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2d3ea5e85d
Similarly to what was done for program types and map types, add a set of
probes to test the availability of the different eBPF helper functions
on the current system.
For each known program type, all known helpers are tested, in order to
establish a compatibility matrix. Output is provided as a set of lists
of available helpers, one per program type.
Sample output:
# bpftool feature probe kernel
...
Scanning eBPF helper functions...
eBPF helpers supported for program type socket_filter:
- bpf_map_lookup_elem
- bpf_map_update_elem
- bpf_map_delete_elem
...
eBPF helpers supported for program type kprobe:
- bpf_map_lookup_elem
- bpf_map_update_elem
- bpf_map_delete_elem
...
# bpftool --json --pretty feature probe kernel
{
...
"helpers": {
"socket_filter_available_helpers": ["bpf_map_lookup_elem", \
"bpf_map_update_elem","bpf_map_delete_elem", ...
],
"kprobe_available_helpers": ["bpf_map_lookup_elem", \
"bpf_map_update_elem","bpf_map_delete_elem", ...
],
...
}
}
v5:
- In libbpf.map, move global symbol to the new LIBBPF_0.0.2 section.
v4:
- Use "enum bpf_func_id" instead of "__u32" in bpf_probe_helper()
declaration for the type of the argument used to pass the id of
the helper to probe.
- Undef BPF_HELPER_MAKE_ENTRY after using it.
v3:
- Do not pass kernel version from bpftool to libbpf probes (kernel
version for testing program with kprobes is retrieved directly from
libbpf).
- Dump one list of available helpers per program type (instead of one
list of compatible program types per helper).
v2:
- Move probes from bpftool to libbpf.
- Test all program types for each helper, print a list of working prog
types for each helper.
- Fall back on include/uapi/linux/bpf.h for names and ids of helpers.
- Remove C-style macros output from this patch.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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===============
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bpftool-feature
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===============
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-------------------------------------------------------------------------------
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tool for inspection of eBPF-related parameters for Linux kernel or net device
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-------------------------------------------------------------------------------
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:Manual section: 8
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **feature** *COMMAND*
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*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
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*COMMANDS* := { **probe** | **help** }
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MAP COMMANDS
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=============
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| **bpftool** **feature probe** [**kernel**]
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| **bpftool** **feature help**
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DESCRIPTION
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===========
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**bpftool feature probe** [**kernel**]
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Probe the running kernel and dump a number of eBPF-related
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parameters, such as availability of the **bpf()** system call.
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Keyword **kernel** can be omitted.
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Note that when probed, some eBPF helpers (e.g.
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**bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
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print warnings to kernel logs.
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**bpftool feature help**
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Print short help message.
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OPTIONS
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=======
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-h, --help
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Print short generic help message (similar to **bpftool help**).
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-v, --version
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Print version number (similar to **bpftool version**).
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-j, --json
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Generate JSON output. For commands that cannot produce JSON, this
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option has no effect.
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-p, --pretty
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Generate human-readable JSON output. Implies **-j**.
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SEE ALSO
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========
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**bpf**\ (2),
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**bpf-helpers**\ (7),
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**bpftool**\ (8),
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**bpftool-prog**\ (8),
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**bpftool-map**\ (8),
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**bpftool-cgroup**\ (8),
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**bpftool-net**\ (8),
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**bpftool-perf**\ (8)
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