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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690823198; bh=FRZSQDS+XeV4uVWI+vRMHfLJQSlvsz3j8APAeSBXyRQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bjm4JuEER9ekFbVY94POgdKp2Wdg7qWVx6hscEfKciMqwhhw59FWXry9S2NvII1Xq W3KuimbOcMaS273TtbohajLtObRWhakR+zWHG4dJMdH+TUI359NBI6kFirlh7ptA8m xmis3n4ZlpVhtH/ApHSALFTqS1okKA2N6d41f3tKDzE3C9W2NUXGOrcBYsyTmday6X DyOom4vW6QZlu3XiBGJaGSb/r4uoRzm3B5gXFrWVM7A3M5ae9K2U5cyWu8R6soUdQS Qb226g+YzUYUbWXgF3ofLisOvmT1M2W2T9+GDWHr/KJVwgtnQU+2t53hf4JgrPKBz0 pMpifqPOlQcIQ== Date: Mon, 31 Jul 2023 18:06:28 +0100 From: Mark Brown To: "Edgecombe, Rick P" Cc: "corbet@lwn.net" , "ardb@kernel.org" , "maz@kernel.org" , "shuah@kernel.org" , "Szabolcs.Nagy@arm.com" , "keescook@chromium.org" , "james.morse@arm.com" , "debug@rivosinc.com" , "akpm@linux-foundation.org" , "catalin.marinas@arm.com" , "oleg@redhat.com" , "arnd@arndb.de" , "ebiederm@xmission.com" , "will@kernel.org" , "suzuki.poulose@arm.com" , "oliver.upton@linux.dev" , "hjl.tools@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "linux-kselftest@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "paul.walmsley@sifive.com" , "aou@eecs.berkeley.edu" , "palmer@dabbelt.com" , "linux-doc@vger.kernel.org" , "kvmarm@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-arch@vger.kernel.org" Subject: Re: [PATCH v3 21/36] arm64/mm: Implement map_shadow_stack() Message-ID: <0a6c90d6-f790-4036-a364-d4761fdd0e95@sirena.org.uk> References: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> <20230731-arm64-gcs-v3-21-cddf9f980d98@kernel.org> <5461c56cf4896f18bddaa66c3beec7b909fc8fb9.camel@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; 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charset=us-ascii Content-Disposition: inline On Mon, Jul 31, 2023 at 03:56:50PM +0000, Edgecombe, Rick P wrote: > On Mon, 2023-07-31 at 14:43 +0100, Mark Brown wrote: > Any thoughts on the questions at the end of this mail? > https://lore.kernel.org/lkml/7a4c97f68347d4188286c543cdccaa12577cdb9e.camel@intel.com/ Those are: > Someday when the x86 side is finally upstream I have a manpage for > map_shadow_stack. Any differences on the arm side would need to be > documented, but I'm not sure why there should be any differences. Like, > why not use the same flags? Or have a new flag for token+end marker > that x86 can use as well? Ah, it wasn't clear to me that this was a question rather than just open decisions about the eventual manpage. Looking again I think what you're asking about is that I see that at some point in development I lost the SHADOW_STACK_SET_TOKEN flag which x86 has. I suspect that was a rebasing issue as it wasn't a deliberate decision, there's no reason we couldn't have that. Other than that and the fact that we add both a stack swap token and a top of stack marker I'm not aware of any differences. --qSNeFAfZluwl23Q1 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmTH6hMACgkQJNaLcl1U h9C+/gf/fsd2+OP2IaWypYsnLbn4+Z1/XZAFZ/PaT8xKzJcuY77+Lo6ndMnLLuOt lJFPNM7SLDezZnZg8F06EmCFpye2/RpYHqaT1bXNOoYwl4yTF/xA5G5etJ/I3h7G fjaivE8ywdwUVINFANweDX+K+sCPIrepHdmGTdpGhasbLKOUg632qN9NaEKc5anx xCI48CteSjjSMr4a1Fwk6PavgzpONlo6DkUl0vlHevKJazDzFCApCQvVAITtCVYm eX0DriUi0Leu4vALeh7sbw/a1P0YkzRNZ16ydPLPmyGlQHgA6wSJ9+Nb5BdPe4xv 5gXikyjfTIEVFjyHFKfoj74bAtq0SA== =Wdxm -----END PGP SIGNATURE----- --qSNeFAfZluwl23Q1--