kernel/linux.git/tools/lib/bpf/libbpf.h, branch v4.4.4

bpf tools: Add new API bpf_object__get_kversion()

2015-11-06T18:56:41+00:00

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: Wang Nan Cc: Jiri Olsa Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Improve libbpf error reporting

2015-11-06T18:52:41+00:00

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: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

tools lib bpf: Fix compiler warning on CentOS 6

2015-11-03T15:13:31+00:00

CC libbpf.o cc1: warnings being treated as errors libbpf.c: In function 'bpf_program__title': libbpf.c:1037: error: declaration of 'dup' shadows a global declaration /usr/include/unistd.h:528: error: shadowed declaration is here mv: cannot stat `./.libbpf.o.tmp': No such file or directory make[3]: *** [libbpf.o] Error 1 make[2]: *** [libbpf-in.o] Error 2 make[1]: *** [/linux/tools/lib/bpf/libbpf.a] Error 2 make[1]: *** Waiting for unfinished jobs.... Signed-off-by: Namhyung Kim Cc: David Ahern Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1446549665-2342-1-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: New API to get name from a BPF object

2015-08-31T19:53:15+00:00

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: Wang Nan Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1440742821-44548-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Link all bpf objects onto a list

2015-08-07T13:16:59+00:00

To allow enumeration of all bpf_objects, keep them in a list (hidden to caller). bpf_object__for_each_safe() is introduced to do this iteration. It is safe even user close the object during iteration. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-23-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Introduce accessors for struct bpf_program

2015-08-07T13:16:59+00:00

This patch introduces accessors for user of libbpf to retrieve section name and fd of a opened/loaded eBPF program. 'struct bpf_prog_handler' is used for that purpose. Accessors of programs section name and file descriptor are provided. Set/get private data are also impelmented. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Link: http://lkml.kernel.org/r/1435716878-189507-21-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Create eBPF maps defined in an object file

2015-08-07T13:16:58+00:00

This patch creates maps based on 'map' section in object file using bpf_create_map(), and stores the fds into an array in 'struct bpf_object'. Previous patches parse ELF object file and collects required data, but doesn't play with the kernel. They belong to the 'opening' phase. This patch is the first patch in 'loading' phase. The 'loaded' field is introduced in 'struct bpf_object' to avoid loading an object twice, because the loading phase clears resources collected during the opening which becomes useless after loading. In this patch, maps_buf is cleared. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-17-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Record map accessing instructions for each program

2015-08-07T13:16:58+00:00

This patch records the indices of instructions which are needed to be relocated. That information is saved in the 'reloc_desc' field in 'struct bpf_program'. In the loading phase (this patch takes effect in the opening phase), the collected instructions will be replaced by map loading instructions. Since we are going to close the ELF file and clear all data at the end of the 'opening' phase, the ELF information will no longer be valid in the 'loading' phase. We have to locate the instructions before maps are loaded, instead of directly modifying the instruction. 'struct bpf_map_def' is introduced in this patch to let us know how many maps are defined in the object. This is the third part of map relocation. The principle of map relocation is described in commit message of 'bpf tools: Collect symbol table from SHT_SYMTAB section'. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-15-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Read eBPF object from buffer

2015-08-07T13:16:56+00:00

To support dynamic compiling, this patch allows caller to pass a in-memory buffer to libbpf by bpf_object__open_buffer(). libbpf calls elf_memory() to open it as ELF object file. Because __bpf_object__open() collects all required data and won't need that buffer anymore, libbpf uses that buffer directly instead of clone a new buffer. Caller of libbpf can free that buffer or use it do other things after bpf_object__open_buffer() return. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-7-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

bpf tools: Open eBPF object file and do basic validation

2015-08-07T13:16:56+00:00

This patch defines basic interface of libbpf. 'struct bpf_object' will be the handler of each object file. Its internal structure is hide to user. eBPF object files are compiled by LLVM as ELF format. In this patch, libelf is used to open those files, read EHDR and do basic validation according to e_type and e_machine. All elf related staffs are grouped together and reside in efile field of 'struct bpf_object'. bpf_object__elf_finish() is introduced to clear it. After all eBPF programs in an object file are loaded, related ELF information is useless. Close the object file and free those memory. The zfree() and zclose() functions are introduced to ensure setting NULL pointers and negative file descriptors after resources are released. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-6-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo