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Merged
merged 4 commits into from
Feb 12, 2020
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bpftool: Allow to select sections and filter probes #1

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86be601
bpftool: Move out sections to separate functions
vadorovsky Feb 5, 2020
2162c93
bpftool: Allow to select a specific section to probe
vadorovsky Feb 6, 2020
54a654f
bpftool: Add arguments for filtering in and filtering out probes
vadorovsky Feb 6, 2020
28f1e45
bpftool: Update documentation of "bpftool feature" command
vadorovsky Feb 12, 2020
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34 changes: 29 additions & 5 deletions tools/bpf/bpftool/Documentation/bpftool-feature.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -19,19 +19,42 @@ SYNOPSIS
FEATURE COMMANDS
================

| **bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]]
| **bpftool** **feature probe** [*COMPONENT*] [**section** [*SECTION*]] [**filter_in** *PATTERN*] [**filter_out** *PATTERN*] [**macros** [**prefix** *PREFIX*]]
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If section is passed, then SECTION is not optional. We should have [**section** *SECTION*] instead of [**section** [*SECTION*]] I think? (Here and below)

| **bpftool** **feature help**
|
| *COMPONENT* := { **kernel** | **dev** *NAME* }
| *SECTION* := { **system_config** | **syscall_config** | **program_types** | **map_types** | **helpers** | **misc** }

DESCRIPTION
===========
**bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]]
**bpftool feature probe** [**kernel**] [**section** [*SECTION*]] [**filter_in** *PATTERN*] [**filter_out** *PATTERN*] [**macros** [**prefix** *PREFIX*]]
Probe the running kernel and dump a number of eBPF-related
parameters, such as availability of the **bpf()** system call,
JIT status, eBPF program types availability, eBPF helper
functions availability, and more.

If the **section** keyword is passed, only the specified
probes section will be checked and printed. The only section
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s/section whis is probed/probe which is performed/ ?

which is always going to be probed is **syscall_config**,
but if the other section was provided as an argument,
**syscall_config** check will perform silently without
printing the result and bpftool will exit if the bpf()
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s/bpf()/**bpf()**/

(here and below)

syscall is not abailable (because in that case performing
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s/abailable/available/

other checks relying on the bpf() system call does not make
sense).

If the **filter_in** keyword is passed, only checks with
names matching the given *PATTERN* are going the be printed
and performed.

If the **filter_out** keyword is passed, checks with names
matching the given *PATTERN* are not going to be printed and
performed.

**filter_in** is executed before **filter_out** which means
that **filter_out** is always applied only on probes
selected by **filter_in** if both arguments are used together.
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“Please refer to the **regex**\ (7) man page for details on the syntax for *PATTERN*.”


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
Expand All @@ -48,12 +71,13 @@ DESCRIPTION
**bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
print warnings to kernel logs.

**bpftool feature probe dev** *NAME* [**macros** [**prefix** *PREFIX*]]
**bpftool feature probe dev** *NAME* [**section** [*SECTION*]] [**filter_in** *PATTERN*] [**filter_out** *PATTERN*] [**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 **section**, **filter_in**, **filter_out**,
**macros** and **prefix** have the same role as when probing
the kernel.

**bpftool feature help**
Print short help message.
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