6 Commits

Author SHA1 Message Date
Andrii Nakryiko
51aede2c77 scripts/bpf: Fix xdp_md forward declaration typo
commit e0b68fb186b251374adbd870f99b1ecea236e770 upstream.

Fix typo in struct xpd_md, generated from bpf_helpers_doc.py, which is
causing compilation warnings for programs using bpf_helpers.h

Fixes: 7a387bed47f7 ("scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191010042534.290562-1-andriin@fb.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-01 13:06:11 +01:00
Gianmarco Lusvardi
40a0959efe bpf, scripts: Correct GPL license name
[ Upstream commit e37243b65d528a8a9f8b9a57a43885f8e8dfc15c ]

The bpf_doc script refers to the GPL as the "GNU Privacy License".
I strongly suspect that the author wanted to refer to the GNU General
Public License, under which the Linux kernel is released, as, to the
best of my knowledge, there is no license named "GNU Privacy License".
This patch corrects the license name in the script accordingly.

Fixes: 56a092c89505 ("bpf: add script and prepare bpf.h for new helpers documentation")
Signed-off-by: Gianmarco Lusvardi <glusvardi@posteo.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20240213230544.930018-3-glusvardi@posteo.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:06:11 +01:00
Andrii Nakryiko
e30c7a0607 scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions
[ Upstream commit 7a387bed47f7e80e257d966cd64a3e92a63e26a1 ]

Enhance scripts/bpf_helpers_doc.py to emit C header with BPF helper
definitions (to be included from libbpf's bpf_helpers.h).

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: e37243b65d52 ("bpf, scripts: Correct GPL license name")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:06:11 +01:00
Quentin Monnet
eeacb7166d bpf: change eBPF helper doc parsing script to allow for smaller indent
Documentation for eBPF helpers can be parsed from bpf.h and eventually
turned into a man page. Commit 6f96674dbd8c ("bpf: relax constraints on
formatting for eBPF helper documentation") changed the script used to
parse it, in order to allow for different indent style and to ease the
work for writing documentation for future helpers.

The script currently considers that the first tab can be replaced by 6
to 8 spaces. But the documentation for bpf_fib_lookup() uses a mix of
tabs (for the "Description" part) and of spaces ("Return" part), and
only has 5 space long indent for the latter.

We probably do not want to change the values accepted by the script each
time a new helper gets a new indent style. However, it is worth noting
that with those 5 spaces, the "Description" and "Return" part *look*
aligned in the generated patch and in `git show`, so it is likely other
helper authors will use the same length. Therefore, allow for helper
documentation to use 5 spaces only for the first indent level.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-17 17:34:43 +02:00
Quentin Monnet
6f96674dbd bpf: relax constraints on formatting for eBPF helper documentation
The Python script used to parse and extract eBPF helpers documentation
from include/uapi/linux/bpf.h expects a very specific formatting for the
descriptions (single dot represents a space, '>' stands for a tab):

    /*
     ...
     *.int bpf_helper(list of arguments)
     *.>    Description
     *.>    >       Start of description
     *.>    >       Another line of description
     *.>    >       And yet another line of description
     *.>    Return
     *.>    >       0 on success, or a negative error in case of failure
     ...
     */

This is too strict, and painful for developers who wants to add
documentation for new helpers. Worse, it is extremely difficult to check
that the formatting is correct during reviews. Change the format
expected by the script and make it more flexible. The script now works
whether or not the initial space (right after the star) is present, and
accepts both tabs and white spaces (or a combination of both) for
indenting description sections and contents.

Concretely, something like the following would now be supported:

    /*
     ...
     *int bpf_helper(list of arguments)
     *......Description
     *.>    >       Start of description...
     *>     >       Another line of description
     *..............And yet another line of description
     *>     Return
     *.>    ........0 on success, or a negative error in case of failure
     ...
     */

While at it, remove unnecessary carets from each regex used with match()
in the script. They are redundant, as match() tries to match from the
beginning of the string by default.

v2: Remove unnecessary caret when a regex is used with match().

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-02 17:46:50 +02:00
Quentin Monnet
56a092c895 bpf: add script and prepare bpf.h for new helpers documentation
Remove previous "overview" of eBPF helpers from user bpf.h header.
Replace it by a comment explaining how to process the new documentation
(to come in following patches) with a Python script to produce RST, then
man page documentation.

Also add the aforementioned Python script under scripts/. It is used to
process include/uapi/linux/bpf.h and to extract helper descriptions, to
turn it into a RST document that can further be processed with rst2man
to produce a man page. The script takes one "--filename <path/to/file>"
option. If the script is launched from scripts/ in the kernel root
directory, it should be able to find the location of the header to
parse, and "--filename <path/to/file>" is then optional. If it cannot
find the file, then the option becomes mandatory. RST-formatted
documentation is printed to standard output.

Typical workflow for producing the final man page would be:

    $ ./scripts/bpf_helpers_doc.py \
            --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
    $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
    $ man /tmp/bpf-helpers.7

Note that the tool kernel-doc cannot be used to document eBPF helpers,
whose signatures are not available directly in the header files
(pre-processor directives are used to produce them at the beginning of
the compilation process).

v4:
- Also remove overviews for newly added bpf_xdp_adjust_tail() and
  bpf_skb_get_xfrm_state().
- Remove vague statement about what helpers are restricted to GPL
  programs in "LICENSE" section for man page footer.
- Replace license boilerplate with SPDX tag for Python script.

v3:
- Change license for man page.
- Remove "for safety reasons" from man page header text.
- Change "packets metadata" to "packets" in man page header text.
- Move and fix comment on helpers introducing no overhead.
- Remove "NOTES" section from man page footer.
- Add "LICENSE" section to man page footer.
- Edit description of file include/uapi/linux/bpf.h in man page footer.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-04-27 00:21:58 +02:00