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Date: Thu, 22 Jan 2015 08:02:20 -0800 From: Victor Kamensky <victor.kamensky@...aro.org> To: Russell King - ARM Linux <linux@....linux.org.uk> Cc: Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, David Ahern <dsahern@...il.com>, Will Deacon <will.deacon@....com>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...hat.com>, Adrian Hunter <adrian.hunter@...el.com>, Jiri Olsa <jolsa@...hat.com>, Avi Kivity <avi@...udius-systems.com>, Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>, Anton Blanchard <anton@...ba.org>, Dave Martin <Dave.Martin@....com>, open list <linux-kernel@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org> Subject: Re: [PATCH V2 2/3] perf symbols: improve abi compliance in arm mapping symbols handling On 22 January 2015 at 07:29, Russell King - ARM Linux <linux@....linux.org.uk> wrote: > On Wed, Jan 21, 2015 at 08:52:57PM -0800, Victor Kamensky wrote: >> Both Arm and Aarch64 ELF ABI allow mapping symbols be in from >> either "$d" or "$d.<any>". But current code that handles mapping >> symbols only deals with the first, dollar character and a single >> letter, case. >> >> The patch adds handling of the second case with period >> followed by any characters. >> >> Suggested-by: Russell King <linux@....linux.org.uk> >> Suggested-by: Will Deacon <will.deacon@....com> >> Signed-off-by: Victor Kamensky <victor.kamensky@...aro.org> >> Acked-by: Will Deacon <will.deacon@....com> >> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl> >> Cc: Paul Mackerras <paulus@...ba.org> >> Cc: Ingo Molnar <mingo@...hat.com> >> Cc: Arnaldo Carvalho de Melo <acme@...nel.org> >> Cc: Adrian Hunter <adrian.hunter@...el.com> >> Cc: Jiri Olsa <jolsa@...hat.com> >> Cc: Namhyung Kim <namhyung@...nel.org> >> Cc: Avi Kivity <avi@...udius-systems.com> >> Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> >> Cc: Anton Blanchard <anton@...ba.org> >> Cc: David Ahern <dsahern@...il.com> >> Cc: Dave Martin <Dave.Martin@....com> >> --- >> tools/perf/util/symbol-elf.c | 9 ++++----- >> 1 file changed, 4 insertions(+), 5 deletions(-) >> >> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c >> index 1e188dd..7fd35d6 100644 >> --- a/tools/perf/util/symbol-elf.c >> +++ b/tools/perf/util/symbol-elf.c >> @@ -857,17 +857,16 @@ int dso__load_sym(struct dso *dso, struct map *map, >> * don't identify functions, so will confuse the profile >> * output: */ >> if (ehdr.e_machine == EM_ARM) { >> - if (!strcmp(elf_name, "$a") || >> - !strcmp(elf_name, "$d") || >> - !strcmp(elf_name, "$t")) >> + if (elf_name[0] == '$' && strchr("adt", elf_name[1]) >> + && (elf_name[2] == '\0' || elf_name[2] == '.')) >> 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")) >> + if (elf_name[0] == '$' && strchr("dx", elf_name[1]) >> + && (elf_name[2] == '\0' || elf_name[2] == '.')) >> continue; >> } > > Why not fix this first? Then, all you'd need to do would be to change > the test for EM_ARM to EM_ARM or EM_AARCH64, and add the 'x' into the > strchr() string. In previously discussed [1] I proposed two variants and ask for people's preferences. Will replied that he did not care and let me choose that I like. It seems to me that you more like variant 2 (provided here for reference again). It would replace patch 1 and patch 2 of version 2. Please confirm. I don't practically care much and can use either. I personally preferred variant 1 because in variant 2 $x will be filtered on ARM V7, but V7 ABI does not say anything about $x, only Aarch64 does. I.e special symbols do to match between V7 and V8 exactly. But as it is already in other places like kallsyms, I agree practically it may not matter. If you give your node to variant 2 (as below) I can report this miniseries: Please let me know Variant 2: >From c8d08ebddc61203daf21b17c891c26c1d08e14f1 Mon Sep 17 00:00:00 2001 From: Victor Kamensky <victor.kamensky@...aro.org> Date: Mon, 12 Jan 2015 14:13:36 -0800 Subject: [PATCH 1/2] perf symbols: Ignore mapping symbols on aarch64 Aarch64 ELF files use mapping symbols with special names $x, $d to identify regions of Aarch64 code (see Aarch64 ELF ABI - "ARM IHI 0056B", section "4.5.4 Mapping symbols"). The patch filters out these symbols at load time, similar to "696b97a perf symbols: Ignore mapping symbols on ARM" changes done for ARM before V8. Also added handling of mapping symbols that has format "$d.<any>" and similar for both cases. Note we are not making difference between EM_ARM and EM_AARCH64 mapping symbols instead code handles superset of both. Signed-off-by: Victor Kamensky <victor.kamensky@...aro.org> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl> Cc: Paul Mackerras <paulus@...ba.org> Cc: Ingo Molnar <mingo@...hat.com> Cc: Arnaldo Carvalho de Melo <acme@...nel.org> Cc: Adrian Hunter <adrian.hunter@...el.com> Cc: Jiri Olsa <jolsa@...hat.com> Cc: Namhyung Kim <namhyung@...nel.org> Cc: Avi Kivity <avi@...udius-systems.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> Cc: Anton Blanchard <anton@...ba.org> Cc: David Ahern <dsahern@...il.com> Cc: Will Deacon <will.deacon@....com> Cc: Russell King <linux@....linux.org.uk> Cc: Dave Martin <Dave.Martin@....com> --- tools/perf/util/symbol-elf.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 06fcd1b..b2eb0f9 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -856,10 +856,9 @@ int dso__load_sym(struct dso *dso, struct map *map, /* Reject ARM ELF "mapping symbols": these aren't unique and * don't identify functions, so will confuse the profile * output: */ - if (ehdr.e_machine == EM_ARM) { - if (!strcmp(elf_name, "$a") || - !strcmp(elf_name, "$d") || - !strcmp(elf_name, "$t")) + if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { + if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) + && (elf_name[2] == '\0' || elf_name[2] == '.')) continue; } -- 1.9.3 Thanks, Victor [1] https://lkml.org/lkml/2015/1/14/1019 > -- > FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up > according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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