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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 4204EC282CE for ; Wed, 22 May 2019 14:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2252420879 for ; Wed, 22 May 2019 14:46:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729637AbfEVOqU (ORCPT ); Wed, 22 May 2019 10:46:20 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35962 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729621AbfEVOqS (ORCPT ); Wed, 22 May 2019 10:46:18 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4MEhtij053426 for ; Wed, 22 May 2019 10:46:17 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2sn85es43u-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 22 May 2019 10:46:17 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 22 May 2019 15:46:12 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4MEkB0j49545378 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 22 May 2019 14:46:12 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D5BE311C05B; Wed, 22 May 2019 14:46:11 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 99DFD11C052; Wed, 22 May 2019 14:46:11 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 22 May 2019 14:46:11 +0000 (GMT) From: Thomas Richter To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org Cc: brueckner@linux.vnet.ibm.com, heiko.carstens@de.ibm.com, Thomas Richter Subject: [PATCH 3/3] perf record: Fix s390 missing module symbol and warning for non-root users Date: Wed, 22 May 2019 16:46:01 +0200 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190522144601.50763-1-tmricht@linux.ibm.com> References: <20190522144601.50763-1-tmricht@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19052214-0012-0000-0000-0000031E547A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052214-0013-0000-0000-000021570A1E Message-Id: <20190522144601.50763-4-tmricht@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-22_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905220104 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Command 'perf record' and 'perf report' on a system without kernel debuginfo packages uses /proc/kallsyms and /proc/modules to find addresses for kernel and module symbols. On x86 this works for root and non-root users. On s390, when invoked as non-root user, many of the following warnings are shown and module symbols are missing: proc/{kallsyms,modules} inconsistency while looking for "[sha1_s390]" module! Command 'perf record' creates a list of module start addresses by parsing the output of /proc/modules and creates a PERF_RECORD_MMAP record for the kernel and each module. The following function call sequence is executed: machine__create_kernel_maps machine__create_module modules__parse machine__create_module --> for each line in /proc/modules arch__fix_module_text_start Function arch__fix_module_text_start() is s390 specific. It opens file /sys/module//sections/.text to extract the module's .text section start address. On s390 the module loader prepends a header before the first section, whereas on x86 the module's text section address is identical the the module's load address. However module section files are root readable only. For non-root the read operation fails and machine__create_module() returns an error. Command perf record does not generate any PERF_RECORD_MMAP record for loaded modules. Later command perf report complains about missing module maps. To fix this function arch__fix_module_text_start() always returns success. For root users there is no change, for non-root users the module's load address is used as module's text start address (the prepended header then counts as part of the text section). This enable non-root users to use module symbols and avoid the warning when perf report is executed. Output before: [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP 0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text Output after: [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP 0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text 0 0x1b8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../autofs4.ko.xz 0 0x250 [0xa8]: PERF_RECORD_MMAP ... x /lib/modules/.../sha_common.ko.xz 0 0x2f8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../des_generic.ko.xz Signed-off-by: Thomas Richter Reviewed-by: Hendrik Brueckner --- tools/perf/arch/s390/util/machine.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c index 0b2054007314..a19690a17291 100644 --- a/tools/perf/arch/s390/util/machine.c +++ b/tools/perf/arch/s390/util/machine.c @@ -5,16 +5,19 @@ #include "util.h" #include "machine.h" #include "api/fs/fs.h" +#include "debug.h" int arch__fix_module_text_start(u64 *start, const char *name) { + u64 m_start = *start; char path[PATH_MAX]; snprintf(path, PATH_MAX, "module/%.*s/sections/.text", (int)strlen(name) - 2, name + 1); - - if (sysfs__read_ull(path, (unsigned long long *)start) < 0) - return -1; + if (sysfs__read_ull(path, (unsigned long long *)start) < 0) { + pr_debug2("Using module %s start:%#lx\n", path, m_start); + *start = m_start; + } return 0; } -- 2.19.1