linux.git/tools/perf/util/bpf-loader.h, branch master

perf parse-events: Remove BPF event support

2023-08-15T19:41:48+00:00

New features like the BPF --filter support in perf record have made the
BPF event functionality somewhat redundant. As shown by commit
fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF
map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix
libbpf 1.0+ compatibility") the BPF event support hasn't been well
maintained and it adds considerable complexity in areas like event
parsing, not least as '/' is a separator for event modifiers as well as
in paths.

This patch removes support in the event parser for BPF events and then
the associated functions are removed. This leads to the removal of whole
source files like bpf-loader.c.  Removing support means that augmented
syscalls in perf trace is broken, this will be fixed in a later commit
adding support using BPF skeletons.

The removal of BPF events causes an unused label warning from flex
generated code, so update build to ignore it:

  ```
  util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label]
  2704 | find_rule: /* we branch to this label when backing up */
  ```

Committer notes:

Extracted from a larger patch that was also removing the support for
linking with libllvm and libclang, that were an alternative to using an
external clang execution to compile the .c event source code into BPF
bytecode.

Testing it:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Bad event or PMU

  Unabled to find PMU or event on a PMU of 'home'

  Initial error:
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Cannot find PMU `home'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf trace [] []
      or: perf trace [] --  []
      or: perf trace record [] []
      or: perf trace record [] --  []

      -e, --event    event/syscall selector. use 'perf list' to list available events
  #

Signed-off-by: Ian Rogers 
Acked-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Anshuman Khandual 
Cc: Athira Rajeev 
Cc: Brendan Gregg 
Cc: Carsten Haitzler 
Cc: Eduard Zingerman 
Cc: Fangrui Song 
Cc: He Kuang 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Nathan Chancellor 
Cc: Naveen N. Rao 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Rob Herring 
Cc: Tiezhu Yang 
Cc: Tom Rix 
Cc: Wang Nan 
Cc: Wang ShaoBo 
Cc: Yang Jihong 
Cc: Yonghong Song 
Cc: YueHaibing 
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo 

Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Enclose libbpf.h include within HAVE_LIBBPF_SUPPORT

2020-11-04T12:42:40+00:00

As it uses the 'deprecated' attribute in a way that breaks the build
with old gcc compilers, so to continue being able to build in such
systems where NO_LIBBPF=1 is being used, enclose it under
HAVE_LIBBPF_SUPPORT.

   1 centos:6          : FAIL gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23)
   2 oraclelinux:6     : FAIL gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23.0.1)

    CC       /tmp/build/perf/builtin-record.o
  In file included from util/bpf-loader.h:11,
                   from builtin-record.c:39:
  /git/linux/tools/lib/bpf/libbpf.h:203: error: wrong number of arguments specified for 'deprecated' attribute

Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Rename struct perf_evlist to struct evlist

2019-07-29T21:34:42+00:00

Rename struct perf_evlist to struct evlist, so we don't have a name
clash when we add struct perf_evlist in libperf.

Committer notes:

Added fixes to build on arm64, from Jiri and from me
(tools/perf/util/cs-etm.c)

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Alexey Budankov 
Cc: Andi Kleen 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20190721112506.12306-6-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Rename struct perf_evsel to struct evsel

2019-07-29T21:34:42+00:00

Rename struct perf_evsel to struct evsel, so we don't have a name clash
when we add struct perf_evsel in libperf.

Committer notes:

Added fixes for arm64, provided by Jiri.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Alexey Budankov 
Cc: Andi Kleen 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20190721112506.12306-5-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Store backpointer to attached bpf_object

2019-07-29T21:34:41+00:00

We may want to get to this bpf_object, to search for other BPF programs,
etc.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Luis Cláudio Gonçalves 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-3y8hrb6lszjfi23vjlic3cib@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf-loader: Remove unecessary includes from bpf-loader.h

2019-02-06T13:00:39+00:00

To cut the header dep tree, to get unecessary object rebuilds to be
reduced when a change happens in headers.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-ph72xhl9moqa0g1hxcyudwfn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Make bpf__setup_output_event() return the bpf-output event

2018-08-08T18:55:58+00:00

We're calling it to setup that event, and we'll need it later to decide
if the bpf-output event we're handling is the one setup for a specific
purpose, return it using ERR_PTR, etc.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-zhachv7il2n1lopt9aonwhu7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Add bpf__setup_output_event() strerror() counterpart

2018-08-08T18:55:56+00:00

That is just bpf__strerror_setup_stdout() renamed to the more general
"setup_output_event" method, keep the existing stdout() as a wrapper.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-nwnveo428qn0b48axj50vkc7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Generalize bpf__setup_stdout()

2018-08-08T18:55:56+00:00

We will use it to set up other bpf-output events, for instance to
generate augmented syscall entry tracepoints with pointer contents.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-4r7kw0nsyi4vyz6xm1tzx6a3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman