linux-kernel - Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions

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Date:   Fri, 21 Jul 2017 20:35:45 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        keescook@...omium.org, matt@...eblueprint.co.uk,
        tglx@...utronix.de, hpa@...or.com, izumi.taku@...fujitsu.com,
        fanc.fnst@...fujitsu.com, thgarnie@...gle.com,
        n-horiguchi@...jp.nec.com
Subject: Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be
 randomized in mirror regions

On 07/21/17 at 12:33pm, Ingo Molnar wrote:
> 
> * Baoquan He <bhe@...hat.com> wrote:
> 
> > Kernel text may be located in non-mirror regions (movable zone) when both
> > address range mirroring feature and KASLR are enabled.
> > 
> > The address range mirroring feature arranges such mirror region into
> > normal zone and other region into movable zone in order to locate
> > kernel code and data in mirror region. The physical memory region
> > whose descriptors in EFI memory map has EFI_MEMORY_MORE_RELIABLE
> > attribute (bit: 16) are mirrored.
> > 
> > If efi is detected, iterate efi memory map and pick the mirror region to
> > process for adding candidate of randomization slot. If efi is disabled
> > or no mirror region found, still process e820 memory map.
> 
> Please read your own changelogs and capitalize 'EFI' consistently!
> 
> Also, what is unclear to me after reading this changelog, what does this patch 
> actually achieve, relative to existing behavior?
> 
> It would be helpful if it was structured like this:
> 
>     Previous behavior was that the kernel would ...
> 
>     This patch changes the old behavior so that the kernel now ...

Sure, I will check the patch log and change all 'efi' to 'EFI'. And
rewrite the log according to the suggested format. Thanks a lot!

Thanks
Baoquan