From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by sourceware.org (Postfix) with ESMTPS id AC128385802B for ; Fri, 7 Jan 2022 13:11:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org AC128385802B Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1477460A3D; Fri, 7 Jan 2022 13:11:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59FD1C36AE0; Fri, 7 Jan 2022 13:10:58 +0000 (UTC) Date: Fri, 7 Jan 2022 13:10:55 +0000 From: Mark Brown To: Catalin Marinas Cc: Jeremy Linton , Szabolcs Nagy , Will Deacon , "H . J . Lu" , Yu-cheng Yu , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org, Mark Rutland Subject: Re: [PATCH v7 0/4] arm64: Enable BTI for the executable as well as the interpreter Message-ID: References: <20211115152714.3205552-1-broonie@kernel.org> <20211209111048.GM3294453@arm.com> <101d8e84-7429-bbf1-0271-5436eca0eea2@arm.com> <8550afd2-268d-a25f-88fd-0dd0b184ca23@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="WUnyaILR2EzduwUB" Content-Disposition: inline In-Reply-To: X-Cookie: teamwork, n.: X-Spam-Status: No, score=-5.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Jan 2022 13:11:04 -0000 --WUnyaILR2EzduwUB Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jan 07, 2022 at 12:01:17PM +0000, Catalin Marinas wrote: > Regarding (1), I don't remember whether we decided to do it this way > because it was more complicated to handle it in the kernel (like the 4 > more patches in this series) or because we wanted to leave the option to > the dynamic loader. It would be good to clarify this and we may have a > small window, as Jeremy said, where changing the ABI won't cause > problems (well, hopefully, there's still a risk). My understanding is that it was basically just a "let's defer everything to userspace" thing. It means that userspace is responsible for turning on BTI and is therefore responsible for any workarounds which are needed for problematic binaries, it's the absolute minimum the kernel can be responsible for. This all predates my involvement though. --WUnyaILR2EzduwUB Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmHYO94ACgkQJNaLcl1U h9Ce4gf9HW2dbZA6hQxBtat8BUQXOT3EeumgfxSkto+pcuzocpfOp/jbtrm0+SPz 2cmGCfZAZP9z4WiAYaMaSmnLysybYOkgOpvxUJeAsn1684BarvRcCaXs0Lt/poAN EiIeZG+dtIwqZNUbmImQ4cPAwiJ9y7gAE+Wlb4wRFR6UvQsBUbsi6L5pDOYlaFUf pms4C2qpfxlk4+sFJ9f2AdKL8ik3lSVn3NoFHbgpjzQOeDxaM8lfnYmFTkt48AvP AL2+akkI4LcefXg/fT/8GQYrdVv4FTIjQA63IsG/kyV2/zcTl2hoAJl83euM1ht6 2opcJwqh5xIZP9YyWtcpTozuZHdpbQ== =Yp3G -----END PGP SIGNATURE----- --WUnyaILR2EzduwUB--