Re: [External] [PATCH 2/2] riscv: kexec_file: Support loading Image binary file
From: yunhui cui
Date: Mon Feb 19 2024 - 22:09:58 EST
Hi Song Shuai,
On Mon, Feb 19, 2024 at 5:53 PM Song Shuai <songshuaishuai@xxxxxxxxxxx> wrote:
>
>
> 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-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regso machine_kexec.o
> >> -obj-$(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.
Okay, so are arm64/x86.
> 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.
Have you tested it with the top commit of linux-next? Can you share the .config?
Thanks