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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, debug@rivosinc.com, szabolcs.nagy@arm.com, torvalds@linux-foundation.org, Yu-cheng Yu , Pengfei Xu Subject: Re: [PATCH v9 23/42] Documentation/x86: Add CET shadow stack description Message-ID: <1f04fa59-6ca9-4f18-b138-6c33e164b6c2@sirena.org.uk> References: <20230613001108.3040476-1-rick.p.edgecombe@intel.com> <20230613001108.3040476-24-rick.p.edgecombe@intel.com> <0b7cae2a-ae5b-40d8-9ae7-10aea5a57fd6@sirena.org.uk> <87y1knh729.fsf@oldenburg.str.redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="CHHivuSQNQZBIb3Y" Content-Disposition: inline In-Reply-To: <87y1knh729.fsf@oldenburg.str.redhat.com> X-Cookie: Not a flying toy. X-Rspamd-Queue-Id: 8FA161C0020 X-Rspam-User: X-Stat-Signature: jhmia79918cec1brbdnxzkogerqbi9by X-Rspamd-Server: rspam01 X-HE-Tag: 1686669346-665944 X-HE-Meta: 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 Mq3Wa447 IGSyNTHu28dX8x4iM7ySeG89i1pXdrDN+9dxICKni6H1OKaOjjnuIDYBO/RxtrOvmFftFeujR6Z0FP657AAx45q6uzrQldMewrNFjxsIkD7zEd8yUr7Vd24+yDO+29+ipUbJp1/k/tMA5lSarnvA9RchioYAoR9Xjd8+mvU5huKTkpbiBMf7b4r+3EOxeQ8YI/32+YAvAciL5ZE8iNONMiiwJpCbvV4N3O3ZlCVVUPr2pFCwEZAqtDFvspysPUrwejSvYKYAOf5mF3CGzWtUJKsukrcCwwXnNZaaZRA7LnP/vZs5MF+NoWqRY9tGkmex9vN2MvbsM1d5hZ5pEd4mmd6Pjg9PYB/fT+jd/P+xAg7mZ+0fDRlTuL03i9iXONFeuFyFjGv9z7fKRzasFp1gzVPDGWHNbOchawky5 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --CHHivuSQNQZBIb3Y Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Jun 13, 2023 at 02:37:18PM +0200, Florian Weimer wrote: > > I appreciate it's very late in the development of this series but given > > that there are very similar features on both arm64 and riscv would it > > make sense to make these just regular prctl()s, arch_prctl() isn't used > > on other architectures and it'd reduce the amount of arch specific work > > that userspace needs to do if the interface is shared. > Has the Arm feature been fully disclosed? Unfortunately no, it's not yet been folded into the ARM. The system registers and instructions are in the latest XML releases but that's not the full story. > I would expect the integration with stack switching and unwinding > differs between architectures even if the core mechanism is similar. > It's probably tempting to handle shadow stack placement differently, > too. Yeah, there's likely to be some differences (though given the amount of discussion on the x86 implementation I'm trying to follow the decisions there as much as reasonable on the basis that we should hopefully come to the same conclusions). It seemed worth mentioning as a needless bump, OTOH I defninitely don't see it as critical. --CHHivuSQNQZBIb3Y Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmSIiBMACgkQJNaLcl1U h9DYKAf/Vz3wx22uDdLyCBpiG7PQdfsvx6Gsa3OkqligILXiOR/RqMgrq58a10CL 1Y83LNYyJWuUw541NRW64qugDHs9G2NwIpxrgeD3mBQibPyJoJyFsEOia0VFOvB/ jEcMyC/PLUl6W0LBP7P/tyDcf6UyZY5mhI32w4k5JHImx4iNswSTcS5bEMrkbs/J wcEZi8RTKT6XeWHM1Y7Ky3oQax1I8b1G3pzGa6WK0c5fNstN0QRY6hpMFKknp1sR yygF1dgoS3kygw4ZeBsmpkmGJKETDGsCpqteh2JQ7XV2i2kEJe8IeOD/NAcPl43V Sovm7EiMjuwISm0hPggYtQ+vsFGHrg== =tl5C -----END PGP SIGNATURE----- --CHHivuSQNQZBIb3Y--