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

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Date:   Wed, 8 Mar 2017 18:17:50 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Bhupesh Sharma <bhsharma@...hat.com>,
        Dave Young <dyoung@...hat.com>, linux-kernel@...r.kernel.org,
        linux-efi@...r.kernel.org, thgarnie@...gle.com,
        Kees Cook <keescook@...omium.org>,
        Thomas Gleixner <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 10:35am, Borislav Petkov wrote:
> On Wed, Mar 08, 2017 at 05:09:55PM +0800, Baoquan He wrote:
> > Yes, it looks better. I can repost with this change. Thanks.
> 
> No it doesn't:

All right, I will just update the code comment. Just back ported kaslr
to our OS product, people reviewed and found the upper boundary of kaslr
mm region is EFI_VA_START, that's not correct, it has to be corrected
firstly in upstream. Then found the confusion in code comment.

Change or keep it, both is fine to me.

Thanks!

> 
> #define EFI_VA_START     ( -4 * (_AC(1, UL) << 30))
> #define EFI_VA_END       (-68 * (_AC(1, UL) << 30))
> 
> That's -4G (the shift by 30) and -68G, respectively.
> 
> > > #define EFI_VA_START    _AC(0xfffffffeffffffff, UL)
> > > #define EFI_VA_END    _AC(0xffffffef00000000, UL)
> 
> That is something which I need to type into a calculator first.
> 
> Can you guys point your attention to something which is really broken
> and stop wasting your time? And there's enough really broken crap left
> and right...
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Good mailing practices for 400: avoid top-posting and trim the reply.