From nobody Sun Feb 8 11:21:40 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2B4BC7EE2E for ; Fri, 9 Jun 2023 22:43:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231183AbjFIWnz (ORCPT ); Fri, 9 Jun 2023 18:43:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229552AbjFIWny (ORCPT ); Fri, 9 Jun 2023 18:43:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D4E63A87 for ; Fri, 9 Jun 2023 15:43:53 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id CD7BF65781 for ; Fri, 9 Jun 2023 22:43:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C060CC433EF; Fri, 9 Jun 2023 22:43:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686350632; bh=pFXxi/+k0vgMNVbo/aKTzxMO8ok6BkKhrmW5ZW5j7JE=; h=From:Date:Subject:To:Cc:From; b=Um6tyhVDVM1tBkhRxlYN3csYLcMYhwLbZYn+iQ5SUOEptjd2UUFzM/uY1NmTRJHgJ WO8ommVW0albmjJPqdXnzDCP2yNWJ5f7b3G4OXLUoizF+JGETrIJ2Q3CrZ0SXS3pYI TRt0h2nXOX+uprOG8gIs+zqnLAemelRr1YsjfLeUCRJbwhY4jceYpuhDZdTCmJbtHl IgdNVEfCcsN4hvPLRo8diIzhFADpzUqclgKlJw/SWTI90E6BnvbDrYVhmovtCc6vxO 3r0VaPZLZKo3DEQs5yy9GuozF6rJqLK9l0T2IXFAZ5zx3wOEk3eXbgae+CQL4ufVZz SmnpYTy/4EozA== From: Mark Brown Date: Fri, 09 Jun 2023 23:43:41 +0100 Subject: [PATCH v2] arm64/fpsimd: Exit streaming mode when flushing tasks MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230607-arm64-flush-svcr-v2-1-827306001841@kernel.org> X-B4-Tracking: v=1; b=H4sIAByrg2QC/32NQQ7CIBAAv9Jwdg1gQ1tP/sP0ALgtpBXMoqhp+ ndpH+BxJpnMwhKSx8TO1cIIs08+hgLyUDHrdBgR/K0wk1yeuOINaLqrGob5lRykbAnqxtpG6dY aY1nJjE4IhnSwbgvfkaZNPwgH/9lP176w8+kZ6buPs9jsn0cWIKBppdBKdB1yfZmQAs7HSCPr1 3X9AYVnDo/IAAAA To: Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Anders Roxell , Naresh Kamboju , Mark Brown X-Mailer: b4 0.13-dev-bfdf5 X-Developer-Signature: v=1; a=openpgp-sha256; l=1193; i=broonie@kernel.org; h=from:subject:message-id; bh=pFXxi/+k0vgMNVbo/aKTzxMO8ok6BkKhrmW5ZW5j7JE=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBkg6sl7hwnoCTpgzs8tkHwo1tsLhOytwBi8AEz9daW wkZDurmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZIOrJQAKCRAk1otyXVSH0EfMB/ 4iqKhRm1wjF7Flf4wvqcjNAsKMrWOvwFpKn3Lrf+4Bnw4/p3udF9Gl/+wf1UjPsnl/L41AjgkzW/23 cga9vRpCvRnQUYLzc61LYJSOmlNKCTUgcRV/8yZjxxsqj3ExOrQqTF2FpQUcBiY4Dk4v7RqFnnQdF3 19VLxC5QgFeOGysFPDaPN6MMuk4HMCLpbdtz7K5SBF9eLLhY9C/hTbGMHvml/l50VQZL5iYypbRtcZ YeQ+HkZTIa2U3HeWheolO1FvUOgNzxc5GkvytsYdAatWZkL5aYy3fTuyAOZTF9cTNg8kYOhfQsAq+o VV61IbAAB/7AYYE+lUorxFwRWlpW+r X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ensure there is no path where we might attempt to save SME state after we flush a task by updating the SVCR register state as well as updating our in memory state. I haven't seen a specific case where this is happening or seen a path where it might happen but for the cost of a single low overhead instruction it seems sensible to close the potential gap. Signed-off-by: Mark Brown --- Changes in v2: - Do a full SMSTOP to cover ZA as well. - Link to v1: https://lore.kernel.org/r/20230607-arm64-flush-svcr-v1-1-7821= a6199e0a@kernel.org --- arch/arm64/kernel/fpsimd.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 2fbafa5cc7ac..7a1aeb95d7c3 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1649,6 +1649,7 @@ void fpsimd_flush_thread(void) =20 fpsimd_flush_thread_vl(ARM64_VEC_SME); current->thread.svcr =3D 0; + sme_smstop(); } =20 current->thread.fp_type =3D FP_STATE_FPSIMD; --- base-commit: 44c026a73be8038f03dbdeef028b642880cf1511 change-id: 20230607-arm64-flush-svcr-47cc76a8cbbc Best regards, --=20 Mark Brown