Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753618Ab3IEQtP (ORCPT ); Thu, 5 Sep 2013 12:49:15 -0400 Received: from mail-vc0-f178.google.com ([209.85.220.178]:60407 "EHLO mail-vc0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752693Ab3IEQtO (ORCPT ); Thu, 5 Sep 2013 12:49:14 -0400 MIME-Version: 1.0 In-Reply-To: <20130905163030.GF1100@krava.brq.redhat.com> References: <1378317854-25965-1-git-send-email-jean.pihet@linaro.org> <1378317854-25965-4-git-send-email-jean.pihet@linaro.org> <20130905163030.GF1100@krava.brq.redhat.com> Date: Thu, 5 Sep 2013 18:49:13 +0200 Message-ID: Subject: Re: [PATCH 3/3] perf: parse the .debug_frame section in case .eh_frame is not present From: Jean Pihet To: Jiri Olsa Cc: Will Deacon , "linux-kernel@vger.kernel.org" , "linaro-kernel@lists.linaro.org" , "linux-arm-kernel@lists.infradead.org" , Patch Tracking Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7148 Lines: 196 Hi Jiri, On 5 September 2013 18:30, Jiri Olsa wrote: > On Wed, Sep 04, 2013 at 08:04:14PM +0200, Jean Pihet wrote: >> On ARM the debug info is not present in the .eh_frame sections but >> instead in .debug_frame. >> Use libunwind to load and parse the debug info. > > hum, cannot make final link: > > $ make LIBUNWIND_DIR=/opt/libunwind/ > CHK -fstack-protector-all > CHK -Wstack-protector > CHK -Wvolatile-register-var > CHK -D_FORTIFY_SOURCE=2 > CHK bionic > CHK libelf > CHK libdw > CHK -DLIBELF_MMAP > CHK -DLIBELF_MMAP > CHK libunwind > CHK libaudit > > ... > > make[1]: `liblk.a' is up to date. > SUBDIR /home/jolsa/linux-perf/tools/lib/traceevent/ > LINK perf > libperf.a(unwind.o): In function `find_proc_info': > /home/jolsa/linux-perf/tools/perf/util/unwind.c:339: undefined reference to `_Ux86_64_dwarf_find_debug_frame' > collect2: ld returned 1 exit status > make: *** [perf] Error 1 > > > I'm using the latest code from git://git.sv.gnu.org/libunwind.git > > Looks like dwarf_find_debug_frame is not exported, although > it looks like it is based on what I see in libunwind sources ;-) > > What did I miss? Weird, I do not have the error on x86_64. I am investigating this and will come back to you asap. > > Also few typo comments below.. > > thanks, > jirka > >> >> Signed-off-by: Jean Pihet >> --- >> tools/perf/util/unwind.c | 70 +++++++++++++++++++++++++++++++++++++----------- >> 1 file changed, 54 insertions(+), 16 deletions(-) >> >> diff --git a/tools/perf/util/unwind.c b/tools/perf/util/unwind.c >> index 958723b..5353b32 100644 >> --- a/tools/perf/util/unwind.c >> +++ b/tools/perf/util/unwind.c >> @@ -39,6 +39,14 @@ UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as, >> >> #define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table) >> >> +extern int >> +UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug, >> + unw_word_t ip, unw_word_t segbase, >> + const char *obj_name, unw_word_t start, >> + unw_word_t end); >> + >> +#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame) >> + >> #define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */ >> #define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */ >> >> @@ -245,8 +253,9 @@ static int unwind_spec_ehframe(struct dso *dso, struct machine *machine, >> return 0; >> } >> >> -static int read_unwind_spec(struct dso *dso, struct machine *machine, >> - u64 *table_data, u64 *segbase, u64 *fde_count) >> +static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, >> + u64 *table_data, u64 *segbase, >> + u64 *fde_count) >> { >> int ret = -EINVAL, fd; >> u64 offset; >> @@ -255,6 +264,7 @@ static int read_unwind_spec(struct dso *dso, struct machine *machine, >> if (fd < 0) >> return -EINVAL; >> >> + /* Check the .eh_frame section for unwinding info */ >> offset = elf_section_offset(fd, ".eh_frame_hdr"); >> close(fd); >> >> @@ -263,10 +273,27 @@ static int read_unwind_spec(struct dso *dso, struct machine *machine, >> table_data, segbase, >> fde_count); >> >> - /* TODO .debug_frame check if eh_frame_hdr fails */ >> return ret; >> } >> >> +static int read_unwind_spec_debug_frame(struct dso *dso, >> + struct machine *machine, u64 *offset) >> +{ > > some strange formatting issue ^^^ ;-) I am using 4-spaces tabs. scripts/checkpatch.pl reported it to me in the form of too long lines. Should I change the code to 8-spaces tabs? Thx! Jean > > >> + int fd = dso__data_fd(dso, machine); >> + >> + if (fd < 0) >> + return -EINVAL; >> + >> + /* Check the .debug_frame section for unwinding info */ >> + *offset = elf_section_offset(fd, ".debug_frame"); >> + close(fd); >> + >> + if (*offset) >> + return 0; >> + >> + return -EINVAL; >> +} >> + >> static struct map *find_map(unw_word_t ip, struct unwind_info *ui) >> { >> struct addr_location al; >> @@ -291,20 +318,31 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi, >> >> pr_debug("unwind: find_proc_info dso %s\n", map->dso->name); >> >> - if (read_unwind_spec(map->dso, ui->machine, >> - &table_data, &segbase, &fde_count)) >> - return -EINVAL; >> + /* Check the .eh_frame section for unwinding info */ >> + if (!read_unwind_spec_eh_frame(map->dso, ui->machine, >> + &table_data, &segbase, &fde_count)) { > > ditto ^^^ > >> + memset(&di, 0, sizeof(di)); >> + di.format = UNW_INFO_FORMAT_REMOTE_TABLE; >> + di.start_ip = map->start; >> + di.end_ip = map->end; >> + di.u.rti.segbase = map->start + segbase; >> + di.u.rti.table_data = map->start + table_data; >> + di.u.rti.table_len = fde_count * sizeof(struct table_entry) >> + / sizeof(unw_word_t); >> + return dwarf_search_unwind_table(as, ip, &di, pi, >> + need_unwind_info, arg); > > ditto ^^^ > >> + } >> + >> + /* Check the .debug_frame section for unwinding info */ >> + if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) { >> + memset(&di, 0, sizeof(di)); >> + dwarf_find_debug_frame(0, &di, ip, 0, map->dso->name, >> + map->start, map->end); >> + return dwarf_search_unwind_table(as, ip, &di, pi, >> + need_unwind_info, arg); > > ditto ^^^ > >> + } >> >> - memset(&di, 0, sizeof(di)); >> - di.format = UNW_INFO_FORMAT_REMOTE_TABLE; >> - di.start_ip = map->start; >> - di.end_ip = map->end; >> - di.u.rti.segbase = map->start + segbase; >> - di.u.rti.table_data = map->start + table_data; >> - di.u.rti.table_len = fde_count * sizeof(struct table_entry) >> - / sizeof(unw_word_t); >> - return dwarf_search_unwind_table(as, ip, &di, pi, >> - need_unwind_info, arg); >> + return -EINVAL; >> } >> >> static int access_fpreg(unw_addr_space_t __maybe_unused as, >> -- >> 1.7.11.7 >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/