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Date:   Thu, 29 Apr 2021 19:49:21 +0200
From:   Jonathan =?utf-8?Q?Neusch=C3=A4fer?= <j.neuschaefer@gmx.net>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>, j.neuschaefer@gmx.net,
        jniethe5@gmail.com, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/32: Fix boot failure with CONFIG_STACKPROTECTOR
Message-ID: <YIrxoYIjH9L8Fqzs@latitude>
References: <b688fe82927b330349d9e44553363fa451ea4d95.1619715114.git.christophe.leroy@csgroup.eu>
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On Thu, Apr 29, 2021 at 04:52:09PM +0000, Christophe Leroy wrote:
> Commit 7c95d8893fb5 ("powerpc: Change calling convention for
> create_branch() et. al.") complexified the frame of function
> do_feature_fixups(), leading to GCC setting up a stack
> guard when CONFIG_STACKPROTECTOR is selected.
>=20
> The problem is that do_feature_fixups() is called very early
> while 'current' in r2 is not set up yet and the code is still
> not at the final address used at link time.
>=20
> So, like other instrumentation, stack protection needs to be
> deactivated for feature-fixups.c and code-patching.c
>=20
> Reported-by: Jonathan Neuschaefer <j.neuschaefer@gmx.net>
> Fixes: 7c95d8893fb5 ("powerpc: Change calling convention for create_branc=
h() et. al.")
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---

Thank you for looking into this issue. This patch does indeed fix my
issue.

Tested-by: Jonathan Neuschaefer <j.neuschaefer@gmx.net>


Thanks again,
Jonathan

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