From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id B65E2C433EF for ; Wed, 2 Mar 2022 14:36:04 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2E2E149EDE; Wed, 2 Mar 2022 09:36:04 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Gidowwbe3Wys; Wed, 2 Mar 2022 09:36:03 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 05AC249EE1; Wed, 2 Mar 2022 09:36:03 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 85F2049ED6 for ; Wed, 2 Mar 2022 09:36:01 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AiUORHnsneAG for ; Wed, 2 Mar 2022 09:36:00 -0500 (EST) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 67BE049ED5 for ; Wed, 2 Mar 2022 09:36:00 -0500 (EST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E4876B81FFA; Wed, 2 Mar 2022 14:35:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84AB2C004E1; Wed, 2 Mar 2022 14:35:54 +0000 (UTC) Date: Wed, 2 Mar 2022 14:35:50 +0000 From: Catalin Marinas To: Mark Brown Subject: Re: [PATCH v12 08/40] arm64/sme: Manually encode SME instructions Message-ID: References: <20220225165923.1474372-1-broonie@kernel.org> <20220225165923.1474372-9-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220225165923.1474372-9-broonie@kernel.org> Cc: Basant Kumar Dwivedi , Will Deacon , Luis Machado , Szabolcs Nagy , Marc Zyngier , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, Alan Hayward , Shuah Khan , kvmarm@lists.cs.columbia.edu, Salil Akerkar X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, Feb 25, 2022 at 04:58:51PM +0000, Mark Brown wrote: > As with SVE rather than impose ambitious toolchain requirements for SME > we manually encode the few instructions which we require in order to > perform the work the kernel needs to do. The instructions used to save > and restore context are provided as assembler macros while those for > entering and leaving streaming mode are done in asm volatile blocks > since they are expected to be used from C. > > We could do the SMSTART and SMSTOP operations with read/modify/write > cycles on SVCR but using the aliases provided for individual field > accesses should be slightly faster. These instructions are aliases for > MSR but since our minimum toolchain requirements are old enough to mean > that we can't use the sX_X_cX_cX_X form and they always use xzr rather > than taking a value like write_sysreg_s() wants we just use .inst. > > Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm