From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932494AbeEHPVw (ORCPT ); Tue, 8 May 2018 11:21:52 -0400 Received: from mga01.intel.com ([192.55.52.88]:59291 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754632AbeEHPVu (ORCPT ); Tue, 8 May 2018 11:21:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,378,1520924400"; d="scan'208";a="37761239" To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , linux-kernel , linux-perf-users@vger.kernel.org From: Alexey Budankov Subject: [PATCH v2]: perf/x86: store user space frame-pointer value on a sample Message-ID: <31205dc8-b756-e12b-0249-2ed06c2db9c9@linux.intel.com> Date: Tue, 8 May 2018 18:21:36 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Store user space frame-pointer value (BP register) into Perf trace on a sample for a process so the value becomes available when unwinding call stacks for functions gaining event samples. Signed-off-by: Alexey Budankov --- arch/x86/kernel/perf_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index e47b2dbbdef3..8d68658eff7f 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -156,7 +156,13 @@ void perf_get_regs_user(struct perf_regs *regs_user, * Most system calls don't save these registers, don't report them. */ regs_user_copy->bx = -1; - regs_user_copy->bp = -1; + /* + * Store user space frame-pointer value on sample + * to facilitate stack unwinding for cases when + * user space executable code has such support + * enabled at compile time; + */ + regs_user_copy->bp = user_regs->bp; regs_user_copy->r12 = -1; regs_user_copy->r13 = -1; regs_user_copy->r14 = -1;