[PATCH] riscv: Implement free_initrd_mem.

[Palmer Dabbelt]

On Tue, 20 Feb 2018 05:50:43 PST (-0800), shea at shealevy.com wrote:
> Signed-off-by: Shea Levy <shea at shealevy.com>
> ---
>  arch/riscv/mm/init.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index c77df8142be2..1c832b541e95 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -66,5 +66,11 @@ void free_initmem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>  void free_initrd_mem(unsigned long start, unsigned long end)
>  {
> +	if (start == initrd_start)
> +		start = round_down(start, PAGE_SIZE);
> +	if (end == initrd_end)
> +		end = round_up(end, PAGE_SIZE);
> +
> +	free_reserved_area((void *)start, (void *)end, -1, "initrd");
>  }
>  #endif /* CONFIG_BLK_DEV_INITRD */

It looks like everyone is doing something slightly different here:

* arm64 doesn't round to a page size, and has keep_initrd.
* arm calls poison_init_mem(), and has keep_initrd.
* sparc64 doesn't round, and doesn't have a keep_initrd.
* mips doesn't round, and doesn't have a keep_initrd.
* x86 rounds end to a page size but not start, and doesn't have a keep_initrd.

It feels like this should be something generic.  I'm adding linux-kernel to see 
what people think.