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  1. 14 12月, 2017 1 次提交
    • R
      libbpf: add ability to guess program type based on section name · 583c9009
      由 Roman Gushchin 提交于 
      The bpf_prog_load() function will guess program type if it's not
specified explicitly. This functionality will be used to implement
loading of different programs without asking a user to specify
the program type. In first order it will be used by bpftool.
Signed-off-by: NRoman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      583c9009
  3. 06 10月, 2017 2 次提交
  5. 29 9月, 2017 1 次提交
    • M
      bpf: libbpf: Provide basic API support to specify BPF obj name · 88cda1c9
      由 Martin KaFai Lau 提交于 
      This patch extends the libbpf to provide API support to
allow specifying BPF object name.

In tools/lib/bpf/libbpf, the C symbol of the function
and the map is used.  Regarding section name, all maps are
under the same section named "maps".  Hence, section name
is not a good choice for map's name.  To be consistent with
map, bpf_prog also follows and uses its function symbol as
the prog's name.

This patch adds logic to collect function's symbols in libbpf.
There is existing codes to collect the map's symbols and no change
is needed.

The bpf_load_program_name() and bpf_map_create_name() are
added to take the name argument.  For the other bpf_map_create_xxx()
variants, a name argument is directly added to them.

In samples/bpf, bpf_load.c in particular, the symbol is also
used as the map's name and the map symbols has already been
collected in the existing code.  For bpf_prog, bpf_load.c does
not collect the function symbol name.  We can consider to collect
them later if there is a need to continue supporting the bpf_load.c.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Acked-by: NAlexei Starovoitov <ast@fb.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      88cda1c9
  7. 21 8月, 2017 1 次提交
  9. 17 8月, 2017 1 次提交
  11. 02 4月, 2017 1 次提交
  13. 01 2月, 2017 3 次提交
    • J
      tools lib bpf: Add bpf_object__pin() · d5148d85
      由 Joe Stringer 提交于 
      Add a new API to pin a BPF object to the filesystem. The user can
specify the path within a BPF filesystem to pin the object.
Programs will be pinned under a subdirectory named the same as the
program, with each instance appearing as a numbered file under that
directory, and maps will be pinned under the path using the name of
the map as the file basename.

For example, with the directory '/sys/fs/bpf/foo' and a BPF object which
contains two instances of a program named 'bar', and a map named 'baz':

/sys/fs/bpf/foo/bar/0
/sys/fs/bpf/foo/bar/1
/sys/fs/bpf/foo/baz
Signed-off-by: NJoe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170126212001.14103-4-joe@ovn.org
[ Check snprintf >= for truncation, as snprintf(bf, size, ...) == size also means truncation ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      d5148d85
    • J
      tools lib bpf: Add bpf_map__pin() · b6989f35
      由 Joe Stringer 提交于 
      Add a new API to pin a BPF map to the filesystem. The user can specify
the path full path within a BPF filesystem to pin the map.
Signed-off-by: NJoe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170126212001.14103-3-joe@ovn.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b6989f35
    • J
      tools lib bpf: Add BPF program pinning APIs · f367540c
      由 Joe Stringer 提交于 
      Add new APIs to pin a BPF program (or specific instances) to the
filesystem.  The user can specify the path full path within a BPF
filesystem to pin the program.

bpf_program__pin_instance(prog, path, n) will pin the nth instance of
'prog' to the specified path.

bpf_program__pin(prog, path) will create the directory 'path' (if it
does not exist) and pin each instance within that directory. For
instance, path/0, path/1, path/2.

Committer notes:

- Add missing headers for mkdir()

- Check strdup() for failure

- Check snprintf >= size, not >, as == also means truncated, see 'man
  snprintf', return value.

- Conditionally define BPF_FS_MAGIC, as it isn't in magic.h in older
  systems and we're not yet having a tools/include/uapi/linux/magic.h
  copy.

- Do not include linux/magic.h, not present in older distros.
Signed-off-by: NJoe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170126212001.14103-2-joe@ovn.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      f367540c
  15. 26 1月, 2017 4 次提交
  17. 16 12月, 2016 1 次提交
  19. 29 11月, 2016 2 次提交
  21. 25 11月, 2016 1 次提交
    • E
      tools lib bpf: Fix maps resolution · 4708bbda
      由 Eric Leblond 提交于 
      It is not correct to assimilate the elf data of the maps section to an
array of map definition. In fact the sizes differ. The offset provided
in the symbol section has to be used instead.

This patch fixes a bug causing a elf with two maps not to load
correctly.

Wang Nan added:

This patch requires a name for each BPF map, so array of BPF maps is not
allowed. This restriction is reasonable, because kernel verifier forbid
indexing BPF map from such array unless the index is a fixed value, but
if the index is fixed why not merging it into name?

For example:

Program like this:
  ...
  unsigned long cpu = get_smp_processor_id();
  int *pval = map_lookup_elem(&map_array[cpu], &key);
  ...

Generates bytecode like this:

0: (b7) r1 = 0
1: (63) *(u32 *)(r10 -4) = r1
2: (b7) r1 = 680997
3: (63) *(u32 *)(r10 -8) = r1
4: (85) call 8
5: (67) r0 <<= 4
6: (18) r1 = 0x112dd000
8: (0f) r0 += r1
9: (bf) r2 = r10
10: (07) r2 += -4
11: (bf) r1 = r0
12: (85) call 1

Where instruction 8 is the computation, 8 and 11 render r1 to an invalid
value for function map_lookup_elem, causes verifier report error.
Signed-off-by: NEric Leblond <eric@regit.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Wang Nan <wangnan0@huawei.com>
[ Merge bpf_object__init_maps_name into bpf_object__init_maps.
  Fix segfault for buggy BPF script Validate obj->maps ]
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161115040617.69788-5-wangnan0@huawei.comSigned-off-by: NWang Nan <wangnan0@huawei.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4708bbda
  23. 26 7月, 2016 1 次提交
  25. 14 7月, 2016 2 次提交
  27. 05 7月, 2016 1 次提交
  29. 29 6月, 2016 1 次提交
  31. 07 6月, 2016 7 次提交
  33. 26 1月, 2016 1 次提交
    • W
      perf bpf: Check relocation target section · 666810e8
      由 Wang Nan 提交于 
      Libbpf should check the target section before doing relocation to ensure
the relocation is correct. If not, a bug in LLVM causes an error. See
[1].  Also, if an incorrect BPF script uses both global variable and
map, global variable whould be treated as map and be relocated without
error.

This patch saves the id of the map section into obj->efile and compare
target section of a relocation symbol against it during relocation.

Previous patch introduces a test case about this problem.  After this
patch:

  # ~/perf test BPF
  37: Test BPF filter                                          :
  37.1: Test basic BPF filtering                               : Ok
  37.2: Test BPF prologue generation                           : Ok
  37.3: Test BPF relocation checker                            : Ok

  # perf test -v BPF
  ...
  37.3: Test BPF relocation checker                            :
  ...
  libbpf: loading object '[bpf_relocation_test]' from buffer
  libbpf: section .strtab, size 126, link 0, flags 0, type=3
  libbpf: section .text, size 0, link 0, flags 6, type=1
  libbpf: section .data, size 0, link 0, flags 3, type=1
  libbpf: section .bss, size 0, link 0, flags 3, type=8
  libbpf: section func=sys_write, size 104, link 0, flags 6, type=1
  libbpf: found program func=sys_write
  libbpf: section .relfunc=sys_write, size 16, link 10, flags 0, type=9
  libbpf: section maps, size 16, link 0, flags 3, type=1
  libbpf: maps in [bpf_relocation_test]: 16 bytes
  libbpf: section license, size 4, link 0, flags 3, type=1
  libbpf: license of [bpf_relocation_test] is GPL
  libbpf: section version, size 4, link 0, flags 3, type=1
  libbpf: kernel version of [bpf_relocation_test] is 40400
  libbpf: section .symtab, size 144, link 1, flags 0, type=2
  libbpf: map 0 is "my_table"
  libbpf: collecting relocating info for: 'func=sys_write'
  libbpf: Program 'func=sys_write' contains non-map related relo data pointing to section 65522
  bpf: failed to load buffer
  Compile BPF program failed.
  test child finished with 0
  ---- end ----
  Test BPF filter subtest 2: Ok

[1] https://llvm.org/bugs/show_bug.cgi?id=26243Signed-off-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1453715801-7732-3-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      666810e8
  35. 11 12月, 2015 2 次提交
    • W
      tools lib bpf: Fetch map names from correct strtab · 77ba9a5b
      由 Wang Nan 提交于 
      Namhyung Kim pointed out a potential problem in original code that it
fetches names of maps from section header string table, which is used
to store section names.

Original code doesn't cause error because of a LLVM behavior that, it
combines shstrtab into strtab. For example:

 $ echo 'int func() {return 0;}' | x86_64-oe-linux-clang -x c -o temp.o -c -
 $ readelf -h ./temp.o
 ELF Header:
   Magic:   7f 45 4c 46 02 01 01 03 00 00 00 00 00 00 00 00
   ...
   Section header string table index: 1
 $ readelf -S ./temp.o
 There are 10 section headers, starting at offset 0x288:

 Section Headers:
   [Nr] Name              Type             Address           Offset
        Size              EntSize          Flags  Link  Info  Align
   [ 0]                   NULL             0000000000000000  00000000
        0000000000000000  0000000000000000           0     0     0
   [ 1] .strtab           STRTAB           0000000000000000  00000230
        0000000000000051  0000000000000000           0     0     1
        ...
 $ readelf -p .strtab ./temp.o

 String dump of section '.strtab':
   [     1]  .text
   [     7]  .comment
   [    10]  .bss
   [    15]  .note.GNU-stack
   [    25]  .rela.eh_frame
   [    34]  func
   [    39]  .strtab
   [    41]  .symtab
   [    49]  .data
   [    4f]  -

 $ readelf -p .shstrtab ./temp.o
 readelf: Warning: Section '.shstrtab' was not dumped because it does not exist!

Where, 'section header string table index' points to '.strtab', and
symbol names are also stored there.

However, in case of gcc:

 $ echo 'int func() {return 0;}' | gcc -x c -o temp.o -c -
 $ readelf -p .shstrtab ./temp.o

 String dump of section '.shstrtab':
   [     1]  .symtab
   [     9]  .strtab
   [    11]  .shstrtab
   [    1b]  .text
   [    21]  .data
   [    27]  .bss
   [    2c]  .comment
   [    35]  .note.GNU-stack
   [    45]  .rela.eh_frame
 $ readelf -p .strtab ./temp.o

 String dump of section '.strtab':
   [     1]  func

They are separated sections.

Although original code doesn't cause error, we'd better use canonical
method for fetching symbol names to avoid potential behavior changing.
This patch learns from readelf's code, fetches string from sh_link
of .symbol section.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Reported-and-Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1449541544-67621-3-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      77ba9a5b
    • W
      tools lib bpf: Check return value of strdup when reading map names · 973170e6
      由 Wang Nan 提交于 
      Commit 561bbcca ("tools lib bpf:
Extract and collect map names from BPF object file") forgets checking
return value of strdup(). This patch fixes it. It also checks names
pointer before strcmp() for safety.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Fixes: 561bbcca ("tools lib bpf: Extract and collect map names from BPF object file")
Link: http://lkml.kernel.org/r/1449541544-67621-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      973170e6
  37. 28 11月, 2015 2 次提交
  39. 19 11月, 2015 1 次提交
    • W
      bpf tools: Load a program with different instances using preprocessor · b580563e
      由 Wang Nan 提交于 
      This patch is a preparation for BPF prologue support which allows
generating a series of BPF bytecode for fetching kernel data before
calling program code. With the newly introduced multiple instances
support, perf is able to create different prologues for different kprobe
points.

Before this patch, a bpf_program can be loaded into kernel only once,
and get the only resulting fd. What this patch does is to allow creating
and loading different variants of one bpf_program, then fetching their
fds.

Here we describe the basic idea in this patch. The detailed description
of the newly introduced APIs can be found in comments in the patch body.

The key of this patch is the new mechanism in bpf_program__load().
Instead of loading BPF program into kernel directly, it calls a
'pre-processor' to generate program instances which would be finally
loaded into the kernel based on the original code. To enable the
generation of multiple instances, libbpf passes an index to the
pre-processor so it know which instance is being loaded.

Pre-processor should be called from libbpf's user (perf) using
bpf_program__set_prep(). The number of instances and the relationship
between indices and the target instance should be clear when calling
bpf_program__set_prep().

To retrieve a fd for a specific instance of a program,
bpf_program__nth_fd() is introduced. It returns the resulting fd
according to index.
Signed-off-by: NHe Kuang <hekuang@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447675815-166222-8-git-send-email-wangnan0@huawei.comSigned-off-by: NWang Nan <wangnan0@huawei.com>
[ Enclosed multi-line if/else blocks with {}, (*func_ptr)() -> func_ptr() ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b580563e
  41. 07 11月, 2015 2 次提交
    • W
      bpf tools: Add new API bpf_object__get_kversion() · 45825d8a
      由 Wang Nan 提交于 
      bpf_object__get_kversion() can be used to fetch value of object's
'version' section. Following patch will use it for error reporting.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-3-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      45825d8a
    • W
      bpf tools: Improve libbpf error reporting · 6371ca3b
      由 Wang Nan 提交于 
      In this patch, a series of libbpf specific error numbers and
libbpf_strerror() are introduced to help reporting errors.

Functions are updated to pass correct the error number through the
CHECK_ERR() macro.

All users of bpf_object__open{_buffer}() and bpf_program__title() in
perf are modified accordingly. In addition, due to the error codes
changing, bpf__strerror_load() is also modified to use them.

bpf__strerror_head() is also changed accordingly so it can parse libbpf
errors. bpf_loader_strerror() is introduced for that purpose, and will
be improved by the following patch.

load_program() is improved not to dump log buffer if it is empty. log
buffer is also used to deduce whether the error was caused by an invalid
program or other problem.

v1 -> v2:

 - Using macro for error code.

 - Fetch error message based on array index, eliminate for-loop.

 - Use log buffer to detect the reason of failure. 3 new error code
   are introduced to replace LIBBPF_ERRNO__LOAD.

In v1:

  # perf record -e ./test_ill_program.o ls
  event syntax error: './test_ill_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  # perf record -e ./test_kversion_nomatch_program.o ls
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  # perf record -e ./test_big_program.o ls
  event syntax error: './test_big_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  In v2:

  # perf record -e ./test_ill_program.o ls
  event syntax error: './test_ill_program.o'
                       \___ Kernel verifier blocks program loading
  SKIP

  # perf record -e ./test_kversion_nomatch_program.o
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ Incorrect kernel version
  SKIP
  (Will be further improved by following patches)

  # perf record -e ./test_big_program.o
  event syntax error: './test_big_program.o'
                       \___ Program too big
  SKIP
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      6371ca3b
  43. 03 11月, 2015 1 次提交
  45. 01 9月, 2015 1 次提交
    • W
      bpf tools: New API to get name from a BPF object · acf860ae
      由 Wang Nan 提交于 
      Before this patch there's no way to connect a loaded bpf object
to its source file. However, during applying perf's '--filter' to BPF
object, without this connection makes things harder, because perf loads
all programs together, but '--filter' setting is for each object.

The API of bpf_object__open_buffer() is changed to allow passing a name.
Fortunately, at this time there's only one user of it (perf test LLVM),
so we change it together.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440742821-44548-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      acf860ae