基礎設施
eBPF Runtime
The Linux kernel contains the eBPF runtime required to run eBPF programs. It implements the bpf(2) system call for interacting with programs, maps, BTF and various attachment points where eBPF programs can be executed from. The kernel contains a eBPF verifier in order to check programs for safety and a JIT compiler to translate programs to native machine code. User space tooling such as bpftool and libbpf are also maintained as part of the upstream kernel.
eBPF Backend
The LLVM compiler infrastructure contains the eBPF backend required to translate programs written in a C-like syntax to eBPF instructions. LLVM generates eBPF ELF files which contain program code, map descriptions, relocation information and BTF meta data. These ELF files contain all necessary information for eBPF loaders such as libbpf to prepare and load programs into the Linux kernel. The LLVM project also contains additional developer tools such as an eBPF object file disassembler.
eBPF Backend
The GCC compiler comes with an eBPF backend starting from GCC 10. Up to that point, LLVM has been the only compiler which supports generating eBPF ELF files. The GCC port is roughly equivalent to the LLVM eBPF support. There are some missing bits of functionality but the GCC community is working to close these gaps over time. GCC also contains eBPF binutils as well as eBPF gdb support for debugging of eBPF code that is traditionally consumed by the Linux kernel. Included as part of this is an eBPF simulator for gdb.
Command-line tool to inspect and manage eBPF objects
Powered by libbpf, bpftool is the reference utility to quickly inspect and manage BPF objects on a Linux system. Use it to list, dump, or load eBPF programs and maps, to generate skeletons for eBPF applications, to statically link eBPF programs from different object files, or to perform various other eBPF-related tasks.