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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D17EC433EF for ; Fri, 22 Oct 2021 15:37:33 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 07F10610D0 for ; Fri, 22 Oct 2021 15:37:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 07F10610D0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Cc:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=Zj95FWUyS3KUeo4xj+tfL6z472KRky4aKne+NJkzO/Q=; b=3AaerYYSLaKkSuSdxFAgDmbSAB rJZKFI8XpEn6BIj2/f+0rbKltvlC12cdseelGOrqpf7ZFdxDOjQO0yycavXz5loPnuvBk/Eii36aw kcZ+fqeeiXcaFe/Yj9Pdd5c7f8u/M2UUTXK4+id5dbYbEFbpTRuC/IYA1260go2Xk2KIDIByJ1rfI sH3A9d7TH6v0ooszmF/AfEUec8WLlSUIlb4YnOvBucNFEu8OWse5s2sb00fiFhHbBLBpQC58S/UR2 oiVxM4ruztECo4InO3cglU+Fpq46ZXHXZaEiEaFpFZup/FmkbLfK5WNQyiUSsPOQ/hygStNQvX8TZ sgm9v0AQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdwam-00BQtK-K4; Fri, 22 Oct 2021 15:36:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdwab-00BQqy-5Q for linux-arm-kernel@lists.infradead.org; Fri, 22 Oct 2021 15:36:14 +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 9D7701396; Fri, 22 Oct 2021 08:36:09 -0700 (PDT) Received: from [10.57.27.181] (unknown [10.57.27.181]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 641373F99C; Fri, 22 Oct 2021 08:36:07 -0700 (PDT) Subject: Re: [RFCv1 4/4] perf: arm_spe: Dynamically switch PID tracing to contextidr To: Leo Yan , Catalin Marinas , Will Deacon , Mark Rutland , Kees Cook , Ard Biesheuvel , Sami Tolvanen , Nicholas Piggin , James Morse , Marc Zyngier , Joey Gouly , Peter Collingbourne , Vincenzo Frascino , "Peter Zijlstra (Intel)" , Stephane Eranian , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211021134530.206216-1-leo.yan@linaro.org> <20211021134530.206216-5-leo.yan@linaro.org> From: James Clark Message-ID: <854fb1a2-e5f1-f237-685f-8ddb0557c98b@arm.com> Date: Fri, 22 Oct 2021 16:36:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211021134530.206216-5-leo.yan@linaro.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211022_083613_318913_097E67C9 X-CRM114-Status: GOOD ( 16.05 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 21/10/2021 14:45, Leo Yan wrote: > Now Arm64 provides API for enabling and disable PID tracing, Arm SPE > driver invokes these functions to dynamically enable it during > profiling when the program runs in root PID name space, and disable PID > tracing when the perf event is stopped. > > Device drivers should not depend on CONFIG_PID_IN_CONTEXTIDR for PID > tracing, so this patch uses the consistent condition for setting bit > EL1_CX for PMSCR. Hi Leo, I've been testing this change, but I'm seeing something strange. Not sure if it's a problem on my side or not yet. With this command: sudo ./perf record -vvv -e arm_spe//u -- taskset --cpu-list 1 bash -c ls I'm only seeing 0 values for context: sudo ./perf report -D | grep CONTEXT . 00038dce: 65 00 00 00 00 CONTEXT 0x0 el2 . 00038e0e: 65 00 00 00 00 CONTEXT 0x0 el2 I added a printk to the function, and I see it print non zero values, although there are some zero ones mixed in there too: diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 0c1669db19a1..8f0fb43a5fac 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -33,7 +33,8 @@ static inline void contextidr_thread_switch(struct task_struct *next) if (!static_branch_unlikely(&contextidr_in_use)) return; - write_sysreg(task_pid_nr(next), contextidr_el1); + printk("Set %d\n", task_pid_nr(next)); + write_sysreg(task_pid_nr(next), contextidr_el2); isb(); } Results in this: [ 53.257905] Set 77 [ 53.257909] Set 0 [ 53.258180] Set 77 [ 53.258183] Set 0 [ 53.258385] Set 309 [ 53.258385] Set 172 [ 53.258425] Set 77 [ 53.258443] Set 990 [ 53.258449] Set 77 [ 53.258455] Set 990 [ 53.258467] Set 310 [ 53.258719] Set 7 [ 53.258728] Set 77 [ 53.258731] Set 0 [ 53.258733] Set 0 [ 53.258738] Set 7 Without your patchset I don't get 0 values in the SPE trace anymore: . 0000050e: 65 b1 01 00 00 CONTEXT 0x1b1 el2 . 0000054e: 65 b1 01 00 00 CONTEXT 0x1b1 el2 . 0000058e: 65 ac 01 00 00 CONTEXT 0x1ac el2 . 000005ce: 65 ac 01 00 00 CONTEXT 0x1ac el2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel