1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Firmware Assisted dump: A robust mechanism to get reliable kernel crash
   4 * dump with assistance from firmware. This approach does not use kexec,
   5 * instead firmware assists in booting the kdump kernel while preserving
   6 * memory contents. The most of the code implementation has been adapted
   7 * from phyp assisted dump implementation written by Linas Vepstas and
   8 * Manish Ahuja
   9 *
  10 * Copyright 2011 IBM Corporation
  11 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
  12 */
  13
  14#undef DEBUG
  15#define pr_fmt(fmt) "fadump: " fmt
  16
  17#include <linux/string.h>
  18#include <linux/memblock.h>
  19#include <linux/delay.h>
  20#include <linux/seq_file.h>
  21#include <linux/crash_dump.h>
  22#include <linux/kobject.h>
  23#include <linux/sysfs.h>
  24#include <linux/slab.h>
  25#include <linux/cma.h>
  26#include <linux/hugetlb.h>
  27
  28#include <asm/debugfs.h>
  29#include <asm/page.h>
  30#include <asm/prom.h>
  31#include <asm/fadump.h>
  32#include <asm/fadump-internal.h>
  33#include <asm/setup.h>
  34#include <asm/interrupt.h>
  35
  36/*
  37 * The CPU who acquired the lock to trigger the fadump crash should
  38 * wait for other CPUs to enter.
  39 *
  40 * The timeout is in milliseconds.
  41 */
  42#define CRASH_TIMEOUT		500
  43
  44static struct fw_dump fw_dump;
  45
  46static void __init fadump_reserve_crash_area(u64 base);
  47
  48#ifndef CONFIG_PRESERVE_FA_DUMP
  49
  50static struct kobject *fadump_kobj;
  51
  52static atomic_t cpus_in_fadump;
  53static DEFINE_MUTEX(fadump_mutex);
  54
  55static struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false };
  56
  57#define RESERVED_RNGS_SZ	16384 /* 16K - 128 entries */
  58#define RESERVED_RNGS_CNT	(RESERVED_RNGS_SZ / \
  59				 sizeof(struct fadump_memory_range))
  60static struct fadump_memory_range rngs[RESERVED_RNGS_CNT];
  61static struct fadump_mrange_info
  62reserved_mrange_info = { "reserved", rngs, RESERVED_RNGS_SZ, 0, RESERVED_RNGS_CNT, true };
  63
  64static void __init early_init_dt_scan_reserved_ranges(unsigned long node);
  65
  66#ifdef CONFIG_CMA
  67static struct cma *fadump_cma;
  68
  69/*
  70 * fadump_cma_init() - Initialize CMA area from a fadump reserved memory
  71 *
  72 * This function initializes CMA area from fadump reserved memory.
  73 * The total size of fadump reserved memory covers for boot memory size
  74 * + cpu data size + hpte size and metadata.
  75 * Initialize only the area equivalent to boot memory size for CMA use.
  76 * The reamining portion of fadump reserved memory will be not given
  77 * to CMA and pages for thoes will stay reserved. boot memory size is
  78 * aligned per CMA requirement to satisy cma_init_reserved_mem() call.
  79 * But for some reason even if it fails we still have the memory reservation
  80 * with us and we can still continue doing fadump.
  81 */
  82static int __init fadump_cma_init(void)
  83{
  84	unsigned long long base, size;
  85	int rc;
  86
  87	if (!fw_dump.fadump_enabled)
  88		return 0;
  89
  90	/*
  91	 * Do not use CMA if user has provided fadump=nocma kernel parameter.
  92	 * Return 1 to continue with fadump old behaviour.
  93	 */
  94	if (fw_dump.nocma)
  95		return 1;
  96
  97	base = fw_dump.reserve_dump_area_start;
  98	size = fw_dump.boot_memory_size;
  99
 100	if (!size)
 101		return 0;
 102
 103	rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
 104	if (rc) {
 105		pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
 106		/*
 107		 * Though the CMA init has failed we still have memory
 108		 * reservation with us. The reserved memory will be
 109		 * blocked from production system usage.  Hence return 1,
 110		 * so that we can continue with fadump.
 111		 */
 112		return 1;
 113	}
 114
 115	/*
 116	 * So we now have successfully initialized cma area for fadump.
 117	 */
 118	pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
 119		"bytes of memory reserved for firmware-assisted dump\n",
 120		cma_get_size(fadump_cma),
 121		(unsigned long)cma_get_base(fadump_cma) >> 20,
 122		fw_dump.reserve_dump_area_size);
 123	return 1;
 124}
 125#else
 126static int __init fadump_cma_init(void) { return 1; }
 127#endif /* CONFIG_CMA */
 128
 129/* Scan the Firmware Assisted dump configuration details. */
 130int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
 131				      int depth, void *data)
 132{
 133	if (depth == 0) {
 134		early_init_dt_scan_reserved_ranges(node);
 135		return 0;
 136	}
 137
 138	if (depth != 1)
 139		return 0;
 140
 141	if (strcmp(uname, "rtas") == 0) {
 142		rtas_fadump_dt_scan(&fw_dump, node);
 143		return 1;
 144	}
 145
 146	if (strcmp(uname, "ibm,opal") == 0) {
 147		opal_fadump_dt_scan(&fw_dump, node);
 148		return 1;
 149	}
 150
 151	return 0;
 152}
 153
 154/*
 155 * If fadump is registered, check if the memory provided
 156 * falls within boot memory area and reserved memory area.
 157 */
 158int is_fadump_memory_area(u64 addr, unsigned long size)
 159{
 160	u64 d_start, d_end;
 161
 162	if (!fw_dump.dump_registered)
 163		return 0;
 164
 165	if (!size)
 166		return 0;
 167
 168	d_start = fw_dump.reserve_dump_area_start;
 169	d_end = d_start + fw_dump.reserve_dump_area_size;
 170	if (((addr + size) > d_start) && (addr <= d_end))
 171		return 1;
 172
 173	return (addr <= fw_dump.boot_mem_top);
 174}
 175
 176int should_fadump_crash(void)
 177{
 178	if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
 179		return 0;
 180	return 1;
 181}
 182
 183int is_fadump_active(void)
 184{
 185	return fw_dump.dump_active;
 186}
 187
 188/*
 189 * Returns true, if there are no holes in memory area between d_start to d_end,
 190 * false otherwise.
 191 */
 192static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
 193{
 194	phys_addr_t reg_start, reg_end;
 195	bool ret = false;
 196	u64 i, start, end;
 197
 198	for_each_mem_range(i, &reg_start, &reg_end) {
 199		start = max_t(u64, d_start, reg_start);
 200		end = min_t(u64, d_end, reg_end);
 201		if (d_start < end) {
 202			/* Memory hole from d_start to start */
 203			if (start > d_start)
 204				break;
 205
 206			if (end == d_end) {
 207				ret = true;
 208				break;
 209			}
 210
 211			d_start = end + 1;
 212		}
 213	}
 214
 215	return ret;
 216}
 217
 218/*
 219 * Returns true, if there are no holes in boot memory area,
 220 * false otherwise.
 221 */
 222bool is_fadump_boot_mem_contiguous(void)
 223{
 224	unsigned long d_start, d_end;
 225	bool ret = false;
 226	int i;
 227
 228	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 229		d_start = fw_dump.boot_mem_addr[i];
 230		d_end   = d_start + fw_dump.boot_mem_sz[i];
 231
 232		ret = is_fadump_mem_area_contiguous(d_start, d_end);
 233		if (!ret)
 234			break;
 235	}
 236
 237	return ret;
 238}
 239
 240/*
 241 * Returns true, if there are no holes in reserved memory area,
 242 * false otherwise.
 243 */
 244bool is_fadump_reserved_mem_contiguous(void)
 245{
 246	u64 d_start, d_end;
 247
 248	d_start	= fw_dump.reserve_dump_area_start;
 249	d_end	= d_start + fw_dump.reserve_dump_area_size;
 250	return is_fadump_mem_area_contiguous(d_start, d_end);
 251}
 252
 253/* Print firmware assisted dump configurations for debugging purpose. */
 254static void fadump_show_config(void)
 255{
 256	int i;
 257
 258	pr_debug("Support for firmware-assisted dump (fadump): %s\n",
 259			(fw_dump.fadump_supported ? "present" : "no support"));
 260
 261	if (!fw_dump.fadump_supported)
 262		return;
 263
 264	pr_debug("Fadump enabled    : %s\n",
 265				(fw_dump.fadump_enabled ? "yes" : "no"));
 266	pr_debug("Dump Active       : %s\n",
 267				(fw_dump.dump_active ? "yes" : "no"));
 268	pr_debug("Dump section sizes:\n");
 269	pr_debug("    CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
 270	pr_debug("    HPTE region size   : %lx\n", fw_dump.hpte_region_size);
 271	pr_debug("    Boot memory size   : %lx\n", fw_dump.boot_memory_size);
 272	pr_debug("    Boot memory top    : %llx\n", fw_dump.boot_mem_top);
 273	pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt);
 274	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 275		pr_debug("[%03d] base = %llx, size = %llx\n", i,
 276			 fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]);
 277	}
 278}
 279
 280/**
 281 * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
 282 *
 283 * Function to find the largest memory size we need to reserve during early
 284 * boot process. This will be the size of the memory that is required for a
 285 * kernel to boot successfully.
 286 *
 287 * This function has been taken from phyp-assisted dump feature implementation.
 288 *
 289 * returns larger of 256MB or 5% rounded down to multiples of 256MB.
 290 *
 291 * TODO: Come up with better approach to find out more accurate memory size
 292 * that is required for a kernel to boot successfully.
 293 *
 294 */
 295static __init u64 fadump_calculate_reserve_size(void)
 296{
 297	u64 base, size, bootmem_min;
 298	int ret;
 299
 300	if (fw_dump.reserve_bootvar)
 301		pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
 302
 303	/*
 304	 * Check if the size is specified through crashkernel= cmdline
 305	 * option. If yes, then use that but ignore base as fadump reserves
 306	 * memory at a predefined offset.
 307	 */
 308	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 309				&size, &base);
 310	if (ret == 0 && size > 0) {
 311		unsigned long max_size;
 312
 313		if (fw_dump.reserve_bootvar)
 314			pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
 315
 316		fw_dump.reserve_bootvar = (unsigned long)size;
 317
 318		/*
 319		 * Adjust if the boot memory size specified is above
 320		 * the upper limit.
 321		 */
 322		max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
 323		if (fw_dump.reserve_bootvar > max_size) {
 324			fw_dump.reserve_bootvar = max_size;
 325			pr_info("Adjusted boot memory size to %luMB\n",
 326				(fw_dump.reserve_bootvar >> 20));
 327		}
 328
 329		return fw_dump.reserve_bootvar;
 330	} else if (fw_dump.reserve_bootvar) {
 331		/*
 332		 * 'fadump_reserve_mem=' is being used to reserve memory
 333		 * for firmware-assisted dump.
 334		 */
 335		return fw_dump.reserve_bootvar;
 336	}
 337
 338	/* divide by 20 to get 5% of value */
 339	size = memblock_phys_mem_size() / 20;
 340
 341	/* round it down in multiples of 256 */
 342	size = size & ~0x0FFFFFFFUL;
 343
 344	/* Truncate to memory_limit. We don't want to over reserve the memory.*/
 345	if (memory_limit && size > memory_limit)
 346		size = memory_limit;
 347
 348	bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
 349	return (size > bootmem_min ? size : bootmem_min);
 350}
 351
 352/*
 353 * Calculate the total memory size required to be reserved for
 354 * firmware-assisted dump registration.
 355 */
 356static unsigned long get_fadump_area_size(void)
 357{
 358	unsigned long size = 0;
 359
 360	size += fw_dump.cpu_state_data_size;
 361	size += fw_dump.hpte_region_size;
 362	size += fw_dump.boot_memory_size;
 363	size += sizeof(struct fadump_crash_info_header);
 364	size += sizeof(struct elfhdr); /* ELF core header.*/
 365	size += sizeof(struct elf_phdr); /* place holder for cpu notes */
 366	/* Program headers for crash memory regions. */
 367	size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
 368
 369	size = PAGE_ALIGN(size);
 370
 371	/* This is to hold kernel metadata on platforms that support it */
 372	size += (fw_dump.ops->fadump_get_metadata_size ?
 373		 fw_dump.ops->fadump_get_metadata_size() : 0);
 374	return size;
 375}
 376
 377static int __init add_boot_mem_region(unsigned long rstart,
 378				      unsigned long rsize)
 379{
 380	int i = fw_dump.boot_mem_regs_cnt++;
 381
 382	if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
 383		fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
 384		return 0;
 385	}
 386
 387	pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n",
 388		 i, rstart, (rstart + rsize));
 389	fw_dump.boot_mem_addr[i] = rstart;
 390	fw_dump.boot_mem_sz[i] = rsize;
 391	return 1;
 392}
 393
 394/*
 395 * Firmware usually has a hard limit on the data it can copy per region.
 396 * Honour that by splitting a memory range into multiple regions.
 397 */
 398static int __init add_boot_mem_regions(unsigned long mstart,
 399				       unsigned long msize)
 400{
 401	unsigned long rstart, rsize, max_size;
 402	int ret = 1;
 403
 404	rstart = mstart;
 405	max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize;
 406	while (msize) {
 407		if (msize > max_size)
 408			rsize = max_size;
 409		else
 410			rsize = msize;
 411
 412		ret = add_boot_mem_region(rstart, rsize);
 413		if (!ret)
 414			break;
 415
 416		msize -= rsize;
 417		rstart += rsize;
 418	}
 419
 420	return ret;
 421}
 422
 423static int __init fadump_get_boot_mem_regions(void)
 424{
 425	unsigned long size, cur_size, hole_size, last_end;
 426	unsigned long mem_size = fw_dump.boot_memory_size;
 427	phys_addr_t reg_start, reg_end;
 428	int ret = 1;
 429	u64 i;
 430
 431	fw_dump.boot_mem_regs_cnt = 0;
 432
 433	last_end = 0;
 434	hole_size = 0;
 435	cur_size = 0;
 436	for_each_mem_range(i, &reg_start, &reg_end) {
 437		size = reg_end - reg_start;
 438		hole_size += (reg_start - last_end);
 
 439
 440		if ((cur_size + size) >= mem_size) {
 441			size = (mem_size - cur_size);
 442			ret = add_boot_mem_regions(reg_start, size);
 443			break;
 444		}
 445
 446		mem_size -= size;
 447		cur_size += size;
 448		ret = add_boot_mem_regions(reg_start, size);
 449		if (!ret)
 450			break;
 451
 452		last_end = reg_end;
 453	}
 454	fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
 455
 456	return ret;
 457}
 458
 459/*
 460 * Returns true, if the given range overlaps with reserved memory ranges
 461 * starting at idx. Also, updates idx to index of overlapping memory range
 462 * with the given memory range.
 463 * False, otherwise.
 464 */
 465static bool overlaps_reserved_ranges(u64 base, u64 end, int *idx)
 466{
 467	bool ret = false;
 468	int i;
 469
 470	for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) {
 471		u64 rbase = reserved_mrange_info.mem_ranges[i].base;
 472		u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size;
 473
 474		if (end <= rbase)
 475			break;
 476
 477		if ((end > rbase) &&  (base < rend)) {
 478			*idx = i;
 479			ret = true;
 480			break;
 481		}
 482	}
 483
 484	return ret;
 485}
 486
 487/*
 488 * Locate a suitable memory area to reserve memory for FADump. While at it,
 489 * lookup reserved-ranges & avoid overlap with them, as they are used by F/W.
 490 */
 491static u64 __init fadump_locate_reserve_mem(u64 base, u64 size)
 492{
 493	struct fadump_memory_range *mrngs;
 494	phys_addr_t mstart, mend;
 495	int idx = 0;
 496	u64 i, ret = 0;
 497
 498	mrngs = reserved_mrange_info.mem_ranges;
 499	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 500				&mstart, &mend, NULL) {
 501		pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n",
 502			 i, mstart, mend, base);
 503
 504		if (mstart > base)
 505			base = PAGE_ALIGN(mstart);
 506
 507		while ((mend > base) && ((mend - base) >= size)) {
 508			if (!overlaps_reserved_ranges(base, base+size, &idx)) {
 509				ret = base;
 510				goto out;
 511			}
 512
 513			base = mrngs[idx].base + mrngs[idx].size;
 514			base = PAGE_ALIGN(base);
 515		}
 516	}
 517
 518out:
 519	return ret;
 520}
 521
 522int __init fadump_reserve_mem(void)
 523{
 524	u64 base, size, mem_boundary, bootmem_min;
 
 525	int ret = 1;
 526
 527	if (!fw_dump.fadump_enabled)
 528		return 0;
 529
 530	if (!fw_dump.fadump_supported) {
 531		pr_info("Firmware-Assisted Dump is not supported on this hardware\n");
 532		goto error_out;
 533	}
 534
 535	/*
 536	 * Initialize boot memory size
 537	 * If dump is active then we have already calculated the size during
 538	 * first kernel.
 539	 */
 540	if (!fw_dump.dump_active) {
 541		fw_dump.boot_memory_size =
 542			PAGE_ALIGN(fadump_calculate_reserve_size());
 543#ifdef CONFIG_CMA
 544		if (!fw_dump.nocma) {
 
 545			fw_dump.boot_memory_size =
 546				ALIGN(fw_dump.boot_memory_size,
 547				      FADUMP_CMA_ALIGNMENT);
 548		}
 549#endif
 550
 551		bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
 552		if (fw_dump.boot_memory_size < bootmem_min) {
 553			pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n",
 554			       fw_dump.boot_memory_size, bootmem_min);
 555			goto error_out;
 556		}
 557
 558		if (!fadump_get_boot_mem_regions()) {
 559			pr_err("Too many holes in boot memory area to enable fadump\n");
 560			goto error_out;
 561		}
 562	}
 563
 564	/*
 565	 * Calculate the memory boundary.
 566	 * If memory_limit is less than actual memory boundary then reserve
 567	 * the memory for fadump beyond the memory_limit and adjust the
 568	 * memory_limit accordingly, so that the running kernel can run with
 569	 * specified memory_limit.
 570	 */
 571	if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
 572		size = get_fadump_area_size();
 573		if ((memory_limit + size) < memblock_end_of_DRAM())
 574			memory_limit += size;
 575		else
 576			memory_limit = memblock_end_of_DRAM();
 577		printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
 578				" dump, now %#016llx\n", memory_limit);
 579	}
 580	if (memory_limit)
 581		mem_boundary = memory_limit;
 582	else
 583		mem_boundary = memblock_end_of_DRAM();
 584
 585	base = fw_dump.boot_mem_top;
 586	size = get_fadump_area_size();
 587	fw_dump.reserve_dump_area_size = size;
 588	if (fw_dump.dump_active) {
 589		pr_info("Firmware-assisted dump is active.\n");
 590
 591#ifdef CONFIG_HUGETLB_PAGE
 592		/*
 593		 * FADump capture kernel doesn't care much about hugepages.
 594		 * In fact, handling hugepages in capture kernel is asking for
 595		 * trouble. So, disable HugeTLB support when fadump is active.
 596		 */
 597		hugetlb_disabled = true;
 598#endif
 599		/*
 600		 * If last boot has crashed then reserve all the memory
 601		 * above boot memory size so that we don't touch it until
 602		 * dump is written to disk by userspace tool. This memory
 603		 * can be released for general use by invalidating fadump.
 604		 */
 605		fadump_reserve_crash_area(base);
 606
 607		pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr);
 608		pr_debug("Reserve dump area start address: 0x%lx\n",
 609			 fw_dump.reserve_dump_area_start);
 610	} else {
 611		/*
 612		 * Reserve memory at an offset closer to bottom of the RAM to
 613		 * minimize the impact of memory hot-remove operation.
 614		 */
 615		base = fadump_locate_reserve_mem(base, size);
 
 
 
 
 616
 617		if (!base || (base + size > mem_boundary)) {
 618			pr_err("Failed to find memory chunk for reservation!\n");
 619			goto error_out;
 620		}
 621		fw_dump.reserve_dump_area_start = base;
 622
 623		/*
 624		 * Calculate the kernel metadata address and register it with
 625		 * f/w if the platform supports.
 626		 */
 627		if (fw_dump.ops->fadump_setup_metadata &&
 628		    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
 629			goto error_out;
 630
 631		if (memblock_reserve(base, size)) {
 632			pr_err("Failed to reserve memory!\n");
 633			goto error_out;
 634		}
 635
 636		pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
 637			(size >> 20), base, (memblock_phys_mem_size() >> 20));
 638
 639		ret = fadump_cma_init();
 640	}
 641
 642	return ret;
 643error_out:
 644	fw_dump.fadump_enabled = 0;
 645	return 0;
 646}
 647
 648/* Look for fadump= cmdline option. */
 649static int __init early_fadump_param(char *p)
 650{
 651	if (!p)
 652		return 1;
 653
 654	if (strncmp(p, "on", 2) == 0)
 655		fw_dump.fadump_enabled = 1;
 656	else if (strncmp(p, "off", 3) == 0)
 657		fw_dump.fadump_enabled = 0;
 658	else if (strncmp(p, "nocma", 5) == 0) {
 659		fw_dump.fadump_enabled = 1;
 660		fw_dump.nocma = 1;
 661	}
 662
 663	return 0;
 664}
 665early_param("fadump", early_fadump_param);
 666
 667/*
 668 * Look for fadump_reserve_mem= cmdline option
 669 * TODO: Remove references to 'fadump_reserve_mem=' parameter,
 670 *       the sooner 'crashkernel=' parameter is accustomed to.
 671 */
 672static int __init early_fadump_reserve_mem(char *p)
 673{
 674	if (p)
 675		fw_dump.reserve_bootvar = memparse(p, &p);
 676	return 0;
 677}
 678early_param("fadump_reserve_mem", early_fadump_reserve_mem);
 679
 680void crash_fadump(struct pt_regs *regs, const char *str)
 681{
 682	unsigned int msecs;
 683	struct fadump_crash_info_header *fdh = NULL;
 684	int old_cpu, this_cpu;
 685	/* Do not include first CPU */
 686	unsigned int ncpus = num_online_cpus() - 1;
 687
 688	if (!should_fadump_crash())
 689		return;
 690
 691	/*
 692	 * old_cpu == -1 means this is the first CPU which has come here,
 693	 * go ahead and trigger fadump.
 694	 *
 695	 * old_cpu != -1 means some other CPU has already on it's way
 696	 * to trigger fadump, just keep looping here.
 697	 */
 698	this_cpu = smp_processor_id();
 699	old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
 700
 701	if (old_cpu != -1) {
 702		atomic_inc(&cpus_in_fadump);
 703
 704		/*
 705		 * We can't loop here indefinitely. Wait as long as fadump
 706		 * is in force. If we race with fadump un-registration this
 707		 * loop will break and then we go down to normal panic path
 708		 * and reboot. If fadump is in force the first crashing
 709		 * cpu will definitely trigger fadump.
 710		 */
 711		while (fw_dump.dump_registered)
 712			cpu_relax();
 713		return;
 714	}
 715
 716	fdh = __va(fw_dump.fadumphdr_addr);
 717	fdh->crashing_cpu = crashing_cpu;
 718	crash_save_vmcoreinfo();
 719
 720	if (regs)
 721		fdh->regs = *regs;
 722	else
 723		ppc_save_regs(&fdh->regs);
 724
 725	fdh->online_mask = *cpu_online_mask;
 726
 727	/*
 728	 * If we came in via system reset, wait a while for the secondary
 729	 * CPUs to enter.
 730	 */
 731	if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) {
 732		msecs = CRASH_TIMEOUT;
 733		while ((atomic_read(&cpus_in_fadump) < ncpus) && (--msecs > 0))
 734			mdelay(1);
 735	}
 736
 737	fw_dump.ops->fadump_trigger(fdh, str);
 738}
 739
 740u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
 741{
 742	struct elf_prstatus prstatus;
 743
 744	memset(&prstatus, 0, sizeof(prstatus));
 745	/*
 746	 * FIXME: How do i get PID? Do I really need it?
 747	 * prstatus.pr_pid = ????
 748	 */
 749	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
 750	buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
 751			      &prstatus, sizeof(prstatus));
 752	return buf;
 753}
 754
 755void fadump_update_elfcore_header(char *bufp)
 756{
 
 757	struct elf_phdr *phdr;
 758
 
 759	bufp += sizeof(struct elfhdr);
 760
 761	/* First note is a place holder for cpu notes info. */
 762	phdr = (struct elf_phdr *)bufp;
 763
 764	if (phdr->p_type == PT_NOTE) {
 765		phdr->p_paddr	= __pa(fw_dump.cpu_notes_buf_vaddr);
 766		phdr->p_offset	= phdr->p_paddr;
 767		phdr->p_filesz	= fw_dump.cpu_notes_buf_size;
 768		phdr->p_memsz = fw_dump.cpu_notes_buf_size;
 769	}
 770	return;
 771}
 772
 773static void *fadump_alloc_buffer(unsigned long size)
 774{
 775	unsigned long count, i;
 776	struct page *page;
 777	void *vaddr;
 778
 779	vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 780	if (!vaddr)
 781		return NULL;
 782
 783	count = PAGE_ALIGN(size) / PAGE_SIZE;
 784	page = virt_to_page(vaddr);
 785	for (i = 0; i < count; i++)
 786		mark_page_reserved(page + i);
 787	return vaddr;
 788}
 789
 790static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
 791{
 792	free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
 793}
 794
 795s32 fadump_setup_cpu_notes_buf(u32 num_cpus)
 796{
 797	/* Allocate buffer to hold cpu crash notes. */
 798	fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
 799	fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
 800	fw_dump.cpu_notes_buf_vaddr =
 801		(unsigned long)fadump_alloc_buffer(fw_dump.cpu_notes_buf_size);
 802	if (!fw_dump.cpu_notes_buf_vaddr) {
 803		pr_err("Failed to allocate %ld bytes for CPU notes buffer\n",
 804		       fw_dump.cpu_notes_buf_size);
 805		return -ENOMEM;
 806	}
 807
 808	pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n",
 809		 fw_dump.cpu_notes_buf_size,
 810		 fw_dump.cpu_notes_buf_vaddr);
 811	return 0;
 812}
 813
 814void fadump_free_cpu_notes_buf(void)
 815{
 816	if (!fw_dump.cpu_notes_buf_vaddr)
 817		return;
 818
 819	fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr,
 820			   fw_dump.cpu_notes_buf_size);
 821	fw_dump.cpu_notes_buf_vaddr = 0;
 822	fw_dump.cpu_notes_buf_size = 0;
 823}
 824
 825static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info)
 826{
 827	if (mrange_info->is_static) {
 828		mrange_info->mem_range_cnt = 0;
 829		return;
 830	}
 831
 832	kfree(mrange_info->mem_ranges);
 833	memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0,
 834	       (sizeof(struct fadump_mrange_info) - RNG_NAME_SZ));
 
 835}
 836
 837/*
 838 * Allocate or reallocate mem_ranges array in incremental units
 839 * of PAGE_SIZE.
 840 */
 841static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info)
 842{
 843	struct fadump_memory_range *new_array;
 844	u64 new_size;
 845
 846	new_size = mrange_info->mem_ranges_sz + PAGE_SIZE;
 847	pr_debug("Allocating %llu bytes of memory for %s memory ranges\n",
 848		 new_size, mrange_info->name);
 849
 850	new_array = krealloc(mrange_info->mem_ranges, new_size, GFP_KERNEL);
 851	if (new_array == NULL) {
 852		pr_err("Insufficient memory for setting up %s memory ranges\n",
 853		       mrange_info->name);
 854		fadump_free_mem_ranges(mrange_info);
 855		return -ENOMEM;
 856	}
 857
 858	mrange_info->mem_ranges = new_array;
 859	mrange_info->mem_ranges_sz = new_size;
 860	mrange_info->max_mem_ranges = (new_size /
 861				       sizeof(struct fadump_memory_range));
 862	return 0;
 863}
 864
 865static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info,
 866				       u64 base, u64 end)
 867{
 868	struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges;
 869	bool is_adjacent = false;
 870	u64 start, size;
 871
 872	if (base == end)
 873		return 0;
 874
 875	/*
 876	 * Fold adjacent memory ranges to bring down the memory ranges/
 877	 * PT_LOAD segments count.
 878	 */
 879	if (mrange_info->mem_range_cnt) {
 880		start = mem_ranges[mrange_info->mem_range_cnt - 1].base;
 881		size  = mem_ranges[mrange_info->mem_range_cnt - 1].size;
 882
 883		if ((start + size) == base)
 884			is_adjacent = true;
 885	}
 886	if (!is_adjacent) {
 887		/* resize the array on reaching the limit */
 888		if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) {
 889			int ret;
 890
 891			if (mrange_info->is_static) {
 892				pr_err("Reached array size limit for %s memory ranges\n",
 893				       mrange_info->name);
 894				return -ENOSPC;
 895			}
 896
 897			ret = fadump_alloc_mem_ranges(mrange_info);
 898			if (ret)
 899				return ret;
 900
 901			/* Update to the new resized array */
 902			mem_ranges = mrange_info->mem_ranges;
 903		}
 904
 905		start = base;
 906		mem_ranges[mrange_info->mem_range_cnt].base = start;
 907		mrange_info->mem_range_cnt++;
 908	}
 909
 910	mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start);
 911	pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
 912		 mrange_info->name, (mrange_info->mem_range_cnt - 1),
 913		 start, end - 1, (end - start));
 914	return 0;
 915}
 916
 917static int fadump_exclude_reserved_area(u64 start, u64 end)
 918{
 919	u64 ra_start, ra_end;
 920	int ret = 0;
 921
 922	ra_start = fw_dump.reserve_dump_area_start;
 923	ra_end = ra_start + fw_dump.reserve_dump_area_size;
 924
 925	if ((ra_start < end) && (ra_end > start)) {
 926		if ((start < ra_start) && (end > ra_end)) {
 927			ret = fadump_add_mem_range(&crash_mrange_info,
 928						   start, ra_start);
 929			if (ret)
 930				return ret;
 931
 932			ret = fadump_add_mem_range(&crash_mrange_info,
 933						   ra_end, end);
 934		} else if (start < ra_start) {
 935			ret = fadump_add_mem_range(&crash_mrange_info,
 936						   start, ra_start);
 937		} else if (ra_end < end) {
 938			ret = fadump_add_mem_range(&crash_mrange_info,
 939						   ra_end, end);
 940		}
 941	} else
 942		ret = fadump_add_mem_range(&crash_mrange_info, start, end);
 943
 944	return ret;
 945}
 946
 947static int fadump_init_elfcore_header(char *bufp)
 948{
 949	struct elfhdr *elf;
 950
 951	elf = (struct elfhdr *) bufp;
 952	bufp += sizeof(struct elfhdr);
 953	memcpy(elf->e_ident, ELFMAG, SELFMAG);
 954	elf->e_ident[EI_CLASS] = ELF_CLASS;
 955	elf->e_ident[EI_DATA] = ELF_DATA;
 956	elf->e_ident[EI_VERSION] = EV_CURRENT;
 957	elf->e_ident[EI_OSABI] = ELF_OSABI;
 958	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
 959	elf->e_type = ET_CORE;
 960	elf->e_machine = ELF_ARCH;
 961	elf->e_version = EV_CURRENT;
 962	elf->e_entry = 0;
 963	elf->e_phoff = sizeof(struct elfhdr);
 964	elf->e_shoff = 0;
 965#if defined(_CALL_ELF)
 966	elf->e_flags = _CALL_ELF;
 967#else
 968	elf->e_flags = 0;
 969#endif
 970	elf->e_ehsize = sizeof(struct elfhdr);
 971	elf->e_phentsize = sizeof(struct elf_phdr);
 972	elf->e_phnum = 0;
 973	elf->e_shentsize = 0;
 974	elf->e_shnum = 0;
 975	elf->e_shstrndx = 0;
 976
 977	return 0;
 978}
 979
 980/*
 981 * Traverse through memblock structure and setup crash memory ranges. These
 982 * ranges will be used create PT_LOAD program headers in elfcore header.
 983 */
 984static int fadump_setup_crash_memory_ranges(void)
 985{
 986	u64 i, start, end;
 987	int ret;
 
 988
 989	pr_debug("Setup crash memory ranges.\n");
 990	crash_mrange_info.mem_range_cnt = 0;
 991
 992	/*
 993	 * Boot memory region(s) registered with firmware are moved to
 994	 * different location at the time of crash. Create separate program
 995	 * header(s) for this memory chunk(s) with the correct offset.
 996	 */
 997	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 998		start = fw_dump.boot_mem_addr[i];
 999		end = start + fw_dump.boot_mem_sz[i];
1000		ret = fadump_add_mem_range(&crash_mrange_info, start, end);
1001		if (ret)
1002			return ret;
1003	}
1004
1005	for_each_mem_range(i, &start, &end) {
 
 
 
1006		/*
1007		 * skip the memory chunk that is already added
1008		 * (0 through boot_memory_top).
1009		 */
1010		if (start < fw_dump.boot_mem_top) {
1011			if (end > fw_dump.boot_mem_top)
1012				start = fw_dump.boot_mem_top;
1013			else
1014				continue;
1015		}
1016
1017		/* add this range excluding the reserved dump area. */
1018		ret = fadump_exclude_reserved_area(start, end);
1019		if (ret)
1020			return ret;
1021	}
1022
1023	return 0;
1024}
1025
1026/*
1027 * If the given physical address falls within the boot memory region then
1028 * return the relocated address that points to the dump region reserved
1029 * for saving initial boot memory contents.
1030 */
1031static inline unsigned long fadump_relocate(unsigned long paddr)
1032{
1033	unsigned long raddr, rstart, rend, rlast, hole_size;
1034	int i;
1035
1036	hole_size = 0;
1037	rlast = 0;
1038	raddr = paddr;
1039	for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1040		rstart = fw_dump.boot_mem_addr[i];
1041		rend = rstart + fw_dump.boot_mem_sz[i];
1042		hole_size += (rstart - rlast);
1043
1044		if (paddr >= rstart && paddr < rend) {
1045			raddr += fw_dump.boot_mem_dest_addr - hole_size;
1046			break;
1047		}
1048
1049		rlast = rend;
1050	}
1051
1052	pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr);
1053	return raddr;
1054}
1055
1056static int fadump_create_elfcore_headers(char *bufp)
1057{
1058	unsigned long long raddr, offset;
1059	struct elf_phdr *phdr;
1060	struct elfhdr *elf;
1061	int i, j;
1062
1063	fadump_init_elfcore_header(bufp);
1064	elf = (struct elfhdr *)bufp;
1065	bufp += sizeof(struct elfhdr);
1066
1067	/*
1068	 * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
1069	 * will be populated during second kernel boot after crash. Hence
1070	 * this PT_NOTE will always be the first elf note.
1071	 *
1072	 * NOTE: Any new ELF note addition should be placed after this note.
1073	 */
1074	phdr = (struct elf_phdr *)bufp;
1075	bufp += sizeof(struct elf_phdr);
1076	phdr->p_type = PT_NOTE;
1077	phdr->p_flags = 0;
1078	phdr->p_vaddr = 0;
1079	phdr->p_align = 0;
1080
1081	phdr->p_offset = 0;
1082	phdr->p_paddr = 0;
1083	phdr->p_filesz = 0;
1084	phdr->p_memsz = 0;
1085
1086	(elf->e_phnum)++;
1087
1088	/* setup ELF PT_NOTE for vmcoreinfo */
1089	phdr = (struct elf_phdr *)bufp;
1090	bufp += sizeof(struct elf_phdr);
1091	phdr->p_type	= PT_NOTE;
1092	phdr->p_flags	= 0;
1093	phdr->p_vaddr	= 0;
1094	phdr->p_align	= 0;
1095
1096	phdr->p_paddr	= fadump_relocate(paddr_vmcoreinfo_note());
1097	phdr->p_offset	= phdr->p_paddr;
1098	phdr->p_memsz	= phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
1099
1100	/* Increment number of program headers. */
1101	(elf->e_phnum)++;
1102
1103	/* setup PT_LOAD sections. */
1104	j = 0;
1105	offset = 0;
1106	raddr = fw_dump.boot_mem_addr[0];
1107	for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) {
1108		u64 mbase, msize;
1109
1110		mbase = crash_mrange_info.mem_ranges[i].base;
1111		msize = crash_mrange_info.mem_ranges[i].size;
1112		if (!msize)
1113			continue;
1114
1115		phdr = (struct elf_phdr *)bufp;
1116		bufp += sizeof(struct elf_phdr);
1117		phdr->p_type	= PT_LOAD;
1118		phdr->p_flags	= PF_R|PF_W|PF_X;
1119		phdr->p_offset	= mbase;
1120
1121		if (mbase == raddr) {
1122			/*
1123			 * The entire real memory region will be moved by
1124			 * firmware to the specified destination_address.
1125			 * Hence set the correct offset.
1126			 */
1127			phdr->p_offset = fw_dump.boot_mem_dest_addr + offset;
1128			if (j < (fw_dump.boot_mem_regs_cnt - 1)) {
1129				offset += fw_dump.boot_mem_sz[j];
1130				raddr = fw_dump.boot_mem_addr[++j];
1131			}
1132		}
1133
1134		phdr->p_paddr = mbase;
1135		phdr->p_vaddr = (unsigned long)__va(mbase);
1136		phdr->p_filesz = msize;
1137		phdr->p_memsz = msize;
1138		phdr->p_align = 0;
1139
1140		/* Increment number of program headers. */
1141		(elf->e_phnum)++;
1142	}
1143	return 0;
1144}
1145
1146static unsigned long init_fadump_header(unsigned long addr)
1147{
1148	struct fadump_crash_info_header *fdh;
1149
1150	if (!addr)
1151		return 0;
1152
1153	fdh = __va(addr);
1154	addr += sizeof(struct fadump_crash_info_header);
1155
1156	memset(fdh, 0, sizeof(struct fadump_crash_info_header));
1157	fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
1158	fdh->elfcorehdr_addr = addr;
1159	/* We will set the crashing cpu id in crash_fadump() during crash. */
1160	fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
1161
1162	return addr;
1163}
1164
1165static int register_fadump(void)
1166{
1167	unsigned long addr;
1168	void *vaddr;
1169	int ret;
1170
1171	/*
1172	 * If no memory is reserved then we can not register for firmware-
1173	 * assisted dump.
1174	 */
1175	if (!fw_dump.reserve_dump_area_size)
1176		return -ENODEV;
1177
1178	ret = fadump_setup_crash_memory_ranges();
1179	if (ret)
1180		return ret;
1181
1182	addr = fw_dump.fadumphdr_addr;
1183
1184	/* Initialize fadump crash info header. */
1185	addr = init_fadump_header(addr);
1186	vaddr = __va(addr);
1187
1188	pr_debug("Creating ELF core headers at %#016lx\n", addr);
1189	fadump_create_elfcore_headers(vaddr);
1190
1191	/* register the future kernel dump with firmware. */
1192	pr_debug("Registering for firmware-assisted kernel dump...\n");
1193	return fw_dump.ops->fadump_register(&fw_dump);
1194}
1195
1196void fadump_cleanup(void)
1197{
1198	if (!fw_dump.fadump_supported)
1199		return;
1200
1201	/* Invalidate the registration only if dump is active. */
1202	if (fw_dump.dump_active) {
1203		pr_debug("Invalidating firmware-assisted dump registration\n");
1204		fw_dump.ops->fadump_invalidate(&fw_dump);
1205	} else if (fw_dump.dump_registered) {
1206		/* Un-register Firmware-assisted dump if it was registered. */
1207		fw_dump.ops->fadump_unregister(&fw_dump);
1208		fadump_free_mem_ranges(&crash_mrange_info);
1209	}
1210
1211	if (fw_dump.ops->fadump_cleanup)
1212		fw_dump.ops->fadump_cleanup(&fw_dump);
1213}
1214
1215static void fadump_free_reserved_memory(unsigned long start_pfn,
1216					unsigned long end_pfn)
1217{
1218	unsigned long pfn;
1219	unsigned long time_limit = jiffies + HZ;
1220
1221	pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
1222		PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
1223
1224	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1225		free_reserved_page(pfn_to_page(pfn));
1226
1227		if (time_after(jiffies, time_limit)) {
1228			cond_resched();
1229			time_limit = jiffies + HZ;
1230		}
1231	}
1232}
1233
1234/*
1235 * Skip memory holes and free memory that was actually reserved.
1236 */
1237static void fadump_release_reserved_area(u64 start, u64 end)
1238{
1239	unsigned long reg_spfn, reg_epfn;
1240	u64 tstart, tend, spfn, epfn;
1241	int i;
1242
1243	spfn = PHYS_PFN(start);
1244	epfn = PHYS_PFN(end);
1245
1246	for_each_mem_pfn_range(i, MAX_NUMNODES, &reg_spfn, &reg_epfn, NULL) {
1247		tstart = max_t(u64, spfn, reg_spfn);
1248		tend   = min_t(u64, epfn, reg_epfn);
1249
1250		if (tstart < tend) {
1251			fadump_free_reserved_memory(tstart, tend);
1252
1253			if (tend == epfn)
1254				break;
1255
1256			spfn = tend;
1257		}
1258	}
1259}
1260
1261/*
1262 * Sort the mem ranges in-place and merge adjacent ranges
1263 * to minimize the memory ranges count.
1264 */
1265static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info)
1266{
1267	struct fadump_memory_range *mem_ranges;
1268	struct fadump_memory_range tmp_range;
1269	u64 base, size;
1270	int i, j, idx;
1271
1272	if (!reserved_mrange_info.mem_range_cnt)
1273		return;
1274
1275	/* Sort the memory ranges */
1276	mem_ranges = mrange_info->mem_ranges;
1277	for (i = 0; i < mrange_info->mem_range_cnt; i++) {
1278		idx = i;
1279		for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) {
1280			if (mem_ranges[idx].base > mem_ranges[j].base)
1281				idx = j;
1282		}
1283		if (idx != i) {
1284			tmp_range = mem_ranges[idx];
1285			mem_ranges[idx] = mem_ranges[i];
1286			mem_ranges[i] = tmp_range;
1287		}
1288	}
1289
1290	/* Merge adjacent reserved ranges */
1291	idx = 0;
1292	for (i = 1; i < mrange_info->mem_range_cnt; i++) {
1293		base = mem_ranges[i-1].base;
1294		size = mem_ranges[i-1].size;
1295		if (mem_ranges[i].base == (base + size))
1296			mem_ranges[idx].size += mem_ranges[i].size;
1297		else {
1298			idx++;
1299			if (i == idx)
1300				continue;
1301
1302			mem_ranges[idx] = mem_ranges[i];
1303		}
1304	}
1305	mrange_info->mem_range_cnt = idx + 1;
1306}
1307
1308/*
1309 * Scan reserved-ranges to consider them while reserving/releasing
1310 * memory for FADump.
1311 */
1312static void __init early_init_dt_scan_reserved_ranges(unsigned long node)
1313{
 
1314	const __be32 *prop;
1315	int len, ret = -1;
1316	unsigned long i;
1317
1318	/* reserved-ranges already scanned */
1319	if (reserved_mrange_info.mem_range_cnt != 0)
1320		return;
1321
1322	prop = of_get_flat_dt_prop(node, "reserved-ranges", &len);
1323	if (!prop)
1324		return;
1325
1326	/*
1327	 * Each reserved range is an (address,size) pair, 2 cells each,
1328	 * totalling 4 cells per range.
1329	 */
1330	for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
1331		u64 base, size;
1332
1333		base = of_read_number(prop + (i * 4) + 0, 2);
1334		size = of_read_number(prop + (i * 4) + 2, 2);
1335
1336		if (size) {
1337			ret = fadump_add_mem_range(&reserved_mrange_info,
1338						   base, base + size);
1339			if (ret < 0) {
1340				pr_warn("some reserved ranges are ignored!\n");
1341				break;
1342			}
1343		}
1344	}
1345
1346	/* Compact reserved ranges */
1347	sort_and_merge_mem_ranges(&reserved_mrange_info);
1348}
1349
1350/*
1351 * Release the memory that was reserved during early boot to preserve the
1352 * crash'ed kernel's memory contents except reserved dump area (permanent
1353 * reservation) and reserved ranges used by F/W. The released memory will
1354 * be available for general use.
1355 */
1356static void fadump_release_memory(u64 begin, u64 end)
1357{
1358	u64 ra_start, ra_end, tstart;
1359	int i, ret;
1360
 
 
1361	ra_start = fw_dump.reserve_dump_area_start;
1362	ra_end = ra_start + fw_dump.reserve_dump_area_size;
1363
1364	/*
1365	 * If reserved ranges array limit is hit, overwrite the last reserved
1366	 * memory range with reserved dump area to ensure it is excluded from
1367	 * the memory being released (reused for next FADump registration).
1368	 */
1369	if (reserved_mrange_info.mem_range_cnt ==
1370	    reserved_mrange_info.max_mem_ranges)
1371		reserved_mrange_info.mem_range_cnt--;
1372
1373	ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end);
1374	if (ret != 0)
 
 
 
 
 
 
 
 
 
 
 
 
 
1375		return;
 
1376
1377	/* Get the reserved ranges list in order first. */
1378	sort_and_merge_mem_ranges(&reserved_mrange_info);
1379
1380	/* Exclude reserved ranges and release remaining memory */
1381	tstart = begin;
1382	for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) {
1383		ra_start = reserved_mrange_info.mem_ranges[i].base;
1384		ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size;
1385
1386		if (tstart >= ra_end)
1387			continue;
1388
1389		if (tstart < ra_start)
1390			fadump_release_reserved_area(tstart, ra_start);
1391		tstart = ra_end;
1392	}
1393
1394	if (tstart < end)
1395		fadump_release_reserved_area(tstart, end);
1396}
1397
1398static void fadump_invalidate_release_mem(void)
1399{
1400	mutex_lock(&fadump_mutex);
1401	if (!fw_dump.dump_active) {
1402		mutex_unlock(&fadump_mutex);
1403		return;
1404	}
1405
1406	fadump_cleanup();
1407	mutex_unlock(&fadump_mutex);
1408
1409	fadump_release_memory(fw_dump.boot_mem_top, memblock_end_of_DRAM());
1410	fadump_free_cpu_notes_buf();
1411
1412	/*
1413	 * Setup kernel metadata and initialize the kernel dump
1414	 * memory structure for FADump re-registration.
1415	 */
1416	if (fw_dump.ops->fadump_setup_metadata &&
1417	    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
1418		pr_warn("Failed to setup kernel metadata!\n");
1419	fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1420}
1421
1422static ssize_t release_mem_store(struct kobject *kobj,
1423				 struct kobj_attribute *attr,
1424				 const char *buf, size_t count)
1425{
1426	int input = -1;
1427
1428	if (!fw_dump.dump_active)
1429		return -EPERM;
1430
1431	if (kstrtoint(buf, 0, &input))
1432		return -EINVAL;
1433
1434	if (input == 1) {
1435		/*
1436		 * Take away the '/proc/vmcore'. We are releasing the dump
1437		 * memory, hence it will not be valid anymore.
1438		 */
1439#ifdef CONFIG_PROC_VMCORE
1440		vmcore_cleanup();
1441#endif
1442		fadump_invalidate_release_mem();
1443
1444	} else
1445		return -EINVAL;
1446	return count;
1447}
1448
1449/* Release the reserved memory and disable the FADump */
1450static void unregister_fadump(void)
1451{
1452	fadump_cleanup();
1453	fadump_release_memory(fw_dump.reserve_dump_area_start,
1454			      fw_dump.reserve_dump_area_size);
1455	fw_dump.fadump_enabled = 0;
1456	kobject_put(fadump_kobj);
1457}
1458
1459static ssize_t enabled_show(struct kobject *kobj,
1460			    struct kobj_attribute *attr,
1461			    char *buf)
1462{
1463	return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1464}
1465
1466static ssize_t mem_reserved_show(struct kobject *kobj,
1467				 struct kobj_attribute *attr,
1468				 char *buf)
1469{
1470	return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
1471}
1472
1473static ssize_t registered_show(struct kobject *kobj,
1474			       struct kobj_attribute *attr,
1475			       char *buf)
1476{
1477	return sprintf(buf, "%d\n", fw_dump.dump_registered);
1478}
1479
1480static ssize_t registered_store(struct kobject *kobj,
1481				struct kobj_attribute *attr,
1482				const char *buf, size_t count)
1483{
1484	int ret = 0;
1485	int input = -1;
1486
1487	if (!fw_dump.fadump_enabled || fw_dump.dump_active)
1488		return -EPERM;
1489
1490	if (kstrtoint(buf, 0, &input))
1491		return -EINVAL;
1492
1493	mutex_lock(&fadump_mutex);
1494
1495	switch (input) {
1496	case 0:
1497		if (fw_dump.dump_registered == 0) {
1498			goto unlock_out;
1499		}
1500
1501		/* Un-register Firmware-assisted dump */
1502		pr_debug("Un-register firmware-assisted dump\n");
1503		fw_dump.ops->fadump_unregister(&fw_dump);
1504		break;
1505	case 1:
1506		if (fw_dump.dump_registered == 1) {
1507			/* Un-register Firmware-assisted dump */
1508			fw_dump.ops->fadump_unregister(&fw_dump);
1509		}
1510		/* Register Firmware-assisted dump */
1511		ret = register_fadump();
1512		break;
1513	default:
1514		ret = -EINVAL;
1515		break;
1516	}
1517
1518unlock_out:
1519	mutex_unlock(&fadump_mutex);
1520	return ret < 0 ? ret : count;
1521}
1522
1523static int fadump_region_show(struct seq_file *m, void *private)
1524{
1525	if (!fw_dump.fadump_enabled)
1526		return 0;
1527
1528	mutex_lock(&fadump_mutex);
1529	fw_dump.ops->fadump_region_show(&fw_dump, m);
1530	mutex_unlock(&fadump_mutex);
1531	return 0;
1532}
1533
1534static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
1535static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
1536static struct kobj_attribute register_attr = __ATTR_RW(registered);
1537static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
1538
1539static struct attribute *fadump_attrs[] = {
1540	&enable_attr.attr,
1541	&register_attr.attr,
1542	&mem_reserved_attr.attr,
1543	NULL,
1544};
1545
1546ATTRIBUTE_GROUPS(fadump);
1547
1548DEFINE_SHOW_ATTRIBUTE(fadump_region);
1549
1550static void fadump_init_files(void)
1551{
 
1552	int rc = 0;
1553
1554	fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
1555	if (!fadump_kobj) {
1556		pr_err("failed to create fadump kobject\n");
1557		return;
1558	}
1559
1560	debugfs_create_file("fadump_region", 0444, powerpc_debugfs_root, NULL,
1561			    &fadump_region_fops);
 
 
 
 
 
 
 
 
1562
1563	if (fw_dump.dump_active) {
1564		rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
1565		if (rc)
1566			pr_err("unable to create release_mem sysfs file (%d)\n",
1567			       rc);
1568	}
1569
1570	rc = sysfs_create_groups(fadump_kobj, fadump_groups);
1571	if (rc) {
1572		pr_err("sysfs group creation failed (%d), unregistering FADump",
1573		       rc);
1574		unregister_fadump();
1575		return;
1576	}
1577
1578	/*
1579	 * The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
1580	 * create symlink at old location to maintain backward compatibility.
1581	 *
1582	 *      - fadump_enabled -> fadump/enabled
1583	 *      - fadump_registered -> fadump/registered
1584	 *      - fadump_release_mem -> fadump/release_mem
1585	 */
1586	rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1587						  "enabled", "fadump_enabled");
1588	if (rc) {
1589		pr_err("unable to create fadump_enabled symlink (%d)", rc);
1590		return;
1591	}
1592
1593	rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1594						  "registered",
1595						  "fadump_registered");
1596	if (rc) {
1597		pr_err("unable to create fadump_registered symlink (%d)", rc);
1598		sysfs_remove_link(kernel_kobj, "fadump_enabled");
1599		return;
1600	}
1601
1602	if (fw_dump.dump_active) {
1603		rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
1604							  fadump_kobj,
1605							  "release_mem",
1606							  "fadump_release_mem");
1607		if (rc)
1608			pr_err("unable to create fadump_release_mem symlink (%d)",
1609			       rc);
1610	}
1611	return;
1612}
1613
1614/*
1615 * Prepare for firmware-assisted dump.
1616 */
1617int __init setup_fadump(void)
1618{
1619	if (!fw_dump.fadump_supported)
1620		return 0;
1621
1622	fadump_init_files();
1623	fadump_show_config();
1624
1625	if (!fw_dump.fadump_enabled)
1626		return 1;
1627
 
1628	/*
1629	 * If dump data is available then see if it is valid and prepare for
1630	 * saving it to the disk.
1631	 */
1632	if (fw_dump.dump_active) {
1633		/*
1634		 * if dump process fails then invalidate the registration
1635		 * and release memory before proceeding for re-registration.
1636		 */
1637		if (fw_dump.ops->fadump_process(&fw_dump) < 0)
1638			fadump_invalidate_release_mem();
1639	}
1640	/* Initialize the kernel dump memory structure for FAD registration. */
1641	else if (fw_dump.reserve_dump_area_size)
1642		fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1643
 
 
1644	return 1;
1645}
1646subsys_initcall(setup_fadump);
1647#else /* !CONFIG_PRESERVE_FA_DUMP */
1648
1649/* Scan the Firmware Assisted dump configuration details. */
1650int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
1651				      int depth, void *data)
1652{
1653	if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0))
1654		return 0;
1655
1656	opal_fadump_dt_scan(&fw_dump, node);
1657	return 1;
1658}
1659
1660/*
1661 * When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
1662 * preserve crash data. The subsequent memory preserving kernel boot
1663 * is likely to process this crash data.
1664 */
1665int __init fadump_reserve_mem(void)
1666{
1667	if (fw_dump.dump_active) {
1668		/*
1669		 * If last boot has crashed then reserve all the memory
1670		 * above boot memory to preserve crash data.
1671		 */
1672		pr_info("Preserving crash data for processing in next boot.\n");
1673		fadump_reserve_crash_area(fw_dump.boot_mem_top);
1674	} else
1675		pr_debug("FADump-aware kernel..\n");
1676
1677	return 1;
1678}
1679#endif /* CONFIG_PRESERVE_FA_DUMP */
1680
1681/* Preserve everything above the base address */
1682static void __init fadump_reserve_crash_area(u64 base)
1683{
1684	u64 i, mstart, mend, msize;
 
1685
1686	for_each_mem_range(i, &mstart, &mend) {
1687		msize  = mend - mstart;
 
1688
1689		if ((mstart + msize) < base)
1690			continue;
1691
1692		if (mstart < base) {
1693			msize -= (base - mstart);
1694			mstart = base;
1695		}
1696
1697		pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data",
1698			(msize >> 20), mstart);
1699		memblock_reserve(mstart, msize);
1700	}
1701}
1702
1703unsigned long __init arch_reserved_kernel_pages(void)
1704{
1705	return memblock_reserved_size() / PAGE_SIZE;
1706}