From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A133E13DDCA for ; Tue, 18 Jun 2024 17:34:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718732097; cv=none; b=KJfvknbwn2sN+wT7Emik2WPyX1nm0QmjpC2nT6YQWM0Ft5wyd8qVGYiw5IcJY2ewXjHsI/yd/G8xaL83hxbPNEM4zNeNk6NbFxodUqZz7uTi6iiB76EDad2pBifDUdhF25S+J3xlsEEvrIAJPFl+QcTI4LJnhgwqUvbIUdA/6js= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718732097; c=relaxed/simple; bh=Eg9SpS2Lrzw+GME75YTsQ7NIJ1lZ88nPumulLSrni4s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qfueo4Vu4VTppM72tT8B9JwoMYQZxrUQigEZ5+2uCibMMb3wNFP5d1Wq/uGZnc43BGmtvsV0TTuPIqOGXa4+O8zB1A24Bsc6RA9dJ6hibWzn0NIvIlXT9YEizwedWzylkHXeXPiNrp1oEP1UbQM+H3LrmFUuUK6GpirqT9mdVJU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UqjUMCIB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UqjUMCIB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EAE1C3277B; Tue, 18 Jun 2024 17:34:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718732097; bh=Eg9SpS2Lrzw+GME75YTsQ7NIJ1lZ88nPumulLSrni4s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UqjUMCIBfZ961IPd1+RltT7pZDVUeV56jBdGUE33xuEuVk3+7qC4NP2Sv/OlEzaiO pF071j7ZS4Yk7zQ4BwaFZ50arxlTh/1Q8fZA9ja95OxfKj8fVrsL6qgk6YOTdMHA6e H0miICxZXLEtla+86g5cODiFbB1Q4YSXBaUGX/mRDDxH+vbKQVTz85Sd85tqk5FCav ukOki3h1U/UFPTvO8Ve5E4BJppdP30bDWyvYfRHwccumfQAOk2U1Qv3hep3nxPacrG JLW3MUNs9tqPzff0kiXv7UQfpGkcdFdEsT4SLPRwiFDQeD3uIKdwUqLxsY+fjmBcfL Nya+Iq4mSOeig== Date: Tue, 18 Jun 2024 18:34:50 +0100 From: Conor Dooley To: Andrew Jones Cc: =?iso-8859-1?Q?Cl=E9ment_L=E9ger?= , linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, devicetree@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, conor.dooley@microchip.com, anup@brainfault.org, atishp@atishpatra.org, robh@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, christoph.muellner@vrull.eu, heiko@sntech.de, charlie@rivosinc.com, David.Laight@aculab.com, parri.andrea@gmail.com, luxu.kernel@bytedance.com Subject: Re: [PATCH v3 4/6] riscv: hwprobe: export Zawrs ISA extension Message-ID: <20240618-hurler-aerospace-1e42dc3c7fe9@spud> References: <20240426100820.14762-8-ajones@ventanamicro.com> <20240426100820.14762-12-ajones@ventanamicro.com> <20240618-581fb4c20b4fe05d76eafa44@orel> <20240618-deftly-operation-de4f8ac260d5@spud> <20240618-e898082d22cbc508c5655f84@orel> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="XaeHdozvGsU2g9qA" Content-Disposition: inline In-Reply-To: <20240618-e898082d22cbc508c5655f84@orel> --XaeHdozvGsU2g9qA Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 18, 2024 at 07:05:41PM +0200, Andrew Jones wrote: > On Tue, Jun 18, 2024 at 05:59:22PM GMT, Conor Dooley wrote: > > On Tue, Jun 18, 2024 at 06:01:04PM +0200, Andrew Jones wrote: > > > On Tue, Jun 18, 2024 at 03:48:59PM GMT, Cl=E9ment L=E9ger wrote: > > > > On 26/04/2024 12:08, Andrew Jones wrote: > > > >=20 > > > > BTW, the spec also states that "When the TW (Timeout Wait) bit in > > > > mstatus is set and WRS.NTO is executed in any privilege mode other = than > > > > M mode, and it does not complete within an implementation-specific > > > > bounded time limit, the WRS.NTO instruction will cause an illegal > > > > instruction exception." so I guess the process will be killed in th= is case ? > > >=20 > > > We don't expect mstatus.TW to be set. If it is, then wfi would likely= kill > > > the kernel before wrs.nto gets a chance to, but one or the other will > > > certainly ensure usermode never gets a chance to try it :-) > > >=20 > > > We have a handful of these assumptions about how M-mode has configured > > > things prior to Linux starting. It'd be good if we documented them all > > > somewhere. > >=20 > > Boot.rst :) If you're adding a new assumption, I think it should go > > there. >=20 > It's an old assumption (wfi has been counting on it since the beginning of > time). But documenting it, along with anything else similar to it, in > boot.rst is a good idea. I've added that to my TODO. Misunderstanding of "new" I think, I meant new to documentation not just new to the kernel :) --XaeHdozvGsU2g9qA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZnHFOgAKCRB4tDGHoIJi 0hdZAP96LbqLFt2MaBozG2La5ffSTyWhHlM4MRkvTGUYw1JObgEAjxFOUiYt642G EOEzP7700TwtctflvGwM6iVYrmX+Ggw= =TKEy -----END PGP SIGNATURE----- --XaeHdozvGsU2g9qA--