From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Wed, 14 Jan 2015 11:22:10 +0000 Subject: [PATCH 1/2] perf symbols: Ignore mapping symbols on aarch64 In-Reply-To: <1421168344-5363-1-git-send-email-victor.kamensky@linaro.org> References: <1421168344-5363-1-git-send-email-victor.kamensky@linaro.org> Message-ID: <20150114112210.GF4050@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Jan 13, 2015 at 04:59:03PM +0000, Victor Kamensky wrote: > Aarch64 ELF files use mapping symbols with special names $x, $d > to identify regions of Aarch64 code (see Aarch64 ELF ABI - "ARM > IHI 0056B", section "4.5.4 Mapping symbols"). > > The patch filters out these symbols at load time, similar to > "696b97a perf symbols: Ignore mapping symbols on ARM" changes > done for ARM before V8. > > Signed-off-by: Victor Kamensky > Cc: Peter Zijlstra > Cc: Paul Mackerras > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Adrian Hunter > Cc: Jiri Olsa > Cc: Namhyung Kim > Cc: Avi Kivity > Cc: Masami Hiramatsu > Cc: Anton Blanchard > Cc: David Ahern > Cc: Will Deacon > Cc: Dave Martin > --- > tools/perf/util/symbol-elf.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 06fcd1b..1e188dd 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -862,6 +862,14 @@ int dso__load_sym(struct dso *dso, struct map *map, > !strcmp(elf_name, "$t")) > continue; > } > + /* Reject Aarch64 ELF "mapping symbols": these aren't unique and > + * don't identify functions, so will confuse the profile > + * output: */ > + if (ehdr.e_machine == EM_AARCH64) { > + if (!strcmp(elf_name, "$x") || > + !strcmp(elf_name, "$d")) > + continue; > + } Do we need to skip $x.* and $d.* too? I doubt GCC generates them, but they are permitted by the ELF ABI. Will From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752251AbbANLWS (ORCPT ); Wed, 14 Jan 2015 06:22:18 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:33748 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751139AbbANLWR (ORCPT ); Wed, 14 Jan 2015 06:22:17 -0500 Date: Wed, 14 Jan 2015 11:22:10 +0000 From: Will Deacon To: Victor Kamensky Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Adrian Hunter , Jiri Olsa , Avi Kivity , Masami Hiramatsu , Anton Blanchard , David Ahern , Dave P Martin , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 1/2] perf symbols: Ignore mapping symbols on aarch64 Message-ID: <20150114112210.GF4050@arm.com> References: <1421168344-5363-1-git-send-email-victor.kamensky@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1421168344-5363-1-git-send-email-victor.kamensky@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 13, 2015 at 04:59:03PM +0000, Victor Kamensky wrote: > Aarch64 ELF files use mapping symbols with special names $x, $d > to identify regions of Aarch64 code (see Aarch64 ELF ABI - "ARM > IHI 0056B", section "4.5.4 Mapping symbols"). > > The patch filters out these symbols at load time, similar to > "696b97a perf symbols: Ignore mapping symbols on ARM" changes > done for ARM before V8. > > Signed-off-by: Victor Kamensky > Cc: Peter Zijlstra > Cc: Paul Mackerras > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Adrian Hunter > Cc: Jiri Olsa > Cc: Namhyung Kim > Cc: Avi Kivity > Cc: Masami Hiramatsu > Cc: Anton Blanchard > Cc: David Ahern > Cc: Will Deacon > Cc: Dave Martin > --- > tools/perf/util/symbol-elf.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 06fcd1b..1e188dd 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -862,6 +862,14 @@ int dso__load_sym(struct dso *dso, struct map *map, > !strcmp(elf_name, "$t")) > continue; > } > + /* Reject Aarch64 ELF "mapping symbols": these aren't unique and > + * don't identify functions, so will confuse the profile > + * output: */ > + if (ehdr.e_machine == EM_AARCH64) { > + if (!strcmp(elf_name, "$x") || > + !strcmp(elf_name, "$d")) > + continue; > + } Do we need to skip $x.* and $d.* too? I doubt GCC generates them, but they are permitted by the ELF ABI. Will