __init early_init_dt_scan_root(void) 928 { 929 const __be32 *prop; 930 const void *fdt = initial_boot_params; 931 int node = fdt_path_offset(fdt, "/"); 932 933 if (node < 0) 934 return -ENODEV; 935 936 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT; 937 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT; 938 939 prop = of_get_flat_dt_prop(node, "#size-cells", NULL); 940 if (!WARN(!prop, "No '#size-cells' in root node\n")) 941 dt_root_size_cells = be32_to_cpup(prop); 942 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells); 943 944 prop = of_get_flat_dt_prop(node, "#address-cells", NULL); 945 if (!WARN(!prop, "No '#address-cells' in root node\n")) 946 dt_root_addr_cells = be32_to_cpup(prop); 947 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells); 948 949 return 0; 950 } 951 952 u64 __init dt_mem_next_cell(int s, const __be32 **cellp) 953 { 954 const __be32 *p = *cellp; 955 956 *cellp = p + s; 957 return of_read_number(p, s); 958 } 959 960 /* 961 * early_init_dt_scan_memory - Look for and parse memory nodes 962 */ 963 int __init early_init_dt_scan_memory(void) 964 { 965 int node, found_memory = 0; 966 const void *fdt = initial_boot_params; 967 968 fdt_for_each_subnode(node, fdt, 0) { 969 const char *type = of_get_flat_dt_prop(node, "device_type", NULL); 970 const __be32 *reg, *endp; 971 int l; 972 bool hotpluggable; 973 974 /* We are scanning "memory" nodes only */ 975 if (type == NULL || strcmp(type, "memory") != 0) 976 continue; 977 978 if (!of_fdt_device_is_available(fdt, node)) 979 continue; 980 981 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l); 982 if (reg == NULL) 983 reg = of_get_flat_dt_prop(node, "reg", &l); 984 if (reg == NULL) 985 continue; 986 987 endp = reg + (l / sizeof(__be32)); 988 hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL); 989 990 pr_debug("memory scan node %s, reg size %d,\n", 991 fdt_get_name(fdt, node, NULL), l); 992 993 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { 994 u64 base, size; 995 996 base = dt_mem_next_cell(dt_root_addr_cells, ®); 997 size = dt_mem_next_cell(dt_root_size_cells, ®); 998 999 if (size == 0) 1000 continue; 1001 pr_debug(" - %llx, %llx\n", base, size); 1002 1003 early_init_dt_add_memory_arch(base, size); 1004 1005 found_memory = 1; 1006 1007 if (!hotpluggable) 1008 continue; 1009 1010 if (memblock_mark_hotplug(base, size)) 1011 pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n", 1012 base, base + size); 1013 } 1014 } 1015 return found_memory; 1016 } 1017 1018 int __init early_init_dt_scan_chosen(char *cmdline) 1019 { 1020 int l, node; 1021 const char *p; 1022 const void *rng_seed; 1023 const void *fdt = initial_boot_params; 1024 1025 node = fdt_path_offset(fdt, "/chosen"); 1026 if (node < 0) 1027 node = fdt_path_offset(fdt, "/chosen@0"); 1028 if (node < 0) 1029 /* Handle the cmdline config options even if no /chosen node */ 1030 goto handle_cmdline; 1031 1032 chosen_node_offset = node; 1033 1034 early_init_dt_check_for_initrd(node); 1035 early_init_dt_check_for_elfcorehdr(node); 1036 1037 rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); 1038 if (rng_seed && l > 0) { 1039 add_bootloader_randomness(rng_seed, l); 1040 1041 /* try to clear seed so it won't be found. */ 1042 fdt_nop_property(initial_boot_params, node, "rng-seed"); 1043 1044 /* update CRC check value */ 1045 of_fdt_crc32 = crc32_be(~0, initial_boot_params, 1046 fdt_totalsize(initial_boot_params)); 1047 } 1048 1049 /* Retrieve command line */ 1050 p = of_get_flat_dt_prop(node, "bootargs", &l); 1051 if (p != NULL && l > 0) 1052 strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE)); 1053 1054 handle_cmdline: 1055 /* 1056 * CONFIG_CMDLINE is meant to be a default in case nothing else 1057 * managed to set the command line, unless CONFIG_CMDLINE_FORCE 1058 * is set in which case we override whatever was found earlier. 1059 */ 1060 #ifdef CONFIG_CMDLINE 1061 #if defined(CONFIG_CMDLINE_EXTEND) 1062 strlcat(cmdline, " ", COMMAND_LINE_SIZE); 1063 strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1064 #elif defined(CONFIG_CMDLINE_FORCE) 1065 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1066 #else 1067 /* No arguments from boot loader, use kernel's cmdl*/ 1068 if (!((char *)cmdline)[0]) 1069 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 1070 #endif 1071 #endif /* CONFIG_CMDLINE */ 1072 1073 pr_debug("Command line is: %s\n", (char *)cmdline); 1074 1075 return 0; 1076 } 1077 1078 #ifndef MIN_MEMBLOCK_ADDR 1079 #define MIN_MEMBLOCK_ADDR __pa(PAGE_OFFSET) 1080 #endif 1081 #ifndef MAX_MEMBLOCK_ADDR 1082 #define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0) 1083 #endif 1084 1085 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size) 1086 { 1087 const u64 phys_offset = MIN_MEMBLOCK_ADDR; 1088 1089 if (size < PAGE_SIZE - (base & ~PAGE_MASK)) { 1090 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1091 base, base + size); 1092 return; 1093 } 1094 1095 if (!PAGE_ALIGNED(base)) { 1096 size -= PAGE_SIZE - (base & ~PAGE_MASK); 1097 base = PAGE_ALIGN(base); 1098 } 1099 size &= PAGE_MASK; 1100 1101 if (base > MAX_MEMBLOCK_ADDR) { 1102 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1103 base, base + size); 1104 return; 1105 } 1106 1107 if (base + size - 1 > MAX_MEMBLOCK_ADDR) { 1108 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n", 1109 ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size); 1110 size = MAX_MEMBLOCK_ADDR - base + 1; 1111 } 1112 1113 if (base + size < phys_offset) { 1114 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n", 1115 base, base + size); 1116 return; 1117 } 1118 if (base < phys_offset) { 1119 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n", 1120 base, phys_offset); 1121 size -= phys_offset - base; 1122 base = phys_offset; 1123 } 1124 memblock_add(base, size); 1125 } 1126 1127 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align) 1128 { 1129 void *ptr = memblock_alloc(size, align); 1130 1131 if (!ptr) 1132 panic("%s: Failed to allocate %llu bytes align=0x%llx\n", 1133 __func__, size, align); 1134 1135 return ptr; 1136 } 1137 1138 bool __init early_init_dt_verify(void *dt_virt, phys_addr_t dt_phys) 1139 { 1140 if (!dt_virt) 1141 return false; 1142 1143 /* check device tree validity */ 1144 if (fdt_check_header(dt_virt)) 1145 return false; 1146 1147 /* Setup flat device-tree pointer */ 1148 initial_boot_params = dt_virt; 1149 initial_boot_params_pa = dt_phys; 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 *dt_virt, phys_addr_t dt_phys) 1177 { 1178 bool status; 1179 1180 status = early_init_dt_verify(dt_virt, dt_phys); 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 /* Save the statically-placed regions in the reserved_mem array */ 1216 fdt_scan_reserved_mem_reg_nodes(); 1217 1218 /* Don't use the bootloader provided DTB if ACPI is enabled */ 1219 if (!acpi_disabled) 1220 fdt = NULL; 1221 1222 /* 1223 * Populate an empty root node when ACPI is enabled or bootloader 1224 * doesn't provide one. 1225 */ 1226 if (!fdt) { 1227 fdt = (void *) __dtb_empty_root_begin; 1228 /* fdt_totalsize() will be used for copy size */ 1229 if (fdt_totalsize(fdt) > 1230 __dtb_empty_root_end - __dtb_empty_root_begin) { 1231 pr_err("invalid size in dtb_empty_root\n"); 1232 return; 1233 } 1234 of_fdt_crc32 = crc32_be(~0, fdt, fdt_totalsize(fdt)); 1235 fdt = copy_device_tree(fdt); 1236 } 1237 1238 __unflatten_device_tree(fdt, NULL, &of_root, 1239 early_init_dt_alloc_memory_arch, false); 1240 1241 /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ 1242 of_alias_scan(early_init_dt_alloc_memory_arch); 1243 1244 unittest_unflatten_overlay_base(); 1245 } 1246 1247 /** 1248 * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob 1249 * 1250 * Copies and unflattens the device-tree passed by the firmware, creating the 1251 * tree of struct device_node. It also fills the "name" and "type" 1252 * pointers of the nodes so the normal device-tree walking functions 1253 * can be used. This should only be used when the FDT memory has not been 1254 * reserved such is the case when the FDT is built-in to the kernel init 1255 * section. If the FDT memory is reserved already then unflatten_device_tree 1256 * should be used instead. 1257 */ 1258 void __init unflatten_and_copy_device_tree(void) 1259 { 1260 if (initial_boot_params) 1261 initial_boot_params = copy_device_tree(initial_boot_params); 1262 1263 unflatten_device_tree(); 1264 } 1265 1266 #ifdef CONFIG_SYSFS 1267 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj, 1268 struct bin_attribute *bin_attr, 1269 char *buf, loff_t off, size_t count) 1270 { 1271 memcpy(buf, initial_boot_params + off, count); 1272 return count; 1273 } 1274 1275 static int __init of_fdt_raw_init(void) 1276 { 1277 static struct bin_attribute of_fdt_raw_attr = 1278 __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0); 1279 1280 if (!initial_boot_params) 1281 return 0; 1282 1283 if (of_fdt_crc32 != crc32_be(~0, initial_boot_params, 1284 fdt_totalsize(initial_boot_params))) { 1285 pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n"); 1286 return 0; 1287 } 1288 of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params); 1289 return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr); 1290 } 1291 late_initcall(of_fdt_raw_init); 1292 #endif 1293 1294 #endif /* CONFIG_OF_EARLY_FLATTREE */ 1295