kcore can be used to view the running kernel object code. However,
kcore changes as modules are loaded and unloaded, and when the kernel
decides to modify its own code. Consequently it is useful to create a
copy of kcore at a particular time. Unlike vmlinux, kcore is not unique
for a given build-id. And in addition, the kallsyms and modules files
are also needed. The tool therefore creates a directory:
~/.debug/[kernel.kcore]/<build-id>/<YYYYmmddHHMMSShh>
which contains: kcore, kallsyms and modules.
Note that the copied kcore contains only code sections. See the
kcore_copy() function for how that is determined.
The tool will not make additional copies of kcore if there is already
one with the same modules at the same addresses.
Currently, perf tools will not look for kcore in the cache. That is
addressed in another patch.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/525BF849.5030405@intel.com
[ renamed 'index' to 'idx' to avoid shadowing string.h symbol in f12,
use at least one member initializer when initializing a struct to
zeros, also to fix the build on f12 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This reverts commit de95ab5364.
Markus Trippelsdorf reported that this commit broke 'perf top':
> I just see a gray screen with no text at all. Sometimes the
> following error messages are printed:
>
> *** Error in `perf': invalid fastbin entry (free): 0x00000000029b18c0
> ***
> *** Error in `perf': malloc(): memory corruption (fast): 0x0000000000ee0b10 ***
While this code is fixable, the commit itself fails on several levels:
- it should have been a separate helper function
- why the heck does it do strchr() twice
- it casts a const char * over into char *
- sloppy style
- it's not even a regression fix!
So lets revert it and re-try the patch in v3.13.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new "object code reading" test shows that it is not possible to read
object code from vmlinux. That is because the mappings do not map to
the dso. This patch fixes that.
A side-effect of changing the kernel map is that the "reloc" offset must
be taken into account. As a result of that separate map functions for
relocation are no longer needed.
Also fixing up the maps to match the symbols no longer makes sense and
so is not done.
The vmlinux dso data_type is now set to either DSO_BINARY_TYPE__VMLINUX
or DSO_BINARY_TYPE__GUEST_VMLINUX as approprite, which enables the
correct file name to be determined by dso__binary_type_file().
This patch breaks the "vmlinux symtab matches kallsyms" test. That is
fixed in a following patch.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1375875537-4509-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The elf.h header file is used for NO_LIBELF build too so it should be
included anyway. Also remove duplicated include of the header file in
symbol-*.c. This patch fixes following build error on NO_LIBELF build:
CC tests/hists_link.o
tests/hists_link.c: In function ‘setup_fake_machine’:
tests/hists_link.c:132:8: error: ‘STB_GLOBAL’ undeclared (first use in this function)
tests/hists_link.c:132:8: note: each undeclared identifier is reported only once for each function it appears in
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
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/1356679009-32122-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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>
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>
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>
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>
