linux-kernel - Re: [RFC PATCH] kbuild: add -fno-PIE

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Message-ID: <874m41mz4h.fsf@turtle.gmx.de>
Date:   Mon, 24 Oct 2016 19:32:30 +0200
From:   Sven Joachim <svenjoac@....de>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     Joe Perches <joe@...ches.com>, Adam Borowski <kilobyte@...band.pl>,
        Michal Marek <mmarek@...e.com>, linux-kbuild@...r.kernel.org,
        linux-kernel@...r.kernel.org, ben@...adent.org.uk
Subject: Re: [RFC PATCH] kbuild: add -fno-PIE

On 2016-10-24 09:43 +0200, Sebastian Andrzej Siewior wrote:

> On 2016-10-24 09:38:49 [+0200], Sven Joachim wrote:
>> 
>> But make still fails with it. :-(
>
> try setting CONFIG_CC_STACKPROTECTOR_NONE=y and please let me know if
> the resulting kernel built with v3.2 gcc boots & works.

Sorry, I don't have gcc 3.2 around, and my gcc 3.3 environment produces
assembler errors in arch/x86/entry/entry_32.S.  Maybe binutils 2.15 is
not recent enough anymore?

Anyway, with CONFIG_CC_STACKPROTECTOR=y it is necessary to add -fno-pie
in scripts/gcc-x86_64-has-stack-protector.sh as well, because that
script invokes the compiler without KBUILD_CFLAGS.  That's probably not
a problem since -fstack-protector is newer than -fno-pie.  The attached
patch works for me with Debian's gcc-6 package.

Cheers,
       Sven

View attachment "0001-kbuild-add-fno-pie-to-KBUILD_CFLAGS.patch" of type "text/x-diff" (2036 bytes)