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path: root/tools/perf/util/symbol-elf.c
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2012-08-20perf symbols: Fix builds with NO_LIBELF setDavid Ahern
Build currently fails: $ make -C tools/perf O=/tmp/pbuild NO_LIBELF=1 util/symbol.c: In function ‘dso__load’: util/symbol.c:1128:27: error: ‘struct symsrc’ has no member named ‘dynsym’ CC /tmp/pbuild/util/pager.o make: *** [/tmp/pbuild/util/symbol.o] Error 1 make: *** Waiting for unfinished jobs.... Moving the dynsym reference to symbol-elf.c reveals that NO_LIBELF requires NO_LIBUNWIND: $ make -C tools/perf O=/tmp/pbuild NO_LIBELF=1 LINK /tmp/pbuild/perf /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_offset': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:176: undefined reference to `elf_begin' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:181: undefined reference to `gelf_getehdr' /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_by_name': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:157: undefined reference to `elf_nextscn' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:160: undefined reference to `gelf_getshdr' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:161: undefined reference to `elf_strptr' /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_offset': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:190: undefined reference to `elf_end' /tmp/pbuild/libperf.a(unwind.o): In function `read_unwind_spec': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:190: undefined reference to `elf_end' collect2: ld returned 1 exit status make: *** [/tmp/pbuild/perf] Error 1 make: Leaving directory `/opt/sw/ahern/perf.git/tools/perf' This patch fixes both. Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/1345391234-71906-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Use both runtime and debug imagesCody P Schafer
We keep both a 'runtime' elf image as well as a 'debug' elf image around and generate symbols by looking at both of these. This eliminates the need for the want_symtab/goto restart mechanism combined with iterating over and reopening the elf images a second time. Also give dso__synthsize_plt_symbols() the runtime image (which has dynsyms) instead of the symbol image (which may only have a symtab and no dynsyms). Previously if a debug image was found all runtime images were ignored. This fixes 2 issues: - Symbol resolution to failure on PowerPC systems with debug symbols installed, as the debug images lack a '.opd' section which contains function descriptors. - On all archs, plt synthesis failed when a debug image was loaded and that debug image lacks a dynsym section while a runtime image has a dynsym section. Assumptions: - If a .opd section exists, it is contained in the highest priority image with a dynsym section. - This generally implies that the debug image lacks a dynsym section (ie: it is marked as NO_BITS). Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-17-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Convert dso__load_syms to take 2 symsrc'sCody P Schafer
To properly handle platforms with an opd section, both a runtime image (which contains the opd section but possibly lacks symbols) and a symbol image (which probably lacks an opd section but has symbols). The next patch ("perf symbol: use both runtime and debug images") adjusts the callsite in dso__load() to take advantage of being able to pass both runtime & debug images. Assumptions made here: - The opd section, if it exists in the runtime image, has headers in both the runtime image and the debug/syms image. - The index of the opd section (again, only if it exists in the runtime image) is the same in both the runtime and debug/symbols image. Both of these are true on RHEL, but it is unclear how accurate they are in general (on platforms with function descriptors in opd sections). Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-16-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Factor want_symtab out of dso__load_sym()Cody P Schafer
Only one callsite of dso__load_sym() uses the want_symtab functionality, so place the logic at the callsite instead of within dso__load_sym(). This sets us up for removal of want_symtab completely once we keep multiple elf handles (within symsrc's) around. Setup for the later patch "perf symbols: Use both runtime and debug images" Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-15-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Switch dso__synthesize_plt_symbols() to use symsrcCody P Schafer
Previously dso__synthesize_plt_symbols() was reopening the elf file to obtain dynsyms from it. Rather than reopen the file, use the already opened reference within the symsrc to access it. Setup for the later patch "perf symbols: Use both runtime and debug images" Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-14-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Set symtab_type in dso__load_symCody P Schafer
In certain cases, dso__load requires dso->symbol_type to be set prior to calling it. With the introduction of symsrc*, the symtab_type is now stored in a symsrc which is then passed to dso__load_sym(). Change dso__load_sym() to use the symtab_type from them symsrc (setting dso->symtab_type as well). Setup for later patch "perf symbols: Use both runtime and debug images" Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-13-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Introduce symsrc structure.Cody P Schafer
Factors opening of certain sections & tracking certain elf info into an external structure. The goal here is to keep multiple elfs (and their looked up sections/indexes) around during the symbol generation process (in dso__load()). We need this to properly resolve symbols on PPC due to the use of function descriptors & the .opd section (ie: symbols which are functions don't point to their actual location, they point to their function descriptor in .opd which contains their actual location. It would be possible to just keep the (Elf *) around, but then we'd end up with duplicate code for looking up the same sections and checking for the existence of an important section wouldn't be as clean (and we need to keep the Elf stuff confined to symtab-elf.c). Utilized by the later patch "perf symbols: Use both runtime and debug images" Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-12-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Avoid segfault in elf_strptrCody P Schafer
If we call elf_section_by_name() with a truncated elf image (ie: the file header indicates that the section headers are placed past the end of the file), elf_strptr() causes a segfault within libelf. Avoid this by checking that we can access the section string table properly. Should really be fixed in libelf/elfutils. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-10-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Don't try to synthesize plt without dynstrCody P Schafer
If .dynsym exists but .dynstr is empty (NO_BITS or size==0), a segfault occurs. Avoid this by checking that .dynstr is not empty. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-6-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-13perf symbols: Only un-prelink non-zero symbolsCody P Schafer
Prelink only adjusts the addresses of non-zero symbols. Do the same when we reverse the adjustments. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-4-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-09perf symbols: Split out util/symbol-elf.cNamhyung Kim
Factor out the dependency of ELF handling into separate symbol-elf.c file. It is a preparation of building a minimalistic version perf tools which doesn't depend on the elfutils. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344228082-15569-3-git-send-email-namhyung@kernel.org [ committer note: removed blank line at symbol-elf.c EOF ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>