arm64: Add arm64 kexec support

Add kexec reboot support for ARM64 platforms.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Tested-By: Pratyush Anand <panand@redhat.com>
Tested-By: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

16 files changed, 1230 insertions, 2 deletions

diff --git a/configure.ac b/configure.ac
index 2bc5767..252b048 100644
--- a/configure.ac
+++ b/configure.ac
@@ -34,6 +34,9 @@ case $target_cpu in
 		ARCH="ppc64"
 		SUBARCH="LE"
 		;;
+	aarch64* )
+		ARCH="arm64"
+		;;
 	arm* )
 		ARCH="arm"
 		;;
diff --git a/kexec/Makefile b/kexec/Makefile
index cc3f08b..39f365f 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -79,6 +79,7 @@ KEXEC_SRCS			+= $($(ARCH)_DT_OPS)
 
 include $(srcdir)/kexec/arch/alpha/Makefile
 include $(srcdir)/kexec/arch/arm/Makefile
+include $(srcdir)/kexec/arch/arm64/Makefile
 include $(srcdir)/kexec/arch/i386/Makefile
 include $(srcdir)/kexec/arch/ia64/Makefile
 include $(srcdir)/kexec/arch/m68k/Makefile
diff --git a/kexec/arch/arm64/Makefile b/kexec/arch/arm64/Makefile
new file mode 100644
index 0000000..37414dc
--- /dev/null
+++ b/kexec/arch/arm64/Makefile
@@ -0,0 +1,40 @@
+
+arm64_FS2DT += kexec/fs2dt.c
+arm64_FS2DT_INCLUDE += -include $(srcdir)/kexec/arch/arm64/kexec-arm64.h \
+	-include $(srcdir)/kexec/arch/arm64/crashdump-arm64.h
+
+arm64_DT_OPS += kexec/dt-ops.c
+
+arm64_CPPFLAGS += -I $(srcdir)/kexec/
+
+arm64_KEXEC_SRCS += \
+	kexec/arch/arm64/kexec-arm64.c \
+	kexec/arch/arm64/kexec-image-arm64.c \
+	kexec/arch/arm64/kexec-elf-arm64.c \
+	kexec/arch/arm64/crashdump-arm64.c
+
+arm64_ARCH_REUSE_INITRD =
+arm64_ADD_SEGMENT =
+arm64_VIRT_TO_PHYS =
+arm64_PHYS_TO_VIRT =
+
+dist += $(arm64_KEXEC_SRCS) \
+	kexec/arch/arm64/Makefile \
+	kexec/arch/arm64/kexec-arm64.h \
+	kexec/arch/arm64/crashdump-arm64.h
+
+ifdef HAVE_LIBFDT
+
+LIBS += -lfdt
+
+else
+
+include $(srcdir)/kexec/libfdt/Makefile.libfdt
+
+libfdt_SRCS += $(LIBFDT_SRCS:%=kexec/libfdt/%)
+
+arm64_CPPFLAGS += -I$(srcdir)/kexec/libfdt
+
+arm64_KEXEC_SRCS += $(libfdt_SRCS)
+
+endif
diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
new file mode 100644
index 0000000..d2272c8
--- /dev/null
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -0,0 +1,21 @@
+/*
+ * ARM64 crashdump.
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <linux/elf.h>
+
+#include "kexec.h"
+#include "crashdump.h"
+#include "crashdump-arm64.h"
+#include "kexec-arm64.h"
+#include "kexec-elf.h"
+
+struct memory_ranges usablemem_rgns = {};
+
+int is_crashkernel_mem_reserved(void)
+{
+	return 0;
+}
diff --git a/kexec/arch/arm64/crashdump-arm64.h b/kexec/arch/arm64/crashdump-arm64.h
new file mode 100644
index 0000000..f33c7a2
--- /dev/null
+++ b/kexec/arch/arm64/crashdump-arm64.h
@@ -0,0 +1,12 @@
+/*
+ * ARM64 crashdump.
+ */
+
+#if !defined(CRASHDUMP_ARM64_H)
+#define CRASHDUMP_ARM64_H
+
+#include "kexec.h"
+
+extern struct memory_ranges usablemem_rgns;
+
+#endif
diff --git a/kexec/arch/arm64/image-header.h b/kexec/arch/arm64/image-header.h
new file mode 100644
index 0000000..158d411
--- /dev/null
+++ b/kexec/arch/arm64/image-header.h
@@ -0,0 +1,146 @@
+/*
+ * ARM64 binary image header.
+ */
+
+#if !defined(__ARM64_IMAGE_HEADER_H)
+#define __ARM64_IMAGE_HEADER_H
+
+#include <endian.h>
+#include <stdint.h>
+
+/**
+ * struct arm64_image_header - arm64 kernel image header.
+ *
+ * @pe_sig: Optional PE format 'MZ' signature.
+ * @branch_code: Reserved for instructions to branch to stext.
+ * @text_offset: The image load offset in LSB byte order.
+ * @image_size: An estimated size of the memory image size in LSB byte order.
+ * @flags: Bit flags in LSB byte order:
+ *   Bit 0:   Image byte order: 1=MSB.
+ *   Bit 1-2: Kernel page size: 1=4K, 2=16K, 3=64K.
+ *   Bit 3:   Image placement: 0=low.
+ * @reserved_1: Reserved.
+ * @magic: Magic number, "ARM\x64".
+ * @pe_header: Optional offset to a PE format header.
+ **/
+
+struct arm64_image_header {
+	uint8_t pe_sig[2];
+	uint16_t branch_code[3];
+	uint64_t text_offset;
+	uint64_t image_size;
+	uint64_t flags;
+	uint64_t reserved_1[3];
+	uint8_t magic[4];
+	uint32_t pe_header;
+};
+
+static const uint8_t arm64_image_magic[4] = {'A', 'R', 'M', 0x64U};
+static const uint8_t arm64_image_pe_sig[2] = {'M', 'Z'};
+static const uint64_t arm64_image_flag_be = (1UL << 0);
+static const uint64_t arm64_image_flag_page_size = (3UL << 1);
+static const uint64_t arm64_image_flag_placement = (1UL << 3);
+
+/**
+ * enum arm64_header_page_size
+ */
+
+enum arm64_header_page_size {
+	arm64_header_page_size_invalid = 0,
+	arm64_header_page_size_4k,
+	arm64_header_page_size_16k,
+	arm64_header_page_size_64k
+};
+
+/**
+ * arm64_header_check_magic - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if header is OK.
+ */
+
+static inline int arm64_header_check_magic(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (h->magic[0] == arm64_image_magic[0]
+		&& h->magic[1] == arm64_image_magic[1]
+		&& h->magic[2] == arm64_image_magic[2]
+		&& h->magic[3] == arm64_image_magic[3]);
+}
+
+/**
+ * arm64_header_check_pe_sig - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if 'MZ' signature is found.
+ */
+
+static inline int arm64_header_check_pe_sig(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (h->pe_sig[0] == arm64_image_pe_sig[0]
+		&& h->pe_sig[1] == arm64_image_pe_sig[1]);
+}
+
+/**
+ * arm64_header_check_msb - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if the image was built as big endian.
+ */
+
+static inline int arm64_header_check_msb(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (le64toh(h->flags) & arm64_image_flag_be) >> 0;
+}
+
+/**
+ * arm64_header_page_size
+ */
+
+static inline enum arm64_header_page_size arm64_header_page_size(
+	const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (le64toh(h->flags) & arm64_image_flag_page_size) >> 1;
+}
+
+/**
+ * arm64_header_placement
+ *
+ * Returns non-zero if the image has no physical placement restrictions.
+ */
+
+static inline int arm64_header_placement(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (le64toh(h->flags) & arm64_image_flag_placement) >> 3;
+}
+
+static inline uint64_t arm64_header_text_offset(
+	const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return le64toh(h->text_offset);
+}
+
+static inline uint64_t arm64_header_image_size(
+	const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return le64toh(h->image_size);
+}
+
+#endif
diff --git a/kexec/arch/arm64/include/arch/options.h b/kexec/arch/arm64/include/arch/options.h
new file mode 100644
index 0000000..a17d933
--- /dev/null
+++ b/kexec/arch/arm64/include/arch/options.h
@@ -0,0 +1,39 @@
+#if !defined(KEXEC_ARCH_ARM64_OPTIONS_H)
+#define KEXEC_ARCH_ARM64_OPTIONS_H
+
+#define OPT_APPEND		((OPT_MAX)+0)
+#define OPT_DTB			((OPT_MAX)+1)
+#define OPT_INITRD		((OPT_MAX)+2)
+#define OPT_REUSE_CMDLINE	((OPT_MAX)+3)
+#define OPT_ARCH_MAX		((OPT_MAX)+4)
+
+#define KEXEC_ARCH_OPTIONS \
+	KEXEC_OPTIONS \
+	{ "append",        1, NULL, OPT_APPEND }, \
+	{ "command-line",  1, NULL, OPT_APPEND }, \
+	{ "dtb",           1, NULL, OPT_DTB }, \
+	{ "initrd",        1, NULL, OPT_INITRD }, \
+	{ "ramdisk",       1, NULL, OPT_INITRD }, \
+	{ "reuse-cmdline", 0, NULL, OPT_REUSE_CMDLINE }, \
+
+#define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR /* Only accept long arch options. */
+#define KEXEC_ALL_OPTIONS KEXEC_ARCH_OPTIONS
+#define KEXEC_ALL_OPT_STR KEXEC_ARCH_OPT_STR
+
+static const char arm64_opts_usage[] __attribute__ ((unused)) =
+"     --append=STRING       Set the kernel command line to STRING.\n"
+"     --command-line=STRING Set the kernel command line to STRING.\n"
+"     --dtb=FILE            Use FILE as the device tree blob.\n"
+"     --initrd=FILE         Use FILE as the kernel initial ramdisk.\n"
+"     --ramdisk=FILE        Use FILE as the kernel initial ramdisk.\n"
+"     --reuse-cmdline       Use kernel command line from running system.\n";
+
+struct arm64_opts {
+	const char *command_line;
+	const char *dtb;
+	const char *initrd;
+};
+
+extern struct arm64_opts arm64_opts;
+
+#endif
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
new file mode 100644
index 0000000..2e8839a
--- /dev/null
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -0,0 +1,615 @@
+/*
+ * ARM64 kexec.
+ */
+
+#define _GNU_SOURCE
+
+#include <assert.h>
+#include <errno.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <libfdt.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <linux/elf-em.h>
+#include <elf.h>
+
+#include "kexec.h"
+#include "kexec-arm64.h"
+#include "crashdump.h"
+#include "crashdump-arm64.h"
+#include "dt-ops.h"
+#include "fs2dt.h"
+#include "kexec-syscall.h"
+#include "arch/options.h"
+
+/* Global varables the core kexec routines expect. */
+
+unsigned char reuse_initrd;
+
+off_t initrd_base;
+off_t initrd_size;
+
+const struct arch_map_entry arches[] = {
+	{ "aarch64", KEXEC_ARCH_ARM64 },
+	{ "aarch64_be", KEXEC_ARCH_ARM64 },
+	{ NULL, 0 },
+};
+
+struct file_type file_type[] = {
+	{"vmlinux", elf_arm64_probe, elf_arm64_load, elf_arm64_usage},
+	{"Image", image_arm64_probe, image_arm64_load, image_arm64_usage},
+};
+
+int file_types = sizeof(file_type) / sizeof(file_type[0]);
+
+/* arm64 global varables. */
+
+struct arm64_opts arm64_opts;
+struct arm64_mem arm64_mem = {
+	.phys_offset = arm64_mem_ngv,
+	.vp_offset = arm64_mem_ngv,
+};
+
+uint64_t get_phys_offset(void)
+{
+	assert(arm64_mem.phys_offset != arm64_mem_ngv);
+	return arm64_mem.phys_offset;
+}
+
+uint64_t get_vp_offset(void)
+{
+	assert(arm64_mem.vp_offset != arm64_mem_ngv);
+	return arm64_mem.vp_offset;
+}
+
+/**
+ * arm64_process_image_header - Process the arm64 image header.
+ *
+ * Make a guess that KERNEL_IMAGE_SIZE will be enough for older kernels.
+ */
+
+int arm64_process_image_header(const struct arm64_image_header *h)
+{
+#if !defined(KERNEL_IMAGE_SIZE)
+# define KERNEL_IMAGE_SIZE MiB(16)
+#endif
+
+	if (!arm64_header_check_magic(h))
+		return -EFAILED;
+
+	if (h->image_size) {
+		arm64_mem.text_offset = arm64_header_text_offset(h);
+		arm64_mem.image_size = arm64_header_image_size(h);
+	} else {
+		/* For 3.16 and older kernels. */
+		arm64_mem.text_offset = 0x80000;
+		arm64_mem.image_size = KERNEL_IMAGE_SIZE;
+		fprintf(stderr,
+			"kexec: %s: Warning: Kernel image size set to %lu MiB.\n"
+			"  Please verify compatability with lodaed kernel.\n",
+			__func__, KERNEL_IMAGE_SIZE / 1024UL / 1024UL);
+	}
+
+	return 0;
+}
+
+void arch_usage(void)
+{
+	printf(arm64_opts_usage);
+}
+
+int arch_process_options(int argc, char **argv)
+{
+	static const char short_options[] = KEXEC_OPT_STR "";
+	static const struct option options[] = {
+		KEXEC_ARCH_OPTIONS
+		{ 0 }
+	};
+	int opt;
+	char *cmdline = NULL;
+	const char *append = NULL;
+
+	for (opt = 0; opt != -1; ) {
+		opt = getopt_long(argc, argv, short_options, options, 0);
+
+		switch (opt) {
+		case OPT_APPEND:
+			append = optarg;
+			break;
+		case OPT_REUSE_CMDLINE:
+			cmdline = get_command_line();
+			break;
+		case OPT_DTB:
+			arm64_opts.dtb = optarg;
+			break;
+		case OPT_INITRD:
+			arm64_opts.initrd = optarg;
+			break;
+		case OPT_PANIC:
+			die("load-panic (-p) not supported");
+			break;
+		default:
+			break; /* Ignore core and unknown options. */
+		}
+	}
+
+	arm64_opts.command_line = concat_cmdline(cmdline, append);
+
+	dbgprintf("%s:%d: command_line: %s\n", __func__, __LINE__,
+		arm64_opts.command_line);
+	dbgprintf("%s:%d: initrd: %s\n", __func__, __LINE__,
+		arm64_opts.initrd);
+	dbgprintf("%s:%d: dtb: %s\n", __func__, __LINE__, arm64_opts.dtb);
+
+	return 0;
+}
+
+/**
+ * struct dtb - Info about a binary device tree.
+ *
+ * @buf: Device tree data.
+ * @size: Device tree data size.
+ * @name: Shorthand name of this dtb for messages.
+ * @path: Filesystem path.
+ */
+
+struct dtb {
+	char *buf;
+	off_t size;
+	const char *name;
+	const char *path;
+};
+
+/**
+ * dump_reservemap - Dump the dtb's reservemap.
+ */
+
+static void dump_reservemap(const struct dtb *dtb)
+{
+	int i;
+
+	for (i = 0; ; i++) {
+		uint64_t address;
+		uint64_t size;
+
+		fdt_get_mem_rsv(dtb->buf, i, &address, &size);
+
+		if (!size)
+			break;
+
+		dbgprintf("%s: %s {%" PRIx64 ", %" PRIx64 "}\n", __func__,
+			dtb->name, address, size);
+	}
+}
+
+/**
+ * set_bootargs - Set the dtb's bootargs.
+ */
+
+static int set_bootargs(struct dtb *dtb, const char *command_line)
+{
+	int result;
+
+	if (!command_line || !command_line[0])
+		return 0;
+
+	result = dtb_set_bootargs(&dtb->buf, &dtb->size, command_line);
+
+	if (result) {
+		fprintf(stderr,
+			"kexec: Set device tree bootargs failed.\n");
+		return -EFAILED;
+	}
+
+	return 0;
+}
+
+/**
+ * read_proc_dtb - Read /proc/device-tree.
+ */
+
+static int read_proc_dtb(struct dtb *dtb)
+{
+	int result;
+	struct stat s;
+	static const char path[] = "/proc/device-tree";
+
+	result = stat(path, &s);
+
+	if (result) {
+		dbgprintf("%s: %s\n", __func__, strerror(errno));
+		return -EFAILED;
+	}
+
+	dtb->path = path;
+	create_flatten_tree((char **)&dtb->buf, &dtb->size, NULL);
+
+	return 0;
+}
+
+/**
+ * read_sys_dtb - Read /sys/firmware/fdt.
+ */
+
+static int read_sys_dtb(struct dtb *dtb)
+{
+	int result;
+	struct stat s;
+	static const char path[] = "/sys/firmware/fdt";
+
+	result = stat(path, &s);
+
+	if (result) {
+		dbgprintf("%s: %s\n", __func__, strerror(errno));
+		return -EFAILED;
+	}
+
+	dtb->path = path;
+	dtb->buf = slurp_file(path, &dtb->size);
+
+	return 0;
+}
+
+/**
+ * read_1st_dtb - Read the 1st stage kernel's dtb.
+ */
+
+static int read_1st_dtb(struct dtb *dtb)
+{
+	int result;
+
+	dtb->name = "dtb_sys";
+	result = read_sys_dtb(dtb);
+
+	if (!result)
+		goto on_success;
+
+	dtb->name = "dtb_proc";
+	result = read_proc_dtb(dtb);
+
+	if (!result)
+		goto on_success;
+
+	dbgprintf("%s: not found\n", __func__);
+	return -EFAILED;
+
+on_success:
+	dbgprintf("%s: found %s\n", __func__, dtb->path);
+	return 0;
+}
+
+/**
+ * setup_2nd_dtb - Setup the 2nd stage kernel's dtb.
+ */
+
+static int setup_2nd_dtb(struct dtb *dtb, char *command_line)
+{
+	int result;
+
+	result = fdt_check_header(dtb->buf);
+
+	if (result) {
+		fprintf(stderr, "kexec: Invalid 2nd device tree.\n");
+		return -EFAILED;
+	}
+
+	result = set_bootargs(dtb, command_line);
+
+	dump_reservemap(dtb);
+
+	return result;
+}
+
+unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
+{
+	unsigned long hole;
+
+	hole = locate_hole(info,
+		arm64_mem.text_offset + arm64_mem.image_size,
+		MiB(2), 0, ULONG_MAX, 1);
+
+	if (hole == ULONG_MAX)
+		dbgprintf("%s: locate_hole failed\n", __func__);
+
+	return hole;
+}
+
+/**
+ * arm64_load_other_segments - Prepare the dtb, initrd and purgatory segments.
+ */
+
+int arm64_load_other_segments(struct kexec_info *info,
+	unsigned long image_base)
+{
+	int result;
+	unsigned long dtb_base;
+	unsigned long hole_min;
+	unsigned long hole_max;
+	char *initrd_buf = NULL;
+	struct dtb dtb;
+	char command_line[COMMAND_LINE_SIZE] = "";
+
+	if (arm64_opts.command_line) {
+		strncpy(command_line, arm64_opts.command_line,
+			sizeof(command_line));
+		command_line[sizeof(command_line) - 1] = 0;
+	}
+
+	if (arm64_opts.dtb) {
+		dtb.name = "dtb_user";
+		dtb.buf = slurp_file(arm64_opts.dtb, &dtb.size);
+	} else {
+		result = read_1st_dtb(&dtb);
+
+		if (result) {
+			fprintf(stderr,
+				"kexec: Error: No device tree available.\n");
+			return -EFAILED;
+		}
+	}
+
+	result = setup_2nd_dtb(&dtb, command_line);
+
+	if (result)
+		return -EFAILED;
+
+	/* Put the other segments after the image. */
+
+	hole_min = image_base + arm64_mem.image_size;
+	hole_max = ULONG_MAX;
+
+	if (arm64_opts.initrd) {
+		initrd_buf = slurp_file(arm64_opts.initrd, &initrd_size);
+
+		if (!initrd_buf)
+			fprintf(stderr, "kexec: Empty ramdisk file.\n");
+		else {
+			/*
+			 * Put the initrd after the kernel.  As specified in
+			 * booting.txt, align to 1 GiB.
+			 */
+
+			initrd_base = add_buffer_phys_virt(info, initrd_buf,
+				initrd_size, initrd_size, GiB(1),
+				hole_min, hole_max, 1, 0);
+
+			/* initrd_base is valid if we got here. */
+
+			dbgprintf("initrd: base %lx, size %lxh (%ld)\n",
+				initrd_base, initrd_size, initrd_size);
+
+			/* Check size limit as specified in booting.txt. */
+
+			if (initrd_base - image_base + initrd_size > GiB(32)) {
+				fprintf(stderr, "kexec: Error: image + initrd too big.\n");
+				return -EFAILED;
+			}
+
+			result = dtb_set_initrd((char **)&dtb.buf,
+				&dtb.size, initrd_base,
+				initrd_base + initrd_size);
+
+			if (result)
+				return -EFAILED;
+		}
+	}
+
+	/* Check size limit as specified in booting.txt. */
+
+	if (dtb.size > MiB(2)) {
+		fprintf(stderr, "kexec: Error: dtb too big.\n");
+		return -EFAILED;
+	}
+
+	dtb_base = add_buffer_phys_virt(info, dtb.buf, dtb.size, dtb.size,
+		0, hole_min, hole_max, 1, 0);
+
+	/* dtb_base is valid if we got here. */
+
+	dbgprintf("dtb:    base %lx, size %lxh (%ld)\n", dtb_base, dtb.size,
+		dtb.size);
+
+	elf_rel_build_load(info, &info->rhdr, purgatory, purgatory_size,
+		hole_min, hole_max, 1, 0);
+
+	info->entry = (void *)elf_rel_get_addr(&info->rhdr, "purgatory_start");
+
+	elf_rel_set_symbol(&info->rhdr, "arm64_kernel_entry", &image_base,
+		sizeof(image_base));
+
+	elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
+		sizeof(dtb_base));
+
+	return 0;
+}
+
+/**
+ * virt_to_phys - For processing elf file values.
+ */
+
+unsigned long virt_to_phys(unsigned long v)
+{
+	unsigned long p;
+
+	p = v - get_vp_offset() + get_phys_offset();
+
+	return p;
+}
+
+/**
+ * phys_to_virt - For crashdump setup.
+ */
+
+unsigned long phys_to_virt(struct crash_elf_info *elf_info,
+	unsigned long long p)
+{
+	unsigned long v;
+
+	v = p - get_phys_offset() + elf_info->page_offset;
+
+	return v;
+}
+
+/**
+ * add_segment - Use virt_to_phys when loading elf files.
+ */
+
+void add_segment(struct kexec_info *info, const void *buf, size_t bufsz,
+	unsigned long base, size_t memsz)
+{
+	add_segment_phys_virt(info, buf, bufsz, base, memsz, 1);
+}
+
+/**
+ * get_memory_ranges_iomem_cb - Helper for get_memory_ranges_iomem.
+ */
+
+static int get_memory_ranges_iomem_cb(void *data, int nr, char *str,
+	unsigned long long base, unsigned long long length)
+{
+	struct memory_range *r;
+
+	if (nr >= KEXEC_SEGMENT_MAX)
+		return -1;
+
+	r = (struct memory_range *)data + nr;
+	r->type = RANGE_RAM;
+	r->start = base;
+	r->end = base + length - 1;
+
+	set_phys_offset(r->start);
+
+	dbgprintf("%s: %016llx - %016llx : %s", __func__, r->start,
+		r->end, str);
+
+	return 0;
+}
+
+/**
+ * get_memory_ranges_iomem - Try to get the memory ranges from /proc/iomem.
+ */
+
+static int get_memory_ranges_iomem(struct memory_range *array,
+	unsigned int *count)
+{
+	*count = kexec_iomem_for_each_line("System RAM\n",
+		get_memory_ranges_iomem_cb, array);
+
+	if (!*count) {
+		dbgprintf("%s: failed: No RAM found.\n", __func__);
+		return -EFAILED;
+	}
+
+	return 0;
+}
+
+/**
+ * get_memory_ranges - Try to get the memory ranges some how.
+ */
+
+int get_memory_ranges(struct memory_range **range, int *ranges,
+	unsigned long kexec_flags)
+{
+	static struct memory_range array[KEXEC_SEGMENT_MAX];
+	unsigned int count;
+	int result;
+
+	result = get_memory_ranges_iomem(array, &count);
+
+	*range = result ? NULL : array;
+	*ranges = result ? 0 : count;
+
+	return result;
+}
+
+int arch_compat_trampoline(struct kexec_info *info)
+{
+	return 0;
+}
+
+int machine_verify_elf_rel(struct mem_ehdr *ehdr)
+{
+	return (ehdr->e_machine == EM_AARCH64);
+}
+
+void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
+	unsigned long r_type, void *ptr, unsigned long address,
+	unsigned long value)
+{
+#if !defined(R_AARCH64_ABS64)
+# define R_AARCH64_ABS64 257
+#endif
+
+#if !defined(R_AARCH64_LD_PREL_LO19)
+# define R_AARCH64_LD_PREL_LO19 273
+#endif
+
+#if !defined(R_AARCH64_ADR_PREL_LO21)
+# define R_AARCH64_ADR_PREL_LO21 274
+#endif
+
+#if !defined(R_AARCH64_JUMP26)
+# define R_AARCH64_JUMP26 282
+#endif
+
+#if !defined(R_AARCH64_CALL26)
+# define R_AARCH64_CALL26 283
+#endif
+
+	uint64_t *loc64;
+	uint32_t *loc32;
+	uint64_t *location = (uint64_t *)ptr;
+	uint64_t data = *location;
+	const char *type = NULL;
+
+	switch(r_type) {
+	case R_AARCH64_ABS64:
+		type = "ABS64";
+		loc64 = ptr;
+		*loc64 = cpu_to_elf64(ehdr, elf64_to_cpu(ehdr, *loc64) + value);
+		break;
+	case R_AARCH64_LD_PREL_LO19:
+		type = "LD_PREL_LO19";
+		loc32 = ptr;
+		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
+			+ (((value - address) << 3) & 0xffffe0));
+		break;
+	case R_AARCH64_ADR_PREL_LO21:
+		if (value & 3)
+			die("%s: ERROR Unaligned value: %lx\n", __func__,
+				value);
+		type = "ADR_PREL_LO21";
+		loc32 = ptr;
+		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
+			+ (((value - address) << 3) & 0xffffe0));
+		break;
+	case R_AARCH64_JUMP26:
+		type = "JUMP26";
+		loc32 = ptr;
+		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
+			+ (((value - address) >> 2) & 0x3ffffff));
+		break;
+	case R_AARCH64_CALL26:
+		type = "CALL26";
+		loc32 = ptr;
+		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
+			+ (((value - address) >> 2) & 0x3ffffff));
+		break;
+	default:
+		die("%s: ERROR Unknown type: %lu\n", __func__, r_type);
+		break;
+	}
+
+	dbgprintf("%s: %s %016lx->%016lx\n", __func__, type, data, *location);
+}
+
+void arch_reuse_initrd(void)
+{
+	reuse_initrd = 1;
+}
+
+void arch_update_purgatory(struct kexec_info *UNUSED(info))
+{
+}
diff --git a/kexec/arch/arm64/kexec-arm64.h b/kexec/arch/arm64/kexec-arm64.h
new file mode 100644
index 0000000..bac62f8
--- /dev/null
+++ b/kexec/arch/arm64/kexec-arm64.h
@@ -0,0 +1,71 @@
+/*
+ * ARM64 kexec.
+ */
+
+#if !defined(KEXEC_ARM64_H)
+#define KEXEC_ARM64_H
+
+#include <stdbool.h>
+#include <sys/types.h>
+
+#include "image-header.h"
+#include "kexec.h"
+
+#define KEXEC_SEGMENT_MAX 16
+
+#define BOOT_BLOCK_VERSION 17
+#define BOOT_BLOCK_LAST_COMP_VERSION 16
+#define COMMAND_LINE_SIZE 512
+
+#define KiB(x) ((x) * 1024UL)
+#define MiB(x) (KiB(x) * 1024UL)
+#define GiB(x) (MiB(x) * 1024UL)
+
+int elf_arm64_probe(const char *kernel_buf, off_t kernel_size);
+int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
+	off_t kernel_size, struct kexec_info *info);
+void elf_arm64_usage(void);
+
+int image_arm64_probe(const char *kernel_buf, off_t kernel_size);
+int image_arm64_load(int argc, char **argv, const char *kernel_buf,
+	off_t kernel_size, struct kexec_info *info);
+void image_arm64_usage(void);
+
+off_t initrd_base;
+off_t initrd_size;
+
+/**
+ * struct arm64_mem - Memory layout info.
+ */
+
+struct arm64_mem {
+	uint64_t phys_offset;
+	uint64_t text_offset;
+	uint64_t image_size;
+	uint64_t vp_offset;
+};
+
+#define arm64_mem_ngv UINT64_MAX
+struct arm64_mem arm64_mem;
+
+uint64_t get_phys_offset(void);
+uint64_t get_vp_offset(void);
+
+static inline void reset_vp_offset(void)
+{
+	arm64_mem.vp_offset = arm64_mem_ngv;
+}
+
+static inline void set_phys_offset(uint64_t v)
+{
+	if (arm64_mem.phys_offset == arm64_mem_ngv
+		|| v < arm64_mem.phys_offset)
+		arm64_mem.phys_offset = v;
+}
+
+int arm64_process_image_header(const struct arm64_image_header *h);
+unsigned long arm64_locate_kernel_segment(struct kexec_info *info);
+int arm64_load_other_segments(struct kexec_info *info,
+	unsigned long image_base);
+
+#endif
diff --git a/kexec/arch/arm64/kexec-elf-arm64.c b/kexec/arch/arm64/kexec-elf-arm64.c
new file mode 100644
index 0000000..daf8bf0
--- /dev/null
+++ b/kexec/arch/arm64/kexec-elf-arm64.c
@@ -0,0 +1,146 @@
+/*
+ * ARM64 kexec elf support.
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <linux/elf.h>
+
+#include "kexec-arm64.h"
+#include "kexec-elf.h"
+#include "kexec-syscall.h"
+
+int elf_arm64_probe(const char *kernel_buf, off_t kernel_size)
+{
+	struct mem_ehdr ehdr;
+	int result;
+
+	result = build_elf_exec_info(kernel_buf, kernel_size, &ehdr, 0);
+
+	if (result < 0) {
+		dbgprintf("%s: Not an ELF executable.\n", __func__);
+		goto on_exit;
+	}
+
+	if (ehdr.e_machine != EM_AARCH64) {
+		dbgprintf("%s: Not an AARCH64 ELF executable.\n", __func__);
+		result = -1;
+		goto on_exit;
+	}
+
+	result = 0;
+on_exit:
+	free_elf_info(&ehdr);
+	return result;
+}
+
+int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
+	off_t kernel_size, struct kexec_info *info)
+{
+	const struct arm64_image_header *header = NULL;
+	unsigned long kernel_segment;
+	struct mem_ehdr ehdr;
+	int result;
+	int i;
+
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		fprintf(stderr, "kexec: kdump not yet supported on arm64\n");
+		return -EFAILED;
+	}
+
+	result = build_elf_exec_info(kernel_buf, kernel_size, &ehdr, 0);
+
+	if (result < 0) {
+		dbgprintf("%s: build_elf_exec_info failed\n", __func__);
+		goto exit;
+	}
+
+	/* Find and process the arm64 image header. */
+
+	for (i = 0; i < ehdr.e_phnum; i++) {
+		struct mem_phdr *phdr = &ehdr.e_phdr[i];
+		unsigned long header_offset;
+
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		/*
+		 * When CONFIG_ARM64_RANDOMIZE_TEXT_OFFSET=y the image header
+		 * could be offset in the elf segment.  The linker script sets
+		 * ehdr.e_entry to the start of text.
+		 */
+
+		header_offset = ehdr.e_entry - phdr->p_vaddr;
+
+		header = (const struct arm64_image_header *)(
+			kernel_buf + phdr->p_offset + header_offset);
+
+		if (!arm64_process_image_header(header)) {
+			dbgprintf("%s: e_entry:        %016llx\n", __func__,
+				ehdr.e_entry);
+			dbgprintf("%s: p_vaddr:        %016llx\n", __func__,
+				phdr->p_vaddr);
+			dbgprintf("%s: header_offset:  %016lx\n", __func__,
+				header_offset);
+
+			break;
+		}
+	}
+
+	if (i == ehdr.e_phnum) {
+		dbgprintf("%s: Valid arm64 header not found\n", __func__);
+		result = -EFAILED;
+		goto exit;
+	}
+
+	kernel_segment = arm64_locate_kernel_segment(info);
+
+	if (kernel_segment == ULONG_MAX) {
+		dbgprintf("%s: Kernel segment is not allocated\n", __func__);
+		result = -EFAILED;
+		goto exit;
+	}
+
+	arm64_mem.vp_offset = _ALIGN_DOWN(ehdr.e_entry, MiB(2));
+	arm64_mem.vp_offset -= kernel_segment - get_phys_offset();
+
+	dbgprintf("%s: kernel_segment: %016lx\n", __func__, kernel_segment);
+	dbgprintf("%s: text_offset:    %016lx\n", __func__,
+		arm64_mem.text_offset);
+	dbgprintf("%s: image_size:     %016lx\n", __func__,
+		arm64_mem.image_size);
+	dbgprintf("%s: phys_offset:    %016lx\n", __func__,
+		arm64_mem.phys_offset);
+	dbgprintf("%s: vp_offset:      %016lx\n", __func__,
+		arm64_mem.vp_offset);
+	dbgprintf("%s: PE format:      %s\n", __func__,
+		(arm64_header_check_pe_sig(header) ? "yes" : "no"));
+
+	/* load the kernel */
+	result = elf_exec_load(&ehdr, info);
+
+	if (result) {
+		dbgprintf("%s: elf_exec_load failed\n", __func__);
+		goto exit;
+	}
+
+	result = arm64_load_other_segments(info, kernel_segment
+		+ arm64_mem.text_offset);
+
+exit:
+	reset_vp_offset();
+	free_elf_info(&ehdr);
+	if (result)
+		fprintf(stderr, "kexec: Bad elf image file, load failed.\n");
+	return result;
+}
+
+void elf_arm64_usage(void)
+{
+	printf(
+"     An ARM64 ELF image, big or little endian.\n"
+"     Typically vmlinux or a stripped version of vmlinux.\n\n");
+}
diff --git a/kexec/arch/arm64/kexec-image-arm64.c b/kexec/arch/arm64/kexec-image-arm64.c
new file mode 100644
index 0000000..42d2ea7
--- /dev/null
+++ b/kexec/arch/arm64/kexec-image-arm64.c
@@ -0,0 +1,41 @@
+/*
+ * ARM64 kexec binary image support.
+ */
+
+#define _GNU_SOURCE
+#include "kexec-arm64.h"
+
+int image_arm64_probe(const char *kernel_buf, off_t kernel_size)
+{
+	const struct arm64_image_header *h;
+
+	if (kernel_size < sizeof(struct arm64_image_header)) {
+		dbgprintf("%s: No arm64 image header.\n", __func__);
+		return -1;
+	}
+
+	h = (const struct arm64_image_header *)(kernel_buf);
+
+	if (!arm64_header_check_magic(h)) {
+		dbgprintf("%s: Bad arm64 image header.\n", __func__);
+		return -1;
+	}
+
+	fprintf(stderr, "kexec: ARM64 binary image files are currently NOT SUPPORTED.\n");
+	return -1;
+}
+
+int image_arm64_load(int argc, char **argv, const char *kernel_buf,
+	off_t kernel_size, struct kexec_info *info)
+{
+	return -1;
+}
+
+void image_arm64_usage(void)
+{
+	printf(
+"     An ARM64 binary image, compressed or not, big or little endian.\n"
+"     Typically an Image, Image.gz or Image.lzma file.\n\n");
+	printf(
+"     ARM64 binary image files are currently NOT SUPPORTED.\n\n");
+}
diff --git a/kexec/kexec-syscall.h b/kexec/kexec-syscall.h
index ce2e20b..c0d0bea 100644
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -39,8 +39,8 @@
 #ifdef __s390__
 #define __NR_kexec_load		277
 #endif
-#ifdef __arm__
-#define __NR_kexec_load		__NR_SYSCALL_BASE + 347  
+#if defined(__arm__) || defined(__arm64__)
+#define __NR_kexec_load		__NR_SYSCALL_BASE + 347
 #endif
 #if defined(__mips__)
 #define __NR_kexec_load                4311
@@ -108,6 +108,7 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #define KEXEC_ARCH_PPC64   (21 << 16)
 #define KEXEC_ARCH_IA_64   (50 << 16)
 #define KEXEC_ARCH_ARM     (40 << 16)
+#define KEXEC_ARCH_ARM64   (183 << 16)
 #define KEXEC_ARCH_S390    (22 << 16)
 #define KEXEC_ARCH_SH      (42 << 16)
 #define KEXEC_ARCH_MIPS_LE (10 << 16)
@@ -153,5 +154,8 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #ifdef __m68k__
 #define KEXEC_ARCH_NATIVE	KEXEC_ARCH_68K
 #endif
+#if defined(__arm64__)
+#define KEXEC_ARCH_NATIVE	KEXEC_ARCH_ARM64
+#endif
 
 #endif /* KEXEC_SYSCALL_H */
diff --git a/purgatory/Makefile b/purgatory/Makefile
index 2b5c061..ca0443c 100644
--- a/purgatory/Makefile
+++ b/purgatory/Makefile
@@ -19,6 +19,7 @@ dist += purgatory/Makefile $(PURGATORY_SRCS)				\
 
 include $(srcdir)/purgatory/arch/alpha/Makefile
 include $(srcdir)/purgatory/arch/arm/Makefile
+include $(srcdir)/purgatory/arch/arm64/Makefile
 include $(srcdir)/purgatory/arch/i386/Makefile
 include $(srcdir)/purgatory/arch/ia64/Makefile
 include $(srcdir)/purgatory/arch/mips/Makefile
diff --git a/purgatory/arch/arm64/Makefile b/purgatory/arch/arm64/Makefile
new file mode 100644
index 0000000..636abea
--- /dev/null
+++ b/purgatory/arch/arm64/Makefile
@@ -0,0 +1,18 @@
+
+arm64_PURGATORY_EXTRA_CFLAGS = \
+	-mcmodel=large \
+	-fno-stack-protector \
+	-fno-asynchronous-unwind-tables \
+	-Wundef \
+	-Werror-implicit-function-declaration \
+	-Wdeclaration-after-statement \
+	-Werror=implicit-int \
+	-Werror=strict-prototypes
+
+arm64_PURGATORY_SRCS += \
+	purgatory/arch/arm64/entry.S \
+	purgatory/arch/arm64/purgatory-arm64.c
+
+dist += \
+	$(arm64_PURGATORY_SRCS) \
+	purgatory/arch/arm64/Makefile
diff --git a/purgatory/arch/arm64/entry.S b/purgatory/arch/arm64/entry.S
new file mode 100644
index 0000000..adf16f4
--- /dev/null
+++ b/purgatory/arch/arm64/entry.S
@@ -0,0 +1,51 @@
+/*
+ * ARM64 purgatory.
+ */
+
+.macro	size, sym:req
+	.size \sym, . - \sym
+.endm
+
+.text
+
+.globl purgatory_start
+purgatory_start:
+
+	adr	x19, .Lstack
+	mov	sp, x19
+
+	bl	purgatory
+
+	/* Start new image. */
+	ldr	x17, arm64_kernel_entry
+	ldr	x0, arm64_dtb_addr
+	mov	x1, xzr
+	mov	x2, xzr
+	mov	x3, xzr
+	br	x17
+
+size purgatory_start
+
+.ltorg
+
+.align 4
+	.rept	256
+	.quad	0
+	.endr
+.Lstack:
+
+.data
+
+.align 3
+
+.globl arm64_kernel_entry
+arm64_kernel_entry:
+	.quad	0
+size arm64_kernel_entry
+
+.globl arm64_dtb_addr
+arm64_dtb_addr:
+	.quad	0
+size arm64_dtb_addr
+
+.end
\ No newline at end of file
diff --git a/purgatory/arch/arm64/purgatory-arm64.c b/purgatory/arch/arm64/purgatory-arm64.c
new file mode 100644
index 0000000..fe50fcf
--- /dev/null
+++ b/purgatory/arch/arm64/purgatory-arm64.c
@@ -0,0 +1,19 @@
+/*
+ * ARM64 purgatory.
+ */
+
+#include <stdint.h>
+#include <purgatory.h>
+
+void putchar(int ch)
+{
+	/* Nothing for now */
+}
+
+void post_verification_setup_arch(void)
+{
+}
+
+void setup_arch(void)
+{
+}