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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Fri, 23 Jun 2023 17:41:09 -0700
Message-ID: <CAM9d7ch9MfCS02+-4FRDvrDVDK+f8qtqYr5m0abegg9PXJncHQ@mail.gmail.com>
Subject: Re: [PATCH v4 0/4] Bring back vmlinux.h generation
To:     Ian Rogers <irogers@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        James Clark <james.clark@arm.com>,
        Tiezhu Yang <yangtiezhu@loongson.cn>,
        Yang Jihong <yangjihong1@huawei.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org
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On Thu, Jun 22, 2023 at 9:14 PM Ian Rogers <irogers@google.com> 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