Re: [PATCH v1 RESEND 2/2] x86/efi: Clean up a minor mistake in code comment

From: Ard Biesheuvel
Date: Fri Mar 24 2017 - 04:58:00 EST


On 23 March 2017 at 03:27, Baoquan He <bhe@xxxxxxxxxx> wrote:
> EFI allocate runtime services regions from EFI_VA_START, -4G, down
> to -64G, EFI_VA_END.

OK, so is the size of the region 60 GB or 64 GB? This suggests 60 GB,
but the comment you update suggests 64 GB.

> The mechanism was introduced in
> commit d2f7cbe7b26a7 ("x86/efi: Runtime services virtual mapping").
>
> Clean it up to avoid confusion.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Cc: linux-efi@xxxxxxxxxxxxxxx
> ---
> arch/x86/platform/efi/efi_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index a4695da..6cbf9e0 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -47,7 +47,7 @@
> #include <asm/pgalloc.h>
>
> /*
> - * We allocate runtime services regions bottom-up, starting from -4G, i.e.
> + * We allocate runtime services regions top-down, starting from -4G, i.e.
> * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
> */
> static u64 efi_va = EFI_VA_START;
> --
> 2.5.5
>