kernel/crash_reserve.c - linux - Git at Google

 // 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"

 /* 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("crashkernel: 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("crahskernel: 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,
 					   const char *suffix)
 {
 	char *cur = cmdline;

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

 	/* check with suffix */
 	if (strncmp(cur, suffix, strlen(suffix))) {
 		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 		return -EINVAL;
 	}
 	cur += strlen(suffix);
 	if (*cur != ' ' && *cur != '\0') {
 		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 		return -EINVAL;
 	}

 	return 0;
 }

 static __init char *get_last_crashkernel(char *cmdline,
 			     const char *name,
 			     const char *suffix)
 {
 	char *p = cmdline, *ck_cmdline = NULL;

 	/* find crashkernel and use the last one if there are more */
 	p = strstr(p, name);
 	while (p) {
 		char *end_p = strchr(p, ' ');
 		char *q;

 		if (!end_p)
 			end_p = p + strlen(p);

 		if (!suffix) {
 			int i;

 			/* skip the one with any known suffix */
 			for (i = 0; suffix_tbl[i]; i++) {
 				q = end_p - strlen(suffix_tbl[i]);
 				if (!strncmp(q, suffix_tbl[i],
 					     strlen(suffix_tbl[i])))
 					goto next;
 			}
 			ck_cmdline = p;
 		} else {
 			q = end_p - strlen(suffix);
 			if (!strncmp(q, suffix, strlen(suffix)))
 				ck_cmdline = p;
 		}
 next:
 		p = strstr(p+1, name);
 	}

 	return ck_cmdline;
 }

 static int __init __parse_crashkernel(char *cmdline,
 			     unsigned long long system_ram,
 			     unsigned long long *crash_size,
 			     unsigned long long *crash_base,
 			     const char *suffix)
 {
 	char *first_colon, *first_space;
 	char *ck_cmdline;
 	char *name = "crashkernel=";

 	BUG_ON(!crash_size || !crash_base);
 	*crash_size = 0;
 	*crash_base = 0;

 	ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
 	if (!ck_cmdline)
 		return -ENOENT;

 	ck_cmdline += strlen(name);

 	if (suffix)
 		return parse_crashkernel_suffix(ck_cmdline, crash_size,
 				suffix);
 	/*
 	 * if the commandline contains a ':', then that's the extended
 	 * syntax -- if not, it must be the classic syntax
 	 */
 	first_colon = strchr(ck_cmdline, ':');
 	first_space = strchr(ck_cmdline, ' ');
 	if (first_colon && (!first_space || first_colon < first_space))
 		return parse_crashkernel_mem(ck_cmdline, system_ram,
 				crash_size, crash_base);

 	return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
 }

 /*
  * That function is the entry point for command line parsing and should be
  * called from the arch-specific code.
  *
  * If crashkernel=,high|low is supported on architecture, non-NULL values
  * should be passed to parameters 'low_size' and 'high'.
  */
 int __init parse_crashkernel(char *cmdline,
 			     unsigned long long system_ram,
 			     unsigned long long *crash_size,
 			     unsigned long long *crash_base,
 			     unsigned long long *low_size,
 			     bool *high)
 {
 	int ret;

 	/* crashkernel=X[@offset] */
 	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
 				crash_base, NULL);
 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
 	/*
 	 * If non-NULL 'high' passed in and no normal crashkernel
 	 * setting detected, try parsing crashkernel=,high|low.
 	 */
 	if (high && ret == -ENOENT) {
 		ret = __parse_crashkernel(cmdline, 0, crash_size,
 				crash_base, suffix_tbl[SUFFIX_HIGH]);
 		if (ret || !*crash_size)
 			return -EINVAL;

 		/*
 		 * crashkernel=Y,low can be specified or not, but invalid value
 		 * is not allowed.
 		 */
 		ret = __parse_crashkernel(cmdline, 0, low_size,
 				crash_base, suffix_tbl[SUFFIX_LOW]);
 		if (ret == -ENOENT) {
 			*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
 			ret = 0;
 		} else if (ret) {
 			return ret;
 		}

 		*high = true;
 	}
 #endif
 	if (!*crash_size)
 		ret = -EINVAL;

 	return ret;
 }

 /*
  * Add a dummy early_param handler to mark crashkernel= as a known command line
  * parameter and suppress incorrect warnings in init/main.c.
  */
 static int __init parse_crashkernel_dummy(char *arg)
 {
 	return 0;
 }
 early_param("crashkernel", parse_crashkernel_dummy);

 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
 static int __init reserve_crashkernel_low(unsigned long long low_size)
 {
 #ifdef CONFIG_64BIT
 	unsigned long long low_base;

 	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
 	if (!low_base) {
 		pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
 		return -ENOMEM;
 	}

 	pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
 		low_base, low_base + low_size, low_size >> 20);

 	crashk_low_res.start = low_base;
 	crashk_low_res.end   = low_base + low_size - 1;
 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 	insert_resource(&iomem_resource, &crashk_low_res);
 #endif
 #endif
 	return 0;
 }

 void __init reserve_crashkernel_generic(char *cmdline,
 			     unsigned long long crash_size,
 			     unsigned long long crash_base,
 			     unsigned long long crash_low_size,
 			     bool high)
 {
 	unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
 	bool fixed_base = false;

 	/* User specifies base address explicitly. */
 	if (crash_base) {
 		fixed_base = true;
 		search_base = crash_base;
 		search_end = crash_base + crash_size;
 	} else if (high) {
 		search_base = CRASH_ADDR_LOW_MAX;
 		search_end = CRASH_ADDR_HIGH_MAX;
 	}

 retry:
 	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
 					       search_base, search_end);
 	if (!crash_base) {
 		/*
 		 * For crashkernel=size[KMG]@offset[KMG], print out failure
 		 * message if can't reserve the specified region.
 		 */
 		if (fixed_base) {
 			pr_warn("crashkernel reservation failed - memory is in use.\n");
 			return;
 		}

 		/*
 		 * For crashkernel=size[KMG], if the first attempt was for
 		 * low memory, fall back to high memory, the minimum required
 		 * low memory will be reserved later.
 		 */
 		if (!high && search_end == CRASH_ADDR_LOW_MAX) {
 			search_end = CRASH_ADDR_HIGH_MAX;
 			search_base = CRASH_ADDR_LOW_MAX;
 			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
 			goto retry;
 		}

 		/*
 		 * For crashkernel=size[KMG],high, if the first attempt was
 		 * for high memory, fall back to low memory.
 		 */
 		if (high && search_end == CRASH_ADDR_HIGH_MAX) {
 			search_end = CRASH_ADDR_LOW_MAX;
 			search_base = 0;
 			if (search_end != CRASH_ADDR_HIGH_MAX)
 				goto retry;
 		}
 		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 			crash_size);
 		return;
 	}

 	if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
 	     crash_low_size && reserve_crashkernel_low(crash_low_size)) {
 		memblock_phys_free(crash_base, crash_size);
 		return;
 	}

 	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
 		crash_base, crash_base + crash_size, crash_size >> 20);

 	/*
 	 * The crashkernel memory will be removed from the kernel linear
 	 * map. Inform kmemleak so that it won't try to access it.
 	 */
 	kmemleak_ignore_phys(crash_base);
 	if (crashk_low_res.end)
 		kmemleak_ignore_phys(crashk_low_res.start);

 	crashk_res.start = crash_base;
 	crashk_res.end = crash_base + crash_size - 1;
 #ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 	insert_resource(&iomem_resource, &crashk_res);
 #endif
 }

 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 static __init int insert_crashkernel_resources(void)
 {
 	if (crashk_res.start < crashk_res.end)
 		insert_resource(&iomem_resource, &crashk_res);

 	if (crashk_low_res.start < crashk_low_res.end)
 		insert_resource(&iomem_resource, &crashk_low_res);

 	return 0;
 }
 early_initcall(insert_crashkernel_resources);
 #endif
 #endif
	// 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"

	/* 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("crashkernel: 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("crahskernel: 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,
	const char *suffix)
	{
	char *cur = cmdline;

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

	/* check with suffix */
	if (strncmp(cur, suffix, strlen(suffix))) {
	pr_warn("crashkernel: unrecognized char: %c\n", *cur);
	return -EINVAL;
	}
	cur += strlen(suffix);
	if (cur != ' ' && cur != '\0') {
	pr_warn("crashkernel: unrecognized char: %c\n", *cur);
	return -EINVAL;
	}

	return 0;
	}

	static __init char get_last_crashkernel(char cmdline,
	const char *name,
	const char *suffix)
	{
	char p = cmdline, ck_cmdline = NULL;

	/* find crashkernel and use the last one if there are more */
	p = strstr(p, name);
	while (p) {
	char *end_p = strchr(p, ' ');
	char *q;

	if (!end_p)
	end_p = p + strlen(p);

	if (!suffix) {
	int i;

	/* skip the one with any known suffix */
	for (i = 0; suffix_tbl[i]; i++) {
	q = end_p - strlen(suffix_tbl[i]);
	if (!strncmp(q, suffix_tbl[i],
	strlen(suffix_tbl[i])))
	goto next;
	}
	ck_cmdline = p;
	} else {
	q = end_p - strlen(suffix);
	if (!strncmp(q, suffix, strlen(suffix)))
	ck_cmdline = p;
	}
	next:
	p = strstr(p+1, name);
	}

	return ck_cmdline;
	}

	static int __init __parse_crashkernel(char *cmdline,
	unsigned long long system_ram,
	unsigned long long *crash_size,
	unsigned long long *crash_base,
	const char *suffix)
	{
	char first_colon, first_space;
	char *ck_cmdline;
	char *name = "crashkernel=";

	BUG_ON(!crash_size \|\| !crash_base);
	*crash_size = 0;
	*crash_base = 0;

	ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
	if (!ck_cmdline)
	return -ENOENT;

	ck_cmdline += strlen(name);

	if (suffix)
	return parse_crashkernel_suffix(ck_cmdline, crash_size,
	suffix);
	/*
	* if the commandline contains a ':', then that's the extended
	* syntax -- if not, it must be the classic syntax
	*/
	first_colon = strchr(ck_cmdline, ':');
	first_space = strchr(ck_cmdline, ' ');
	if (first_colon && (!first_space \|\| first_colon < first_space))
	return parse_crashkernel_mem(ck_cmdline, system_ram,
	crash_size, crash_base);

	return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
	}

	/*
	* That function is the entry point for command line parsing and should be
	* called from the arch-specific code.
	*
	* If crashkernel=,high\|low is supported on architecture, non-NULL values
	* should be passed to parameters 'low_size' and 'high'.
	*/
	int __init parse_crashkernel(char *cmdline,
	unsigned long long system_ram,
	unsigned long long *crash_size,
	unsigned long long *crash_base,
	unsigned long long *low_size,
	bool *high)
	{
	int ret;

	/* crashkernel=X[@offset] */
	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
	crash_base, NULL);
	#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
	/*
	* If non-NULL 'high' passed in and no normal crashkernel
	* setting detected, try parsing crashkernel=,high\|low.
	*/
	if (high && ret == -ENOENT) {
	ret = __parse_crashkernel(cmdline, 0, crash_size,
	crash_base, suffix_tbl[SUFFIX_HIGH]);
	if (ret \|\| !*crash_size)
	return -EINVAL;

	/*
	* crashkernel=Y,low can be specified or not, but invalid value
	* is not allowed.
	*/
	ret = __parse_crashkernel(cmdline, 0, low_size,
	crash_base, suffix_tbl[SUFFIX_LOW]);
	if (ret == -ENOENT) {
	*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
	ret = 0;
	} else if (ret) {
	return ret;
	}

	*high = true;
	}
	#endif
	if (!*crash_size)
	ret = -EINVAL;

	return ret;
	}

	/*
	* Add a dummy early_param handler to mark crashkernel= as a known command line
	* parameter and suppress incorrect warnings in init/main.c.
	*/
	static int __init parse_crashkernel_dummy(char *arg)
	{
	return 0;
	}
	early_param("crashkernel", parse_crashkernel_dummy);

	#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
	static int __init reserve_crashkernel_low(unsigned long long low_size)
	{
	#ifdef CONFIG_64BIT
	unsigned long long low_base;

	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
	if (!low_base) {
	pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
	return -ENOMEM;
	}

	pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
	low_base, low_base + low_size, low_size >> 20);

	crashk_low_res.start = low_base;
	crashk_low_res.end = low_base + low_size - 1;
	#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
	insert_resource(&iomem_resource, &crashk_low_res);
	#endif
	#endif
	return 0;
	}

	void __init reserve_crashkernel_generic(char *cmdline,
	unsigned long long crash_size,
	unsigned long long crash_base,
	unsigned long long crash_low_size,
	bool high)
	{
	unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
	bool fixed_base = false;

	/* User specifies base address explicitly. */
	if (crash_base) {
	fixed_base = true;
	search_base = crash_base;
	search_end = crash_base + crash_size;
	} else if (high) {
	search_base = CRASH_ADDR_LOW_MAX;
	search_end = CRASH_ADDR_HIGH_MAX;
	}

	retry:
	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
	search_base, search_end);
	if (!crash_base) {
	/*
	* For crashkernel=size[KMG]@offset[KMG], print out failure
	* message if can't reserve the specified region.
	*/
	if (fixed_base) {
	pr_warn("crashkernel reservation failed - memory is in use.\n");
	return;
	}

	/*
	* For crashkernel=size[KMG], if the first attempt was for
	* low memory, fall back to high memory, the minimum required
	* low memory will be reserved later.
	*/
	if (!high && search_end == CRASH_ADDR_LOW_MAX) {
	search_end = CRASH_ADDR_HIGH_MAX;
	search_base = CRASH_ADDR_LOW_MAX;
	crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
	goto retry;
	}

	/*
	* For crashkernel=size[KMG],high, if the first attempt was
	* for high memory, fall back to low memory.
	*/
	if (high && search_end == CRASH_ADDR_HIGH_MAX) {
	search_end = CRASH_ADDR_LOW_MAX;
	search_base = 0;
	if (search_end != CRASH_ADDR_HIGH_MAX)
	goto retry;
	}
	pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
	crash_size);
	return;
	}

	if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
	crash_low_size && reserve_crashkernel_low(crash_low_size)) {
	memblock_phys_free(crash_base, crash_size);
	return;
	}

	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
	crash_base, crash_base + crash_size, crash_size >> 20);

	/*
	* The crashkernel memory will be removed from the kernel linear
	* map. Inform kmemleak so that it won't try to access it.
	*/
	kmemleak_ignore_phys(crash_base);
	if (crashk_low_res.end)
	kmemleak_ignore_phys(crashk_low_res.start);

	crashk_res.start = crash_base;
	crashk_res.end = crash_base + crash_size - 1;
	#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
	insert_resource(&iomem_resource, &crashk_res);
	#endif
	}

	#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
	static __init int insert_crashkernel_resources(void)
	{
	if (crashk_res.start < crashk_res.end)
	insert_resource(&iomem_resource, &crashk_res);

	if (crashk_low_res.start < crashk_low_res.end)
	insert_resource(&iomem_resource, &crashk_low_res);

	return 0;
	}
	early_initcall(insert_crashkernel_resources);
	#endif
	#endif