kernel/tools/lib/bpf, branch linux-4.16.y

tools/libbpf: Avoid possibly using uninitialized variable

2018-02-20T20:08:20Z

Fixes a GCC maybe-uninitialized warning introduced by 48cca7e44f9f. "text" is only initialized inside the if statement so only print debug info there. Fixes: 48cca7e44f9f ("libbpf: add support for bpf_call") Signed-off-by: Jeremy Cline Signed-off-by: Daniel Borkmann

tools/libbpf: handle issues with bpf ELF objects containing .eh_frames

2018-02-08T23:25:12Z

V3: More generic skipping of relo-section (suggested by Daniel) If clang >= 4.0.1 is missing the option '-target bpf', it will cause llc/llvm to create two ELF sections for "Exception Frames", with section names '.eh_frame' and '.rel.eh_frame'. The BPF ELF loader library libbpf fails when loading files with these sections. The other in-kernel BPF ELF loader in samples/bpf/bpf_load.c, handle this gracefully. And iproute2 loader also seems to work with these "eh" sections. The issue in libbpf is caused by bpf_object__elf_collect() skipping some sections, and later when performing relocation it will be pointing to a skipped section, as these sections cannot be found by bpf_object__find_prog_by_idx() in bpf_object__collect_reloc(). This is a general issue that also occurs for other sections, like debug sections which are also skipped and can have relo section. As suggested by Daniel. To avoid keeping state about all skipped sections, instead perform a direct qlookup in the ELF object. Lookup the section that the relo-section points to and check if it contains executable machine instructions (denoted by the sh_flags SHF_EXECINSTR). Use this check to also skip irrelevant relo-sections. Note, for samples/bpf/ the '-target bpf' parameter to clang cannot be used due to incompatibility with asm embedded headers, that some of the samples include. This is explained in more details by Yonghong Song in bpf_devel_QA. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann

tools/libbpf: improve the pr_debug statements to contain section numbers

2018-02-08T23:24:38Z

While debugging a bpf ELF loading issue, I needed to correlate the ELF section number with the failed relocation section reference. Thus, add section numbers/index to the pr_debug. In debug mode, also print section that were skipped. This helped me identify that a section (.eh_frame) was skipped, and this was the reason the relocation section (.rel.eh_frame) could not find that section number. The section numbers corresponds to the readelf tools Section Headers [Nr]. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann

libbpf: complete list of strings for guessing program type

2018-02-08T10:59:50Z

It seems that the type guessing feature for libbpf, based on the name of the ELF section the program is located in, was inspired from samples/bpf/prog_load.c, which was not used by any sample for loading programs of certain types such as TC actions and classifiers, or LWT-related types. As a consequence, libbpf is not able to guess the type of such programs and to load them automatically if type is not provided to the `bpf_load_prog()` function. Add ELF section names associated to those eBPF program types so that they can be loaded with e.g. bpftool as well. Signed-off-by: Quentin Monnet Reviewed-by: Jakub Kicinski Signed-off-by: Daniel Borkmann

libbpf: add missing SPDX-License-Identifier

2018-02-03T01:53:48Z

Signed-off-by: Eric Leblond Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov

libbpf: add error reporting in XDP

2018-02-03T01:53:48Z

Parse netlink ext attribute to get the error message returned by the card. Code is partially take from libnl. We add netlink.h to the uapi include of tools. And we need to avoid include of userspace netlink header to have a successful build of sample so nlattr.h has a define to avoid the inclusion. Using a direct define could have been an issue as NLMSGERR_ATTR_MAX can change in the future. We also define SOL_NETLINK if not defined to avoid to have to copy socket.h for a fixed value. Signed-off-by: Eric Leblond Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov

libbpf: add function to setup XDP

2018-02-03T01:53:48Z

Most of the code is taken from set_link_xdp_fd() in bpf_load.c and slightly modified to be library compliant. Signed-off-by: Eric Leblond Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov

tools: add netlink.h and if_link.h in tools uapi

2018-02-03T01:53:47Z

The headers are necessary for libbpf compilation on system with older version of the headers. Signed-off-by: Eric Leblond Signed-off-by: Alexei Starovoitov

libbpf: Makefile set specified permission mode

2018-01-17T00:18:10Z

The third parameter to do_install was not used by $(INSTALL) command. Fix this by only setting the -m option when the third parameter is supplied. The use of a third parameter was introduced in commit eb54e522a000 ("bpf: install libbpf headers on 'make install'"). Without this change, the header files are install as executables files (755). Fixes: eb54e522a000 ("bpf: install libbpf headers on 'make install'") Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann

libbpf: cleanup Makefile, remove unused elements

2018-01-17T00:18:10Z

The plugin_dir_SQ variable is not used, remove it. The function update_dir is also unused, remove it. The variable $VERSION_FILES is empty, remove it. These all originates from the introduction of the Makefile, and is likely a copy paste from tools/lib/traceevent/Makefile. Fixes: 1b76c13e4b36 ("bpf tools: Introduce 'bpf' library and add bpf feature check") Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann