Re: [RFC PATCH 1/9] memblock: Permit existing reserved regions to be marked RSRV_KERN

[Mike Rapoport <rppt@kernel.org>]

On Fri, Mar 06, 2026 at 04:57:05PM +0100, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Permit existing memblock reservations to be marked as RSRV_KERN. This
> will be used by the EFI code on x86 to distinguish between reservations
> of boot services data regions that have actual significance to the
> kernel and regions that are reserved temporarily to work around buggy
> firmware.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  include/linux/memblock.h |  1 +
>  mm/memblock.c            | 15 +++++++++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 6ec5e9ac0699..9eac4f268359 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -155,6 +155,7 @@ int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
>  int memblock_mark_nomap(phys_addr_t base, phys_addr_t size);
>  int memblock_clear_nomap(phys_addr_t base, phys_addr_t size);
>  int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size);
> +int memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size);
>  int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size);
>  int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size);
>  
> diff --git a/mm/memblock.c b/mm/memblock.c
> index b3ddfdec7a80..2505ce8b319c 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1115,6 +1115,21 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t
>  				    MEMBLOCK_RSRV_NOINIT);
>  }
>  
> +/**
> + * memblock_reserved_mark_kern - Mark a reserved memory region with flag
> + * MEMBLOCK_RSRV_KERN
> + *
> + * @base: the base phys addr of the region
> + * @size: the size of the region
> + *
> + * Return: 0 on success, -errno on failure.
> + */
> +int __init_memblock memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size)
> +{
> +	return memblock_setclr_flag(&memblock.reserved, base, size, 1,
> +				    MEMBLOCK_RSRV_KERN);
> +}
> +
>  /**
>   * memblock_mark_kho_scratch - Mark a memory region as MEMBLOCK_KHO_SCRATCH.
>   * @base: the base phys addr of the region
> -- 
> 2.53.0.473.g4a7958ca14-goog
> 

-- 
Sincerely yours,
Mike.