linux-kernel - Re: [PATCH v3 11/13] riscv/kexec: refactor for kernel/Kconfig.kexec

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Message-ID: <20230628-urologist-faction-42ebe5372206@wendy>
Date:   Wed, 28 Jun 2023 09:20:36 +0100
From:   Conor Dooley <conor.dooley@...rochip.com>
To:     Eric DeVolder <eric.devolder@...cle.com>
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Subject: Re: [PATCH v3 11/13] riscv/kexec: refactor for kernel/Kconfig.kexec

Hey Eric,

On Mon, Jun 26, 2023 at 12:13:30PM -0400, Eric DeVolder wrote:
> The kexec and crash kernel options are provided in the common
> kernel/Kconfig.kexec. Utilize the common options and provide
> the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the

> equivalent set of KEXEC and CRASH options.

I find this diff a little hard to follow (since the other half off the
change is in another patch), so it may be me missing something, but are
you sure?

> 
> Signed-off-by: Eric DeVolder <eric.devolder@...cle.com>
> ---
>  arch/riscv/Kconfig | 48 ++++++++++++++--------------------------------
>  1 file changed, 14 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 5966ad97c30c..c484abd9bbfd 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -585,48 +585,28 @@ config RISCV_BOOT_SPINWAIT
>  
>  	  If unsure what to do here, say N.
>  
> -config KEXEC
> -	bool "Kexec system call"
> -	depends on MMU
> +config ARCH_SUPPORTS_KEXEC
> +	def_bool MMU
> +
> +config ARCH_SELECTS_KEXEC
> +	def_bool y
> +	depends on KEXEC
>  	select HOTPLUG_CPU if SMP
> -	select KEXEC_CORE
> -	help
> -	  kexec is a system call that implements the ability to shutdown your
> -	  current kernel, and to start another kernel. It is like a reboot
> -	  but it is independent of the system firmware. And like a reboot
> -	  you can start any kernel with it, not just Linux.
>  
> -	  The name comes from the similarity to the exec system call.
> +config ARCH_SUPPORTS_KEXEC_FILE
> +	def_bool 64BIT && MMU && CRYPTO=y && CRYPTO_SHA256=y

This looks like a change to me. Previously, only KEXEC_PURGATORY
required these crypto options to be like so, but now KEXEC_FILE needs
them too.

What am I missing?

Cheers,
Conor.

>  
> -config KEXEC_FILE
> -	bool "kexec file based systmem call"
> -	depends on 64BIT && MMU
> -	select HAVE_IMA_KEXEC if IMA
> -	select KEXEC_CORE
> +config ARCH_SELECTS_KEXEC_FILE
> +	def_bool y
> +	depends on KEXEC_FILE
>  	select KEXEC_ELF
> -	help
> -	  This is new version of kexec system call. This system call is
> -	  file based and takes file descriptors as system call argument
> -	  for kernel and initramfs as opposed to list of segments as
> -	  accepted by previous system call.
> -
> -	  If you don't know what to do here, say Y.
> +	select HAVE_IMA_KEXEC if IMA
>  
>  config ARCH_HAS_KEXEC_PURGATORY
>  	def_bool KEXEC_FILE
> -	depends on CRYPTO=y
> -	depends on CRYPTO_SHA256=y
>  
> -config CRASH_DUMP
> -	bool "Build kdump crash kernel"
> -	help
> -	  Generate crash dump after being started by kexec. This should
> -	  be normally only set in special crash dump kernels which are
> -	  loaded in the main kernel with kexec-tools into a specially
> -	  reserved region and then later executed after a crash by
> -	  kdump/kexec.
> -
> -	  For more details see Documentation/admin-guide/kdump/kdump.rst
> +config ARCH_SUPPORTS_CRASH_DUMP
> +	def_bool y
>  
>  config COMPAT
>  	bool "Kernel support for 32-bit U-mode"
> -- 
> 2.31.1
>

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