Re: [External] [PATCH 2/2] riscv: kexec_file: Support loading Image binary file
From: Song Shuai
Date: Mon Feb 19 2024 - 04:53:20 EST
Hi, yunhui:
在 2024/2/16 16:54, yunhui cui 写道:
Hi Shuai,
On Thu, Sep 14, 2023 at 10:09 AM Song Shuai <songshuaishuai@xxxxxxxxxxx> wrote:
This patch creates image_kexec_ops to load Image binary file
for kexec_file_load() syscall.
Signed-off-by: Song Shuai <songshuaishuai@xxxxxxxxxxx>
---
arch/riscv/include/asm/image.h | 2 +
arch/riscv/include/asm/kexec.h | 1 +
arch/riscv/kernel/Makefile | 2 +-
arch/riscv/kernel/kexec_image.c | 97 ++++++++++++++++++++++++++
arch/riscv/kernel/machine_kexec_file.c | 1 +
5 files changed, 102 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/kernel/kexec_image.c
diff --git a/arch/riscv/include/asm/image.h b/arch/riscv/include/asm/image.h
index e0b319af3681..8927a6ea1127 100644
--- a/arch/riscv/include/asm/image.h
+++ b/arch/riscv/include/asm/image.h
@@ -30,6 +30,8 @@
RISCV_HEADER_VERSION_MINOR)
#ifndef __ASSEMBLY__
+#define riscv_image_flag_field(flags, field)\
+ (((flags) >> field##_SHIFT) & field##_MASK)
/**
* struct riscv_image_header - riscv kernel image header
* @code0: Executable code
diff --git a/arch/riscv/include/asm/kexec.h b/arch/riscv/include/asm/kexec.h
index 518825fe4160..b9ee8346cc8c 100644
--- a/arch/riscv/include/asm/kexec.h
+++ b/arch/riscv/include/asm/kexec.h
@@ -56,6 +56,7 @@ extern riscv_kexec_method riscv_kexec_norelocate;
#ifdef CONFIG_KEXEC_FILE
extern const struct kexec_file_ops elf_kexec_ops;
+extern const struct kexec_file_ops image_kexec_ops;
struct purgatory_info;
int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 1c62c639e875..9ecba3231a36 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -86,7 +86,7 @@ endif
obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regs.o machine_kexec.o
-obj-$(CONFIG_KEXEC_FILE) += kexec_elf.o machine_kexec_file.o
+obj-$(CONFIG_KEXEC_FILE) += kexec_elf.o kexec_image.o machine_kexec_file.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o
diff --git a/arch/riscv/kernel/kexec_image.c b/arch/riscv/kernel/kexec_image.c
new file mode 100644
index 000000000000..b6aa7f59bd53
--- /dev/null
+++ b/arch/riscv/kernel/kexec_image.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V Kexec image loader
+ *
+ */
+
+#define pr_fmt(fmt) "kexec_file(Image): " fmt
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/pe.h>
+#include <linux/string.h>
+#include <asm/byteorder.h>
+#include <asm/image.h>
+
+static int image_probe(const char *kernel_buf, unsigned long kernel_len)
+{
+ const struct riscv_image_header *h =
+ (const struct riscv_image_header *)(kernel_buf);
+
+ if (!h || (kernel_len < sizeof(*h)))
+ return -EINVAL;
+
+ /* According to Documentation/riscv/boot-image-header.rst,
+ * use "magic2" field to check when version >= 0.2.
+ */
+
+ if (h->version >= RISCV_HEADER_VERSION &&
+ memcmp(&h->magic2, RISCV_IMAGE_MAGIC2, sizeof(h->magic2)))
+ return -EINVAL;
+
+ return 0;
+}
+
+static void *image_load(struct kimage *image,
+ char *kernel, unsigned long kernel_len,
+ char *initrd, unsigned long initrd_len,
+ char *cmdline, unsigned long cmdline_len)
+{
+ struct riscv_image_header *h;
+ u64 flags;
+ bool be_image, be_kernel;
+ struct kexec_buf kbuf;
+ int ret;
+
+ /* Check Image header */
+ h = (struct riscv_image_header *)kernel;
+ if (!h->image_size) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Check endianness */
+ flags = le64_to_cpu(h->flags);
+ be_image = riscv_image_flag_field(flags, RISCV_IMAGE_FLAG_BE);
+ be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
+ if (be_image != be_kernel) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Load the kernel image */
+ kbuf.image = image;
+ kbuf.buf_min = 0;
+ kbuf.buf_max = ULONG_MAX;
+ kbuf.top_down = false;
+
+ kbuf.buffer = kernel;
+ kbuf.bufsz = kernel_len;
+ kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+ kbuf.memsz = le64_to_cpu(h->image_size);
+ kbuf.buf_align = le64_to_cpu(h->text_offset);
+
+ ret = kexec_add_buffer(&kbuf);
+ if (ret) {
+ pr_err("Error add kernel image ret=%d\n", ret);
+ goto out;
+ }
+
+ image->start = kbuf.mem;
+
+ pr_info("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ kbuf.mem, kbuf.bufsz, kbuf.memsz);
pr_info() or pr_debug()? >
+
+ ret = load_extra_segments(image, kbuf.mem, kbuf.memsz,
+ initrd, initrd_len, cmdline, cmdline_len);
+
+out:
+ return ret ? ERR_PTR(ret) : NULL;
+}
+
+const struct kexec_file_ops image_kexec_ops = {
+ .probe = image_probe,
+ .load = image_load,
+};
diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
index aedb8c16a283..5dc700834f1e 100644
--- a/arch/riscv/kernel/machine_kexec_file.c
+++ b/arch/riscv/kernel/machine_kexec_file.c
@@ -17,6 +17,7 @@
const struct kexec_file_ops * const kexec_file_loaders[] = {
&elf_kexec_ops,
+ &image_kexec_ops,
NULL
};
--
2.20.1
I tested these two patches. It works when
CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY is not enabled. When
CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY is enabled, the error is as
follows:
[45.712019] Unknown rela relocation: 34
[45.712258] Error loading purgatory ret=-8
How to fix it? >
Thanks，
Yunhui
Thanks for your attention to this series and RV kdump/kexec stack.
As you noticed, this series and the kexec-tools RV support patches[1]
didn't get any positive responses and have been suspended for a few
months. And I'm now struggling in my own job, so really sorry that I
have no time to continue these works.
Although that, I would like to reply to your comments in case anyone
wants to push this series:
Comment1: Why rename elf_kexec.c to kexec_elf.c ？
- s390 uses kexec_{elf,image}.c file names, so I followed it.
Comment2: pr_info() or pr_debug()?
- pr_debug() seems better.
Comment3: Unknown rela relocation: 34
- The CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY was enabled when I posted
this series, I didn't see this relocation error at that time.
If you want to fix this relocation error, you need to figure out who
hold the R_RISCV_ADD16 (34), and how it was generated (compiler options
or other RV kernel configures). This commit 0f5f46a869a5 ("riscv: kexec:
Remove -fPIE for PURGATORY_CFLAGS") may help.
[1]:
https://lore.kernel.org/kexec/DA84A55096BADE15+594e239a-ff6a-368f-ae92-b6cfebbf8dc0@xxxxxxxxxxx/
--
Thanks
Song Shuai