linux/tools/lib/bpf/libbpf.map, branch v6.0

libbpf: Add bpf_obj_get_opts()

2022-07-29T22:30:06Z

Add an extensible variant of bpf_obj_get() capable of setting the `file_flags` parameter. This parameter is needed to enable unprivileged access to BPF maps. Without a method like this, users must manually make the syscall. Signed-off-by: Joe Burton Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220729202727.3311806-1-jevburton.kernel@gmail.com

libbpf: add ksyscall/kretsyscall sections support for syscall kprobes

2022-07-19T16:33:18Z

Add SEC("ksyscall")/SEC("ksyscall/") and corresponding kretsyscall variants (for return kprobes) to allow users to kprobe syscall functions in kernel. These special sections allow to ignore complexities and differences between kernel versions and host architectures when it comes to syscall wrapper and corresponding ___sys_ vs __se_sys_ differences, depending on whether host kernel has CONFIG_ARCH_HAS_SYSCALL_WRAPPER (though libbpf itself doesn't rely on /proc/config.gz for detecting this, see BPF_KSYSCALL patch for how it's done internally). Combined with the use of BPF_KSYSCALL() macro, this allows to just specify intended syscall name and expected input arguments and leave dealing with all the variations to libbpf. In addition to SEC("ksyscall+") and SEC("kretsyscall+") add bpf_program__attach_ksyscall() API which allows to specify syscall name at runtime and provide associated BPF cookie value. At the moment SEC("ksyscall") and bpf_program__attach_ksyscall() do not handle all the calling convention quirks for mmap(), clone() and compat syscalls. It also only attaches to "native" syscall interfaces. If host system supports compat syscalls or defines 32-bit syscalls in 64-bit kernel, such syscall interfaces won't be attached to by libbpf. These limitations may or may not change in the future. Therefore it is recommended to use SEC("kprobe") for these syscalls or if working with compat and 32-bit interfaces is required. Tested-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220714070755.3235561-5-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: perfbuf: Add API to get the ring buffer

2022-07-15T19:53:22Z

Add support for writing a custom event reader, by exposing the ring buffer. With the new API perf_buffer__buffer() you will get access to the raw mmaped()'ed per-cpu underlying memory of the ring buffer. This region contains both the perf buffer data and header (struct perf_event_mmap_page), which manages the ring buffer state (head/tail positions, when accessing the head/tail position it's important to take into consideration SMP). With this type of low level access one can implement different types of consumers here are few simple examples where this API helps with: 1. perf_event_read_simple is allocating using malloc, perhaps you want to handle the wrap-around in some other way. 2. Since perf buf is per-cpu then the order of the events is not guarnteed, for example: Given 3 events where each event has a timestamp t0 < t1 < t2, and the events are spread on more than 1 CPU, then we can end up with the following state in the ring buf: CPU[0] => [t0, t2] CPU[1] => [t1] When you consume the events from CPU[0], you could know there is a t1 missing, (assuming there are no drops, and your event data contains a sequential index). So now one can simply do the following, for CPU[0], you can store the address of t0 and t2 in an array (without moving the tail, so there data is not perished) then move on the CPU[1] and set the address of t1 in the same array. So you end up with something like: void **arr[] = [&t0, &t1, &t2], now you can consume it orderely and move the tails as you process in order. 3. Assuming there are multiple CPUs and we want to start draining the messages from them, then we can "pick" with which one to start with according to the remaining free space in the ring buffer. Signed-off-by: Jon Doron Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220715181122.149224-1-arilou@gmail.com

libbpf: implement bpf_prog_query_opts

2022-06-29T20:21:52Z

Implement bpf_prog_query_opts as a more expendable version of bpf_prog_query. Expose new prog_attach_flags and attach_btf_func_id as well: * prog_attach_flags is a per-program attach_type; relevant only for lsm cgroup program which might have different attach_flags per attach_btf_id * attach_btf_func_id is a new field expose for prog_query which specifies real btf function id for lsm cgroup attachments Acked-by: Martin KaFai Lau Acked-by: Andrii Nakryiko Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20220628174314.1216643-10-sdf@google.com Signed-off-by: Alexei Starovoitov

libbpf: fix up few libbpf.map problems

2022-06-28T20:13:33Z

Seems like we missed to add 2 APIs to libbpf.map and another API was misspelled. Fix it in libbpf.map. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-16-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: remove multi-instance and custom private data APIs

2022-06-28T20:13:32Z

Remove all the public APIs that are related to creating multi-instance bpf_programs through custom preprocessing callback and generally working with them. Also remove all the bpf_{object,map,program}__[set_]priv() APIs. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-10-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: remove most other deprecated high-level APIs

2022-06-28T20:13:32Z

Remove a bunch of high-level bpf_object/bpf_map/bpf_program related APIs. All the APIs related to private per-object/map/prog state, program preprocessing callback, and generally everything multi-instance related is removed in a separate patch. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-9-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: remove prog_info_linear APIs

2022-06-28T20:13:32Z

Remove prog_info_linear-related APIs previously used by perf. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-8-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: clean up perfbuf APIs

2022-06-28T20:13:32Z

Remove deprecated perfbuf APIs and clean up opts structs. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-7-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: remove deprecated BTF APIs

2022-06-28T20:13:32Z

Get rid of deprecated BTF-related APIs. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220627211527.2245459-6-andrii@kernel.org Signed-off-by: Alexei Starovoitov