linux-kernel - Re: [PATCH 1/2] x86/efi: Correct a tiny mistake in code comment

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Message-ID: <20170308081812.GA12600@dhcp-128-65.nay.redhat.com>
Date:   Wed, 8 Mar 2017 16:18:12 +0800
From:   Dave Young <dyoung@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        thgarnie@...gle.com, keescook@...omium.org, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, x86@...nel.org,
        akpm@...ux-foundation.org
Subject: Re: [PATCH 1/2] x86/efi: Correct a tiny mistake in code comment

On 03/08/17 at 03:47pm, Baoquan He wrote:
> EFI allocate runtime services regions down from EFI_VA_START, -4G.
> It should be top-down handling.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  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.

Baoquan, I think original bottom-up is right, it is just considering
-68G as up, see the x86_64 mm.txt. We regard vmalloc as higher address
although from mathematics view it is lower then positive addresses.

>   * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
>   */
>  static u64 efi_va = EFI_VA_START;
> -- 
> 2.5.5
> 

Thanks
Dave