linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2020-08-20	bpf: Add kernel module with user mode driver that populates bpffs.	Alexei Starovoitov	2	-0/+107
	Add kernel module with user mode driver that populates bpffs with BPF iterators. $ mount bpffs /my/bpffs/ -t bpf $ ls -la /my/bpffs/ total 4 drwxrwxrwt 2 root root 0 Jul 2 00:27 . drwxr-xr-x 19 root root 4096 Jul 2 00:09 .. -rw------- 1 root root 0 Jul 2 00:27 maps.debug -rw------- 1 root root 0 Jul 2 00:27 progs.debug The user mode driver will load BPF Type Formats, create BPF maps, populate BPF maps, load two BPF programs, attach them to BPF iterators, and finally send two bpf_link IDs back to the kernel. The kernel will pin two bpf_links into newly mounted bpffs instance under names "progs.debug" and "maps.debug". These two files become human readable. $ cat /my/bpffs/progs.debug id name attached 11 dump_bpf_map bpf_iter_bpf_map 12 dump_bpf_prog bpf_iter_bpf_prog 27 test_pkt_access 32 test_main test_pkt_access test_pkt_access 33 test_subprog1 test_pkt_access_subprog1 test_pkt_access 34 test_subprog2 test_pkt_access_subprog2 test_pkt_access 35 test_subprog3 test_pkt_access_subprog3 test_pkt_access 36 new_get_skb_len get_skb_len test_pkt_access 37 new_get_skb_ifindex get_skb_ifindex test_pkt_access 38 new_get_constant get_constant test_pkt_access The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about all BPF programs currently loaded in the system. This information is unstable and will change from kernel to kernel as ".debug" suffix conveys. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
2020-08-20	bpf: Add BPF program and map iterators as built-in BPF programs.	Alexei Starovoitov	5	-0/+587
	The program and map iterators work similar to seq_file-s. Once the program is pinned in bpffs it can be read with "cat" tool to print human readable output. In this case about BPF programs and maps. For example: $ cat /sys/fs/bpf/progs.debug id name attached 5 dump_bpf_map bpf_iter_bpf_map 6 dump_bpf_prog bpf_iter_bpf_prog $ cat /sys/fs/bpf/maps.debug id name max_entries 3 iterator.rodata 1 To avoid kernel build dependency on clang 10 separate bpf skeleton generation into manual "make" step and instead check-in generated .skel.h into git. Unlike 'bpftool prog show' in-kernel BTF name is used (when available) to print full name of BPF program instead of 16-byte truncated name. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200819042759.51280-3-alexei.starovoitov@gmail.com