From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754151AbdEHKyV (ORCPT ); Mon, 8 May 2017 06:54:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:58965 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752943AbdEHKyU (ORCPT ); Mon, 8 May 2017 06:54:20 -0400 Subject: Re: [PATCH] gcov: support GCC 7.1 To: Andrew Morton References: <8c4084fa-3885-29fe-5fc4-0d4ca199c785@suse.cz> <85a7ed9a-4915-49d9-f17b-888b838107c6@linux.vnet.ibm.com> <3e73df5c-f253-576d-22c3-4f05d96113a0@linux.vnet.ibm.com> Cc: =?UTF-8?Q?Martin_Li=c5=a1ka?= , lkml From: Peter Oberparleiter Date: Mon, 8 May 2017 12:54:13 +0200 MIME-Version: 1.0 In-Reply-To: <3e73df5c-f253-576d-22c3-4f05d96113a0@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 17050810-0008-0000-0000-0000043F49DB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17050810-0009-0000-0000-00001D93213C Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-08_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705080062 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I just realized (admittedly somewhat late) that this hasn't been included yet. However this patch is still required for Linux gcov-profiling to build with GCC 7.1. @Andrew, could you pick this up via your tree? The original post can be found at https://lkml.org/lkml/2016/11/24/293 On 08.12.2016 13:52, Peter Oberparleiter wrote: > On 24.11.2016 13:46, Martin Liška wrote: >> On 11/09/2016 10:21 AM, Peter Oberparleiter wrote: >>> On 31.10.2016 10:35, Martin Liška wrote: >>>> Starting from GCC 7.1, __gcov_exit is a new symbol expected >>>> to be implemented in a profiling runtime. >>> >>> I tested your patch with kernel 4.9-rc4 compiled with GCC 7.0.0 20161107 >>> (experimental) and validated that it fixes the build error due to a >>> missing __gcov_exit symbol. >>> >>> An attempt to read from one of the .gcda files generated by a kernel >>> compiled this way resulted in a crash though. It appears that the number >>> of GCOV_COUNTERS has changed again for GCC 7.x and must be adjusted in >>> the kernel as well. Could you add that to your patch as well? >> >> Hello. >> >> Sorry, this is fixed in second version of the patch. >> >>> Given that GCC 7.1 has not yet been released, I'm wondering if it is >>> safe to program against interfaces that have not yet been fully >>> finalized. Can you provide an indication on whether these gcov-related >>> aspects of GCC might still be changed until release? >> >> Well, we just flipped to stage3 which means that any new features should >> be added to current master. If you prefer we can commit the patch after >> a release of 7.1 will be done? > > I've given this some more thought: if your patch is not applied, GCOV > kernel profiling will definitely not work with GCC 7.x. If it is > applied, there is a high probability that it will work, and a small > chance that additional patches will be required. Overall I would say > this justifies applying the patch now. > >>> As a side note, please post your patches inline instead of as attachment >>> as that helps quoting them in replies. See also >>> linux/Documentation/SubmittingPatches. >> >> Sure, thanks for info. I'm attaching new version: >> >> Starting from GCC 7.1, __gcov_exit is a new symbol expected >> to be implemented in a profiling runtime. Update number of profile >> counters. >> >> Signed-off-by: Martin Liska > > Looks good, thanks! Tested successfully with GCC 7.0.0 20161208 > (experimental) on Linux kernel 4.9-rc8 (compiles successfully and > produces valid kernel .gcda files). > > Andrew, could you pick this change up via your tree? > > Reviewed-by: Peter Oberparleiter > Tested-by: Peter Oberparleiter > >> --- >> kernel/gcov/base.c | 6 ++++++ >> kernel/gcov/gcc_4_7.c | 4 +++- >> 2 files changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c >> index 2f9df37..85dca5d 100644 >> --- a/kernel/gcov/base.c >> +++ b/kernel/gcov/base.c >> @@ -98,6 +98,12 @@ void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters) >> } >> EXPORT_SYMBOL(__gcov_merge_icall_topn); >> >> +void __gcov_exit (void) >> +{ >> + /* Unused. */ >> +} >> +EXPORT_SYMBOL(__gcov_exit); >> + >> /** >> * gcov_enable_events - enable event reporting through gcov_event() >> * >> diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c >> index 6a5c239..46a18e7 100644 >> --- a/kernel/gcov/gcc_4_7.c >> +++ b/kernel/gcov/gcc_4_7.c >> @@ -18,7 +18,9 @@ >> #include >> #include "gcov.h" >> >> -#if (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1) >> +#if (__GNUC__ >= 7) >> +#define GCOV_COUNTERS 9 >> +#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1) >> #define GCOV_COUNTERS 10 >> #elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9 >> #define GCOV_COUNTERS 9 >> -- Peter Oberparleiter Linux on z Systems Development - IBM Germany