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 7AF3BCA5FDD for ; Fri, 2 Oct 2026 12:44:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LynaPcEemc8Fvi0pdqSvue8XBTJnHlD/bhr/8DNTDJE=; b=apfquu3W4xi8NhuxwOy66xYWt8 lrAXjnD0M9HUtmm1qib5nIliRDBZVqpcBGvdoD0qF536uqmR1sQEE2+JcChF9dY4KW1AUkOslVByn pNSsjxqrahmPK7xM37VkqsiGjzn8poUic6yH2gDTCbd7wmrAxMLXirvwkpL3AiSJs4zxpD5tfv6+w r0pPNei3Os9u9e3VqyBhFN7ewoNcFf9VaKfuFSmkXGX2IBqREPIhsxji/0+oT9UW3q61NbHJiCL7Y hnQpfheKTO683VnxlWgzf4GodmuVrIbHz+kJms+BQuCWcWSqCe+qgBGMViQTW147yc/fVQoscv7ah kw+59nMw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCcd9-0000000BbVK-2kk0; Fri, 02 Oct 2026 12:44:51 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCcd8-0000000BbUy-3jm9 for linux-arm-kernel@lists.infradead.org; Fri, 02 Oct 2026 12:44:50 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id F392760A93; Fri, 2 Oct 2026 12:44:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7CCC1F000FF; Fri, 2 Oct 2026 12:44:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790945089; bh=LynaPcEemc8Fvi0pdqSvue8XBTJnHlD/bhr/8DNTDJE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=mnoG2iSMabxxw+PTv5TXCr8x8UA2J9i6P8AwYTSdEEaEC8q9g0s9oV4VZF0e1bZLM t4Qf5KI06OubB1qzyD088zZe4hkWta82J91l67s1whCwbU57Z5VSNtuzsszxEtpwAL RNB564Ra2u29j8JUN/1Eec9Z7owo5I6eRm3qBu7XsJRO8XFI069xrOpzrb28S5ZLSJ bThxaW8o5WHZUvufJ2WVney2gc7xEE2UGnWu7CvQZvFkUm2+xfk5QPK0u+DdcvtFLZ phluqkj9PH0AViV2udz5FuUGCoVRpOrF71yzEf31tZYkWcDOJ6bFkCg7ggKLXT2Qh4 zKeR3PQ4+mICA== Date: Fri, 2 Oct 2026 13:44:44 +0100 From: Will Deacon To: Tomohiro Misono Cc: Catalin Marinas , Mark Rutland , Jonathan Corbet , Shuah Khan , Randy Dunlap , Marc Zyngier , Thomas Gleixner , Radu Rendec , Kohei Enju , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH 3/4] perf: arm_pmu: Add workaround for FUJITSU-MONAKA Erratum E#030002 Message-ID: References: <20261002-monaka-fix-for-upstream-v1-0-4aec0b0cbe34@fujitsu.com> <20261002-monaka-fix-for-upstream-v1-3-4aec0b0cbe34@fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261002-monaka-fix-for-upstream-v1-3-4aec0b0cbe34@fujitsu.com> 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 02, 2026 at 07:26:51PM +0900, Tomohiro Misono wrote: > FUJITSU-MONAKA Erratum E#030002 affects FUJITSU-MONAKA CPU. > > On affected FUJITSU-MONAKA CPUs, after a PMU event counter is > stopped at a value just before overflow, an overflow might still > be incorrectly detected, resulting interrupt storm in some case. > > Work around the erratum by avoiding programming PMU event counters > with values within five counts of overflow. What's the user-visible behaviour of this erratum? It's not entirely clear to me why we need to do anything at all. Will