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Message-ID: <CAJM55Z8D3yJREg0+UtecW3wpgrGKxZYP73Pvbi2oaQfsZf4Gfw@mail.gmail.com>
Date: Thu, 14 Sep 2023 01:37:23 -0700
From: Emil Renner Berthing <emil.renner.berthing@...onical.com>
To: Song Shuai <songshuaishuai@...ylab.org>, paul.walmsley@...ive.com,
palmer@...belt.com, aou@...s.berkeley.edu, lihuafei1@...wei.com,
conor.dooley@...rochip.com, liaochang1@...wei.com,
guoren@...nel.org, ajones@...tanamicro.com, alexghiti@...osinc.com,
evan@...osinc.com, sunilvl@...tanamicro.com,
xianting.tian@...ux.alibaba.com, samitolvanen@...gle.com,
masahiroy@...nel.org, apatel@...tanamicro.com, jszhang@...nel.org,
duwe@...e.de, eric.devolder@...cle.com
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] riscv: kexec_file: Support loading Image binary file
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@...ylab.org>
> ---
> 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
> + 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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> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
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