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Date: Tue, 29 Oct 2019 14:29:53 -0700
From: Thomas Garnier <>
To: Borislav Petkov <>
Cc: Kernel Hardening <>, 
	Kristen Carlson Accardi <>, Kees Cook <>, 
	Thomas Gleixner <>, Ingo Molnar <>, "H. Peter Anvin" <>, 
	"the arch/x86 maintainers" <>, Juergen Gross <>, Peter Zijlstra <>, 
	Boris Ostrovsky <>, Josh Poimboeuf <>, 
	Maran Wilson <>, Feng Tang <>, 
	LKML <>
Subject: Re: [PATCH v9 08/11] x86/boot/64: Adapt assembly for PIE support

On Fri, Aug 9, 2019 at 10:29 AM Borislav Petkov <> wrote:
> chOn Tue, Jul 30, 2019 at 12:12:52PM -0700, Thomas Garnier wrote:
> > Change the assembly code to use only relative references of symbols for the
> > kernel to be PIE compatible.
> >
> > Early at boot, the kernel is mapped at a temporary address while preparing
> > the page table. To know the changes needed for the page table with KASLR,
> These manipulations need to be done regardless of whether KASLR is
> enabled or not. You're basically accomodating them to PIE.
> > the boot code calculate the difference between the expected address of the
> calculates
> > kernel and the one chosen by KASLR. It does not work with PIE because all
> > symbols in code are relatives. Instead of getting the future relocated
> > virtual address, you will get the current temporary mapping.
> Please avoid "you", "we" etc personal pronouns in commit messages.
> > Instructions were changed to have absolute 64-bit references.
> From Documentation/process/submitting-patches.rst:
>  "Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
>   instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
>   to do frotz", as if you are giving orders to the codebase to change
>   its behaviour."

Sorry for the late reply, busy couple months.

I will integrate your feedback in v10. Thanks.

> Thx.
> --
> Regards/Gruss,
>     Boris.
> Good mailing practices for 400: avoid top-posting and trim the reply.

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