From patchwork Thu Feb 16 14:12:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13143207 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 61AF3C64EC4 for ; Thu, 16 Feb 2023 14:14:07 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=nN2vgt1VgoJXeStVnLdFuBT3tAE2Rye27bDNT4q+6rE=; b=QJDmG5WBeo8psZ O8zhzCITFVJdWkJ7kA6IR2c8Oj+Oknl5oFqUwhoMB67vd1aZAtuQIs9bFiSAbXxvunFqlxU8cKo2K HXzSVPRPdQAOT1pnpRtAoAVubnSld7t/Be1+3f6fMcKwW2aCCsCiufVXAxqsqUJ440V45gwVLtti+ k6x7VYfMcAKvwOKkKHzAVqYzl0zqGtOrKbErx+C9GMEf1cxOqFSdNj0Amnt+MzCAzOFJ+/CV+bTek SN/G//JJswlWtFUcSjq7QiP9//rGSIpQyf6U42lHHj+NQpM1I4QvQGdOZc0ZrXCSK24fLOFBgWRGQ ZN5+ediSkLl3jS/6Zz8Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pSf0W-00AXA4-Dg; Thu, 16 Feb 2023 14:13:08 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pSf0K-00AX60-U4 for linux-arm-kernel@bombadil.infradead.org; Thu, 16 Feb 2023 14:12:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=6AnbsUqvia9iqv6iQhEJcNWJ20MaMEePInKnN+DHcis=; b=Hp6OPxAXFfvh5OTpCQEB93vwow 1apWcw6tk216sRXuxOJrp9CB11dw2izTll7RWvZqpJZNArTLSWRLx2NolTwYfY2M0uqJPV7I8GIUU iiisGdqK3O1Mys1geb3dlGkFTPbXr2t2VkIrsSfs1YLQWRmGRA0joJJflqO3YXhGy1M0Z5plbMzcH BuheOYv3HNmOP4SEac+9iQie0cghLjFuaoL8uOb8/NyK+ngr3HhXp5g3Ahm/aNywLLWEfoCtMwD0K MMtln7BGowWAtDRezPc73L6zpIperB9Ti+/FxoRdDelC8wbuPpWcX45lyut1O/FJvnoBxif1oYWEq EsjPTnAA==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pSeza-00AIkh-1p for linux-arm-kernel@lists.infradead.org; Thu, 16 Feb 2023 14:12:55 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5D2AF1682; Thu, 16 Feb 2023 06:13:32 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 51DCA3F703; Thu, 16 Feb 2023 06:12:48 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: asahi@lists.linux.dev, ecurtin@redhat.com, j@jannau.net, lina@asahilina.net, linux-kernel@vger.kernel.org, mark.rutland@arm.com, peterz@infradead.org, ravi.bangoria@amd.com, will@kernel.org Subject: [PATCH 2/2] arm64: perf: reject CHAIN events at creation time Date: Thu, 16 Feb 2023 14:12:39 +0000 Message-Id: <20230216141240.3833272-3-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230216141240.3833272-1-mark.rutland@arm.com> References: <20230216141240.3833272-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230216_141253_314596_AA869F37 X-CRM114-Status: GOOD ( 12.80 ) 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 Currently it's possible for a user to open CHAIN events arbitrarily, which we previously tried to rule out in commit: ca2b497253ad01c8 ("arm64: perf: Reject stand-alone CHAIN events for PMUv3") Which allowed the events to be opened, but prevented them from being scheduled by by using an arm_pmu::filter_match hook to reject the relevant events. The CHAIN event filtering in the arm_pmu::filter_match hook was silently removed in commit: bd27568117664b8b ("perf: Rewrite core context handling") As a result, it's now possible for users to open CHAIN events, and for these to be installed arbitrarily. Fix this by rejecting CHAIN events at creation time. This avoids the creation of events which will never count, and doesn't require using the dynamic filtering. Attempting to open a CHAIN event (0x1e) will now be rejected: | # ./perf stat -e armv8_pmuv3/config=0x1e/ ls | perf | | Performance counter stats for 'ls': | | armv8_pmuv3/config=0x1e/ | | 0.002197470 seconds time elapsed | | 0.000000000 seconds user | 0.002294000 seconds sys Other events (e.g. CPU_CYCLES / 0x11) will open as usual: | # ./perf stat -e armv8_pmuv3/config=0x11/ ls | perf | | Performance counter stats for 'ls': | | 2538761 armv8_pmuv3/config=0x11/ | | 0.002227330 seconds time elapsed | | 0.002369000 seconds user | 0.000000000 seconds sys Fixes: bd27568117664b8b ("perf: Rewrite core context handling") Signed-off-by: Mark Rutland Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Will Deacon --- arch/arm64/kernel/perf_event.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 3e43538f6b72..dde06c0f97f3 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -1063,6 +1063,14 @@ static int __armv8_pmuv3_map_event(struct perf_event *event, &armv8_pmuv3_perf_cache_map, ARMV8_PMU_EVTYPE_EVENT); + /* + * CHAIN events only work when paired with an adjacent counter, and it + * never makes sense for a user to open one in isolation, as they'll be + * rotated arbitrarily. + */ + if (hw_event_id == ARMV8_PMUV3_PERFCTR_CHAIN) + return -EINVAL; + if (armv8pmu_event_is_64bit(event)) event->hw.flags |= ARMPMU_EVT_64BIT;