[PATCH V2] RISC-V: Add support for riscv kexec/kdump on kexec-tools

* [PATCH V2] RISC-V: Add support for riscv kexec/kdump on kexec-tools
@ 2022-10-20  3:15 Xianting Tian
  2022-10-21 15:27 ` Simon Horman
  2022-10-21 15:31 ` [PATCH kexec-tools] github: add RISC-V to workflow Simon Horman
  0 siblings, 2 replies; 11+ messages in thread
From: Xianting Tian @ 2022-10-20  3:15 UTC (permalink / raw)
  To: horms, kexec, mick, yixun.lan; +Cc: guoren

From: Nick Kossifidis <mick@ics.forth.gr>

This patch adds support for loading the ELF kernel image. It parses
the current/provided device tree to determine the system's memory
layout, and /proc/iomem for the various kernel segments.

This patch was firstly developed by Nick Kossifidis, and two fixes (
   1: fail to find free memory area for dtb load when using initrd image,
      lists.infradead.org/pipermail/linux-riscv/2022-August/018398.html;
   2: fix memory range size calculation,
       kexec/arch/riscv/crashdump-riscv.c:line 85
) are contributed by Yixun Lan, Xianting Tian.

Tested on Qemu's rv64 virt machine and SoC of T-Head RISC-V Xuantie 910 CPU.

Tested-by: Yixun Lan <yixun.lan@gmail.com>
Co-developed-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Co-developed-by: Yixun Lan <yixun.lan@gmail.com>
Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
---
Changes
  V1 -> V2:
  1, Rebase the patch to latest kexec code.
  2, Set patch author Nick Kossifidis.

 configure.ac                            |   3 +
 include/elf.h                           |   1 +
 kexec/Makefile                          |   1 +
 kexec/arch/riscv/Makefile               |  35 ++
 kexec/arch/riscv/crashdump-riscv.c      | 140 ++++++++
 kexec/arch/riscv/include/arch/options.h |  43 +++
 kexec/arch/riscv/kexec-elf-riscv.c      | 255 ++++++++++++++
 kexec/arch/riscv/kexec-riscv.c          | 365 +++++++++++++++++++
 kexec/arch/riscv/kexec-riscv.h          |  32 ++
 kexec/dt-ops.c                          | 442 +++++++++++++++++++++++-
 kexec/dt-ops.h                          |   7 +
 kexec/kexec-syscall.h                   |   4 +
 purgatory/Makefile                      |   1 +
 purgatory/arch/riscv/Makefile           |   7 +
 14 files changed, 1335 insertions(+), 1 deletion(-)
 create mode 100644 kexec/arch/riscv/Makefile
 create mode 100644 kexec/arch/riscv/crashdump-riscv.c
 create mode 100644 kexec/arch/riscv/include/arch/options.h
 create mode 100644 kexec/arch/riscv/kexec-elf-riscv.c
 create mode 100644 kexec/arch/riscv/kexec-riscv.c
 create mode 100644 kexec/arch/riscv/kexec-riscv.h
 create mode 100644 purgatory/arch/riscv/Makefile

diff --git a/configure.ac b/configure.ac
index d081c82..9204c37 100644
--- a/configure.ac
+++ b/configure.ac
@@ -61,6 +61,9 @@ case $target_cpu in
 	loongarch*)
 		ARCH="loongarch"
 		;;
+	riscv32|riscv64)
+		ARCH="riscv"
+		;;
 	* )
 		AC_MSG_ERROR([unsupported architecture $target_cpu])
 		;;
diff --git a/include/elf.h b/include/elf.h
index 1c8d2cc..93a5ee5 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -259,6 +259,7 @@ typedef struct
 #define EM_ARC_A5	93		/* ARC Cores Tangent-A5 */
 #define EM_XTENSA	94		/* Tensilica Xtensa Architecture */
 #define EM_AARCH64	183		/* ARM AARCH64 */
+#define EM_RISCV	243		/* RISC-V */
 #define EM_LOONGARCH	258		/* Loongson Loongarch*/
 #define EM_NUM		184
 
diff --git a/kexec/Makefile b/kexec/Makefile
index 8a52e8d..405864a 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -88,6 +88,7 @@ include $(srcdir)/kexec/arch/mips/Makefile
 include $(srcdir)/kexec/arch/cris/Makefile
 include $(srcdir)/kexec/arch/ppc/Makefile
 include $(srcdir)/kexec/arch/ppc64/Makefile
+include $(srcdir)/kexec/arch/riscv/Makefile
 include $(srcdir)/kexec/arch/s390/Makefile
 include $(srcdir)/kexec/arch/sh/Makefile
 include $(srcdir)/kexec/arch/x86_64/Makefile
diff --git a/kexec/arch/riscv/Makefile b/kexec/arch/riscv/Makefile
new file mode 100644
index 0000000..f26cc90
--- /dev/null
+++ b/kexec/arch/riscv/Makefile
@@ -0,0 +1,35 @@
+#
+# kexec riscv
+#
+riscv_KEXEC_SRCS =  kexec/arch/riscv/kexec-riscv.c
+riscv_KEXEC_SRCS += kexec/arch/riscv/kexec-elf-riscv.c
+riscv_KEXEC_SRCS += kexec/arch/riscv/crashdump-riscv.c
+
+riscv_MEM_REGIONS = kexec/mem_regions.c
+
+riscv_DT_OPS += kexec/dt-ops.c
+
+riscv_ARCH_REUSE_INITRD =
+
+riscv_CPPFLAGS += -I $(srcdir)/kexec/
+
+dist += kexec/arch/riscv/Makefile $(riscv_KEXEC_SRCS)			\
+	kexec/arch/riscv/kexec-riscv.h					\
+	kexec/arch/riscv/include/arch/options.h
+
+ifdef HAVE_LIBFDT
+
+LIBS += -lfdt
+
+else
+
+include $(srcdir)/kexec/libfdt/Makefile.libfdt
+
+libfdt_SRCS += $(LIBFDT_SRCS:%=kexec/libfdt/%)
+
+riscv_CPPFLAGS += -I$(srcdir)/kexec/libfdt
+
+riscv_KEXEC_SRCS += $(libfdt_SRCS)
+
+endif
+
diff --git a/kexec/arch/riscv/crashdump-riscv.c b/kexec/arch/riscv/crashdump-riscv.c
new file mode 100644
index 0000000..3ed4fe3
--- /dev/null
+++ b/kexec/arch/riscv/crashdump-riscv.c
@@ -0,0 +1,140 @@
+#include <errno.h>
+#include <linux/elf.h>
+#include <unistd.h>
+
+#include "kexec.h"
+#include "crashdump.h"
+#include "kexec-elf.h"
+#include "mem_regions.h"
+
+static struct crash_elf_info elf_info = {
+#if __riscv_xlen == 64
+	.class		= ELFCLASS64,
+#else
+	.class		= ELFCLASS32,
+#endif
+	.data		= ELFDATA2LSB,
+	.machine	= EM_RISCV,
+};
+
+static struct memory_ranges crash_mem_ranges = {0};
+struct memory_range elfcorehdr_mem = {0};
+
+static unsigned long long get_page_offset(struct kexec_info *info)
+{
+	unsigned long long vaddr_off = 0;
+	unsigned long long page_size = sysconf(_SC_PAGESIZE);
+	unsigned long long init_start = get_kernel_sym("_sinittext");
+
+	/*
+	 * Begining of init section is aligned to page size
+	 */
+	vaddr_off = init_start - page_size;
+
+	return vaddr_off;
+}
+
+int load_elfcorehdr(struct kexec_info *info)
+{
+	struct memory_range crashkern_range = {0};
+	struct memory_range *ranges = NULL;
+	unsigned long start = 0;
+	unsigned long end = 0;
+	unsigned long buf_size = 0;
+	unsigned long elfcorehdr_addr = 0;
+	void* buf = NULL;
+	int i = 0;
+	int ret = 0;
+
+	ret = parse_iomem_single("Kernel code\n", &start, NULL);
+	if (ret) {
+		fprintf(stderr, "Cannot determine kernel physical base addr\n");
+		return -EINVAL;
+	}
+	elf_info.kern_paddr_start = start;
+
+	ret = parse_iomem_single("Kernel bss\n", NULL, &end);
+	if (ret) {
+		fprintf(stderr, "Cannot determine kernel physical bss addr\n");
+		return -EINVAL;
+	}
+	elf_info.kern_paddr_start = start;
+	elf_info.kern_size = end - start;
+
+	elf_info.kern_vaddr_start = get_kernel_sym("_text");
+	if (!elf_info.kern_vaddr_start) {
+		elf_info.kern_vaddr_start = UINT64_MAX;
+	}
+
+	elf_info.page_offset = get_page_offset(info);
+	dbgprintf("page_offset:   %016llx\n", elf_info.page_offset);
+
+	ret = parse_iomem_single("Crash kernel\n", &start, &end);
+	if (ret) {
+		fprintf(stderr, "Cannot determine kernel physical bss addr\n");
+		return -EINVAL;
+	}
+	crashkern_range.start = start;
+	crashkern_range.end = end;
+	crashkern_range.type = RANGE_RESERVED;
+
+	ranges = info->memory_range;
+	for (i = 0; i < info->memory_ranges; i++) {
+		ret = mem_regions_alloc_and_add(&crash_mem_ranges,
+						ranges[i].start,
+						ranges[i].end - ranges[i].start + 1,
+						ranges[i].type);
+		if (ret ) {
+			fprintf(stderr, "Could not create crash_mem_ranges\n");
+			return ret;
+		}
+	}
+
+	ret = mem_regions_alloc_and_exclude(&crash_mem_ranges,
+					    &crashkern_range);
+	if (ret) {
+		fprintf(stderr, "Could not exclude crashkern_range\n");
+		return ret;
+	}
+
+#if __riscv_xlen == 64
+	crash_create_elf64_headers(info, &elf_info, crash_mem_ranges.ranges,
+				   crash_mem_ranges.size, &buf, &buf_size,
+				   ELF_CORE_HEADER_ALIGN);
+
+#else
+	crash_create_elf32_headers(info, &elf_info, crash_mem_ranges.ranges,
+				   crash_mem_ranges.size, &buf, &buf_size,
+				   ELF_CORE_HEADER_ALIGN);
+#endif
+
+
+	elfcorehdr_addr = add_buffer_phys_virt(info, buf, buf_size,
+					       buf_size, 0,
+					       crashkern_range.start,
+					       crashkern_range.end,
+					       -1, 0);
+
+	elfcorehdr_mem.start = elfcorehdr_addr;
+	elfcorehdr_mem.end = elfcorehdr_addr + buf_size - 1;
+
+	dbgprintf("%s: elfcorehdr 0x%llx-0x%llx\n", __func__,
+		  elfcorehdr_mem.start, elfcorehdr_mem.end);
+
+	return 0;
+}
+
+int is_crashkernel_mem_reserved(void)
+{
+	uint64_t start = 0;
+	uint64_t end = 0;
+
+	return parse_iomem_single("Crash kernel\n", &start, &end) == 0 ?
+	       (start != end) : 0;
+}
+
+int get_crash_kernel_load_range(uint64_t *start, uint64_t *end)
+{
+	return parse_iomem_single("Crash kernel\n", start, end);
+}
+
diff --git a/kexec/arch/riscv/include/arch/options.h b/kexec/arch/riscv/include/arch/options.h
new file mode 100644
index 0000000..7c24184
--- /dev/null
+++ b/kexec/arch/riscv/include/arch/options.h
@@ -0,0 +1,43 @@
+#ifndef KEXEC_ARCH_RISCV_OPTIONS_H
+#define KEXEC_ARCH_RISCV_OPTIONS_H
+
+#define OPT_APPEND		((OPT_MAX)+0)
+#define OPT_DTB			((OPT_MAX)+1)
+#define OPT_INITRD		((OPT_MAX)+2)
+#define OPT_CMDLINE		((OPT_MAX)+3)
+#define OPT_REUSE_CMDLINE	((OPT_MAX)+4)
+#define OPT_ARCH_MAX		((OPT_MAX)+5)
+
+/* Options relevant to the architecture (excluding loader-specific ones),
+ * in this case none:
+ */
+#define KEXEC_ARCH_OPTIONS \
+	KEXEC_OPTIONS \
+	{ "append",		1, 0, OPT_APPEND}, \
+	{ "dtb",		1, 0, OPT_DTB }, \
+	{ "initrd",		1, 0, OPT_INITRD }, \
+	{ "command-line",	1, 0, OPT_CMDLINE}, \
+	{ "reuse-cmdline",	0, NULL, OPT_REUSE_CMDLINE }, \
+
+
+#define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR ""
+
+/* The following two #defines list ALL of the options added by all of the
+ * architecture's loaders.
+ * o	main() uses this complete list to scan for its options, ignoring
+ *	arch-specific/loader-specific ones.
+ * o	Then, arch_process_options() uses this complete list to scan for its
+ *	options, ignoring general/loader-specific ones.
+ * o	Then, the file_type[n].load re-scans for options, using
+ *	KEXEC_ARCH_OPTIONS plus its loader-specific options subset.
+ *	Any unrecognised options cause an error here.
+ *
+ * This is done so that main()'s/arch_process_options()'s getopt_long() calls
+ * don't choose a kernel filename from random arguments to options they don't
+ * recognise -- as they now recognise (if not act upon) all possible options.
+ */
+#define KEXEC_ALL_OPTIONS KEXEC_ARCH_OPTIONS
+
+#define KEXEC_ALL_OPT_STR KEXEC_ARCH_OPT_STR
+
+#endif /* KEXEC_ARCH_RISCV_OPTIONS_H */
diff --git a/kexec/arch/riscv/kexec-elf-riscv.c b/kexec/arch/riscv/kexec-elf-riscv.c
new file mode 100644
index 0000000..f3c011c
--- /dev/null
+++ b/kexec/arch/riscv/kexec-elf-riscv.c
@@ -0,0 +1,255 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 FORTH-ICS/CARV
+ *              Nick Kossifidis <mick@ics.forth.gr>
+ */
+
+#include "kexec.h"
+#include "dt-ops.h"		/* For dtb_set/clear_initrd() */
+#include <elf.h>		/* For ELF header handling */
+#include <errno.h>		/* For EFBIG/EINVAL */
+#include <unistd.h>		/* For getpagesize() */
+#include "kexec-syscall.h"	/* For KEXEC_ON_CRASH */
+#include "kexec-riscv.h"
+
+
+/*********\
+* HELPERS *
+\*********/
+
+/*
+ * Go through the available physical memory regions and
+ * find one that can hold an image of the specified size.
+ * Note: This is called after get_memory_ranges so
+ * info->memory_range[] should be populated. Also note that
+ * memory ranges are sorted, so we'll return the first region
+ * that's big enough for holding the image.
+ */
+static int elf_riscv_find_pbase(struct kexec_info *info, off_t *addr,
+				off_t size)
+{
+	int i = 0;
+	off_t start = 0;
+	off_t end = 0;
+	int ret = 0;
+
+	/*
+	 * If this image is for a crash kernel, use the region
+	 * the primary kernel has already reserved for us.
+	 */
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		ret = get_crash_kernel_load_range((uint64_t *) &start,
+						  (uint64_t *) &end);
+		if (!ret) {
+			/*
+			 * Kernel should be aligned to the nearest
+			 * hugepage (2MB for RV64, 4MB for RV32).
+			 */
+#if __riscv_xlen == 64
+			start = _ALIGN_UP(start, 0x200000);
+#else
+			start = _ALIGN_UP(start, 0x400000);
+#endif
+			if (end > start && ((end - start) >= size)) {
+				*addr = start;
+				return 0;
+			}
+
+			return -EFBIG;
+		} else
+			return ENOCRASHKERNEL;
+	}
+
+	for (i = 0; i < info->memory_ranges; i++) {
+		if (info->memory_range[i].type != RANGE_RAM)
+			continue;
+
+		start = info->memory_range[i].start;
+		end = info->memory_range[i].end;
+
+#if __riscv_xlen == 64
+		start = _ALIGN_UP(start, 0x200000);
+#else
+		start = _ALIGN_UP(start, 0x400000);
+#endif
+
+		if (end > start && ((end - start) >= size)) {
+			*addr = start;
+			return 0;
+		}
+	}
+
+	return -EFBIG;
+}
+
+/**************\
+* ENTRY POINTS *
+\**************/
+
+int elf_riscv_probe(const char *buf, off_t len)
+{
+	struct mem_ehdr ehdr = {0};
+	int ret = 0;
+
+	ret = build_elf_exec_info(buf, len, &ehdr, 0);
+	if (ret < 0)
+		goto cleanup;
+
+	if (ehdr.e_machine != EM_RISCV) {
+		fprintf(stderr, "Not for this architecture.\n");
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	ret = 0;
+
+ cleanup:
+	free_elf_info(&ehdr);
+	return ret;
+}
+
+void elf_riscv_usage(void)
+{
+}
+
+int elf_riscv_load(int argc, char **argv, const char *buf, off_t len,
+		   struct kexec_info *info)
+{
+	struct mem_ehdr ehdr = {0};
+	struct mem_phdr *phdr = NULL;
+	off_t new_base_addr = 0;
+	off_t kernel_size = 0;
+	off_t page_size = getpagesize();
+	off_t max_addr = 0;
+	off_t old_base_addr = 0;
+	off_t old_start_addr = 0;
+	int i = 0;
+	int ret = 0;
+
+	if (info->file_mode) {
+		fprintf(stderr, "kexec_file not supported on this "
+				"architecture\n");
+		return -EINVAL;
+	}
+
+	/* Parse the ELF file */
+	ret = build_elf_exec_info(buf, len, &ehdr, 0);
+	if (ret < 0) {
+		fprintf(stderr, "ELF exec parse failed\n");
+		return -EINVAL;
+	}
+
+	max_addr = elf_max_addr(&ehdr);
+	old_base_addr = max_addr;
+	old_start_addr = max_addr;
+
+	/*
+	 * Get the memory footprint, base physical
+	 * and start address of the ELF image
+	 */
+	for (i = 0; i < ehdr.e_phnum; i++) {
+		phdr = &ehdr.e_phdr[i];
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		/*
+		 * Note: According to ELF spec the loadable regions
+		 * are sorted on p_vaddr, not p_paddr.
+		 */
+		if (old_base_addr > phdr->p_paddr)
+			old_base_addr = phdr->p_paddr;
+
+		if (phdr->p_vaddr == ehdr.e_entry ||
+		    phdr->p_paddr == ehdr.e_entry)
+			old_start_addr = phdr->p_paddr;
+
+		kernel_size += _ALIGN_UP(phdr->p_memsz, page_size);
+	}
+
+	if (old_base_addr == max_addr || kernel_size == 0) {
+		fprintf(stderr, "No loadable segments present on the "
+				"provided ELF image\n");
+		return -EINVAL;
+	}
+
+	if (old_start_addr == max_addr) {
+		fprintf(stderr, "Could not find the entry point address of "
+				"provided ELF image\n");
+		return -EINVAL;
+	}
+
+	dbgprintf("Got ELF with total memsz %luKB\n"
+		  "Base paddr: 0x%lX, start_addr: 0x%lX\n",
+		  kernel_size / 1024, old_base_addr, old_start_addr);
+
+	/* Get a continuous physical region that can hold the kernel */
+	ret = elf_riscv_find_pbase(info, &new_base_addr, kernel_size);
+	if (ret < 0) {
+		fprintf(stderr, "Could not find a memory region for the "
+				"provided ELF image\n");
+		return ret;
+	}
+
+	dbgprintf("New base paddr for the ELF: 0x%lX\n", new_base_addr);
+
+	/* Re-set the base physical address of the ELF */
+	for (i = 0; i < ehdr.e_phnum; i++) {
+		phdr = &ehdr.e_phdr[i];
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		phdr->p_paddr -= old_base_addr;
+		phdr->p_paddr += new_base_addr;
+	}
+
+	/* Re-set the entry point address */
+	ehdr.e_entry = (old_start_addr - old_base_addr) + new_base_addr;
+	info->entry = (void *) ehdr.e_entry;
+	dbgprintf("New entry point for the ELF: 0x%llX\n", ehdr.e_entry);
+
+
+	/* Load the ELF executable */
+	ret = elf_exec_load(&ehdr, info);
+	if (ret < 0) {
+		fprintf(stderr, "ELF exec load failed\n");
+		return ret;
+	}
+
+	ret = load_extra_segments(info, new_base_addr,
+				  kernel_size, max_addr);
+	return ret;
+}
+
+
+/*******\
+* STUBS *
+\*******/
+
+int machine_verify_elf_rel(struct mem_ehdr *ehdr)
+{
+	if (ehdr->ei_data != ELFDATA2LSB)
+		return 0;
+#if __riscv_xlen == 64
+	if (ehdr->ei_class != ELFCLASS64)
+#else
+	if (ehdr->ei_class != ELFCLASS32)
+#endif
+		return 0;
+	if (ehdr->e_machine != EM_RISCV)
+		return 0;
+	return 1;
+}
+
+void machine_apply_elf_rel(struct mem_ehdr *UNUSED(ehdr),
+			   struct mem_sym *UNUSED(sym),
+			   unsigned long r_type,
+			   void *UNUSED(location),
+			   unsigned long UNUSED(address),
+			   unsigned long UNUSED(value))
+{
+	switch (r_type) {
+	default:
+		die("Unknown rela relocation: %lu\n", r_type);
+		break;
+	}
+}
diff --git a/kexec/arch/riscv/kexec-riscv.c b/kexec/arch/riscv/kexec-riscv.c
new file mode 100644
index 0000000..fe5dd2d
--- /dev/null
+++ b/kexec/arch/riscv/kexec-riscv.c
@@ -0,0 +1,365 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 FORTH-ICS/CARV
+ *              Nick Kossifidis <mick@ics.forth.gr>
+ */
+
+#include "kexec-syscall.h"	/* For KEXEC_ARCH_RISCV */
+#include "kexec.h"		/* For OPT_MAX and concat_cmdline() */
+#include "mem_regions.h"	/* For mem_regions_sort() */
+#include "dt-ops.h"		/* For dtb_set_bootargs() */
+#include <arch/options.h>	/* For KEXEC_ARCH_OPTIONS */
+#include <getopt.h>		/* For struct option */
+#include <sys/stat.h>		/* For stat() and struct stat */
+#include <stdlib.h>		/* For free() */
+#include <errno.h>		/* For EINVAL */
+#include <libfdt.h>		/* For DeviceTree handling */
+#include "kexec-riscv.h"
+
+const struct arch_map_entry arches[] = {
+	{ "riscv32", KEXEC_ARCH_RISCV },
+	{ "riscv64", KEXEC_ARCH_RISCV },
+	{ NULL, 0 },
+};
+
+
+struct file_type file_type[] = {
+	{"elf-riscv", elf_riscv_probe, elf_riscv_load, elf_riscv_usage},
+};
+int file_types = sizeof(file_type) / sizeof(file_type[0]);
+
+static const char riscv_opts_usage[] =
+"	--append=STRING		Append STRING to the kernel command line.\n"
+"	--dtb=FILE		Use FILE as the device tree blob.\n"
+"	--initrd=FILE		Use FILE as the kernel initial ramdisk.\n"
+"	--cmdline=STRING	Use STRING as the kernel's command line.\n"
+"	--reuse-cmdline		Use kernel command line from running system.\n";
+
+static struct riscv_opts arch_options = {0};
+static struct fdt_image provided_fdt = {0};
+static struct memory_ranges sysmem_ranges = {0};
+
+/****************\
+* COMMON HELPERS *
+\****************/
+
+int load_extra_segments(struct kexec_info *info, uint64_t kernel_base,
+			uint64_t kernel_size, uint64_t max_addr)
+{
+	struct fdt_image *fdt = arch_options.fdt;
+	char *initrd_buf = NULL;
+	off_t initrd_size = 0;
+	uint64_t initrd_base = 0;
+	uint64_t start = 0;
+	uint64_t end = 0;
+	uint64_t min_usable = kernel_base + kernel_size;
+	uint64_t max_usable = max_addr;
+	int ret = 0;
+
+	/* Prepare the device tree */
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		ret = load_elfcorehdr(info);
+		if (ret) {
+			fprintf(stderr, "Couldn't create elfcorehdr\n");
+			return ret;
+		}
+
+		ret = dtb_add_range_property(&fdt->buf, &fdt->size,
+					     elfcorehdr_mem.start, elfcorehdr_mem.end,
+					     "chosen", "linux,elfcorehdr");
+		if (ret) {
+			fprintf(stderr, "Couldn't add elfcorehdr to fdt\n");
+			return ret;
+		}
+
+		ret = get_crash_kernel_load_range(&start, &end);
+		if (ret) {
+			fprintf(stderr, "Couldn't get crashkenel region\n");
+			return ret;
+		}
+
+		ret = dtb_add_range_property(&fdt->buf, &fdt->size, start, end,
+					     "memory", "linux,usable-memory");
+		if (ret) {
+			fprintf(stderr, "Couldn't add usable-memory to fdt\n");
+			return ret;
+		}
+
+		max_usable = end;
+	} else {
+		/*
+		 * Make sure we remove elfcorehdr and usable-memory
+		 * when switching from crash kernel to a normal one.
+		 */
+		dtb_delete_property(fdt->buf, "chosen", "linux,elfcorehdr");
+		dtb_delete_property(fdt->buf, "memory", "linux,usable-memory");
+	}
+
+	/* Do we need to include an initrd image ? */
+	if (!arch_options.initrd_path && !arch_options.initrd_end)
+		dtb_clear_initrd(&fdt->buf, &fdt->size);
+	else if (arch_options.initrd_path) {
+		if (arch_options.initrd_end)
+			fprintf(stderr, "Warning: An initrd image was provided"
+					", will ignore reuseinitrd\n");
+
+		initrd_buf = slurp_file(arch_options.initrd_path,
+					&initrd_size);
+		if (!initrd_buf) {
+			fprintf(stderr, "Couldn't read provided initrd\n");
+			return -EINVAL;
+		}
+
+		initrd_base = add_buffer_phys_virt(info, initrd_buf,
+						   initrd_size,
+						   initrd_size, 0,
+						   min_usable,
+						   max_usable, -1, 0);
+
+		dtb_set_initrd(&fdt->buf, &fdt->size, initrd_base,
+			       initrd_base + initrd_size);
+
+		dbgprintf("Base addr for initrd image: 0x%lX\n", initrd_base);
+		min_usable = initrd_base;
+		max_usable = initrd_base;
+	}
+
+	/* Add device tree */
+	add_buffer_phys_virt(info, fdt->buf, fdt->size, fdt->size, 0,
+			     min_usable, max_usable, -1, 0);
+
+	return 0;
+}
+
+
+/**************\
+* ENTRY POINTS *
+\**************/
+
+void arch_usage(void)
+{
+	printf(riscv_opts_usage);
+}
+
+int arch_process_options(int argc, char **argv)
+{
+	static const struct option options[] = {
+		KEXEC_ARCH_OPTIONS
+		{ 0 },
+	};
+	static const char short_options[] = KEXEC_ARCH_OPT_STR;
+	struct stat st = {0};
+	char *append = NULL;
+	char *cmdline = NULL;
+	void *tmp = NULL;
+	off_t tmp_size = 0;
+	int opt = 0;
+	int ret = 0;
+
+	while ((opt = getopt_long(argc, argv, short_options,
+				  options, 0)) != -1) {
+		switch (opt) {
+		case OPT_APPEND:
+			append = optarg;
+			break;
+		case OPT_CMDLINE:
+			if (cmdline)
+				fprintf(stderr,
+					"Warning: Kernel's cmdline "
+					"set twice !\n");
+			cmdline = optarg;
+			break;
+		case OPT_REUSE_CMDLINE:
+			if (cmdline)
+				fprintf(stderr,
+					"Warning: Kernel's cmdline "
+					"set twice !\n");
+			cmdline = get_command_line();
+			break;
+		case OPT_DTB:
+			ret = stat(optarg, &st);
+			if (ret) {
+				fprintf(stderr,
+					"Could not find the provided dtb !\n");
+				return -EINVAL;
+			}
+			arch_options.fdt_path = optarg;
+			break;
+		case OPT_INITRD:
+			ret = stat(optarg, &st);
+			if (ret) {
+				fprintf(stderr,
+					"Could not find the provided "
+					"initrd image !\n");
+				return -EINVAL;
+			}
+			arch_options.initrd_path = optarg;
+			break;
+		default:
+			break;
+		}
+	}
+
+	/* Handle Kernel's command line */
+	if (append && !cmdline)
+		fprintf(stderr, "Warning: No cmdline provided, "
+				"using append string as cmdline\n");
+	if (!append && !cmdline)
+		fprintf(stderr, "Warning: No cmdline or append string "
+				"provided\n");
+
+	if (append || cmdline)
+		/*
+		 * Note that this also handles the case where "cmdline"
+		 * or "append" is NULL.
+		 */
+		arch_options.cmdline = concat_cmdline(cmdline, append);
+
+	/* Handle FDT image */
+	if (!arch_options.fdt_path) {
+		ret = stat("/sys/firmware/fdt", &st);
+		if (ret) {
+			fprintf(stderr, "No dtb provided and "
+					"/sys/firmware/fdt is not present\n");
+			return -EINVAL;
+		}
+		fprintf(stderr, "Warning: No dtb provided, "
+				"using /sys/firmware/fdt\n");
+		arch_options.fdt_path = "/sys/firmware/fdt";
+	}
+
+	tmp = slurp_file(arch_options.fdt_path, &tmp_size);
+	if (!tmp) {
+		fprintf(stderr, "Couldn't read provided fdt\n");
+		return -EINVAL;
+	}
+
+	ret = fdt_check_header(tmp);
+	if (ret) {
+		fprintf(stderr, "Got an ivalid fdt image !\n");
+		free(tmp);
+		return -EINVAL;
+	}
+	provided_fdt.buf = tmp;
+	provided_fdt.size = tmp_size;
+
+	if (arch_options.cmdline) {
+		ret = dtb_set_bootargs(&provided_fdt.buf, &provided_fdt.size,
+				       arch_options.cmdline);
+		if (ret < 0) {
+			fprintf(stderr, "Could not set bootargs on "
+					"the fdt image\n");
+			return ret;
+		}
+	}
+
+	arch_options.fdt = &provided_fdt;
+
+	return 0;
+}
+
+/*
+ * This one is called after arch_process_options so we already
+ * have an fdt image in place.
+ */
+void arch_reuse_initrd(void)
+{
+	const uint32_t *prop32 = NULL;
+	uint32_t addr_cells = 0;
+	const void *prop = 0;
+	int prop_size = 0;
+	uint64_t initrd_start = 0;
+	uint64_t initrd_end = 0;
+	int chosen_offset = 0;
+	struct fdt_image *fdt = &provided_fdt;
+
+	chosen_offset = fdt_subnode_offset(fdt->buf, 0, "chosen");
+	if (chosen_offset < 0) {
+		fprintf(stderr, "No /chosen node found on fdt image "
+				"unable to reuse initrd\n");
+		return;
+	}
+
+	prop32 = fdt_getprop(fdt->buf, 0, "#address-cells", NULL);
+	if (!prop32) {
+		fprintf(stderr, "No #address-cells property on root node\n");
+		return;
+	}
+	addr_cells = be32_to_cpu(*prop32);
+
+	prop = fdt_getprop(fdt->buf, chosen_offset,
+			   "linux,initrd-start", &prop_size);
+	if (!prop) {
+		fprintf(stderr, "Could not get linux,initrd-start\n");
+		return;
+	}
+	dtb_extract_int_property(&initrd_start, prop, addr_cells);
+
+	prop = fdt_getprop(fdt->buf, chosen_offset,
+			   "linux,initrd-end", &prop_size);
+	if (!prop) {
+		fprintf(stderr, "Could not get linux,initrd-end\n");
+		return;
+	}
+	dtb_extract_int_property(&initrd_end, prop, addr_cells);
+
+	arch_options.initrd_start = initrd_start;
+	arch_options.initrd_end = initrd_end;
+	dbgprintf("initrd_start: 0x%lX, initrd_end: 0x%lX\n",
+		  initrd_start, initrd_end);
+
+}
+
+int get_memory_ranges(struct memory_range **range, int *num_ranges,
+		      unsigned long kexec_flags)
+{
+	const struct fdt_image *fdt = &provided_fdt;
+	struct memory_ranges *extra_ranges = NULL;
+	int i = 0;
+	int ret = 0;
+
+	if (arch_options.initrd_start && arch_options.initrd_end) {
+		int initrd_size = arch_options.initrd_end - arch_options.initrd_start;
+		dbgprintf("Marking current intird image as reserved\n");
+		ret = mem_regions_alloc_and_add(extra_ranges,
+						arch_options.initrd_start,
+						initrd_size,
+						RANGE_RESERVED);
+		if (ret)
+			return ret;
+	}
+
+	ret = dtb_get_memory_ranges(fdt->buf, &sysmem_ranges, extra_ranges);
+	if (ret) {
+		fprintf(stderr, "Could not get memory ranges from device tree (%i) !\n", ret);
+		return ret;
+	}
+
+	*range = sysmem_ranges.ranges;
+	*num_ranges = sysmem_ranges.size;
+
+	dbgprintf("Memory regions:\n");
+	for (i = 0; i < sysmem_ranges.size; i++) {
+		dbgprintf("\t0x%llx - 0x%llx : %s (%i)\n",
+			  sysmem_ranges.ranges[i].start,
+			  sysmem_ranges.ranges[i].end,
+			  sysmem_ranges.ranges[i].type == RANGE_RESERVED ?
+			  "RANGE_RESERVED" : "RANGE_RAM",
+			  sysmem_ranges.ranges[i].type);
+	}
+
+	return 0;
+}
+
+/*******\
+* STUBS *
+\*******/
+
+int arch_compat_trampoline(struct kexec_info *UNUSED(info))
+{
+	return 0;
+}
+
+void arch_update_purgatory(struct kexec_info *UNUSED(info))
+{
+}
diff --git a/kexec/arch/riscv/kexec-riscv.h b/kexec/arch/riscv/kexec-riscv.h
new file mode 100644
index 0000000..c4323a6
--- /dev/null
+++ b/kexec/arch/riscv/kexec-riscv.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 FORTH-ICS/CARV
+ *              Nick Kossifidis <mick@ics.forth.gr>
+ */
+
+struct fdt_image {
+	char	*buf;
+	off_t	size;
+};
+
+struct riscv_opts {
+	char *cmdline;
+	char *fdt_path;
+	char *initrd_path;
+	uint64_t initrd_start;
+	uint64_t initrd_end;
+	struct fdt_image *fdt;
+};
+
+/* crashdump-riscv.c */
+extern struct memory_range elfcorehdr_mem;
+int load_elfcorehdr(struct kexec_info *info);
+
+/* kexec-riscv.c */
+int load_extra_segments(struct kexec_info *info, uint64_t kernel_base,
+			uint64_t kernel_size, uint64_t max_addr);
+
+int elf_riscv_probe(const char *buf, off_t len);
+void elf_riscv_usage(void);
+int elf_riscv_load(int argc, char **argv, const char *buf, off_t len,
+		   struct kexec_info *info);
diff --git a/kexec/dt-ops.c b/kexec/dt-ops.c
index 0a96b75..3e285ab 100644
--- a/kexec/dt-ops.c
+++ b/kexec/dt-ops.c
@@ -4,9 +4,11 @@
 #include <libfdt.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 
 #include "kexec.h"
 #include "dt-ops.h"
+#include "mem_regions.h"
 
 static const char n_chosen[] = "chosen";
 
@@ -95,7 +97,7 @@ int dtb_set_property(char **dtb, off_t *dtb_size, const char *node,
 
 	strcpy(new_node, "/");
 	strcat(new_node, node);
-	
+
 	nodeoffset = fdt_path_offset(new_dtb, new_node);
 
 	if (nodeoffset == -FDT_ERR_NOTFOUND) {
@@ -174,3 +176,441 @@ int dtb_delete_property(char *dtb, const char *node, const char *prop)
 	free(new_node);
 	return result;
 }
+
+static int dtb_get_num_cells(char *dtb, int nodeoffset, uint32_t *addr_cells,
+			     uint32_t *size_cells, bool recursive)
+{
+	const uint32_t *prop32 = NULL;
+	int curr_offset = nodeoffset;
+	int prop_len = 0;
+	*addr_cells = 0;
+	*size_cells = 0;
+
+	do {
+		prop32 = fdt_getprop(dtb, curr_offset, "#address-cells", &prop_len);
+		curr_offset = fdt_parent_offset(dtb, curr_offset);
+	} while (!prop32 && prop_len == -FDT_ERR_NOTFOUND && recursive);
+
+	if (!prop32) {
+		dbgprintf("Could not get #address-cells property for %s (%s)\n",
+			  fdt_get_name(dtb, nodeoffset, NULL), fdt_strerror(nodeoffset));
+		return -EINVAL;
+	}
+	*addr_cells = fdt32_to_cpu(*prop32);
+
+	curr_offset = nodeoffset;
+	do {
+		prop32 = fdt_getprop(dtb, curr_offset, "#size-cells", &prop_len);
+		curr_offset = fdt_parent_offset(dtb, curr_offset);
+	} while (!prop32 && prop_len == -FDT_ERR_NOTFOUND && recursive);
+
+	if (!prop32) {
+		dbgprintf("Could not get #size-cells property for %s (%s)\n",
+			  fdt_get_name(dtb, nodeoffset, NULL), fdt_strerror(nodeoffset));
+		return -EINVAL;
+	}
+	*size_cells = fdt32_to_cpu(*prop32);
+
+	dbgprintf("%s: #address-cells:%d #size-cells:%d\n",
+		 fdt_get_name(dtb, nodeoffset, NULL), *addr_cells, *size_cells);
+
+	return 0;
+}
+
+void dtb_extract_int_property(uint64_t *val, const void *buf, uint32_t cells)
+{
+	const uint32_t *prop32 = NULL;
+	const uint64_t *prop64 = NULL;
+
+	if (cells == 1) {
+		prop32 = (const uint32_t *) buf;
+		*val = (uint64_t) be32_to_cpu(*prop32);
+	} else {
+		/* Skip any leading cells */
+		prop64 = (const uint64_t *) (uint32_t *)buf + cells - 2;
+		*val = (uint64_t) be64_to_cpu(*prop64);
+	}
+}
+
+void dtb_fill_int_property(void *buf, uint64_t val, uint32_t cells)
+{
+	uint32_t prop32 = 0;
+	uint64_t prop64 = 0;
+
+	if (cells == 1) {
+		prop32 = cpu_to_fdt32((uint32_t) val);
+		memcpy(buf, &prop32, sizeof(uint32_t));
+	} else {
+		prop64 = cpu_to_fdt64(val);
+		/* Skip any leading cells */
+		memcpy((uint64_t *)(uint32_t *)buf + cells - 2,
+		       &prop64, sizeof(uint64_t));
+	}
+}
+
+int dtb_add_range_property(char **dtb, off_t *dtb_size, uint64_t start, uint64_t end,
+			   const char *parent, const char *name)
+{
+	uint32_t addr_cells = 0;
+	uint32_t size_cells = 0;
+	char *nodepath = NULL;
+	void *prop = NULL;
+	int nodeoffset = 0;
+	int prop_size = 0;
+	int ret = 0;
+
+	nodepath = malloc(strlen("/") + strlen(parent) + 1);
+	if (!nodepath) {
+		dbgprintf("%s: malloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	strcpy(nodepath, "/");
+	strcat(nodepath, parent);
+
+	nodeoffset = fdt_path_offset(*dtb, nodepath);
+	if (nodeoffset < 0) {
+		dbgprintf("%s: fdt_path_offset(%s) failed: %s\n", __func__,
+			  nodepath, fdt_strerror(nodeoffset));
+		free(nodepath);
+		return nodeoffset;
+	}
+	free(nodepath);
+
+	ret = dtb_get_num_cells(*dtb, nodeoffset, &addr_cells, &size_cells, true);
+	if (ret < 0)
+		return ret;
+
+	/* Can the range fit with the given address/size cells ? */
+	if ((addr_cells == 1) && (start >= (1ULL << 32)))
+		return -EINVAL;
+
+	if ((size_cells == 1) && ((end - start + 1) >= (1ULL << 32)))
+		return -EINVAL;
+
+	prop_size = sizeof(uint32_t) * (addr_cells + size_cells);
+	prop = malloc(prop_size);
+
+	dtb_fill_int_property(prop, start, addr_cells);
+	dtb_fill_int_property((void *)((uint32_t *)prop + addr_cells),
+			      end - start + 1, size_cells);
+
+	/* Add by node path name */
+	return dtb_set_property(dtb, dtb_size, parent, name, prop, prop_size);
+}
+
+/************************\
+* MEMORY RANGES HANDLING *
+\************************/
+
+static int dtb_add_memory_range(struct memory_ranges *mem_ranges, uint64_t start,
+				uint64_t end, unsigned type)
+{
+	struct memory_range this_region = {0};
+	struct memory_range *ranges = mem_ranges->ranges;
+	int i = 0;
+	int ret = 0;
+
+	if (start == end) {
+		dbgprintf("Ignoring empty region\n");
+		return -EINVAL;
+	}
+
+	/* Check if we are adding an existing region */
+	for (i = 0; i < mem_ranges->size; i++) {
+		if (start == ranges[i].start && end == ranges[i].end) {
+			dbgprintf("Duplicate: 0x%lx - 0x%lx\n", start, end);
+
+			if (type == ranges[i].type)
+				return 0;
+			else if (type == RANGE_RESERVED) {
+				ranges[i].type = RANGE_RESERVED;
+				return 0;
+			}
+
+			dbgprintf("Conflicting types for region: 0x%lx - 0x%lx\n",
+				  start, end);
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * Reserved regions may be part of an existing /memory
+	 * region and shouldn't overlap according to spec, so
+	 * since we add /memory regions first, we can exclude
+	 * reserved regions here from the existing /memory regions
+	 * included in ranges[], so that we don't have the same
+	 * region twice.
+	 */
+	if (type == RANGE_RESERVED) {
+		this_region.start = start;
+		this_region.end = end - 1;
+		this_region.type = type;
+		ret = mem_regions_exclude(mem_ranges, &this_region);
+		if (ret)
+			return ret;
+	}
+
+	ret = mem_regions_alloc_and_add(mem_ranges, start,
+					end - start, type);
+
+	return ret;
+}
+
+static int dtb_add_memory_region(char *dtb, int nodeoffset,
+				 struct memory_ranges *mem_ranges, int type)
+{
+	uint32_t root_addr_cells = 0;
+	uint32_t root_size_cells = 0;
+	uint64_t addr = 0;
+	uint64_t size = 0;
+	const char *reg = NULL;
+	int prop_size = 0;
+	int offset = 0;
+	int entry_size = 0;
+	int num_entries = 0;
+	int ret = 0;
+
+	/*
+	 * Get address-cells and size-cells properties (according to
+	 * binding spec these are the same as in the root node)
+	 */
+	ret = dtb_get_num_cells(dtb, 0, &root_addr_cells, &root_size_cells, false);
+	if (ret < 0) {
+		dbgprintf("No address/size cells on root node !\n");
+		return ret;
+	}
+
+	/*
+	 * Parse the reg array, acording to device tree spec it includes
+	 * an arbitary number of <address><size> pairs
+	 */
+	entry_size = (root_addr_cells + root_size_cells) * sizeof(uint32_t);
+	reg = fdt_getprop(dtb, nodeoffset, "reg", &prop_size);
+	if (!reg) {
+		dbgprintf("Warning: Malformed memory region with no reg property (%s) !\n",
+			  fdt_get_name(dtb, nodeoffset, NULL));
+		return -EINVAL;
+	}
+
+	num_entries = prop_size / entry_size;
+	dbgprintf("Got region with %i entries: %s\n", num_entries,
+		  fdt_get_name(dtb, nodeoffset, NULL));
+
+	for (num_entries--; num_entries >= 0; num_entries--) {
+		offset = num_entries * entry_size;
+
+		dtb_extract_int_property(&addr, reg + offset,
+					 root_addr_cells);
+		offset += root_addr_cells * sizeof(uint32_t);
+
+		dtb_extract_int_property(&size, reg + offset,
+					 root_size_cells);
+
+		ret = dtb_add_memory_range(mem_ranges, addr,
+					   addr + size, type);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int dtb_parse_memory_reservations_table(char *dtb, struct memory_ranges *mem_ranges)
+{
+	int total_memrsrv = 0;
+	uint64_t addr = 0;
+	uint64_t size = 0;
+	int ret = 0;
+	int i = 0;
+
+	total_memrsrv = fdt_num_mem_rsv(dtb);
+	for (i = 0; i < total_memrsrv; i++) {
+		ret = fdt_get_mem_rsv(dtb, i, &addr, &size);
+		if (ret)
+			continue;
+		ret = dtb_add_memory_range(mem_ranges, addr, addr + size - 1,
+					   RANGE_RESERVED);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int dtb_get_reserved_memory_node(char *dtb)
+{
+	uint32_t root_addr_cells = 0;
+	uint32_t root_size_cells = 0;
+	uint32_t addr_cells = 0;
+	uint32_t size_cells = 0;
+	int prop_size = 0;
+	int nodeoffset = 0;
+	int ret = 0;
+
+	/* Get address / size cells from root node */
+	ret = dtb_get_num_cells(dtb, 0, &root_addr_cells, &root_size_cells, false);
+	if (ret < 0) {
+		dbgprintf("No address/size cells on root node !\n");
+		return ret;
+	}
+
+	/* This calls fdt_next_node internaly */
+	nodeoffset = fdt_subnode_offset(dtb, 0, "reserved-memory");
+	if (nodeoffset == -FDT_ERR_NOTFOUND) {
+		return nodeoffset;
+	} else if (nodeoffset < 0) {
+		dbgprintf("Error while looking for reserved-memory: %s\n",
+			fdt_strerror(nodeoffset));
+		return nodeoffset;
+	}
+
+	/* Look for the ranges property */
+	fdt_getprop(dtb, nodeoffset, "ranges", &prop_size);
+	if (prop_size < 0) {
+		fprintf(stderr, "Malformed reserved-memory node (no ranges property) !\n");
+		return -EINVAL;
+	}
+
+	/* Verify address-cells / size-cells */
+	ret = dtb_get_num_cells(dtb, nodeoffset, &addr_cells, &size_cells, false);
+	if (ret < 0) {
+		dbgprintf("No address/size cells property on reserved-memory node\n");
+		return ret;
+	}
+
+	if (addr_cells != root_addr_cells) {
+		fprintf(stderr, "Invalid #address-cells property on reserved-memory node\n");
+		return -EINVAL;
+	}
+
+	if (size_cells != root_size_cells) {
+		fprintf(stderr, "Invalid #size-cells property on reserved-memory node\n");
+		return -EINVAL;
+
+	}
+
+	return nodeoffset;
+}
+
+static int dtb_parse_reserved_memory_node(char *dtb, struct memory_ranges *mem_ranges)
+{
+	int nodeoffset = 0;
+	int node_depth = 0;
+	int parent_depth = 0;
+	int ret = 0;
+
+	nodeoffset = dtb_get_reserved_memory_node(dtb);
+	if (nodeoffset == -FDT_ERR_NOTFOUND)
+		return 0;
+	else if (nodeoffset < 0)
+		return nodeoffset;
+
+	/* Got the parent node, check for sub-nodes */
+
+	/* fdt_next_node() increases or decreases depth */
+	node_depth = parent_depth;
+	nodeoffset = fdt_next_node(dtb, nodeoffset, &node_depth);
+	if (ret < 0) {
+		dbgprintf("Unable to get next node: %s\n",
+			  fdt_strerror(ret));
+		return -EINVAL;
+	}
+
+	while (node_depth != parent_depth) {
+
+		ret = dtb_add_memory_region(dtb, nodeoffset,
+					    mem_ranges, RANGE_RESERVED);
+		if (ret)
+			return ret;
+
+		nodeoffset = fdt_next_node(dtb, nodeoffset, &node_depth);
+		if (ret < 0) {
+			dbgprintf("Unable to get next node: %s\n",
+				  fdt_strerror(ret));
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int dtb_parse_memory_nodes(char *dtb, struct memory_ranges *mem_ranges)
+{
+	int nodeoffset = 0;
+	int num_regions = 0;
+	const char* dev_type = 0;
+	int prop_size = 0;
+	int ret = 0;
+
+	for (; ; num_regions++) {
+		nodeoffset = fdt_subnode_offset(dtb, nodeoffset,
+						 "memory");
+		if (nodeoffset < 0)
+			break;
+
+		dbgprintf("Got memory node at depth: %i\n", fdt_node_depth(dtb, nodeoffset));
+
+		/* Look for the device_type  property */
+		dev_type = fdt_getprop(dtb, nodeoffset, "device_type", &prop_size);
+		if (prop_size < 0) {
+			fprintf(stderr, "Malformed /memory node (no device-type property) !\n");
+			return -EINVAL;
+		}
+
+		if (strncmp(dev_type, "memory", prop_size)) {
+			dbgprintf("Got unknown dev_type property: %s\n", dev_type);
+			continue;
+		}
+
+		ret = dtb_add_memory_region(dtb, nodeoffset, mem_ranges, RANGE_RAM);
+		if (ret)
+			return ret;
+	}
+
+	if (!num_regions) {
+		dbgprintf("Malformed dtb, no /memory nodes present !\n");
+		return -EINVAL;
+	}
+
+	dbgprintf("Got %i /memory nodes\n", num_regions);
+
+	return 0;
+}
+
+int dtb_get_memory_ranges(char *dtb, struct memory_ranges *mem_ranges, struct memory_ranges *extra_ranges)
+{
+	int i = 0;
+	int ret = 0;
+
+	/* Fill mem_ranges[] by parsing the device tree */
+	ret = dtb_parse_memory_nodes(dtb, mem_ranges);
+	if (ret)
+		return ret;
+
+	ret = dtb_parse_memory_reservations_table(dtb, mem_ranges);
+	if (ret)
+		return ret;
+
+	ret = dtb_parse_reserved_memory_node(dtb, mem_ranges);
+	if (ret)
+		return ret;
+
+	/* Append any extra ranges provided by the caller (e.g. initrd) */
+	for (i = 0; extra_ranges != NULL && i < extra_ranges->size; i++) {
+		dbgprintf("Adding extra range: 0x%llx - 0x%llx (%s)\n",
+			  extra_ranges->ranges[i].start,
+			  extra_ranges->ranges[i].end,
+			  extra_ranges->ranges[i].type == RANGE_RESERVED ?
+                          "RANGE_RESERVED" : "RANGE_RAM");
+
+		ret = dtb_add_memory_range(mem_ranges, extra_ranges->ranges[i].start,
+                                extra_ranges->ranges[i].end, extra_ranges->ranges[i].type);
+		if (ret)
+			return ret;
+	}
+
+	mem_regions_sort(mem_ranges);
+
+	return 0;
+}
diff --git a/kexec/dt-ops.h b/kexec/dt-ops.h
index 03659ce..3014205 100644
--- a/kexec/dt-ops.h
+++ b/kexec/dt-ops.h
@@ -11,4 +11,11 @@ int dtb_set_property(char **dtb, off_t *dtb_size, const char *node,
 
 int dtb_delete_property(char *dtb, const char *node, const char *prop);
 
+void dtb_extract_int_property(uint64_t *val, const void *buf, uint32_t cells);
+void dtb_fill_int_property(void *buf, uint64_t val, uint32_t cells);
+int dtb_add_range_property(char **dtb, off_t *dtb_size, uint64_t start, uint64_t end,
+                           const char *node, const char* parent);
+int dtb_get_memory_ranges(char *dtb, struct memory_ranges *mem_ranges,
+			  struct memory_ranges *extra_ranges);
+
 #endif
diff --git a/kexec/kexec-syscall.h b/kexec/kexec-syscall.h
index be6ccd5..4cdae84 100644
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -137,6 +137,7 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #define KEXEC_ARCH_MIPS_LE (10 << 16)
 #define KEXEC_ARCH_MIPS    ( 8 << 16)
 #define KEXEC_ARCH_CRIS    (76 << 16)
+#define KEXEC_ARCH_RISCV   (243 << 16)
 #define KEXEC_ARCH_LOONGARCH	(258 << 16)
 
 #define KEXEC_MAX_SEGMENTS 16
@@ -184,5 +185,8 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #if defined(__loongarch__)
 #define KEXEC_ARCH_NATIVE	KEXEC_ARCH_LOONGARCH
 #endif
+#if defined(__riscv__) || defined(__riscv)
+#define KEXEC_ARCH_NATIVE	KEXEC_ARCH_RISCV
+#endif
 
 #endif /* KEXEC_SYSCALL_H */
diff --git a/purgatory/Makefile b/purgatory/Makefile
index 4d2d071..7d1175f 100644
--- a/purgatory/Makefile
+++ b/purgatory/Makefile
@@ -25,6 +25,7 @@ include $(srcdir)/purgatory/arch/ia64/Makefile
 include $(srcdir)/purgatory/arch/mips/Makefile
 include $(srcdir)/purgatory/arch/ppc/Makefile
 include $(srcdir)/purgatory/arch/ppc64/Makefile
+include $(srcdir)/purgatory/arch/riscv/Makefile
 include $(srcdir)/purgatory/arch/s390/Makefile
 include $(srcdir)/purgatory/arch/sh/Makefile
 include $(srcdir)/purgatory/arch/x86_64/Makefile
diff --git a/purgatory/arch/riscv/Makefile b/purgatory/arch/riscv/Makefile
new file mode 100644
index 0000000..8bded71
--- /dev/null
+++ b/purgatory/arch/riscv/Makefile
@@ -0,0 +1,7 @@
+#
+# Purgatory riscv
+#
+
+riscv_PURGATORY_SRCS =
+
+dist += purgatory/arch/sh/Makefile $(riscv_PURGATORY_SRCS)
-- 
2.17.1


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