From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.5 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by inbox.vuxu.org (Postfix) with SMTP id 8429E232D5 for ; Thu, 22 Feb 2024 15:00:11 +0100 (CET) Received: (qmail 15988 invoked by uid 550); 22 Feb 2024 13:56:46 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 9216 invoked from network); 22 Feb 2024 13:54:54 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708610282; bh=qjmPfoVywGfr4jqsh5FJ/yxg8KOM8vjU9JBU7Z2KpR4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aanTBA7Q5SU1zTtPDaMhX4nwG1EogaRTB6711DBMiXTmU8FRFzAcB7zQYgcUM2OaJ XHksqp0nMGR665Zm+lDgT+yDropmULnL8lKiWtjJKJ3NL1ecrCmrLU8OR7ZcsowhNV u+zivFcDWQqEkxqOD8K6xYSAKOOwaNrLKqXv3SiHTMwf1JJvLKTjXxiKAVOfTIyX6A QW2bcztZSCAVxYQoLX8XBJuGKkKkAorTgEuxggq4WcuU6lezBNTj3BInSRIVEXBTih tlOZte74whZIn/QZQ00VCk0r89EM0A76cAGvXtNTTd6uAX30BQpy9H3OHFzXJG137X 8lNOIn1prx5Vg== Date: Thu, 22 Feb 2024 13:57:53 +0000 From: Mark Brown To: "Edgecombe, Rick P" Cc: "dalias@libc.org" , "linux-arch@vger.kernel.org" , "suzuki.poulose@arm.com" , "Szabolcs.Nagy@arm.com" , "musl@lists.openwall.com" , "linux-fsdevel@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "kvmarm@lists.linux.dev" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "catalin.marinas@arm.com" , "oliver.upton@linux.dev" , "palmer@dabbelt.com" , "debug@rivosinc.com" , "aou@eecs.berkeley.edu" , "shuah@kernel.org" , "arnd@arndb.de" , "maz@kernel.org" , "oleg@redhat.com" , "fweimer@redhat.com" , "keescook@chromium.org" , "james.morse@arm.com" , "ebiederm@xmission.com" , "will@kernel.org" , "brauner@kernel.org" , "hjl.tools@gmail.com" , "linux-kselftest@vger.kernel.org" , "paul.walmsley@sifive.com" , "ardb@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , "thiago.bauermann@linaro.org" , "akpm@linux-foundation.org" , "sorear@fastmail.com" , "linux-doc@vger.kernel.org" Message-ID: References: <20240221012736.GQ4163@brightrain.aerifal.cx> <20240221145800.GR4163@brightrain.aerifal.cx> <4a3809e8-61b2-4341-a868-292ba6e64e8a@sirena.org.uk> <20240221175717.GS4163@brightrain.aerifal.cx> <20240221183055.GT4163@brightrain.aerifal.cx> <20240221190639.GU4163@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Y7x2ZPCVf8cy8GEb" Content-Disposition: inline In-Reply-To: X-Cookie: I have accepted Provolone into my life! Subject: Re: [musl] Re: [PATCH v8 00/38] arm64/gcs: Provide support for GCS in userspace --Y7x2ZPCVf8cy8GEb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Feb 21, 2024 at 07:22:21PM +0000, Edgecombe, Rick P wrote: > On Wed, 2024-02-21 at 14:06 -0500, dalias@libc.org wrote: > > It's fine to turn RDSSP into an actual emulated read of the SSP, or > > at > > least an emulated load of zero so that uninitialized data is not left > > in the target register. > We can't intercept RDSSP, but it becomes a NOP by default. (disclaimer > x86-only knowledge). For arm64 we have a separate control GCSCRE0_EL1.nTR for access to GCSPR_EL0 (our SSP equivalent) we can use. > > I have not looked at all the instructions that become #UD but I > > suspect they all have reasonable trivial ways to implement a > > "disabled" version of them that userspace can act upon reasonably. > This would have to be thought through functionally and performance > wise. I'm not opposed if can come up with a fully fleshed out plan. How > serious are you in pursuing musl support, if we had something like > this? Same here, we have to be careful since it's defining ABI in a way that we don't normally provide ABI but if there's a clear case for doing it then... --Y7x2ZPCVf8cy8GEb Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmXXUuAACgkQJNaLcl1U h9CWhgf9ENKHpmQFWkFp9BvnSQpoqzt8GvTsea21+X/Sj2LF1t9awlhI1ZonFcLg kiWOH7voRFXaX11HTooF+5zW0lljzQzeKy6a4cAqvyhV93pQz5U7Tzuk5xqkLe3o mtXBUEWVIO/JPNSAwHNb44hXL7AjS1MEYgj0iqYvqWCYqikKit3kjOjJrc3jdb4y 3NQgra/qAykoQji1F3ZFkEtRyHALvMWET9TzzVyrCoTYPzIRzCWnkkBxKsNMokGC nwxW+cuoESrLNygNc/V3CbbUqAYkdO7AbmSvBvzQ0pboXO5M+p4sPnapddZeoYiK JVmWfU7+hu6JUz1Bj5tBIoRL24Q7Og== =mhhY -----END PGP SIGNATURE----- --Y7x2ZPCVf8cy8GEb--