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Edgecombe" , Deepak Gupta , Ard Biesheuvel , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v4 03/36] arm64/gcs: Document the ABI for Guarded Control Stacks Message-ID: References: <43ec219d-bf20-47b8-a5f8-32bc3b64d487@sirena.org.uk> <38edb5c3-367e-4ab7-8cb7-aa1a5c0e330c@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="CnsHSUBemytPXFhS" Content-Disposition: inline In-Reply-To: X-Cookie: Oh Dad! We're ALL Devo! X-Rspamd-Queue-Id: 4522B1A0027 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 4c7g7dmsmkb46yen6npf4s3hu8sa5sar X-HE-Tag: 1696343222-562715 X-HE-Meta: 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 GGPSB5o4 v/WLDZGeLQ42lAF6/3GijPawpbKhVxtaq9OHhcjkVdRm7Vix3BvVdgQlWXo7iLXC1ZGl5D3Ph/HNsXdYxUQ6JPwbentNs8ywyinr8IJY21CrGmwj3uWKFEx756P4JARj4JWXK0u2n2QbrO+QQ9BuifJWxEvENGmKW9erscGw8vspFajFsxsO0SoAA62BB2CsOoXE1Uro003zIIjUdVYe4WXJg0nqsM2XG8DRg86CjLlEBnIX9fA/W5AhcIUhwVh4r5MR0l9ZGfseolb1+YrJsVmI7Fvy+CnRZsXqUs+A+XXW+IEIhWynPPuRBWRZdP0ee0rnyZG8eL+GcJPg= 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: --CnsHSUBemytPXFhS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Oct 03, 2023 at 09:45:56AM +0100, Szabolcs Nagy wrote: > clone3 seems to have features that are only available in clone3 and > not exposed (reasonably) in libc apis so ppl will use clone3 directly > and those will be hard to fix for gcs (you have to convince upstream > to add future arm64 arch specific changes that they cannot test). Ah, I hadn't realised that there were things that weren't available via libc - that does change the calculation a bit here. I would hope that anything we do for clone3() would work just as well for x86 so the test side should be a bit easier there than if it were a future arm64 thing, though obviously it wouldn't be mandatory on x86 in the way that Catalin wanted it for arm64. > where this analysis might be wrong is that raw clone3 is more likely > used as fork/vfork without a new stack and thus no gcs issue. > even if we have time to fix code, we don't want too many ifdef hacks > just for gcs so it matters how many projects are affected. My impression was that raw usage of the APIs was a specialist enough thing that this was viable, ICBW though - I might not have been searching well enough (clone is an annoying term to search for!). --CnsHSUBemytPXFhS Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmUcJKoACgkQJNaLcl1U h9D1+wf9E8KLlwo7oauOMfMCaEHN33slVADlMHmi/XAO6e+v3qV+f+jIWgnm7QVZ NXQYwsmD9BjcMdlgDmlglFSC1Ui3L1auA8BtZNc0XaYT49uDudcAO4sxApsu0Ei4 YG1WN+8MyabX/ktfHNf2XyosySVjLipmkrlWSJaI89BnELx681xWUf+Ew7KDX6on I62ZOCIMFM9V0kfe8cIbwGsSRXm53lb29tDkOSKWRWQaNw8faH2YiSbmWG4kSF8u +dSRg051fgrBUj1dttRgE3oVlKaOAKF5+XtNe27dNeFpxXMMs6pZTjdZd0Us4QjE ETLB2y5WLQvi5XfxRiQqlJopkuzikA== =/LLg -----END PGP SIGNATURE----- --CnsHSUBemytPXFhS--