Date: Thu, 7 Feb 2019 15:55:35 -0800 From: Thomas Garnier <thgarnie@...omium.org> To: Borislav Petkov <bp@...en8.de> Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com>, Kristen Carlson Accardi <kristen@...ux.intel.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>, "the arch/x86 maintainers" <x86@...nel.org>, "Peter Zijlstra (Intel)" <peterz@...radead.org>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Nadav Amit <namit@...are.com>, Masahiro Yamada <yamada.masahiro@...ionext.com>, LKML <linux-kernel@...r.kernel.org> 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 <bp@...en8.de> 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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