Re: [PATCH 2/2] riscv: kexec_file: Support loading Image binary file
From: Song Shuai
Date: Mon Oct 16 2023 - 01:21:17 EST
在 2023/10/11 18:48, Emil Renner Berthing 写道:
Song Shuai wrote:
在 2023/9/14 16:37, Emil Renner Berthing 写道:
Song Shuai 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)
Hi Song,
This macro is almost FIELD_GET from linux/bitfield.h ..
/**
* 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);
..but here you're just testing a single bit, so since be_image is a bool it
could just be
be_image = flags & RISCV_IMAGE_FLAG_BE_MASK;
/Emil
Hi Emil,
Sorry for the delayed response,
The `flags` field currently only has bit-0 to indicate the kenrel
endianness, your comment looks good in this case.
While considering the future extension of the `flags` feild, the
riscv_image_flag_field() is neccessiry to make callers to require the
bits they want.
Right, but please don't invent your own FIELD_GET then.
Hi Emil,
I tried to use FIELD_PREP/FIELD_GET to set/get the RISCV_IMAGE_FLAG_BE,
but using FIELD_PREP to define the __HEAD_FLAGS (used in head.S) emitted
AS build error and the final .s file looked like:
883 .dword _end - _start
884 .dword (({ ({ do { } while (0); do { } while (0); do { } while
(0); do { } while (0); do { } while (0); }); ((typeof((((1)) <<
(0))))(0) << (__builtin_ffsll((((1)) << (0))) - 1)) & ((((1)) << (0))); }))
IIUC the FIELD_PREP can't work well in this asm context, and using
FILED_GET without FIELD_PREP paired looks not good to me.
The original riscv/*/image.h and the riscv_image_flag_filed() of this
patch just do what arm64 does, so I still like to keep them.
I also found that Patch1 has a build issue due to my previous uncareful
cherry-picking,
V2 will be sent to fix it if you're ok this patch without bitfield armed.
I would like to listen to your advice.
So I prefer to keep this snippet.
+ 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);
+
+ 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
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--
Thanks
Song Shuai
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linux-riscv@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Thanks
Song Shuai