# Re: \[PATCH v2 2/6\] powerpc/kexec\_file: Add KEXEC\_SIG support.

- From: Nayna \<hidden\>
- Date: 2021-12-09 20:22:06 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/12/9525489
- Thread: https://ratatoskr.run/linuxppc-dev/2021/11/1586817/t.md

```text

On 11/25/21 13:02, Michal Suchanek wrote:
> Copy the code from s390x
>
> Signed-off-by: Michal Suchanek<redacted>
> ---
>   arch/powerpc/Kconfig        | 11 +++++++++++
>   arch/powerpc/kexec/elf_64.c | 36 ++++++++++++++++++++++++++++++++++++
>   2 files changed, 47 insertions(+)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index ac0c515552fd..ecc1227a77f1 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -561,6 +561,17 @@ config KEXEC_FILE
>   config ARCH_HAS_KEXEC_PURGATORY
>   	def_bool KEXEC_FILE
>
> +config KEXEC_SIG
> +	bool "Verify kernel signature during kexec_file_load() syscall"
> +	depends on KEXEC_FILE && MODULE_SIG_FORMAT

After manually applying the patch, the build is failing with the following error:

build failed with error "arch/powerpc/kexec/elf_64.o: In function `elf64_verify_sig':
/root/kernel/linus/linux/arch/powerpc/kexec/elf_64.c:160: undefined reference to `verify_appended_signature'"

I see it happened because I didn't have MODULE_SIG enabled. Enabling MODULE_SIG fixes it.

I wonder why not to add "depends on MODULE_SIG" rather than on MODULE_SIG_FORMAT.

Thanks & Regards,

     - Nayna
```