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b=HbeM88beLvexpIibuyARfwJXtbdxo9ki+MlIaadD1gh0a7YVjYtcTdRoEMkoAlF4e f4s7KvHkYTwinGlbPzN4xftfw5YTVc44PcOBAGfyD5v5p3V/xuc07GAi38/ajzMste lLRn5hcLEoGxFfA+bKYQ+HCxOn3t3ZTtcTYNuIF3iQBHbFc/hG4PMLC8CZkXiqsMmG aHw88t8V9rFcpnkoolv/5Eq4fzj5MwWj0igxO5CcSAl/gnWNOpQfabc9yW8MmCu7zo QPGOztI2WwQvoq1Bexuky4J0Oe/Ti2n7x3GnbRyw4SrJN/StBLvUd4yMlXRexkwYwb 7duKxT/HAPulg== Date: Tue, 15 Oct 2024 12:37:24 +0100 From: Mark Brown To: Joey Gouly Cc: Will Deacon , Kevin Brodsky , linux-arm-kernel@lists.infradead.org, nd@arm.com, akpm@linux-foundation.org, aneesh.kumar@kernel.org, aneesh.kumar@linux.ibm.com, anshuman.khandual@arm.com, bp@alien8.de, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, dave.hansen@linux.intel.com, hpa@zytor.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, maz@kernel.org, mingo@redhat.com, mpe@ellerman.id.au, naveen.n.rao@linux.ibm.com, npiggin@gmail.com, oliver.upton@linux.dev, shuah@kernel.org, skhan@linuxfoundation.org, szabolcs.nagy@arm.com, tglx@linutronix.de, x86@kernel.org, kvmarm@lists.linux.dev, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v5 19/30] arm64: add POE signal support Message-ID: <090857dd-979f-4071-9772-8d0053ff361f@sirena.org.uk> References: <20240822151113.1479789-1-joey.gouly@arm.com> <20240822151113.1479789-20-joey.gouly@arm.com> <47e1537f-5b60-4541-aed1-a20e804c137d@arm.com> <20241009144301.GA12453@willie-the-truck> <20241014171023.GA18295@willie-the-truck> <20241015095911.GA3777204@e124191.cambridge.arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="W88ha9UeD6OkiR51" Content-Disposition: inline In-Reply-To: <20241015095911.GA3777204@e124191.cambridge.arm.com> X-Cookie: New customers only. X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 05FAE10000B X-Stat-Signature: pgsnxa8wcd8j3j1znxzuo9rox5tq6e55 X-Rspam-User: X-HE-Tag: 1728992249-428677 X-HE-Meta: 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 EWeBRTki 1ahOLSIvqE1drMW3vzR/kjQzX0J6ksUdq6qpkVf79tuRn68z09nYs5ndv+bGfVJv5/7XVzh3b6DqyJzRAyVoDE5dJP6uC/j3Hr1LmldxKyKIsPuRqIDKCvWhPXhqeIIheehaz5e4tQsDiWwIW2YuF1m1c4AxkzUKuT3rH0XiT+gZ3YULNWpGBWJtJ6YbUU6rcpairCmDyKvq1B1WZFa3s3jYyoda7tqlsUI3X7rG04svAE3B0shp9MNXcRrbHb4FWHPVd/E7N7lUB42UywDAFUv7xWr7t2Ye9aOlJH3EGiHuB5XvNI8+NGBSMWk7FchnWa+qLnT42zCVKV/TtkPD1ubRBFw== 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: List-Subscribe: List-Unsubscribe: --W88ha9UeD6OkiR51 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Oct 15, 2024 at 10:59:11AM +0100, Joey Gouly wrote: > On Mon, Oct 14, 2024 at 06:10:23PM +0100, Will Deacon wrote: > > Looking a little more at this, I think we have quite a weird behaviour > > on arm64 as it stands. It looks like we rely on the signal frame to hold > > the original POR_EL0 so, if for some reason we fail to allocate space > > for the POR context, I think we'll return back from the signal with > > POR_EL0_INIT. That seems bad? > If we don't allocate space for POR_EL0, I think the program recieves SIGSGEV? ... > So I think it's "fine"? Yeah, there's a bunch of other stuff would go badly if we tried to carry on after failing to allocate a signal frame. --W88ha9UeD6OkiR51 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmcOU/MACgkQJNaLcl1U h9BfWgf/eSDT7mJTq3m8uQf08GvOUXMDhZbrgXOWwb+FyP6aWAAddUEovPEavEvc iv7L9TzG/BRu8Dn9feF7LHlXUbcynAzscFgaysXUrafVyKatccR5v1IhGvNyzdeX sUP+mTNHfLoIh5AQA5WfUJHN47Jq9/O1R1cJ/BgYWKlMgbEAMHFqKknfApuV7K2Y S6PpBawO6LvT641x+zS1Vcl+Y7jFRkHt89aLWfhetheuo6f8o2Lc1qBHN4f6kqXp iR7moBoquhONF4SuwZcTIeBXOuRRFTW8GdZNm/iVt6eYJeKf4Vv8aAhun8+Dam1y crxvSRFOp4cZ2VKI+zWNCKFw+nIBZg== =o0Ti -----END PGP SIGNATURE----- --W88ha9UeD6OkiR51--