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Date: Thu, 7 Feb 2019 15:55:35 -0800
From: Thomas Garnier <>
To: Borislav Petkov <>
Cc: Kernel Hardening <>, 
	Kristen Carlson Accardi <>, Thomas Gleixner <>, 
	Ingo Molnar <>, "H. Peter Anvin" <>, 
	"the arch/x86 maintainers" <>, "Peter Zijlstra (Intel)" <>, 
	Ard Biesheuvel <>, Nadav Amit <>, 
	Masahiro Yamada <>, LKML <>
Subject: Re: [PATCH v6 02/27] x86: Use symbol name in jump table for PIE support

On Thu, Feb 7, 2019 at 9:11 AM Borislav Petkov <> wrote:
> On Thu, Feb 07, 2019 at 09:04:45AM -0800, Thomas Garnier wrote:
> > I assume that's an optimisation done by gcc later.
> So why is that change even needed? Where does it break?
> > The P modifier in the documentation does state that it is used to
> > generate PIC code.
> The documentation says:
> "If used for a function, print the PLT suffix and generate PIC code. For
> example, emit foo@PLT instead of ’foo’ for the function foo()."
> when you use %P for a function. Which is not how it is used here.

I did more checks about that. I think Ard's patch to make jump label
relative actually fixed the issue I had with them.

Thanks for spotting this, I will do additional checks and look at
removing this change.

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

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