linux-kernel - Re: [RFC/RFT PATCH 08/19] x86: Use PIE codegen for the relocatable 64-bit kernel

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Message-ID: <CAMj1kXFSGEURMJW0-4uVTBVvwV1YNzE9J8GMFrOtoYdCTu6r1g@mail.gmail.com>
Date: Fri, 9 Jan 2026 23:07:33 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Jan Engelhardt <ej@...i.de>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org, 
	linux-hardening@...r.kernel.org
Subject: Re: [RFC/RFT PATCH 08/19] x86: Use PIE codegen for the relocatable
 64-bit kernel

On Fri, 9 Jan 2026 at 22:34, Jan Engelhardt <ej@...i.de> wrote:
>
>
> On Thursday 2026-01-08 10:25, Ard Biesheuvel wrote:
> >
> >As an intermediate step towards enabling PIE linking for the x86_64
> >KASLR kernel, enable PIE codegen for all C and Rust objects that are
> >linked into the kernel proper. Add a Kconfig option RELOCATABLE_PIE for
> >this, depending on RELR support in the linker, as the relocation tables
> >will blow up the kernel image otherwise.
>
>
> > KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
> >...
> >+
> >+        pie-ccflags-$(CONFIG_CC_IS_GCC) += $(call cc-option.-mdirect-extern-access)
>
> I think that dot there next to -mdirect-extern-accesss should have been
> a comma.
>

Indeed, thanks for spotting that!