[PATCH 4/4] RISC-V: Support loading Image binary file

Björn Töpel
2025-04-09T20:15:03Z

From: Song Shuai <songshuaishuai@tinylab.org>

Add image-riscv file_type to probe/load Image file type,

As for kexec_load, find the pbase aligned text_offset from image header
and prepare segments for this syscall.

for kexec_file_load, setup the related options and let kernel part to
deal with the Image.

Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
---
kexec/arch/riscv/Makefile | 2 +
kexec/arch/riscv/image-header.h | 88 ++++++++++++++++++++++++++
kexec/arch/riscv/kexec-image-riscv.c | 95 ++++++++++++++++++++++++++++
kexec/arch/riscv/kexec-riscv.c | 1 +
kexec/arch/riscv/kexec-riscv.h | 7 ++
5 files changed, 193 insertions(+)
create mode 100644 kexec/arch/riscv/image-header.h
create mode 100644 kexec/arch/riscv/kexec-image-riscv.c

diff --git a/kexec/arch/riscv/Makefile b/kexec/arch/riscv/Makefile
index f26cc9025e77..37ef7603fc38 100644
--- a/kexec/arch/riscv/Makefile
+++ b/kexec/arch/riscv/Makefile
@@ -3,6 +3,7 @@
#
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/kexec-image-riscv.c
riscv_KEXEC_SRCS += kexec/arch/riscv/crashdump-riscv.c

riscv_MEM_REGIONS = kexec/mem_regions.c
@@ -15,6 +16,7 @@ riscv_CPPFLAGS += -I $(srcdir)/kexec/

dist += kexec/arch/riscv/Makefile $(riscv_KEXEC_SRCS) \
kexec/arch/riscv/kexec-riscv.h \
+ kexec/arch/riscv/image-header.h \
kexec/arch/riscv/include/arch/options.h

ifdef HAVE_LIBFDT
diff --git a/kexec/arch/riscv/image-header.h b/kexec/arch/riscv/image-header.h
new file mode 100644
index 000000000000..a6775462358e
--- /dev/null
+++ b/kexec/arch/riscv/image-header.h
@@ -0,0 +1,88 @@
+/*
+ * RISCV64 binary image header.
+ * token from arm64/image-header.h
+ */
+
+#if !defined(__RISCV_IMAGE_HEADER_H)
+#define __RISCV_IMAGE_HEADER_H
+
+#include <endian.h>
+#include <stdint.h>
+
+/**
+ * struct riscv_image_header - riscv kernel image header.
+ *
+ **/
+struct riscv_image_header {
+ uint32_t code0;
+ uint32_t code1;
+ uint64_t text_offset;
+ uint64_t image_size;
+ uint64_t flags;
+ uint32_t version;
+ uint32_t res1;
+ uint64_t res2;
+ uint64_t magic;
+ uint32_t magic2;
+ uint32_t res3;
+};
+
+#define RISCV_IMAGE_MAGIC 0x5643534952
+#define RISCV_IMAGE_MAGIC2 0x05435352
+
+#define RISCV_HEADER_VERSION_MAJOR 0
+#define RISCV_HEADER_VERSION_MINOR 2
+
+#define RISCV_HEADER_VERSION (RISCV_HEADER_VERSION_MAJOR << 16 | \
+ RISCV_HEADER_VERSION_MINOR)
+
+
+static const uint64_t riscv_image_flag_be = (1UL << 0);
+
+/**
+ * riscv_header_check_magic - Helper to check the riscv image header.
+ *
+ * Returns non-zero if header is OK.
+ */
+
+static inline int riscv_header_check_magic(const struct riscv_image_header *h)
+{
+ if (!h)
+ return 0;
+
+ return (h->version >= RISCV_HEADER_VERSION && h->magic2 == RISCV_IMAGE_MAGIC2);
+}
+
+/**
+ * riscv_header_check_endiannes - Helper to check the riscv image header.
+ *
+ * Returns non-zero if the image was built as big endian.
+ */
+
+static inline int riscv_header_check_endiannes(const struct riscv_image_header *h)
+{
+ if (!h)
+ return 0;
+
+ return (le64toh(h->flags) & riscv_image_flag_be) >> 0;
+}
+
+
+
+static inline uint64_t riscv_header_text_offset(const struct riscv_image_header *h)
+{
+ if (!h)
+ return 0;
+
+ return le64toh(h->text_offset);
+}
+
+static inline uint64_t riscv_header_image_size(const struct riscv_image_header *h)
+{
+ if (!h)
+ return 0;
+
+ return le64toh(h->image_size);
+}
+
+#endif
diff --git a/kexec/arch/riscv/kexec-image-riscv.c b/kexec/arch/riscv/kexec-image-riscv.c
new file mode 100644
index 000000000000..6ae7e579fd16
--- /dev/null
+++ b/kexec/arch/riscv/kexec-image-riscv.c
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RISC-V kexec binary image support.
+ *
+ * Author: Song Shuai <songhshuaishuai@tinylab.org>
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include "image-header.h"
+#include "kexec.h"
+#include "kexec-riscv.h"
+#include "kexec-syscall.h"
+#include "arch/options.h"
+
+int image_riscv_probe(const char *kernel_buf, off_t kernel_size)
+{
+ const struct riscv_image_header *h;
+
+ if (kernel_size < sizeof(struct riscv_image_header)) {
+ dbgprintf("%s: No riscv image header.\n", __func__);
+ return -1;
+ }
+
+ h = (const struct riscv_image_header *)(kernel_buf);
+
+ if (!riscv_header_check_magic(h)) {
+ dbgprintf("%s: Bad riscv image header.\n", __func__);
+ return -1;
+ }
+
+ return 0;
+}
+
+int image_riscv_load(int argc, char **argv, const char *kernel_buf,
+ off_t kernel_size, struct kexec_info *info)
+{
+ const struct riscv_image_header *h;
+ unsigned long text_offset, image_size;
+ off_t new_base_addr = 0;
+
+ int ret;
+
+ if (info->file_mode) {
+ return prepare_kexec_file_options(info);
+ }
+
+ h = (const struct riscv_image_header *)(kernel_buf);
+
+ /* Check header */
+ if (!h->image_size){
+ dbgprintf("Kernel image size is NULL\n");
+ ret = EFAILED;
+ goto exit;
+ }
+
+ if(riscv_header_check_endiannes(h)){
+ dbgprintf("Kernel image was built as big endian\n");
+ ret = EFAILED;
+ goto exit;
+ }
+
+ text_offset = riscv_header_text_offset(h);
+ image_size = riscv_header_image_size(h);
+
+ /* Setup the entry and segments */
+
+ ret = riscv_find_pbase(info, &new_base_addr, image_size, text_offset);
+ if (ret < 0) {
+ fprintf(stderr, "Could not find a memory region for the "
+ "provided Image\n");
+ goto exit;
+ }
+
+ info->entry = (void *) new_base_addr;
+ dbgprintf("Entry point for the Image: 0x%lX\n", new_base_addr);
+
+ add_segment(info, kernel_buf, kernel_size, new_base_addr, image_size);
+
+ ret = load_extra_segments(info, text_offset, image_size, ULONG_MAX);
+exit:
+ if (ret)
+ fprintf(stderr, "kexec: load failed.\n");
+ return ret;
+}
+
+void image_riscv_usage(void)
+{
+ printf(
+" An RISC-V binary image, uncompressed, little endian.\n"
+" Typically an Image file.\n\n");
+}
diff --git a/kexec/arch/riscv/kexec-riscv.c b/kexec/arch/riscv/kexec-riscv.c
index 631659301749..f34b46831160 100644
--- a/kexec/arch/riscv/kexec-riscv.c
+++ b/kexec/arch/riscv/kexec-riscv.c
@@ -33,6 +33,7 @@ const struct arch_map_entry arches[] = {

struct file_type file_type[] = {
{"elf-riscv", elf_riscv_probe, elf_riscv_load, elf_riscv_usage},
+ {"image-riscv", image_riscv_probe, image_riscv_load, image_riscv_usage},
};
int file_types = sizeof(file_type) / sizeof(file_type[0]);

diff --git a/kexec/arch/riscv/kexec-riscv.h b/kexec/arch/riscv/kexec-riscv.h
index 618099291117..cfb03779a022 100644
--- a/kexec/arch/riscv/kexec-riscv.h
+++ b/kexec/arch/riscv/kexec-riscv.h
@@ -40,7 +40,14 @@ int load_extra_segments(struct kexec_info *info, uint64_t kernel_base,
int riscv_find_pbase(struct kexec_info *info, off_t *addr,
off_t size, off_t align);

+/* kexec-elf-riscv.c */
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);
+
+/* kexec-image-riscv.c */
+int image_riscv_probe(const char *buf, off_t len);
+void image_riscv_usage(void);
+int image_riscv_load(int argc, char **argv, const char *buf, off_t len,
+ struct kexec_info *info);