ram.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * RAM Oops/Panic logger
   4 *
   5 * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   6 * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/err.h>
  13#include <linux/module.h>
  14#include <linux/version.h>
  15#include <linux/pstore.h>
  16#include <linux/io.h>
  17#include <linux/ioport.h>
  18#include <linux/platform_device.h>
  19#include <linux/slab.h>
  20#include <linux/compiler.h>
  21#include <linux/of.h>
  22#include <linux/of_address.h>
  23#include <linux/mm.h>
  24
  25#include "internal.h"
  26#include "ram_internal.h"
  27
  28#define RAMOOPS_KERNMSG_HDR "===="
  29#define MIN_MEM_SIZE 4096UL
  30
  31static ulong record_size = MIN_MEM_SIZE;
  32module_param(record_size, ulong, 0400);
  33MODULE_PARM_DESC(record_size,
  34		"size of each dump done on oops/panic");
  35
  36static ulong ramoops_console_size = MIN_MEM_SIZE;
  37module_param_named(console_size, ramoops_console_size, ulong, 0400);
  38MODULE_PARM_DESC(console_size, "size of kernel console log");
  39
  40static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  41module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  42MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  43
  44static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
  45module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
  46MODULE_PARM_DESC(pmsg_size, "size of user space message log");
  47
  48static unsigned long long mem_address;
  49module_param_hw(mem_address, ullong, other, 0400);
  50MODULE_PARM_DESC(mem_address,
  51		"start of reserved RAM used to store oops/panic logs");
  52
  53static char *mem_name;
  54module_param_named(mem_name, mem_name, charp, 0400);
  55MODULE_PARM_DESC(mem_name, "name of kernel param that holds addr");
  56
  57static ulong mem_size;
  58module_param(mem_size, ulong, 0400);
  59MODULE_PARM_DESC(mem_size,
  60		"size of reserved RAM used to store oops/panic logs");
  61
  62static unsigned int mem_type;
  63module_param(mem_type, uint, 0400);
  64MODULE_PARM_DESC(mem_type,
  65		"memory type: 0=write-combined (default), 1=unbuffered, 2=cached");
  66
  67static int ramoops_max_reason = -1;
  68module_param_named(max_reason, ramoops_max_reason, int, 0400);
  69MODULE_PARM_DESC(max_reason,
  70		 "maximum reason for kmsg dump (default 2: Oops and Panic) ");
  71
  72static int ramoops_ecc;
  73module_param_named(ecc, ramoops_ecc, int, 0400);
  74MODULE_PARM_DESC(ramoops_ecc,
  75		"if non-zero, the option enables ECC support and specifies "
  76		"ECC buffer size in bytes (1 is a special value, means 16 "
  77		"bytes ECC)");
  78
  79static int ramoops_dump_oops = -1;
  80module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
  81MODULE_PARM_DESC(dump_oops,
  82		 "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics");
  83
  84struct ramoops_context {
  85	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
  86	struct persistent_ram_zone *cprz;	/* Console zone */
  87	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
  88	struct persistent_ram_zone *mprz;	/* PMSG zone */
  89	phys_addr_t phys_addr;
  90	unsigned long size;
  91	unsigned int memtype;
  92	size_t record_size;
  93	size_t console_size;
  94	size_t ftrace_size;
  95	size_t pmsg_size;
  96	u32 flags;
  97	struct persistent_ram_ecc_info ecc_info;
  98	unsigned int max_dump_cnt;
  99	unsigned int dump_write_cnt;
 100	/* _read_cnt need clear on ramoops_pstore_open */
 101	unsigned int dump_read_cnt;
 102	unsigned int console_read_cnt;
 103	unsigned int max_ftrace_cnt;
 104	unsigned int ftrace_read_cnt;
 105	unsigned int pmsg_read_cnt;
 106	struct pstore_info pstore;
 107};
 108
 109static struct platform_device *dummy;
 110
 111static int ramoops_pstore_open(struct pstore_info *psi)
 112{
 113	struct ramoops_context *cxt = psi->data;
 114
 115	cxt->dump_read_cnt = 0;
 116	cxt->console_read_cnt = 0;
 117	cxt->ftrace_read_cnt = 0;
 118	cxt->pmsg_read_cnt = 0;
 119	return 0;
 120}
 121
 122static struct persistent_ram_zone *
 123ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
 124		     struct pstore_record *record)
 125{
 126	struct persistent_ram_zone *prz;
 127
 128	/* Give up if we never existed or have hit the end. */
 129	if (!przs)
 130		return NULL;
 131
 132	prz = przs[id];
 133	if (!prz)
 134		return NULL;
 135
 136	/* Update old/shadowed buffer. */
 137	if (prz->type == PSTORE_TYPE_DMESG)
 138		persistent_ram_save_old(prz);
 139
 140	if (!persistent_ram_old_size(prz))
 141		return NULL;
 142
 143	record->type = prz->type;
 144	record->id = id;
 145
 146	return prz;
 147}
 148
 149static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
 150				  bool *compressed)
 151{
 152	char data_type;
 153	int header_length = 0;
 154
 155	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
 156		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
 157		   &header_length) == 3) {
 158		time->tv_nsec *= 1000;
 159		if (data_type == 'C')
 160			*compressed = true;
 161		else
 162			*compressed = false;
 163	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
 164			  (time64_t *)&time->tv_sec, &time->tv_nsec,
 165			  &header_length) == 2) {
 166		time->tv_nsec *= 1000;
 167		*compressed = false;
 168	} else {
 169		time->tv_sec = 0;
 170		time->tv_nsec = 0;
 171		*compressed = false;
 172	}
 173	return header_length;
 174}
 175
 176static bool prz_ok(struct persistent_ram_zone *prz)
 177{
 178	return !!prz && !!(persistent_ram_old_size(prz) +
 179			   persistent_ram_ecc_string(prz, NULL, 0));
 180}
 181
 182static ssize_t ramoops_pstore_read(struct pstore_record *record)
 183{
 184	ssize_t size = 0;
 185	struct ramoops_context *cxt = record->psi->data;
 186	struct persistent_ram_zone *prz = NULL;
 187	int header_length = 0;
 188	bool free_prz = false;
 189
 190	/*
 191	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
 192	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
 193	 * valid time stamps, so it is initialized to zero.
 194	 */
 195	record->time.tv_sec = 0;
 196	record->time.tv_nsec = 0;
 197	record->compressed = false;
 198
 199	/* Find the next valid persistent_ram_zone for DMESG */
 200	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
 201		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
 202					   record);
 203		if (!prz_ok(prz))
 204			continue;
 205		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
 206						      &record->time,
 207						      &record->compressed);
 208		/* Clear and skip this DMESG record if it has no valid header */
 209		if (!header_length) {
 210			persistent_ram_free_old(prz);
 211			persistent_ram_zap(prz);
 212			prz = NULL;
 213		}
 214	}
 215
 216	if (!prz_ok(prz) && !cxt->console_read_cnt++)
 217		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
 218
 219	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
 220		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
 221
 222	/* ftrace is last since it may want to dynamically allocate memory. */
 223	if (!prz_ok(prz)) {
 224		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
 225		    !cxt->ftrace_read_cnt++) {
 226			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
 227						   record);
 228		} else {
 229			/*
 230			 * Build a new dummy record which combines all the
 231			 * per-cpu records including metadata and ecc info.
 232			 */
 233			struct persistent_ram_zone *tmp_prz, *prz_next;
 234
 235			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
 236					  GFP_KERNEL);
 237			if (!tmp_prz)
 238				return -ENOMEM;
 239			prz = tmp_prz;
 240			free_prz = true;
 241
 242			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 243				prz_next = ramoops_get_next_prz(cxt->fprzs,
 244						cxt->ftrace_read_cnt++, record);
 245
 246				if (!prz_ok(prz_next))
 247					continue;
 248
 249				tmp_prz->ecc_info = prz_next->ecc_info;
 250				tmp_prz->corrected_bytes +=
 251						prz_next->corrected_bytes;
 252				tmp_prz->bad_blocks += prz_next->bad_blocks;
 253
 254				size = pstore_ftrace_combine_log(
 255						&tmp_prz->old_log,
 256						&tmp_prz->old_log_size,
 257						prz_next->old_log,
 258						prz_next->old_log_size);
 259				if (size)
 260					goto out;
 261			}
 262			record->id = 0;
 263		}
 264	}
 265
 266	if (!prz_ok(prz)) {
 267		size = 0;
 268		goto out;
 269	}
 270
 271	size = persistent_ram_old_size(prz) - header_length;
 272
 273	/* ECC correction notice */
 274	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 275
 276	record->buf = kvzalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
 277	if (record->buf == NULL) {
 278		size = -ENOMEM;
 279		goto out;
 280	}
 281
 282	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
 283	       size);
 284
 285	persistent_ram_ecc_string(prz, record->buf + size,
 286				  record->ecc_notice_size + 1);
 287
 288out:
 289	if (free_prz) {
 290		kvfree(prz->old_log);
 291		kfree(prz);
 292	}
 293
 294	return size;
 295}
 296
 297static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 298				     struct pstore_record *record)
 299{
 300	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
 301	size_t len;
 302
 303	len = scnprintf(hdr, sizeof(hdr),
 304		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
 305		(time64_t)record->time.tv_sec,
 306		record->time.tv_nsec / 1000,
 307		record->compressed ? 'C' : 'D');
 308	persistent_ram_write(prz, hdr, len);
 309
 310	return len;
 311}
 312
 313static int notrace ramoops_pstore_write(struct pstore_record *record)
 314{
 315	struct ramoops_context *cxt = record->psi->data;
 316	struct persistent_ram_zone *prz;
 317	size_t size, hlen;
 318
 319	if (record->type == PSTORE_TYPE_CONSOLE) {
 320		if (!cxt->cprz)
 321			return -ENOMEM;
 322		persistent_ram_write(cxt->cprz, record->buf, record->size);
 323		return 0;
 324	} else if (record->type == PSTORE_TYPE_FTRACE) {
 325		int zonenum;
 326
 327		if (!cxt->fprzs)
 328			return -ENOMEM;
 329		/*
 330		 * Choose zone by if we're using per-cpu buffers.
 331		 */
 332		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 333			zonenum = smp_processor_id();
 334		else
 335			zonenum = 0;
 336
 337		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
 338				     record->size);
 339		return 0;
 340	} else if (record->type == PSTORE_TYPE_PMSG) {
 341		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
 342		return -EINVAL;
 343	}
 344
 345	if (record->type != PSTORE_TYPE_DMESG)
 346		return -EINVAL;
 347
 348	/*
 349	 * We could filter on record->reason here if we wanted to (which
 350	 * would duplicate what happened before the "max_reason" setting
 351	 * was added), but that would defeat the purpose of a system
 352	 * changing printk.always_kmsg_dump, so instead log everything that
 353	 * the kmsg dumper sends us, since it should be doing the filtering
 354	 * based on the combination of printk.always_kmsg_dump and our
 355	 * requested "max_reason".
 356	 */
 357
 358	/*
 359	 * Explicitly only take the first part of any new crash.
 360	 * If our buffer is larger than kmsg_bytes, this can never happen,
 361	 * and if our buffer is smaller than kmsg_bytes, we don't want the
 362	 * report split across multiple records.
 363	 */
 364	if (record->part != 1)
 365		return -ENOSPC;
 366
 367	if (!cxt->dprzs)
 368		return -ENOSPC;
 369
 370	prz = cxt->dprzs[cxt->dump_write_cnt];
 371
 372	/*
 373	 * Since this is a new crash dump, we need to reset the buffer in
 374	 * case it still has an old dump present. Without this, the new dump
 375	 * will get appended, which would seriously confuse anything trying
 376	 * to check dump file contents. Specifically, ramoops_read_kmsg_hdr()
 377	 * expects to find a dump header in the beginning of buffer data, so
 378	 * we must to reset the buffer values, in order to ensure that the
 379	 * header will be written to the beginning of the buffer.
 380	 */
 381	persistent_ram_zap(prz);
 382
 383	/* Build header and append record contents. */
 384	hlen = ramoops_write_kmsg_hdr(prz, record);
 385	if (!hlen)
 386		return -ENOMEM;
 387
 388	size = record->size;
 389	if (size + hlen > prz->buffer_size)
 390		size = prz->buffer_size - hlen;
 391	persistent_ram_write(prz, record->buf, size);
 392
 393	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 394
 395	return 0;
 396}
 397
 398static int notrace ramoops_pstore_write_user(struct pstore_record *record,
 399					     const char __user *buf)
 400{
 401	if (record->type == PSTORE_TYPE_PMSG) {
 402		struct ramoops_context *cxt = record->psi->data;
 403
 404		if (!cxt->mprz)
 405			return -ENOMEM;
 406		return persistent_ram_write_user(cxt->mprz, buf, record->size);
 407	}
 408
 409	return -EINVAL;
 410}
 411
 412static int ramoops_pstore_erase(struct pstore_record *record)
 413{
 414	struct ramoops_context *cxt = record->psi->data;
 415	struct persistent_ram_zone *prz;
 416
 417	switch (record->type) {
 418	case PSTORE_TYPE_DMESG:
 419		if (record->id >= cxt->max_dump_cnt)
 420			return -EINVAL;
 421		prz = cxt->dprzs[record->id];
 422		break;
 423	case PSTORE_TYPE_CONSOLE:
 424		prz = cxt->cprz;
 425		break;
 426	case PSTORE_TYPE_FTRACE:
 427		if (record->id >= cxt->max_ftrace_cnt)
 428			return -EINVAL;
 429		prz = cxt->fprzs[record->id];
 430		break;
 431	case PSTORE_TYPE_PMSG:
 432		prz = cxt->mprz;
 433		break;
 434	default:
 435		return -EINVAL;
 436	}
 437
 438	persistent_ram_free_old(prz);
 439	persistent_ram_zap(prz);
 440
 441	return 0;
 442}
 443
 444static struct ramoops_context oops_cxt = {
 445	.pstore = {
 446		.owner	= THIS_MODULE,
 447		.name	= "ramoops",
 448		.open	= ramoops_pstore_open,
 449		.read	= ramoops_pstore_read,
 450		.write	= ramoops_pstore_write,
 451		.write_user	= ramoops_pstore_write_user,
 452		.erase	= ramoops_pstore_erase,
 453	},
 454};
 455
 456static void ramoops_free_przs(struct ramoops_context *cxt)
 457{
 458	int i;
 459
 460	/* Free pmsg PRZ */
 461	persistent_ram_free(&cxt->mprz);
 462
 463	/* Free console PRZ */
 464	persistent_ram_free(&cxt->cprz);
 465
 466	/* Free dump PRZs */
 467	if (cxt->dprzs) {
 468		for (i = 0; i < cxt->max_dump_cnt; i++)
 469			persistent_ram_free(&cxt->dprzs[i]);
 470
 471		kfree(cxt->dprzs);
 472		cxt->dprzs = NULL;
 473		cxt->max_dump_cnt = 0;
 474	}
 475
 476	/* Free ftrace PRZs */
 477	if (cxt->fprzs) {
 478		for (i = 0; i < cxt->max_ftrace_cnt; i++)
 479			persistent_ram_free(&cxt->fprzs[i]);
 480		kfree(cxt->fprzs);
 481		cxt->fprzs = NULL;
 482		cxt->max_ftrace_cnt = 0;
 483	}
 484}
 485
 486static int ramoops_init_przs(const char *name,
 487			     struct device *dev, struct ramoops_context *cxt,
 488			     struct persistent_ram_zone ***przs,
 489			     phys_addr_t *paddr, size_t mem_sz,
 490			     ssize_t record_size,
 491			     unsigned int *cnt, u32 sig, u32 flags)
 492{
 493	int err = -ENOMEM;
 494	int i;
 495	size_t zone_sz;
 496	struct persistent_ram_zone **prz_ar;
 497
 498	/* Allocate nothing for 0 mem_sz or 0 record_size. */
 499	if (mem_sz == 0 || record_size == 0) {
 500		*cnt = 0;
 501		return 0;
 502	}
 503
 504	/*
 505	 * If we have a negative record size, calculate it based on
 506	 * mem_sz / *cnt. If we have a positive record size, calculate
 507	 * cnt from mem_sz / record_size.
 508	 */
 509	if (record_size < 0) {
 510		if (*cnt == 0)
 511			return 0;
 512		record_size = mem_sz / *cnt;
 513		if (record_size == 0) {
 514			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
 515				name, mem_sz, *cnt);
 516			goto fail;
 517		}
 518	} else {
 519		*cnt = mem_sz / record_size;
 520		if (*cnt == 0) {
 521			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
 522				name, mem_sz, record_size);
 523			goto fail;
 524		}
 525	}
 526
 527	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
 528		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 529			name,
 530			mem_sz, (unsigned long long)*paddr,
 531			cxt->size, (unsigned long long)cxt->phys_addr);
 532		goto fail;
 533	}
 534
 535	zone_sz = mem_sz / *cnt;
 536	zone_sz = ALIGN_DOWN(zone_sz, 2);
 537	if (!zone_sz) {
 538		dev_err(dev, "%s zone size == 0\n", name);
 539		goto fail;
 540	}
 541
 542	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
 543	if (!prz_ar)
 544		goto fail;
 545
 546	for (i = 0; i < *cnt; i++) {
 547		char *label;
 548
 549		if (*cnt == 1)
 550			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 551		else
 552			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
 553					  name, i, *cnt - 1);
 554		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
 555					       &cxt->ecc_info,
 556					       cxt->memtype, flags, label);
 557		kfree(label);
 558		if (IS_ERR(prz_ar[i])) {
 559			err = PTR_ERR(prz_ar[i]);
 560			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 561				name, record_size,
 562				(unsigned long long)*paddr, err);
 563
 564			while (i > 0) {
 565				i--;
 566				persistent_ram_free(&prz_ar[i]);
 567			}
 568			kfree(prz_ar);
 569			prz_ar = NULL;
 570			goto fail;
 571		}
 572		*paddr += zone_sz;
 573		prz_ar[i]->type = pstore_name_to_type(name);
 574	}
 575
 576	*przs = prz_ar;
 577	return 0;
 578
 579fail:
 580	*cnt = 0;
 581	return err;
 582}
 583
 584static int ramoops_init_prz(const char *name,
 585			    struct device *dev, struct ramoops_context *cxt,
 586			    struct persistent_ram_zone **prz,
 587			    phys_addr_t *paddr, size_t sz, u32 sig)
 588{
 589	char *label;
 590
 591	if (!sz)
 592		return 0;
 593
 594	if (*paddr + sz - cxt->phys_addr > cxt->size) {
 595		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 596			name, sz, (unsigned long long)*paddr,
 597			cxt->size, (unsigned long long)cxt->phys_addr);
 598		return -ENOMEM;
 599	}
 600
 601	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 602	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
 603				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
 604	kfree(label);
 605	if (IS_ERR(*prz)) {
 606		int err = PTR_ERR(*prz);
 607
 608		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 609			name, sz, (unsigned long long)*paddr, err);
 610		return err;
 611	}
 612
 613	*paddr += sz;
 614	(*prz)->type = pstore_name_to_type(name);
 615
 616	return 0;
 617}
 618
 619/* Read a u32 from a dt property and make sure it's safe for an int. */
 620static int ramoops_parse_dt_u32(struct platform_device *pdev,
 621				const char *propname,
 622				u32 default_value, u32 *value)
 623{
 624	u32 val32 = 0;
 625	int ret;
 626
 627	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
 628	if (ret == -EINVAL) {
 629		/* field is missing, use default value. */
 630		val32 = default_value;
 631	} else if (ret < 0) {
 632		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
 633			propname, ret);
 634		return ret;
 635	}
 636
 637	/* Sanity check our results. */
 638	if (val32 > INT_MAX) {
 639		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
 640		return -EOVERFLOW;
 641	}
 642
 643	*value = val32;
 644	return 0;
 645}
 646
 647static int ramoops_parse_dt(struct platform_device *pdev,
 648			    struct ramoops_platform_data *pdata)
 649{
 650	struct device_node *of_node = pdev->dev.of_node;
 651	struct device_node *parent_node;
 652	struct resource *res;
 653	u32 value;
 654	int ret;
 655
 656	dev_dbg(&pdev->dev, "using Device Tree\n");
 657
 658	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 659	if (!res) {
 660		dev_err(&pdev->dev,
 661			"failed to locate DT /reserved-memory resource\n");
 662		return -EINVAL;
 663	}
 664
 665	pdata->mem_size = resource_size(res);
 666	pdata->mem_address = res->start;
 667	/*
 668	 * Setting "unbuffered" is deprecated and will be ignored if
 669	 * "mem_type" is also specified.
 670	 */
 671	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
 672	/*
 673	 * Setting "no-dump-oops" is deprecated and will be ignored if
 674	 * "max_reason" is also specified.
 675	 */
 676	if (of_property_read_bool(of_node, "no-dump-oops"))
 677		pdata->max_reason = KMSG_DUMP_PANIC;
 678	else
 679		pdata->max_reason = KMSG_DUMP_OOPS;
 680
 681#define parse_u32(name, field, default_value) {				\
 682		ret = ramoops_parse_dt_u32(pdev, name, default_value,	\
 683					    &value);			\
 684		if (ret < 0)						\
 685			return ret;					\
 686		field = value;						\
 687	}
 688
 689	parse_u32("mem-type", pdata->mem_type, pdata->mem_type);
 690	parse_u32("record-size", pdata->record_size, 0);
 691	parse_u32("console-size", pdata->console_size, 0);
 692	parse_u32("ftrace-size", pdata->ftrace_size, 0);
 693	parse_u32("pmsg-size", pdata->pmsg_size, 0);
 694	parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0);
 695	parse_u32("flags", pdata->flags, 0);
 696	parse_u32("max-reason", pdata->max_reason, pdata->max_reason);
 697
 698#undef parse_u32
 699
 700	/*
 701	 * Some old Chromebooks relied on the kernel setting the
 702	 * console_size and pmsg_size to the record size since that's
 703	 * what the downstream kernel did.  These same Chromebooks had
 704	 * "ramoops" straight under the root node which isn't
 705	 * according to the current upstream bindings (though it was
 706	 * arguably acceptable under a prior version of the bindings).
 707	 * Let's make those old Chromebooks work by detecting that
 708	 * we're not a child of "reserved-memory" and mimicking the
 709	 * expected behavior.
 710	 */
 711	parent_node = of_get_parent(of_node);
 712	if (!of_node_name_eq(parent_node, "reserved-memory") &&
 713	    !pdata->console_size && !pdata->ftrace_size &&
 714	    !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
 715		pdata->console_size = pdata->record_size;
 716		pdata->pmsg_size = pdata->record_size;
 717	}
 718	of_node_put(parent_node);
 719
 720	return 0;
 721}
 722
 723static int ramoops_probe(struct platform_device *pdev)
 724{
 725	struct device *dev = &pdev->dev;
 726	struct ramoops_platform_data *pdata = dev->platform_data;
 727	struct ramoops_platform_data pdata_local;
 728	struct ramoops_context *cxt = &oops_cxt;
 729	size_t dump_mem_sz;
 730	phys_addr_t paddr;
 731	int err = -EINVAL;
 732
 733	/*
 734	 * Only a single ramoops area allowed at a time, so fail extra
 735	 * probes.
 736	 */
 737	if (cxt->max_dump_cnt) {
 738		pr_err("already initialized\n");
 739		goto fail_out;
 740	}
 741
 742	if (dev_of_node(dev) && !pdata) {
 743		pdata = &pdata_local;
 744		memset(pdata, 0, sizeof(*pdata));
 745
 746		err = ramoops_parse_dt(pdev, pdata);
 747		if (err < 0)
 748			goto fail_out;
 749	}
 750
 751	/* Make sure we didn't get bogus platform data pointer. */
 752	if (!pdata) {
 753		pr_err("NULL platform data\n");
 754		err = -EINVAL;
 755		goto fail_out;
 756	}
 757
 758	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 759			!pdata->ftrace_size && !pdata->pmsg_size)) {
 760		pr_err("The memory size and the record/console size must be "
 761			"non-zero\n");
 762		err = -EINVAL;
 763		goto fail_out;
 764	}
 765
 766	if (pdata->record_size && !is_power_of_2(pdata->record_size))
 767		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 768	if (pdata->console_size && !is_power_of_2(pdata->console_size))
 769		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 770	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
 771		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 772	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
 773		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
 774
 775	cxt->size = pdata->mem_size;
 776	cxt->phys_addr = pdata->mem_address;
 777	cxt->memtype = pdata->mem_type;
 778	cxt->record_size = pdata->record_size;
 779	cxt->console_size = pdata->console_size;
 780	cxt->ftrace_size = pdata->ftrace_size;
 781	cxt->pmsg_size = pdata->pmsg_size;
 782	cxt->flags = pdata->flags;
 783	cxt->ecc_info = pdata->ecc_info;
 784
 785	paddr = cxt->phys_addr;
 786
 787	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
 788			- cxt->pmsg_size;
 789	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
 790				dump_mem_sz, cxt->record_size,
 791				&cxt->max_dump_cnt, 0, 0);
 792	if (err)
 793		goto fail_init;
 794
 795	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
 796			       cxt->console_size, 0);
 797	if (err)
 798		goto fail_init;
 799
 800	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
 801				cxt->pmsg_size, 0);
 802	if (err)
 803		goto fail_init;
 804
 805	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 806				? nr_cpu_ids
 807				: 1;
 808	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
 809				cxt->ftrace_size, -1,
 810				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
 811				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 812					? PRZ_FLAG_NO_LOCK : 0);
 813	if (err)
 814		goto fail_init;
 815
 816	cxt->pstore.data = cxt;
 817	/*
 818	 * Prepare frontend flags based on which areas are initialized.
 819	 * For ramoops_init_przs() cases, the "max count" variable tells
 820	 * if there are regions present. For ramoops_init_prz() cases,
 821	 * the single region size is how to check.
 822	 */
 823	cxt->pstore.flags = 0;
 824	if (cxt->max_dump_cnt) {
 825		cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
 826		cxt->pstore.max_reason = pdata->max_reason;
 827	}
 828	if (cxt->console_size)
 829		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
 830	if (cxt->max_ftrace_cnt)
 831		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
 832	if (cxt->pmsg_size)
 833		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
 834
 835	/*
 836	 * Since bufsize is only used for dmesg crash dumps, it
 837	 * must match the size of the dprz record (after PRZ header
 838	 * and ECC bytes have been accounted for).
 839	 */
 840	if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
 841		cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
 842		cxt->pstore.buf = kvzalloc(cxt->pstore.bufsize, GFP_KERNEL);
 843		if (!cxt->pstore.buf) {
 844			pr_err("cannot allocate pstore crash dump buffer\n");
 845			err = -ENOMEM;
 846			goto fail_clear;
 847		}
 848	}
 849
 850	err = pstore_register(&cxt->pstore);
 851	if (err) {
 852		pr_err("registering with pstore failed\n");
 853		goto fail_buf;
 854	}
 855
 856	/*
 857	 * Update the module parameter variables as well so they are visible
 858	 * through /sys/module/ramoops/parameters/
 859	 */
 860	mem_size = pdata->mem_size;
 861	mem_address = pdata->mem_address;
 862	record_size = pdata->record_size;
 863	ramoops_max_reason = pdata->max_reason;
 864	ramoops_console_size = pdata->console_size;
 865	ramoops_pmsg_size = pdata->pmsg_size;
 866	ramoops_ftrace_size = pdata->ftrace_size;
 867	mem_type = pdata->mem_type;
 868	ramoops_ecc = pdata->ecc_info.ecc_size;
 869
 870	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
 871		cxt->size, (unsigned long long)cxt->phys_addr,
 872		cxt->ecc_info.ecc_size);
 873
 874	return 0;
 875
 876fail_buf:
 877	kvfree(cxt->pstore.buf);
 878fail_clear:
 879	cxt->pstore.bufsize = 0;
 880fail_init:
 881	ramoops_free_przs(cxt);
 882fail_out:
 883	return err;
 884}
 885
 886static void ramoops_remove(struct platform_device *pdev)
 887{
 888	struct ramoops_context *cxt = &oops_cxt;
 889
 890	pstore_unregister(&cxt->pstore);
 891
 892	kvfree(cxt->pstore.buf);
 893	cxt->pstore.bufsize = 0;
 894
 895	ramoops_free_przs(cxt);
 896}
 897
 898static const struct of_device_id dt_match[] = {
 899	{ .compatible = "ramoops" },
 900	{}
 901};
 902MODULE_DEVICE_TABLE(of, dt_match);
 903
 904static struct platform_driver ramoops_driver = {
 905	.probe		= ramoops_probe,
 906	.remove		= ramoops_remove,
 907	.driver		= {
 908		.name		= "ramoops",
 909		.of_match_table	= dt_match,
 910	},
 911};
 912
 913static inline void ramoops_unregister_dummy(void)
 914{
 915	platform_device_unregister(dummy);
 916	dummy = NULL;
 917}
 918
 919static void __init ramoops_register_dummy(void)
 920{
 921	struct ramoops_platform_data pdata;
 922
 923	if (mem_name) {
 924		phys_addr_t start;
 925		phys_addr_t size;
 926
 927		if (reserve_mem_find_by_name(mem_name, &start, &size)) {
 928			mem_address = start;
 929			mem_size = size;
 930		}
 931	}
 932
 933	/*
 934	 * Prepare a dummy platform data structure to carry the module
 935	 * parameters. If mem_size isn't set, then there are no module
 936	 * parameters, and we can skip this.
 937	 */
 938	if (!mem_size)
 939		return;
 940
 941	pr_info("using module parameters\n");
 942
 943	memset(&pdata, 0, sizeof(pdata));
 944	pdata.mem_size = mem_size;
 945	pdata.mem_address = mem_address;
 946	pdata.mem_type = mem_type;
 947	pdata.record_size = record_size;
 948	pdata.console_size = ramoops_console_size;
 949	pdata.ftrace_size = ramoops_ftrace_size;
 950	pdata.pmsg_size = ramoops_pmsg_size;
 951	/* If "max_reason" is set, its value has priority over "dump_oops". */
 952	if (ramoops_max_reason >= 0)
 953		pdata.max_reason = ramoops_max_reason;
 954	/* Otherwise, if "dump_oops" is set, parse it into "max_reason". */
 955	else if (ramoops_dump_oops != -1)
 956		pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS
 957						     : KMSG_DUMP_PANIC;
 958	/* And if neither are explicitly set, use the default. */
 959	else
 960		pdata.max_reason = KMSG_DUMP_OOPS;
 961	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
 962
 963	/*
 964	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 965	 * (using 1 byte for ECC isn't much of use anyway).
 966	 */
 967	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 968
 969	dummy = platform_device_register_data(NULL, "ramoops", -1,
 970			&pdata, sizeof(pdata));
 971	if (IS_ERR(dummy)) {
 972		pr_info("could not create platform device: %ld\n",
 973			PTR_ERR(dummy));
 974		dummy = NULL;
 975	}
 976}
 977
 978static int __init ramoops_init(void)
 979{
 980	int ret;
 981
 982	ramoops_register_dummy();
 983	ret = platform_driver_register(&ramoops_driver);
 984	if (ret != 0)
 985		ramoops_unregister_dummy();
 986
 987	return ret;
 988}
 989postcore_initcall(ramoops_init);
 990
 991static void __exit ramoops_exit(void)
 992{
 993	platform_driver_unregister(&ramoops_driver);
 994	ramoops_unregister_dummy();
 995}
 996module_exit(ramoops_exit);
 997
 998MODULE_LICENSE("GPL");
 999MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
1000MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");