Re: [PATCH v4 0/4] Bring back vmlinux.h generation

[Namhyung Kim]

On Thu, Jun 22, 2023 at 9:14 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> 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.
>
> v4. Rebase and add Namhyung and Jiri's acked-by.
> 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

Thanks,  I'll take them with the following change.

Namhyung


---
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index b1e62a621f92..90f0eaf179fd 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -132,6 +132,8 @@ include ../scripts/utilities.mak
 # Define EXTRA_TESTS to enable building extra tests useful mainly to perf
 # developers, such as:
 #      x86 instruction decoder - new instructions test
+#
+# Define GEN_VMLINUX_H to generate vmlinux.h from the BTF.

 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL