| Message ID | CAA3XUr2ej57VxAF1D3tbhjcVFtgyvHWKQxMiTBJ9RcmYCUHekQ@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
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On Thu, Jan 15, 2015 at 02:51:06AM +0000, Victor Kamensky wrote: > On 14 January 2015 at 16:03, Russell King - ARM Linux > <linux@arm.linux.org.uk> wrote: > > On Wed, Jan 14, 2015 at 10:38:38AM -0800, Victor Kamensky wrote: > >> >From fed6caab410ddcaf487ff23a3908eca129e50b89 Mon Sep 17 00:00:00 2001 > >> From: Victor Kamensky <victor.kamensky@linaro.org> > >> Date: Wed, 14 Jan 2015 07:42:41 -0800 > >> Subject: [PATCH 3/3] perf symbols: improve abi compliance in arm mapping > >> symbols handling > >> > >> 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: Will Deacon <will.deacon@arm.com> > >> Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > > > > I wonder if it would make more sense to re-use the "is_arm_mapping_symbol" > > thing which we have in kernel/module.c and scripts/kallsyms.c - it > > seems silly to re-invent code which we already have to detect these > > symbols. > > Thanks for pointing this out. I did not know about > "is_arm_mapping_symbol" function. > > Do you suggest we copy one of those functions into tools/perf? > Since tools/perf is separate user-land utility I don't see easy way > how can we reuse those directly. > > Also those functions check for mapping symbols > seems to be more efficient that one I come with, for example > one from scripts/kallsyms.c > > static inline int is_arm_mapping_symbol(const char *str) > { > return str[0] == '$' && strchr("axtd", str[1]) > && (str[2] == '\0' || str[2] == '.'); > } > > But it seems that they are somewhat accurate: because they bundle > EM_ARM and EM_AARCH64 into one case. According to ABIs > for EM_ARM we have $a, $t, $d, $a.<any>, $t.<any>, $d.<any>; > and for EM_AARCH64 we have $x, $d, $x.<any>, $d.<any>. > > How about the following two variants of the patch. It follows the same > mapping handling logic as in other 3 copies of is_arm_mapping_symbol > function in kernel, but it still separate copy in tools/perf code. Personally I > prefer variant 1, but I am fine with variant 2 too, because practically it > will be OK. They both look fine to me; pick your favourite. Acked-by: Will Deacon <will.deacon@arm.com> Will > Variant 1 (as addition to this patch, as above): > > From e08d348bd72d406d8939993d266729d805577c4b Mon Sep 17 00:00:00 2001 > From: Victor Kamensky <victor.kamensky@linaro.org> > Date: Wed, 14 Jan 2015 07:42:41 -0800 > Subject: [PATCH 3/3] perf symbols: improve abi compliance in arm mapping > symbols handling > > Both Arm and Aarch64 ELF ABI allow mapping symbols be in from > either "$d" or "$d.<any>". But current code that handles mapping > symbols only deals with the first, dollar character and a single > letter, case. > > The patch adds handling of the second case with period > followed by any characters. > > Suggested-by: Russell King <linux@arm.linux.org.uk> > Suggested-by: Will Deacon <will.deacon@arm.com> > Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > --- > tools/perf/util/symbol-elf.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 1e188dd..a038c98 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -857,17 +857,16 @@ int dso__load_sym(struct dso *dso, struct map *map, > * don't identify functions, so will confuse the profile > * output: */ > if (ehdr.e_machine == EM_ARM) { > - if (!strcmp(elf_name, "$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; > } > > -- > 1.9.3 > > Variant 2 instead of patch posted with current subject: > > From c8d08ebddc61203daf21b17c891c26c1d08e14f1 Mon Sep 17 00:00:00 2001 > From: Victor Kamensky <victor.kamensky@linaro.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@linaro.org> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > Cc: Adrian Hunter <adrian.hunter@intel.com> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Avi Kivity <avi@cloudius-systems.com> > Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> > Cc: Anton Blanchard <anton@samba.org> > Cc: David Ahern <dsahern@gmail.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Dave Martin <Dave.Martin@arm.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 > > > -- > > FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up > > according to speedtest.net. >
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 1e188dd..a038c98 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; } -- 1.9.3 Variant 2 instead of patch posted with current subject: From c8d08ebddc61203daf21b17c891c26c1d08e14f1 Mon Sep 17 00:00:00 2001 From: Victor Kamensky <victor.kamensky@linaro.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@linaro.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Avi Kivity <avi@cloudius-systems.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anton Blanchard <anton@samba.org> Cc: David Ahern <dsahern@gmail.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Dave Martin <Dave.Martin@arm.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; }