From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 1 Feb 2019 02:31:36 +0000
From: Christopher Lameter <cl@linux.com>
Subject: Re: [PATCH v6 14/27] x86/percpu: Adapt percpu for PIE support
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To: Thomas Garnier <thgarnie@chromium.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>, kristen@linux.intel.com, Andy Lutomirski <luto@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, the arch/x86 maintainers <x86@kernel.org>, Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Juergen Gross <jgross@suse.com>, Stefano Stabellini <sstabellini@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Andi Kleen <ak@linux.intel.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@linux.vnet.ibm.com>, Stephen Rothwell <sfr@canb.auug.org.au>, Cao jin <caoj.fnst@cn.fujitsu.com>, Brijesh Singh <brijesh.singh@amd.com>, Masahiro Yamada <yamada.masahiro@socionext.com>, Joerg Roedel <jroedel@suse.de>, Peter Zijlstra <peterz@infradead.org>, Kees Cook <keescook@chromium.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, LKML <linux-kernel@vger.kernel.org>, xen-devel <xen-devel@lists.xenproject.org>
List-ID: <kernel-hardening.lists.openwall.com>

On Thu, 31 Jan 2019, Thomas Garnier wrote:

> The per-cpu symbols are in a section that is zero based to create
> offsets. The compiler doesn't see them as offsets but as relative
> symbol and try to relocate them. Given the distance between zero and
> the mapped kernel is much larger than the instruction offset range, it
> fails to do it.

We switch that off in the linker. If that does not work with your
modifications then you need to figure out how to update the link
configuration.