[PATCH v3 0/4] Bring back vmlinux.h generation

Ian Rogers
2023-06-09T04:32:51Z

Commit 760ebc45746b ("perf lock contention: Add empty 'struct rq' to
satisfy libbpf 'runqueue' type verification") inadvertently created a
declaration of 'struct rq' that conflicted with a generated
vmlinux.h's:

```
util/bpf_skel/lock_contention.bpf.c:419:8: error: redefinition of 'rq'
struct rq {};
^
/tmp/perf/util/bpf_skel/.tmp/../vmlinux.h:45630:8: note: previous definition is here
struct rq {
^
1 error generated.
```

Fix the issue by moving the declaration to vmlinux.h. So this can't
happen again, bring back build support for generating vmlinux.h then
add build tests.

v3. Address Namhyung's comments on filtering ELF files with readelf.
v2. Rebase on perf-tools-next. Add Andrii's acked-by. Add patch to
filter out kernels that lack a .BTF section and cause the build to
break.

Ian Rogers (4):
perf build: Add ability to build with a generated vmlinux.h
perf bpf: Move the declaration of struct rq
perf test: Add build tests for BUILD_BPF_SKEL
perf build: Filter out BTF sources without a .BTF section

tools/perf/Makefile.config | 4 ++
tools/perf/Makefile.perf | 39 ++++++++++++++++++-
tools/perf/tests/make | 4 ++
tools/perf/util/bpf_skel/.gitignore | 1 +
.../perf/util/bpf_skel/lock_contention.bpf.c | 2 -
.../util/bpf_skel/{ => vmlinux}/vmlinux.h | 10 +++++
6 files changed, 57 insertions(+), 3 deletions(-)
rename tools/perf/util/bpf_skel/{ => vmlinux}/vmlinux.h (90%)