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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 080A0C433F5 for ; Fri, 22 Apr 2022 16:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=nR8Yvtmem9FgkEgvocht15gcAGzUkdYYka70OETsDkE=; b=NGz1iLZ8SAU8pK kpYn2ChxwOfFrGZYx1kq/aZJLuqW75+9zYfmIse9WJ8a2VzmjxTTojoIsDI96LUZtDjYC3AQKkkh3 lWu3Fvcdi1vnaEexcNXzTavIl4dnG9eqN5IXmgFdSB9mK6+qH6fuD8KFugX+q8JMzaBRXIJhPDCNJ 8KIguuhbA7t++TyF8mninpfDr/k3OAXAutVEZGKbXrG9y8l0Pf4/OdDUN3pL56w8PTCgx0I5mQ8IB yVNcjcrAMjjxpm19k2j0wGWRZrvutrneIJ2jWqQZwTtojCJokzb6FN3EK5Oj2rMxqMZh3k+w+cxcP vwfarv87xh80MiI1NvTA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nhw8m-001QuS-RY; Fri, 22 Apr 2022 16:28:17 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nhw8h-001Qru-QD for linux-arm-kernel@lists.infradead.org; Fri, 22 Apr 2022 16:28:13 +0000 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 1AED4B831AD; Fri, 22 Apr 2022 16:28:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D57AEC385A4; Fri, 22 Apr 2022 16:28:05 +0000 (UTC) Date: Fri, 22 Apr 2022 17:28:02 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Marc Zyngier , Shuah Khan , Shuah Khan , Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , Szabolcs Nagy , James Morse , Alexandru Elisei , Suzuki K Poulose , Luca Salabrino , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v14 16/39] arm64/sme: Implement traps and syscall handling for SME Message-ID: References: <20220419112247.711548-1-broonie@kernel.org> <20220419112247.711548-17-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220419112247.711548-17-broonie@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220422_092812_043080_BD9D58EF X-CRM114-Status: GOOD ( 16.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Apr 19, 2022 at 12:22:24PM +0100, Mark Brown wrote: > By default all SME operations in userspace will trap. When this happens > we allocate storage space for the SME register state, set up the SVE > registers and disable traps. We do not need to initialize ZA since the > architecture guarantees that it will be zeroed when enabled and when we > trap ZA is disabled. > > On syscall we exit streaming mode if we were previously in it and ensure > that all but the lower 128 bits of the registers are zeroed while > preserving the state of ZA. This follows the aarch64 PCS for SME, ZA > state is preserved over a function call and streaming mode is exited. > Since the traps for SME do not distinguish between streaming mode SVE > and ZA usage if ZA is in use rather than reenabling traps we instead > zero the parts of the SVE registers not shared with FPSIMD and leave SME > enabled, this simplifies handling SME traps. If ZA is not in use then we > reenable SME traps and fall through to normal handling of SVE. > > Signed-off-by: Mark Brown Re-adding my reviewed-by following the update. Reviewed-by: Catalin Marinas _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel