From patchwork Mon Dec 28 12:49:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 354880 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CA2EC433E9 for ; Mon, 28 Dec 2020 14:26:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D67B522B3B for ; Mon, 28 Dec 2020 14:26:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503817AbgL1O0b (ORCPT ); Mon, 28 Dec 2020 09:26:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:34320 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503804AbgL1O00 (ORCPT ); Mon, 28 Dec 2020 09:26:26 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B709B221F0; Mon, 28 Dec 2020 14:25:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165545; bh=PeJ1Yj5psgqWtPPXCG4oxH/sNvVPUnY6H9cNlzKs/H0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xVBIQsVG7B2M4PBoUUoRPT5Y3x3XB/+Ti5CPRcdqfx2ZRDS/v6hzXF4+scdp4fxNp xzQh+pCpVm1BpZNXtcr+HQu3zuhy5vHFosQYcIBCuI/rzdYisnmgZU5MUm618zzPNb UOJnjc4F/Wz5xtVghICkE/1p5oBnmqhspAQ76VBg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Athira Rajeev , Michael Ellerman Subject: [PATCH 5.10 569/717] powerpc/perf: Exclude kernel samples while counting events in user space. Date: Mon, 28 Dec 2020 13:49:27 +0100 Message-Id: <20201228125048.168549072@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Athira Rajeev commit aa8e21c053d72b6639ea5a7f1d3a1d0209534c94 upstream. Perf event attritube supports exclude_kernel flag to avoid sampling/profiling in supervisor state (kernel). Based on this event attr flag, Monitor Mode Control Register bit is set to freeze on supervisor state. But sometimes (due to hardware limitation), Sampled Instruction Address Register (SIAR) locks on to kernel address even when freeze on supervisor is set. Patch here adds a check to drop those samples. Cc: stable@vger.kernel.org Signed-off-by: Athira Rajeev Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1606289215-1433-1-git-send-email-atrajeev@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/perf/core-book3s.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2125,6 +2125,16 @@ static void record_and_restart(struct pe perf_event_update_userpage(event); /* + * Due to hardware limitation, sometimes SIAR could sample a kernel + * address even when freeze on supervisor state (kernel) is set in + * MMCR2. Check attr.exclude_kernel and address to drop the sample in + * these cases. + */ + if (event->attr.exclude_kernel && record) + if (is_kernel_addr(mfspr(SPRN_SIAR))) + record = 0; + + /* * Finally record data if requested. */ if (record) {