[PATCH v34 01/14] memblock: add memblock_clear_nomap()

[Ard Biesheuvel]

On 28 March 2017 at 07:50, AKASHI Takahiro <takahiro.akashi at linaro.org> wrote:
> This function, with a combination of memblock_mark_nomap(), will be used
> in a later kdump patch for arm64 when it temporarily isolates some range
> of memory from the other memory blocks in order to create a specific
> kernel mapping at boot time.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

> ---
>  include/linux/memblock.h |  1 +
>  mm/memblock.c            | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index bdfc65af4152..e82daffcfc44 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -93,6 +93,7 @@ int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
>  int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
>  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);
>  ulong choose_memblock_flags(void);
>
>  /* Low level functions */
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 696f06d17c4e..2f4ca8104ea4 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -805,6 +805,18 @@ int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
>  }
>
>  /**
> + * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region.
> + * @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_clear_nomap(phys_addr_t base, phys_addr_t size)
> +{
> +       return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
> +}
> +
> +/**
>   * __next_reserved_mem_region - next function for for_each_reserved_region()
>   * @idx: pointer to u64 loop variable
>   * @out_start: ptr to phys_addr_t for start address of the region, can be %NULL
> --
> 2.11.1
>