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Diffstat (limited to 'tools/bpf/bpftool/Documentation/bpftool-feature.rst')
| -rw-r--r-- | tools/bpf/bpftool/Documentation/bpftool-feature.rst | 78 |
1 files changed, 39 insertions, 39 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-feature.rst b/tools/bpf/bpftool/Documentation/bpftool-feature.rst index 4d08f35034a2..e44039f89be7 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-feature.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-feature.rst @@ -1,3 +1,5 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + =============== bpftool-feature =============== @@ -7,31 +9,40 @@ tool for inspection of eBPF-related parameters for Linux kernel or net device :Manual section: 8 +.. include:: substitutions.rst + SYNOPSIS ======== **bpftool** [*OPTIONS*] **feature** *COMMAND* - *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] } + *OPTIONS* := { |COMMON_OPTIONS| } *COMMANDS* := { **probe** | **help** } FEATURE COMMANDS ================ -| **bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]] +| **bpftool** **feature probe** [*COMPONENT*] [**full**] [**unprivileged**] [**macros** [**prefix** *PREFIX*]] +| **bpftool** **feature list_builtins** *GROUP* | **bpftool** **feature help** | | *COMPONENT* := { **kernel** | **dev** *NAME* } +| *GROUP* := { **prog_types** | **map_types** | **attach_types** | **link_types** | **helpers** } DESCRIPTION =========== - **bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]] + **bpftool feature probe** [**kernel**] [**full**] [**macros** [**prefix** *PREFIX*]] Probe the running kernel and dump a number of eBPF-related - parameters, such as availability of the **bpf()** system call, + parameters, such as availability of the **bpf**\ () system call, JIT status, eBPF program types availability, eBPF helper functions availability, and more. + By default, bpftool **does not run probes** for + **bpf_probe_write_user**\ () and **bpf_trace_printk**\() + helpers which print warnings to kernel logs. To enable them + and run all probes, the **full** keyword should be used. + If the **macros** keyword (but not the **-j** option) is passed, a subset of the output is dumped as a list of **#define** macros that are ready to be included in a C @@ -44,47 +55,36 @@ DESCRIPTION Keyword **kernel** can be omitted. If no probe target is specified, probing the kernel is the default behaviour. - Note that when probed, some eBPF helpers (e.g. - **bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may - print warnings to kernel logs. - - **bpftool feature probe dev** *NAME* [**macros** [**prefix** *PREFIX*]] + When the **unprivileged** keyword is used, bpftool will dump + only the features available to a user who does not have the + **CAP_SYS_ADMIN** capability set. The features available in + that case usually represent a small subset of the parameters + supported by the system. Unprivileged users MUST use the + **unprivileged** keyword: This is to avoid misdetection if + bpftool is inadvertently run as non-root, for example. This + keyword is unavailable if bpftool was compiled without + libcap. + + **bpftool feature probe dev** *NAME* [**full**] [**macros** [**prefix** *PREFIX*]] Probe network device for supported eBPF features and dump results to the console. - The two keywords **macros** and **prefix** have the same - role as when probing the kernel. + The keywords **full**, **macros** and **prefix** have the + same role as when probing the kernel. + + **bpftool feature list_builtins** *GROUP* + List items known to bpftool. These can be BPF program types + (**prog_types**), BPF map types (**map_types**), attach types + (**attach_types**), link types (**link_types**), or BPF helper + functions (**helpers**). The command does not probe the system, but + simply lists the elements that bpftool knows from compilation time, + as provided from libbpf (for all object types) or from the BPF UAPI + header (list of helpers). This can be used in scripts to iterate over + BPF types or helpers. **bpftool feature help** Print short help message. OPTIONS ======= - -h, --help - Print short generic help message (similar to **bpftool help**). - - -V, --version - Print version number (similar to **bpftool version**). - - -j, --json - Generate JSON output. For commands that cannot produce JSON, this - option has no effect. - - -p, --pretty - Generate human-readable JSON output. Implies **-j**. - - -d, --debug - Print all logs available from libbpf, including debug-level - information. - -SEE ALSO -======== - **bpf**\ (2), - **bpf-helpers**\ (7), - **bpftool**\ (8), - **bpftool-prog**\ (8), - **bpftool-map**\ (8), - **bpftool-cgroup**\ (8), - **bpftool-net**\ (8), - **bpftool-perf**\ (8), - **bpftool-btf**\ (8) + .. include:: common_options.rst |