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  1. 24 8月, 2022 8 次提交
  3. 06 12月, 2021 4 次提交
  5. 01 10月, 2020 1 次提交
  7. 30 9月, 2020 2 次提交
  9. 29 9月, 2020 8 次提交
  11. 22 9月, 2020 1 次提交
  13. 19 8月, 2020 3 次提交
  15. 14 8月, 2020 1 次提交
    • A
      libbpf: Handle BTF pointer sizes more carefully · 44ad23df
      由 Andrii Nakryiko 提交于 
      With libbpf and BTF it is pretty common to have libbpf built for one
architecture, while BTF information was generated for a different architecture
(typically, but not always, BPF). In such case, the size of a pointer might
differ betweem architectures. libbpf previously was always making an
assumption that pointer size for BTF is the same as native architecture
pointer size, but that breaks for cases where libbpf is built as 32-bit
library, while BTF is for 64-bit architecture.

To solve this, add heuristic to determine pointer size by searching for `long`
or `unsigned long` integer type and using its size as a pointer size. Also,
allow to override the pointer size with a new API btf__set_pointer_size(), for
cases where application knows which pointer size should be used. User
application can check what libbpf "guessed" by looking at the result of
btf__pointer_size(). If it's not 0, then libbpf successfully determined a
pointer size, otherwise native arch pointer size will be used.

For cases where BTF is parsed from ELF file, use ELF's class (32-bit or
64-bit) to determine pointer size.

Fixes: 8a138aed ("bpf: btf: Add BTF support to libbpf")
Fixes: 351131b5 ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-5-andriin@fb.com
      44ad23df
  17. 07 8月, 2020 1 次提交
  19. 03 8月, 2020 1 次提交
  21. 31 7月, 2020 1 次提交
  23. 10 7月, 2020 1 次提交
  25. 09 7月, 2020 1 次提交
  27. 26 3月, 2020 1 次提交
  29. 16 1月, 2020 1 次提交
  31. 11 1月, 2020 1 次提交
  33. 16 12月, 2019 3 次提交
    • P
      libbpf: Fix build by renaming variables · a79ac2d1
      由 Prashant Bhole 提交于 
      In btf__align_of() variable name 't' is shadowed by inner block
declaration of another variable with same name. Patch renames
variables in order to fix it.

  CC       sharedobjs/btf.o
btf.c: In function ‘btf__align_of’:
btf.c:303:21: error: declaration of ‘t’ shadows a previous local [-Werror=shadow]
  303 |   int i, align = 1, t;
      |                     ^
btf.c:283:25: note: shadowed declaration is here
  283 |  const struct btf_type *t = btf__type_by_id(btf, id);
      |

Fixes: 3d208f4c ("libbpf: Expose btf__align_of() API")
Signed-off-by: NPrashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20191216082738.28421-1-prashantbhole.linux@gmail.com
      a79ac2d1
    • A
      libbpf: Support libbpf-provided extern variables · 166750bc
      由 Andrii Nakryiko 提交于 
      Add support for extern variables, provided to BPF program by libbpf. Currently
the following extern variables are supported:
  - LINUX_KERNEL_VERSION; version of a kernel in which BPF program is
    executing, follows KERNEL_VERSION() macro convention, can be 4- and 8-byte
    long;
  - CONFIG_xxx values; a set of values of actual kernel config. Tristate,
    boolean, strings, and integer values are supported.

Set of possible values is determined by declared type of extern variable.
Supported types of variables are:
- Tristate values. Are represented as `enum libbpf_tristate`. Accepted values
  are **strictly** 'y', 'n', or 'm', which are represented as TRI_YES, TRI_NO,
  or TRI_MODULE, respectively.
- Boolean values. Are represented as bool (_Bool) types. Accepted values are
  'y' and 'n' only, turning into true/false values, respectively.
- Single-character values. Can be used both as a substritute for
  bool/tristate, or as a small-range integer:
  - 'y'/'n'/'m' are represented as is, as characters 'y', 'n', or 'm';
  - integers in a range [-128, 127] or [0, 255] (depending on signedness of
    char in target architecture) are recognized and represented with
    respective values of char type.
- Strings. String values are declared as fixed-length char arrays. String of
  up to that length will be accepted and put in first N bytes of char array,
  with the rest of bytes zeroed out. If config string value is longer than
  space alloted, it will be truncated and warning message emitted. Char array
  is always zero terminated. String literals in config have to be enclosed in
  double quotes, just like C-style string literals.
- Integers. 8-, 16-, 32-, and 64-bit integers are supported, both signed and
  unsigned variants. Libbpf enforces parsed config value to be in the
  supported range of corresponding integer type. Integers values in config can
  be:
  - decimal integers, with optional + and - signs;
  - hexadecimal integers, prefixed with 0x or 0X;
  - octal integers, starting with 0.

Config file itself is searched in /boot/config-$(uname -r) location with
fallback to /proc/config.gz, unless config path is specified explicitly
through bpf_object_open_opts' kernel_config_path option. Both gzipped and
plain text formats are supported. Libbpf adds explicit dependency on zlib
because of this, but this shouldn't be a problem, given libelf already depends
on zlib.

All detected extern variables, are put into a separate .extern internal map.
It, similarly to .rodata map, is marked as read-only from BPF program side, as
well as is frozen on load. This allows BPF verifier to track extern values as
constants and perform enhanced branch prediction and dead code elimination.
This can be relied upon for doing kernel version/feature detection and using
potentially unsupported field relocations or BPF helpers in a CO-RE-based BPF
program, while still having a single version of BPF program running on old and
new kernels. Selftests are validating this explicitly for unexisting BPF
helper.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014710.3449601-3-andriin@fb.com
      166750bc
    • A
      libbpf: Expose btf__align_of() API · 3d208f4c
      由 Andrii Nakryiko 提交于 
      Expose BTF API that calculates type alignment requirements.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-7-andriin@fb.com
      3d208f4c
  35. 16 11月, 2019 1 次提交