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 B284A3858D20 for ; Tue, 15 Mar 2022 12:19:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B284A3858D20 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 AC18261527; Tue, 15 Mar 2022 12:19:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3CFCC340E8; Tue, 15 Mar 2022 12:19:37 +0000 (UTC) Date: Tue, 15 Mar 2022 12:19:34 +0000 From: Mark Brown To: Catalin Marinas Cc: Jeremy Linton , Will Deacon , Szabolcs Nagy , "H . J . Lu" , Yu-cheng Yu , Kees Cook , Eric Biederman , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org Subject: Re: [PATCH v11 2/2] arm64: Enable BTI for main executable as well as the interpreter Message-ID: References: <20220308132240.1697784-1-broonie@kernel.org> <20220308132240.1697784-3-broonie@kernel.org> <59fc8a58-5013-606b-f544-8277cda18e50@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Zn5OOgOYreyhG/5Y" Content-Disposition: inline In-Reply-To: X-Cookie: Tax and title extra. X-Spam-Status: No, score=-5.8 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, T_SCC_BODY_TEXT_LINE 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: Tue, 15 Mar 2022 12:19:42 -0000 --Zn5OOgOYreyhG/5Y Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Mar 14, 2022 at 08:57:49AM +0000, Catalin Marinas wrote: > On Tue, Mar 08, 2022 at 12:01:17PM -0600, Jeremy Linton wrote: > > > Resolve this by adding a sysctl abi.bti_main which causes the kernel to > > > checking the BTI property for the main executable and enable BTI if it > > > is present when doing the initial mapping. This sysctl is disabled by > > > default. > > This seems less than ideal, maybe the default can be flipped with a CONFIG > > option? > I'm not keen on config options changing the ABI. If there's a good > chance that this feature won't be turned on (via sysfs) in distros with > MDWE, I'd rather drop the whole series than maintain unused code in the > kernel. I think it's more just that it's a pain to have to also update userspace for something fairly low risk than that it's an insurmountable obstacle. --Zn5OOgOYreyhG/5Y Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmIwhFUACgkQJNaLcl1U h9B+EQf/e5kbNpMgB2L6fsV1GSv1FEr+TMcObpZSeO0ZOhP8ji1gCLy/CUwnf+8p 0IQBQEJ8kpHsgmrtH8DXZeDcpy284Z4ST1fYfzI4sS7nj3U5Af71+n0zjMxtNvSN 9tywEji0AovV8vnFZo1CbwfshCVn9SwaJQR8dVWhIy9c9ju8268HqQ66qHEYNx79 97p6elUKnpdLi/1AeuGF9NgndWfnt27mD1ZSq0K/DUEWel4pLCl0I3kogH1Z49/j Vnzp+2rpjXiP1tc0hJScmTv1goIANTELAW/O6P0pq4Sv9pBx68BWTaWfwfhy6wQ3 1D9ZKticmaF2rEyq3LBNXhrIrk7XFA== =a1ze -----END PGP SIGNATURE----- --Zn5OOgOYreyhG/5Y--