path: root/kernel/crash_core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * crash.c - kernel crash support code.
 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
 */

#include <linux/buildid.h>
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/kexec.h>
#include <linux/memory.h>
#include <linux/cpuhotplug.h>
#include <linux/memblock.h>
#include <linux/kmemleak.h>

#include <asm/page.h>
#include <asm/sections.h>

#include <crypto/sha1.h>

#include "kallsyms_internal.h"
#include "kexec_internal.h"

/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;

/* vmcoreinfo stuff */
unsigned char *vmcoreinfo_data;
size_t vmcoreinfo_size;
u32 *vmcoreinfo_note;

/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
static unsigned char *vmcoreinfo_data_safecopy;

/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
	.name  = "Crash kernel",
	.start = 0,
	.end   = 0,
	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
	.desc  = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
	.name  = "Crash kernel",
	.start = 0,
	.end   = 0,
	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
	.desc  = IORES_DESC_CRASH_KERNEL
};

/*
 * parsing the "crashkernel" commandline
 *
 * this code is intended to be called from architecture specific code
 */


/*
 * This function parses command lines in the format
 *
 *   crashkernel=ramsize-range:size[,...][@offset]
 *
 * The function returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_mem(char *cmdline,
					unsigned long long system_ram,
					unsigned long long *crash_size,
					unsigned long long *crash_base)
{
	char *cur = cmdline, *tmp;
	unsigned long long total_mem = system_ram;

	/*
	 * Firmware sometimes reserves some memory regions for its own use,
	 * so the system memory size is less than the actual physical memory
	 * size. Work around this by rounding up the total size to 128M,
	 * which is enough for most test cases.
	 */
	total_mem = roundup(total_mem, SZ_128M);

	/* for each entry of the comma-separated list */
	do {
		unsigned long long start, end = ULLONG_MAX, size;

		/* get the start of the range */
		start = memparse(cur, &tmp);
		if (cur == tmp) {
			pr_warn("crashkernel: Memory value expected\n");
			return -EINVAL;
		}
		cur = tmp;
		if (*cur != '-') {
			pr_warn("crashkernel: '-' expected\n");
			return -EINVAL;
		}
		cur++;

		/* if no ':' is here, than we read the end */
		if (*cur != ':') {
			end = memparse(cur, &tmp);
			if (cur == tmp) {
				pr_warn("crashkernel: Memory value expected\n");
				return -EINVAL;
			}
			cur = tmp;
			if (end <= start) {
				pr_warn("crashkernel: end <= start\n");
				return -EINVAL;
			}
		}

		if (*cur != ':') {
			pr_warn("crashkernel: ':' expected\n");
			return -EINVAL;
		}
		cur++;

		size = memparse(cur, &tmp);
		if (cur == tmp) {
			pr_warn("Memory value expected\n");
			return -EINVAL;
		}
		cur = tmp;
		if (size >= total_mem) {
			pr_warn("crashkernel: invalid size\n");
			return -EINVAL;
		}

		/* match ? */
		if (total_mem >= start && total_mem < end) {
			*crash_size = size;
			break;
		}
	} while (*cur++ == ',');

	if (*crash_size > 0) {
		while (*cur && *cur != ' ' && *cur != '@')
			cur++;
		if (*cur == '@') {
			cur++;
			*crash_base = memparse(cur, &tmp);
			if (cur == tmp) {
				pr_warn("Memory value expected after '@'\n");
				return -EINVAL;
			}
		}
	} else
		pr_info("crashkernel size resulted in zero bytes\n");

	return 0;
}

/*
 * That function parses "simple" (old) crashkernel command lines like
 *
 *	crashkernel=size[@offset]
 *
 * It returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_simple(char *cmdline,
					   unsigned long long *crash_size,
					   unsigned long long *crash_base)
{
	char *cur = cmdline;

	*crash_size = memparse(cmdline, &cur);
	if (cmdline == cur) {
		pr_warn("crashkernel: memory value expected\n");
		return -EINVAL;
	}

	if (*cur == '@')
		*crash_base = memparse(cur+1, &cur);
	else if (*cur != ' ' && *cur != '\0') {
		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
		return -EINVAL;
	}

	return 0;
}

#define SUFFIX_HIGH 0
#define SUFFIX_LOW  1
#define SUFFIX_NULL 2
static __initdata char *suffix_tbl[] = {
	[SUFFIX_HIGH] = ",high",
	[SUFFIX_LOW]  = ",low",
	[SUFFIX_NULL] = NULL,
};

/*
 * That function parses "suffix"  crashkernel command lines like
 *
 *	crashkernel=size,[high|low]
 *
 * It returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_suffix(char *cmdline,
					   unsigned long long *crash_size