From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 DDB98322C8A for ; Mon, 5 Jan 2026 17:10:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767633010; cv=none; b=kNlL+mXov/nJuEJ9nLa/kwup/x4rlYQQm3D39234sEIUZLHxklWTjtZ2HVsFL6pX0hFQFVJdxt4TV2w6I5sv7LBYVDmwjaOg2syN8WhP3E2AbjGmccSdpYqJxY2yrbXgytEOCdXbfOSepbJh02ITH+hrpEgwz8xElEyuDAShpWs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767633010; c=relaxed/simple; bh=jUe7N1eHE7w7ktm5Q01rBBBQHZpgiCOpuwud7hXJCkk=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nAs6FWLoO8+aD4m9Q50AQsecDnTE/ozQY7MES2xhdQpVpY9FqgY+3ypEreaRpEXpoTkNypbJ1V7FEJteEoPCHtTrB101J/d5s4NQXWgCcFDnLFmpidFPZknq0TCEpJ/fBZFgEiFNQnqye+mnXTaUQB9BlLxLnumWQhgtCx1PXyU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dlLQK2BlRzJ4687; Tue, 6 Jan 2026 01:10:01 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 871764056A; Tue, 6 Jan 2026 01:10:01 +0800 (CST) Received: from localhost (10.126.174.38) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Mon, 5 Jan 2026 17:09:59 +0000 Date: Mon, 5 Jan 2026 17:09:58 +0000 From: Jonathan Cameron To: Ben Horgan CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v2 10/45] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs Message-ID: <20260105170958.00007c32@huawei.com> In-Reply-To: <20251219181147.3404071-11-ben.horgan@arm.com> References: <20251219181147.3404071-1-ben.horgan@arm.com> <20251219181147.3404071-11-ben.horgan@arm.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500012.china.huawei.com (7.191.174.4) To dubpeml100005.china.huawei.com (7.214.146.113) On Fri, 19 Dec 2025 18:11:12 +0000 Ben Horgan wrote: > From: James Morse > > The MPAM system registers will be lost if the CPU is reset during PSCI's > CPU_SUSPEND. > > Add a PM notifier to restore them. > > mpam_thread_switch(current) can't be used as this won't make any changes if > the in-memory copy says the register already has the correct value. In > reality the system register is UNKNOWN out of reset. > > Signed-off-by: James Morse > Signed-off-by: Ben Horgan Reviewed-by: Jonathan Cameron