Re: [PATCH v4 05/19] kho: Add feature header for fine-grained ABI compatibility

["Pasha Tatashin" <pasha.tatashin@soleen.com>]

On Tue Nov 10, 2026 at 12:01 AM EST, Tarun Sahu wrote:

> +/**
> + * DECLARE_KHO_SER - Register a serialized payload structure with KHO.
> + * @name:         Structure tag name (e.g. luo_ser).
> + * @payload_size: Compile-time expected size of struct @name in bytes.
> + * @nr_required:  Total number of defined required features.
> + * @nr_optional:  Total number of defined optional features.
> + *
> + * Size and 8-byte alignment are asserted under CONFIG_64BIT: KHO and LUO are
> + * 64-bit only, while !CONFIG_KEXEC_HANDOVER stubs pull ABI headers into
> + * 32-bit builds where u64 has 4-byte or 2-byte alignment.
> + */
> +#define DECLARE_KHO_SER(name, payload_size, nr_required, nr_optional)	\
> +	static_assert(!IS_ENABLED(CONFIG_64BIT) ||			\
> +		      sizeof(struct name) == (payload_size),		\
> +		      "struct " #name " size mismatch");		\
> +	static_assert(!IS_ENABLED(CONFIG_64BIT) ||			\
> +		      __alignof__(struct name) == 8,			\
> +		      "struct " #name " must be 8-byte aligned");	\
> +	extern struct kho_ser_hdr __kho_ser_hdr_##name;			\

Remove this extern.

> +	enum {								\
> +		__KHO_SER_SIZE_##name = (payload_size),			\
> +		__KHO_SER_NR_REQUIRED_##name = (nr_required),		\
> +		__KHO_SER_NR_OPTIONAL_##name = (nr_optional),		\
> +	}
> +
> +/**
> + * DECLARE_KHO_SER_HDR - Declare a feature header variable, field, or parameter.
> + * @name: Structure tag name registered with DECLARE_KHO_SER().
> + * @decl: Declarator (e.g. *fhdr, **out_fhdr, or * inside DECLARE_KHOSER_PTR).
> + *
> + * Declares @decl with type struct kho_ser_hdr while checking at compile time
> + * that @name was registered with DECLARE_KHO_SER(), documenting which
> + * serialized payload structure a feature header pointer belongs to.
> + */
> +#define DECLARE_KHO_SER_HDR(name, decl)	typeof(__kho_ser_hdr_##name) decl

Remove DECLARE_KHO_SER_HDR, use kho_ser_hdr directly.

-- 
Pasha