From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 7 Feb 2019 18:11:45 +0100
From: Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v6 02/27] x86: Use symbol name in jump table for PIE
 support
Message-ID: <20190207171145.GH2414@zn.tnic>
References: <20190131192533.34130-1-thgarnie@chromium.org>
 <20190131192533.34130-3-thgarnie@chromium.org>
 <20190207121729.GE2414@zn.tnic>
 <CAJcbSZFe+Cn9+gEa4iv56sZE+WXXiHjeR8Mcte9s_HYr8QBrsw@mail.gmail.com>
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To: Thomas Garnier <thgarnie@chromium.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>, Kristen Carlson Accardi <kristen@linux.intel.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, the arch/x86 maintainers <x86@kernel.org>, "Peter Zijlstra (Intel)" <peterz@infradead.org>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Nadav Amit <namit@vmware.com>, Masahiro Yamada <yamada.masahiro@socionext.com>, LKML <linux-kernel@vger.kernel.org>
List-ID: <kernel-hardening.lists.openwall.com>

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.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.