From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vMwrR6twhzDqBm for ; Tue, 14 Feb 2017 19:41:43 +1100 (AEDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1E8UR41015379 for ; Tue, 14 Feb 2017 03:41:41 -0500 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0b-001b2d01.pphosted.com with ESMTP id 28kwv49q2t-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 14 Feb 2017 03:41:40 -0500 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 14 Feb 2017 01:41:40 -0700 Date: Tue, 14 Feb 2017 14:11:34 +0530 From: Ananth N Mavinakayanahalli To: "Naveen N. Rao" Cc: Masami Hiramatsu , Michael Ellerman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 1/3] powerpc: kprobes: fix handling of function offsets on ABIv2 Reply-To: ananth@linux.vnet.ibm.com References: <1b7d5ea08a7e11fbf1fb08dd3536219c94b13591.1487060527.git.naveen.n.rao@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1b7d5ea08a7e11fbf1fb08dd3536219c94b13591.1487060527.git.naveen.n.rao@linux.vnet.ibm.com> Message-Id: <20170214084134.GG29806@in.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Feb 14, 2017 at 02:08:01PM +0530, Naveen N. Rao wrote: > commit 239aeba76409 ("perf powerpc: Fix kprobe and kretprobe handling > with kallsyms on ppc64le") changed how we use the offset field in struct > kprobe on ABIv2. perf now offsets from the GEP (Global entry point) if an > offset is specified and otherwise chooses the LEP (Local entry point). > > Fix the same in kernel for kprobe API users. We do this by extending > kprobe_lookup_name() to accept an additional parameter to indicate the > offset specified with the kprobe registration. If offset is 0, we return > the local function entry and return the global entry point otherwise. > > With: > # cd /sys/kernel/debug/tracing/ > # echo "p _do_fork" >> kprobe_events > # echo "p _do_fork+0x10" >> kprobe_events > > before this patch: > # cat ../kprobes/list > c0000000000d0748 k _do_fork+0x8 [DISABLED] > c0000000000d0758 k _do_fork+0x18 [DISABLED] > c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] > > and after: > # cat ../kprobes/list > c0000000000d04c8 k _do_fork+0x8 [DISABLED] > c0000000000d04d0 k _do_fork+0x10 [DISABLED] > c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] > > Signed-off-by: Naveen N. Rao Acked-by: Ananth N Mavinakayanahalli