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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 C61C5C3524D for ; Mon, 3 Feb 2020 22:27:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91DCD20721 for ; Mon, 3 Feb 2020 22:27:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KnUBd3aC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727177AbgBCW0p (ORCPT ); Mon, 3 Feb 2020 17:26:45 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:37692 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726369AbgBCW0o (ORCPT ); Mon, 3 Feb 2020 17:26:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580768803; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=Yr95hrNi5JfgkOfoS1PjLAI5Z/W4hgT7UGFvqBbgOxM=; b=KnUBd3aCR/tZuJdEITrkOHznPTqA4xfxWfo16IftF+la0cWZZU1Xb5WPC1haR5VboANGsh X+iJ2YFrYl+YR/VN37Z7I0KW8Rc6brm93bRtsrKm7Y8fJDOo5EcrGnl7jXT8Q9f1FWUNZX SSWuryi7XaRxoUzO1dGcbSuOMfjtins= Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-78-9LEhusYPMvS5slWbjfBQjA-1; Mon, 03 Feb 2020 17:26:40 -0500 X-MC-Unique: 9LEhusYPMvS5slWbjfBQjA-1 Received: by mail-pg1-f197.google.com with SMTP id n7so5116351pgt.7 for ; Mon, 03 Feb 2020 14:26:40 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Yr95hrNi5JfgkOfoS1PjLAI5Z/W4hgT7UGFvqBbgOxM=; b=O6BB0sqPUjNFDWfXYq39Pj8NMeYOVUPWD0ehuRAWc86Twgd3N9VPzHrU8YVl8m3XX3 KmCf7KbcFL+Cd+m7wsRqrY9DJj5imn1EnLIFLKNQ8zeB8+GzciDAiffpYqA+pORxrYld Y60/4prWaukx9di9GwcugLTrO7qc8VaalAInJDZfQ1yViJd3dPYlxXAKDRZhlRVhQs/8 wEK4FUFUqdfDaP13BdrdP3/RLlMRY377m66ScLvFGHSPmFftkGwqI2EpkzJmlhn5nmLb NCer3XPmEP+d8OXNgwZDSRJjKH+seATGexHBF7aaVzu6wxTUkhldUOHnb94/ubCMWfCB 20qw== X-Gm-Message-State: APjAAAVGQRIwFm5ldBRYlEmzWUgDhHrr2zEhWJjiAbAm7jhD/JVNQpkl Ljw2jTmLSpYPjkVp5qTKCXaLLKszrJqMcxl2LAfDYw1JCXgBfhQ4QANrtR61LIdiWO7pP2Ye9o1 0HOOv+JhqizNn11A/EpEM4fDW X-Received: by 2002:a63:d406:: with SMTP id a6mr28302965pgh.264.1580768799553; Mon, 03 Feb 2020 14:26:39 -0800 (PST) X-Google-Smtp-Source: APXvYqzCYMKSAbNlHwt3YKkhpBg65LATP/cLjqH1DDC2oSxQhzuOsjngoXE8H7XyY+eiYk4eqMEhiA== X-Received: by 2002:a63:d406:: with SMTP id a6mr28302937pgh.264.1580768799210; Mon, 03 Feb 2020 14:26:39 -0800 (PST) Received: from localhost ([122.177.227.116]) by smtp.gmail.com with ESMTPSA id v9sm466061pja.26.2020.02.03.14.26.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Feb 2020 14:26:38 -0800 (PST) From: Bhupesh Sharma To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bhsharma@redhat.com, bhupesh.linux@gmail.com, Mark Rutland , Will Deacon , Catalin Marinas , Ard Biesheuvel Subject: [PATCH 2/2] perf/arm64: Allow per-task kernel breakpoints Date: Tue, 4 Feb 2020 03:56:24 +0530 Message-Id: <1580768784-25868-3-git-send-email-bhsharma@redhat.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1580768784-25868-1-git-send-email-bhsharma@redhat.com> References: <1580768784-25868-1-git-send-email-bhsharma@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 478fcb2cdb23 ("arm64: Debugging support") disallowed per-task kernel breakpoints on arm64 since these would have potentially complicated the stepping code. However, we now have several use-cases (for e.g. perf) which require per-task address execution h/w breakpoint to be exercised/set on arm64: For e.g. we can set address execution h/w breakpoints, using the format prescribed by 'perf-list' command: mem:[/len][:access] [Hardware breakpoint] Without this patch, currently 'perf stat -e' reports that per-task address execution h/w breakpoints are 'not supported' on arm64. See below: $ TEST_FUNC="vfs_read" $ ADDR=0x`cat /proc/kallsyms | grep -P "\\s$TEST_FUNC\$" | cut -f1 -d' '` $ perf stat -e mem:$ADDR:x -x';' -- cat /proc/cpuinfo > /dev/null ;;mem:0xffff00001031dd68:x;0;100.00;; After this patch, this use-case can be supported: $ TEST_FUNC="vfs_read" $ ADDR=0x`cat /proc/kallsyms | grep -P "\\s$TEST_FUNC\$" | cut -f1 -d' '` $ perf stat -e mem:$ADDR:x -x';' -- cat /proc/cpuinfo > /dev/null 5;;mem:0xfffffe0010361d20:x;912200;100.00;; Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: Ard Biesheuvel Signed-off-by: Bhupesh Sharma --- arch/arm64/kernel/hw_breakpoint.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index 0b727edf4104..c28f04e02845 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -562,13 +562,6 @@ int hw_breakpoint_arch_parse(struct perf_event *bp, hw->address &= ~alignment_mask; hw->ctrl.len <<= offset; - /* - * Disallow per-task kernel breakpoints since these would - * complicate the stepping code. - */ - if (hw->ctrl.privilege == AARCH64_BREAKPOINT_EL1 && bp->hw.target) - return -EINVAL; - return 0; } -- 2.7.4