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Message-ID: <22EFF2C197DC5C5A+f82966f5-90cf-09a5-214e-4b0e87bc6064@tinylab.org>
Date: Wed, 11 Oct 2023 14:03:59 +0800
From: Song Shuai <songshuaishuai@...ylab.org>
To: Emil Renner Berthing <emil.renner.berthing@...onical.com>,
paul.walmsley@...ive.com, palmer@...belt.com,
aou@...s.berkeley.edu, lihuafei1@...wei.com,
conor.dooley@...rochip.com, liaochang1@...wei.com,
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
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@...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
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.
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
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>
--
Thanks
Song Shuai
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