Date: Mon, 8 Apr 2019 11:08:58 -0700 From: Thomas Garnier <thgarnie@...omium.org> To: Christopher Lameter <cl@...ux.com> Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com>, Kristen Carlson Accardi <kristen@...ux.intel.com>, Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, "the arch/x86 maintainers" <x86@...nel.org>, Dennis Zhou <dennis@...nel.org>, Tejun Heo <tj@...nel.org>, Boris Ostrovsky <boris.ostrovsky@...cle.com>, Juergen Gross <jgross@...e.com>, Stefano Stabellini <sstabellini@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, Andi Kleen <ak@...ux.intel.com>, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Michal Hocko <mhocko@...e.com>, Mike Rapoport <rppt@...ux.vnet.ibm.com>, Stephen Rothwell <sfr@...b.auug.org.au>, Cao jin <caoj.fnst@...fujitsu.com>, Brijesh Singh <brijesh.singh@....com>, Masahiro Yamada <yamada.masahiro@...ionext.com>, Joerg Roedel <jroedel@...e.de>, Peter Zijlstra <peterz@...radead.org>, Kees Cook <keescook@...omium.org>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, LKML <linux-kernel@...r.kernel.org>, xen-devel <xen-devel@...ts.xenproject.org> Subject: Re: [PATCH v6 14/27] x86/percpu: Adapt percpu for PIE support On Mon, Apr 8, 2019 at 10:56 AM Christopher Lameter <cl@...ux.com> wrote: > > On Mon, 8 Apr 2019, Thomas Garnier wrote: > > > > It didn't work originally but I will revisit to see if I missed something. > > > > I revisited and couldn't find a way to prevent relocations to the > > percpu section. Without PIE, you can reference absolute address which > > was convenient for percpu. > > Can you switch PIE off for the percpu section? If not maybe the linker > needs to have an additional option? I don't think so or I didn't find any option to do that. Changing the linker might be a bit too much if we have a software solution which doesn't impact performance. > > Cannot imagine that this is not possible. You neeed to be able to > reference registers that are in fixed memory locations. > > > > Christopher: Did you have something specific in mind? > > I thought that we just leave it as is. I would like to as well. I will try couple things at the assembly level instead of the linker and come back to this thread.
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.