diff mbox series

[v2,3/3] arm64: kexec_file: add crash dump support

Message ID 20191114051510.17037-4-takahiro.akashi@linaro.org
State Superseded
Headers show
Series arm64: kexec_file: add kdump | expand

Commit Message

AKASHI Takahiro Nov. 14, 2019, 5:15 a.m. UTC
Enabling crash dump (kdump) includes
* prepare contents of ELF header of a core dump file, /proc/vmcore,
  using crash_prepare_elf64_headers(), and
* add two device tree properties, "linux,usable-memory-range" and
  "linux,elfcorehdr", which represent respectively a memory range
  to be used by crash dump kernel and the header's location

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>

---
 arch/arm64/include/asm/kexec.h         |   4 +
 arch/arm64/kernel/kexec_image.c        |   4 -
 arch/arm64/kernel/machine_kexec_file.c | 106 ++++++++++++++++++++++++-
 3 files changed, 106 insertions(+), 8 deletions(-)

-- 
2.21.0

Comments

Bhupesh Sharma Dec. 4, 2019, 8:44 p.m. UTC | #1
On 11/14/2019 10:45 AM, AKASHI Takahiro wrote:
> Enabling crash dump (kdump) includes

> * prepare contents of ELF header of a core dump file, /proc/vmcore,

>    using crash_prepare_elf64_headers(), and

> * add two device tree properties, "linux,usable-memory-range" and

>    "linux,elfcorehdr", which represent respectively a memory range

>    to be used by crash dump kernel and the header's location

> 

> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

> Cc: Catalin Marinas <catalin.marinas@arm.com>

> Cc: Will Deacon <will.deacon@arm.com>

> Reviewed-by: James Morse <james.morse@arm.com>

> ---

>   arch/arm64/include/asm/kexec.h         |   4 +

>   arch/arm64/kernel/kexec_image.c        |   4 -

>   arch/arm64/kernel/machine_kexec_file.c | 106 ++++++++++++++++++++++++-

>   3 files changed, 106 insertions(+), 8 deletions(-)

> 

> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h

> index 12a561a54128..d24b527e8c00 100644

> --- a/arch/arm64/include/asm/kexec.h

> +++ b/arch/arm64/include/asm/kexec.h

> @@ -96,6 +96,10 @@ static inline void crash_post_resume(void) {}

>   struct kimage_arch {

>   	void *dtb;

>   	unsigned long dtb_mem;

> +	/* Core ELF header buffer */

> +	void *elf_headers;

> +	unsigned long elf_headers_mem;

> +	unsigned long elf_headers_sz;

>   };

>   

>   extern const struct kexec_file_ops kexec_image_ops;

> diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c

> index 29a9428486a5..af9987c154ca 100644

> --- a/arch/arm64/kernel/kexec_image.c

> +++ b/arch/arm64/kernel/kexec_image.c

> @@ -47,10 +47,6 @@ static void *image_load(struct kimage *image,

>   	struct kexec_segment *kernel_segment;

>   	int ret;

>   

> -	/* We don't support crash kernels yet. */

> -	if (image->type == KEXEC_TYPE_CRASH)

> -		return ERR_PTR(-EOPNOTSUPP);

> -

>   	/*

>   	 * We require a kernel with an unambiguous Image header. Per

>   	 * Documentation/arm64/booting.rst, this is the case when image_size

> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c

> index 7b08bf9499b6..f1d1bb895fd2 100644

> --- a/arch/arm64/kernel/machine_kexec_file.c

> +++ b/arch/arm64/kernel/machine_kexec_file.c

> @@ -17,12 +17,15 @@

>   #include <linux/memblock.h>

>   #include <linux/of_fdt.h>

>   #include <linux/random.h>

> +#include <linux/slab.h>

>   #include <linux/string.h>

>   #include <linux/types.h>

>   #include <linux/vmalloc.h>

>   #include <asm/byteorder.h>

>   

>   /* relevant device tree properties */

> +#define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"

> +#define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"

>   #define FDT_PROP_INITRD_START	"linux,initrd-start"

>   #define FDT_PROP_INITRD_END	"linux,initrd-end"

>   #define FDT_PROP_BOOTARGS	"bootargs"

> @@ -40,6 +43,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)

>   	vfree(image->arch.dtb);

>   	image->arch.dtb = NULL;

>   

> +	vfree(image->arch.elf_headers);

> +	image->arch.elf_headers = NULL;

> +	image->arch.elf_headers_sz = 0;

> +

>   	return kexec_image_post_load_cleanup_default(image);

>   }

>   

> @@ -55,6 +62,31 @@ static int setup_dtb(struct kimage *image,

>   

>   	off = ret;

>   

> +	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);

> +	if (ret && ret != -FDT_ERR_NOTFOUND)

> +		goto out;

> +	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);

> +	if (ret && ret != -FDT_ERR_NOTFOUND)

> +		goto out;

> +

> +	if (image->type == KEXEC_TYPE_CRASH) {

> +		/* add linux,elfcorehdr */

> +		ret = fdt_appendprop_addrrange(dtb, 0, off,

> +				FDT_PROP_KEXEC_ELFHDR,

> +				image->arch.elf_headers_mem,

> +				image->arch.elf_headers_sz);

> +		if (ret)

> +			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

> +

> +		/* add linux,usable-memory-range */

> +		ret = fdt_appendprop_addrrange(dtb, 0, off,

> +				FDT_PROP_MEM_RANGE,

> +				crashk_res.start,

> +				crashk_res.end - crashk_res.start + 1);

> +		if (ret)

> +			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

> +	}

> +

>   	/* add bootargs */

>   	if (cmdline) {

>   		ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);

> @@ -125,8 +157,8 @@ static int setup_dtb(struct kimage *image,

>   }

>   

>   /*

> - * More space needed so that we can add initrd, bootargs, kaslr-seed, and

> - * rng-seed.

> + * More space needed so that we can add initrd, bootargs, kaslr-seed,

> + * rng-seed, userable-memory-range and elfcorehdr.


nitpick:
s/userable-memory-range/usable-memory-range

>    */

>   #define DTB_EXTRA_SPACE 0x1000

>   

> @@ -174,6 +206,43 @@ static int create_dtb(struct kimage *image,

>   	}

>   }

>   

> +static int prepare_elf_headers(void **addr, unsigned long *sz)

> +{

> +	struct crash_mem *cmem;

> +	unsigned int nr_ranges;

> +	int ret;

> +	u64 i;

> +	phys_addr_t start, end;

> +

> +	nr_ranges = 1; /* for exclusion of crashkernel region */

> +	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,

> +					MEMBLOCK_NONE, &start, &end, NULL)

> +		nr_ranges++;

> +

> +	cmem = kmalloc(sizeof(struct crash_mem) +

> +			sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL);

> +	if (!cmem)

> +		return -ENOMEM;

> +

> +	cmem->max_nr_ranges = nr_ranges;

> +	cmem->nr_ranges = 0;

> +	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,

> +					MEMBLOCK_NONE, &start, &end, NULL) {

> +		cmem->ranges[cmem->nr_ranges].start = start;

> +		cmem->ranges[cmem->nr_ranges].end = end - 1;

> +		cmem->nr_ranges++;

> +	}

> +

> +	/* Exclude crashkernel region */

> +	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

> +

> +	if (!ret)

> +		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);

> +

> +	kfree(cmem);

> +	return ret;

> +}

> +

>   int load_other_segments(struct kimage *image,

>   			unsigned long kernel_load_addr,

>   			unsigned long kernel_size,

> @@ -181,14 +250,43 @@ int load_other_segments(struct kimage *image,

>   			char *cmdline)

>   {

>   	struct kexec_buf kbuf;

> -	void *dtb = NULL;

> -	unsigned long initrd_load_addr = 0, dtb_len;

> +	void *headers, *dtb = NULL;

> +	unsigned long headers_sz, initrd_load_addr = 0, dtb_len;

>   	int ret = 0;

>   

>   	kbuf.image = image;

>   	/* not allocate anything below the kernel */

>   	kbuf.buf_min = kernel_load_addr + kernel_size;

>   

> +	/* load elf core header */

> +	if (image->type == KEXEC_TYPE_CRASH) {

> +		ret = prepare_elf_headers(&headers, &headers_sz);

> +		if (ret) {

> +			pr_err("Preparing elf core header failed\n");

> +			goto out_err;

> +		}

> +

> +		kbuf.buffer = headers;

> +		kbuf.bufsz = headers_sz;

> +		kbuf.mem = 0;


With commit c19d050f8088 ("arm64/kexec: Use consistent convention of 
initializing 'kxec_buf.mem' with KEXEC_BUF_MEM_UNKNOWN"), we are trying 
to standardize the way of setting up initial value of 'kbuf.mem'. So we 
can use the following notion (in v3?) instead:
		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

> +		kbuf.memsz = headers_sz;

> +		kbuf.buf_align = SZ_64K; /* largest supported page size */

> +		kbuf.buf_max = ULONG_MAX;

> +		kbuf.top_down = true;

> +

> +		ret = kexec_add_buffer(&kbuf);

> +		if (ret) {

> +			vfree(headers);

> +			goto out_err;

> +		}

> +		image->arch.elf_headers = headers;

> +		image->arch.elf_headers_mem = kbuf.mem;

> +		image->arch.elf_headers_sz = headers_sz;

> +

> +		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",

> +			 image->arch.elf_headers_mem, headers_sz, headers_sz);

> +	}

> +

>   	/* load initrd */

>   	if (initrd) {

>   		kbuf.buffer = initrd;

> 


Thanks,
Bhupesh
AKASHI Takahiro Dec. 16, 2019, 1:43 a.m. UTC | #2
I have forgot to address Bhupesh's comment below in my v3.
I'm going to repost my patch.

Thank you, Bhupesh, for your review.

-Takahiro Akashi

On Thu, Dec 05, 2019 at 02:14:14AM +0530, Bhupesh Sharma wrote:
> On 11/14/2019 10:45 AM, AKASHI Takahiro wrote:

> >Enabling crash dump (kdump) includes

> >* prepare contents of ELF header of a core dump file, /proc/vmcore,

> >   using crash_prepare_elf64_headers(), and

> >* add two device tree properties, "linux,usable-memory-range" and

> >   "linux,elfcorehdr", which represent respectively a memory range

> >   to be used by crash dump kernel and the header's location

> >

> >Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

> >Cc: Catalin Marinas <catalin.marinas@arm.com>

> >Cc: Will Deacon <will.deacon@arm.com>

> >Reviewed-by: James Morse <james.morse@arm.com>

> >---

> >  arch/arm64/include/asm/kexec.h         |   4 +

> >  arch/arm64/kernel/kexec_image.c        |   4 -

> >  arch/arm64/kernel/machine_kexec_file.c | 106 ++++++++++++++++++++++++-

> >  3 files changed, 106 insertions(+), 8 deletions(-)

> >

> >diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h

> >index 12a561a54128..d24b527e8c00 100644

> >--- a/arch/arm64/include/asm/kexec.h

> >+++ b/arch/arm64/include/asm/kexec.h

> >@@ -96,6 +96,10 @@ static inline void crash_post_resume(void) {}

> >  struct kimage_arch {

> >  	void *dtb;

> >  	unsigned long dtb_mem;

> >+	/* Core ELF header buffer */

> >+	void *elf_headers;

> >+	unsigned long elf_headers_mem;

> >+	unsigned long elf_headers_sz;

> >  };

> >  extern const struct kexec_file_ops kexec_image_ops;

> >diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c

> >index 29a9428486a5..af9987c154ca 100644

> >--- a/arch/arm64/kernel/kexec_image.c

> >+++ b/arch/arm64/kernel/kexec_image.c

> >@@ -47,10 +47,6 @@ static void *image_load(struct kimage *image,

> >  	struct kexec_segment *kernel_segment;

> >  	int ret;

> >-	/* We don't support crash kernels yet. */

> >-	if (image->type == KEXEC_TYPE_CRASH)

> >-		return ERR_PTR(-EOPNOTSUPP);

> >-

> >  	/*

> >  	 * We require a kernel with an unambiguous Image header. Per

> >  	 * Documentation/arm64/booting.rst, this is the case when image_size

> >diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c

> >index 7b08bf9499b6..f1d1bb895fd2 100644

> >--- a/arch/arm64/kernel/machine_kexec_file.c

> >+++ b/arch/arm64/kernel/machine_kexec_file.c

> >@@ -17,12 +17,15 @@

> >  #include <linux/memblock.h>

> >  #include <linux/of_fdt.h>

> >  #include <linux/random.h>

> >+#include <linux/slab.h>

> >  #include <linux/string.h>

> >  #include <linux/types.h>

> >  #include <linux/vmalloc.h>

> >  #include <asm/byteorder.h>

> >  /* relevant device tree properties */

> >+#define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"

> >+#define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"

> >  #define FDT_PROP_INITRD_START	"linux,initrd-start"

> >  #define FDT_PROP_INITRD_END	"linux,initrd-end"

> >  #define FDT_PROP_BOOTARGS	"bootargs"

> >@@ -40,6 +43,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)

> >  	vfree(image->arch.dtb);

> >  	image->arch.dtb = NULL;

> >+	vfree(image->arch.elf_headers);

> >+	image->arch.elf_headers = NULL;

> >+	image->arch.elf_headers_sz = 0;

> >+

> >  	return kexec_image_post_load_cleanup_default(image);

> >  }

> >@@ -55,6 +62,31 @@ static int setup_dtb(struct kimage *image,

> >  	off = ret;

> >+	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);

> >+	if (ret && ret != -FDT_ERR_NOTFOUND)

> >+		goto out;

> >+	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);

> >+	if (ret && ret != -FDT_ERR_NOTFOUND)

> >+		goto out;

> >+

> >+	if (image->type == KEXEC_TYPE_CRASH) {

> >+		/* add linux,elfcorehdr */

> >+		ret = fdt_appendprop_addrrange(dtb, 0, off,

> >+				FDT_PROP_KEXEC_ELFHDR,

> >+				image->arch.elf_headers_mem,

> >+				image->arch.elf_headers_sz);

> >+		if (ret)

> >+			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

> >+

> >+		/* add linux,usable-memory-range */

> >+		ret = fdt_appendprop_addrrange(dtb, 0, off,

> >+				FDT_PROP_MEM_RANGE,

> >+				crashk_res.start,

> >+				crashk_res.end - crashk_res.start + 1);

> >+		if (ret)

> >+			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

> >+	}

> >+

> >  	/* add bootargs */

> >  	if (cmdline) {

> >  		ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);

> >@@ -125,8 +157,8 @@ static int setup_dtb(struct kimage *image,

> >  }

> >  /*

> >- * More space needed so that we can add initrd, bootargs, kaslr-seed, and

> >- * rng-seed.

> >+ * More space needed so that we can add initrd, bootargs, kaslr-seed,

> >+ * rng-seed, userable-memory-range and elfcorehdr.

> 

> nitpick:

> s/userable-memory-range/usable-memory-range

> 

> >   */

> >  #define DTB_EXTRA_SPACE 0x1000

> >@@ -174,6 +206,43 @@ static int create_dtb(struct kimage *image,

> >  	}

> >  }

> >+static int prepare_elf_headers(void **addr, unsigned long *sz)

> >+{

> >+	struct crash_mem *cmem;

> >+	unsigned int nr_ranges;

> >+	int ret;

> >+	u64 i;

> >+	phys_addr_t start, end;

> >+

> >+	nr_ranges = 1; /* for exclusion of crashkernel region */

> >+	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,

> >+					MEMBLOCK_NONE, &start, &end, NULL)

> >+		nr_ranges++;

> >+

> >+	cmem = kmalloc(sizeof(struct crash_mem) +

> >+			sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL);

> >+	if (!cmem)

> >+		return -ENOMEM;

> >+

> >+	cmem->max_nr_ranges = nr_ranges;

> >+	cmem->nr_ranges = 0;

> >+	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,

> >+					MEMBLOCK_NONE, &start, &end, NULL) {

> >+		cmem->ranges[cmem->nr_ranges].start = start;

> >+		cmem->ranges[cmem->nr_ranges].end = end - 1;

> >+		cmem->nr_ranges++;

> >+	}

> >+

> >+	/* Exclude crashkernel region */

> >+	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

> >+

> >+	if (!ret)

> >+		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);

> >+

> >+	kfree(cmem);

> >+	return ret;

> >+}

> >+

> >  int load_other_segments(struct kimage *image,

> >  			unsigned long kernel_load_addr,

> >  			unsigned long kernel_size,

> >@@ -181,14 +250,43 @@ int load_other_segments(struct kimage *image,

> >  			char *cmdline)

> >  {

> >  	struct kexec_buf kbuf;

> >-	void *dtb = NULL;

> >-	unsigned long initrd_load_addr = 0, dtb_len;

> >+	void *headers, *dtb = NULL;

> >+	unsigned long headers_sz, initrd_load_addr = 0, dtb_len;

> >  	int ret = 0;

> >  	kbuf.image = image;

> >  	/* not allocate anything below the kernel */

> >  	kbuf.buf_min = kernel_load_addr + kernel_size;

> >+	/* load elf core header */

> >+	if (image->type == KEXEC_TYPE_CRASH) {

> >+		ret = prepare_elf_headers(&headers, &headers_sz);

> >+		if (ret) {

> >+			pr_err("Preparing elf core header failed\n");

> >+			goto out_err;

> >+		}

> >+

> >+		kbuf.buffer = headers;

> >+		kbuf.bufsz = headers_sz;

> >+		kbuf.mem = 0;

> 

> With commit c19d050f8088 ("arm64/kexec: Use consistent convention of

> initializing 'kxec_buf.mem' with KEXEC_BUF_MEM_UNKNOWN"), we are trying to

> standardize the way of setting up initial value of 'kbuf.mem'. So we can use

> the following notion (in v3?) instead:

> 		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

> 

> >+		kbuf.memsz = headers_sz;

> >+		kbuf.buf_align = SZ_64K; /* largest supported page size */

> >+		kbuf.buf_max = ULONG_MAX;

> >+		kbuf.top_down = true;

> >+

> >+		ret = kexec_add_buffer(&kbuf);

> >+		if (ret) {

> >+			vfree(headers);

> >+			goto out_err;

> >+		}

> >+		image->arch.elf_headers = headers;

> >+		image->arch.elf_headers_mem = kbuf.mem;

> >+		image->arch.elf_headers_sz = headers_sz;

> >+

> >+		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",

> >+			 image->arch.elf_headers_mem, headers_sz, headers_sz);

> >+	}

> >+

> >  	/* load initrd */

> >  	if (initrd) {

> >  		kbuf.buffer = initrd;

> >

> 

> Thanks,

> Bhupesh

>
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 12a561a54128..d24b527e8c00 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -96,6 +96,10 @@  static inline void crash_post_resume(void) {}
 struct kimage_arch {
 	void *dtb;
 	unsigned long dtb_mem;
+	/* Core ELF header buffer */
+	void *elf_headers;
+	unsigned long elf_headers_mem;
+	unsigned long elf_headers_sz;
 };
 
 extern const struct kexec_file_ops kexec_image_ops;
diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 29a9428486a5..af9987c154ca 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -47,10 +47,6 @@  static void *image_load(struct kimage *image,
 	struct kexec_segment *kernel_segment;
 	int ret;
 
-	/* We don't support crash kernels yet. */
-	if (image->type == KEXEC_TYPE_CRASH)
-		return ERR_PTR(-EOPNOTSUPP);
-
 	/*
 	 * We require a kernel with an unambiguous Image header. Per
 	 * Documentation/arm64/booting.rst, this is the case when image_size
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 7b08bf9499b6..f1d1bb895fd2 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -17,12 +17,15 @@ 
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
 #include <linux/random.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
 #include <asm/byteorder.h>
 
 /* relevant device tree properties */
+#define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"
+#define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"
 #define FDT_PROP_INITRD_START	"linux,initrd-start"
 #define FDT_PROP_INITRD_END	"linux,initrd-end"
 #define FDT_PROP_BOOTARGS	"bootargs"
@@ -40,6 +43,10 @@  int arch_kimage_file_post_load_cleanup(struct kimage *image)
 	vfree(image->arch.dtb);
 	image->arch.dtb = NULL;
 
+	vfree(image->arch.elf_headers);
+	image->arch.elf_headers = NULL;
+	image->arch.elf_headers_sz = 0;
+
 	return kexec_image_post_load_cleanup_default(image);
 }
 
@@ -55,6 +62,31 @@  static int setup_dtb(struct kimage *image,
 
 	off = ret;
 
+	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
+	if (ret && ret != -FDT_ERR_NOTFOUND)
+		goto out;
+
+	if (image->type == KEXEC_TYPE_CRASH) {
+		/* add linux,elfcorehdr */
+		ret = fdt_appendprop_addrrange(dtb, 0, off,
+				FDT_PROP_KEXEC_ELFHDR,
+				image->arch.elf_headers_mem,
+				image->arch.elf_headers_sz);
+		if (ret)
+			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+
+		/* add linux,usable-memory-range */
+		ret = fdt_appendprop_addrrange(dtb, 0, off,
+				FDT_PROP_MEM_RANGE,
+				crashk_res.start,
+				crashk_res.end - crashk_res.start + 1);
+		if (ret)
+			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+	}
+
 	/* add bootargs */
 	if (cmdline) {
 		ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
@@ -125,8 +157,8 @@  static int setup_dtb(struct kimage *image,
 }
 
 /*
- * More space needed so that we can add initrd, bootargs, kaslr-seed, and
- * rng-seed.
+ * More space needed so that we can add initrd, bootargs, kaslr-seed,
+ * rng-seed, userable-memory-range and elfcorehdr.
  */
 #define DTB_EXTRA_SPACE 0x1000
 
@@ -174,6 +206,43 @@  static int create_dtb(struct kimage *image,
 	}
 }
 
+static int prepare_elf_headers(void **addr, unsigned long *sz)
+{
+	struct crash_mem *cmem;
+	unsigned int nr_ranges;
+	int ret;
+	u64 i;
+	phys_addr_t start, end;
+
+	nr_ranges = 1; /* for exclusion of crashkernel region */
+	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
+					MEMBLOCK_NONE, &start, &end, NULL)
+		nr_ranges++;
+
+	cmem = kmalloc(sizeof(struct crash_mem) +
+			sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL);
+	if (!cmem)
+		return -ENOMEM;
+
+	cmem->max_nr_ranges = nr_ranges;
+	cmem->nr_ranges = 0;
+	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
+					MEMBLOCK_NONE, &start, &end, NULL) {
+		cmem->ranges[cmem->nr_ranges].start = start;
+		cmem->ranges[cmem->nr_ranges].end = end - 1;
+		cmem->nr_ranges++;
+	}
+
+	/* Exclude crashkernel region */
+	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+
+	if (!ret)
+		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);
+
+	kfree(cmem);
+	return ret;
+}
+
 int load_other_segments(struct kimage *image,
 			unsigned long kernel_load_addr,
 			unsigned long kernel_size,
@@ -181,14 +250,43 @@  int load_other_segments(struct kimage *image,
 			char *cmdline)
 {
 	struct kexec_buf kbuf;
-	void *dtb = NULL;
-	unsigned long initrd_load_addr = 0, dtb_len;
+	void *headers, *dtb = NULL;
+	unsigned long headers_sz, initrd_load_addr = 0, dtb_len;
 	int ret = 0;
 
 	kbuf.image = image;
 	/* not allocate anything below the kernel */
 	kbuf.buf_min = kernel_load_addr + kernel_size;
 
+	/* load elf core header */
+	if (image->type == KEXEC_TYPE_CRASH) {
+		ret = prepare_elf_headers(&headers, &headers_sz);
+		if (ret) {
+			pr_err("Preparing elf core header failed\n");
+			goto out_err;
+		}
+
+		kbuf.buffer = headers;
+		kbuf.bufsz = headers_sz;
+		kbuf.mem = 0;
+		kbuf.memsz = headers_sz;
+		kbuf.buf_align = SZ_64K; /* largest supported page size */
+		kbuf.buf_max = ULONG_MAX;
+		kbuf.top_down = true;
+
+		ret = kexec_add_buffer(&kbuf);
+		if (ret) {
+			vfree(headers);
+			goto out_err;
+		}
+		image->arch.elf_headers = headers;
+		image->arch.elf_headers_mem = kbuf.mem;
+		image->arch.elf_headers_sz = headers_sz;
+
+		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+			 image->arch.elf_headers_mem, headers_sz, headers_sz);
+	}
+
 	/* load initrd */
 	if (initrd) {
 		kbuf.buffer = initrd;