Re: [PATCH v4 02/30] kho: make debugfs interface optional

[Pratyush Yadav]

On Mon, Sep 29 2025, Pasha Tatashin wrote:

> Currently, KHO is controlled via debugfs interface, but once LUO is
> introduced, it can control KHO, and the debug interface becomes
> optional.
>
> Add a separate config CONFIG_KEXEC_HANDOVER_DEBUG that enables
> the debugfs interface, and allows to inspect the tree.
>
> Move all debugfs related code to a new file to keep the .c files
> clear of ifdefs.
>
> Co-developed-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
> ---
>  MAINTAINERS                      |   3 +-
>  kernel/Kconfig.kexec             |  10 ++
>  kernel/Makefile                  |   1 +
>  kernel/kexec_handover.c          | 255 +++++--------------------------
>  kernel/kexec_handover_debug.c    | 218 ++++++++++++++++++++++++++
>  kernel/kexec_handover_internal.h |  44 ++++++
>  6 files changed, 311 insertions(+), 220 deletions(-)
>  create mode 100644 kernel/kexec_handover_debug.c
>  create mode 100644 kernel/kexec_handover_internal.h
>
[...]
> --- a/kernel/Kconfig.kexec
> +++ b/kernel/Kconfig.kexec
> @@ -109,6 +109,16 @@ config KEXEC_HANDOVER
>  	  to keep data or state alive across the kexec. For this to work,
>  	  both source and target kernels need to have this option enabled.
>  
> +config KEXEC_HANDOVER_DEBUG

Nit: can we call it KEXEC_HANDOVER_DEBUGFS instead? I think we would
like to add a KEXEC_HANDOVER_DEBUG at some point to control debug
asserts for KHO, and the naming would get confusing. And renaming config
symbols is kind of a pain.

> +	bool "kexec handover debug interface"
> +	depends on KEXEC_HANDOVER
> +	depends on DEBUG_FS
> +	help
> +	  Allow to control kexec handover device tree via debugfs
> +	  interface, i.e. finalize the state or aborting the finalization.
> +	  Also, enables inspecting the KHO fdt trees with the debugfs binary
> +	  blobs.
> +
[...]

-- 
Regards,
Pratyush Yadav