kernel/linux.git/tools/lib/bpf/libbpf.h, branch v5.4.151

libbpf: implement BPF CO-RE offset relocation algorithm

2019-08-07T21:43:49+00:00

This patch implements the core logic for BPF CO-RE offsets relocations. Every instruction that needs to be relocated has corresponding bpf_offset_reloc as part of BTF.ext. Relocations are performed by trying to match recorded "local" relocation spec against potentially many compatible "target" types, creating corresponding spec. Details of the algorithm are noted in corresponding comments in the code. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Alexei Starovoitov

libbpf: return previous print callback from libbpf_set_print

2019-07-28T05:36:19+00:00

By returning previously set print callback from libbpf_set_print, it's possible to restore it, eventually. This is useful when running many independent test with one default print function, but overriding log verbosity for particular subset of tests. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

libbpf: add perf buffer API

2019-07-08T13:35:43+00:00

BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program to user space for additional processing. libbpf already has very low-level API to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to use and requires a lot of code to set everything up. This patch adds perf_buffer abstraction on top of it, abstracting setting up and polling per-CPU logic into simple and convenient API, similar to what BCC provides. perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF map entries. It accepts two user-provided callbacks: one for handling raw samples and one for get notifications of lost samples due to buffer overflow. perf_buffer__new_raw() is similar, but provides more control over how perf events are set up (by accepting user-provided perf_event_attr), how they are handled (perf_event_header pointer is passed directly to user-provided callback), and on which CPUs ring buffers are created (it's possible to provide a list of CPUs and corresponding map keys to update). This API allows advanced users fuller control. perf_buffer__poll() is used to fetch ring buffer data across all CPUs, utilizing epoll instance. perf_buffer__free() does corresponding clean up and unsets FDs from BPF map. All APIs are not thread-safe. User should ensure proper locking/coordination if used in multi-threaded set up. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann

libbpf: add raw tracepoint attach API

2019-07-05T20:37:30+00:00

Add a wrapper utilizing bpf_link "infrastructure" to allow attaching BPF programs to raw tracepoints. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann

libbpf: add tracepoint attach API

2019-07-05T20:37:30+00:00

Allow attaching BPF programs to kernel tracepoint BPF hooks specified by category and name. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann

libbpf: add kprobe/uprobe attach API

2019-07-05T20:37:30+00:00

Add ability to attach to kernel and user probes and retprobes. Implementation depends on perf event support for kprobes/uprobes. Signed-off-by: Andrii Nakryiko Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann

libbpf: add ability to attach/detach BPF program to perf event

2019-07-05T20:37:30+00:00

bpf_program__attach_perf_event allows to attach BPF program to existing perf event hook, providing most generic and most low-level way to attach BPF programs. It returns struct bpf_link, which should be passed to bpf_link__destroy to detach and free resources, associated with a link. Signed-off-by: Andrii Nakryiko Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann

libbpf: introduce concept of bpf_link

2019-07-05T20:37:30+00:00

bpf_link is an abstraction of an association of a BPF program and one of many possible BPF attachment points (hooks). This allows to have uniform interface for detaching BPF programs regardless of the nature of link and how it was created. Details of creation and setting up of a specific bpf_link is handled by corresponding attachment methods (bpf_program__attach_xxx) added in subsequent commits. Once successfully created, bpf_link has to be eventually destroyed with bpf_link__destroy(), at which point BPF program is disassociated from a hook and all the relevant resources are freed. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Reviewed-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann

libbpf: constify getter APIs

2019-06-19T00:21:02+00:00

Add const qualifiers to bpf_object/bpf_program/bpf_map arguments for getter APIs. There is no need for them to not be const pointers. Verified that make -C tools/lib/bpf make -C tools/testing/selftests/bpf make -C tools/perf all build without warnings. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

bpf: add a new API libbpf_num_possible_cpus()

2019-06-11T08:36:02+00:00

Adding a new API libbpf_num_possible_cpus() that helps user with per-CPU map operations. Signed-off-by: Hechao Li Signed-off-by: Daniel Borkmann