From: Namhyung Kim <namhyung@kernel.org>
To: hupu <hupu.gm@gmail.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com,
james.clark@linaro.org, nathan@kernel.org,
nick.desaulniers+lkml@gmail.com, morbo@google.com,
justinstitt@google.com, linux-perf-users@vger.kernel.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [RFC 1/2] perf build: Allow passing extra Clang flags via EXTRA_BPF_FLAGS
Date: Tue, 23 Dec 2025 10:20:02 -0800 [thread overview]
Message-ID: <aUrdUjqVEjJW9VBl@google.com> (raw)
In-Reply-To: <20251223084337.3789-2-hupu.gm@gmail.com>
Hello,
On Tue, Dec 23, 2025 at 04:43:34PM +0800, hupu wrote:
> Add support for EXTRA_BPF_FLAGS in the eBPF skeleton build, allowing
> users to pass additional Clang options such as --sysroot or custom
> include paths when cross-compiling perf.
>
> This is primarily intended for cross-build scenarios where the default
> host include paths do not match the target kernel version.
>
> Example usage:
> make perf ARCH="arm64" EXTRA_BPF_FLAGS="--sysroot=..."
>
> Change history:
> v5:
> - Update commit message
> v4:
> - Apply EXTRA_BPF_FLAGS directly to BPF skeleton build command
> instead of modifying CLANG_OPTIONS
> v3:
> - Move the variable description comment to the top of Makefile.perf
> - Update commit message
> v2:
> - Rename EXTRA_CLANG_FLAGS to EXTRA_BPF_FLAGS
> - Update commit message
> v1:
> - Introduce EXTRA_CLANG_FLAGS to allow passing extra Clang options
>
> Signed-off-by: hupu <hupu.gm@gmail.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> ---
> tools/perf/Makefile.perf | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index b3f481a626af..8b8647fd4f41 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -35,6 +35,9 @@ include ../scripts/utilities.mak
> #
> # Define EXTRA_CFLAGS=-m64 or EXTRA_CFLAGS=-m32 as appropriate for cross-builds.
> #
> +# Define EXTRA_BPF_FLAGS="--sysroot=<path>" or other custom include paths for
> +# cross-compiling BPF skeletons
> +#
> # Define EXCLUDE_EXTLIBS=-lmylib to exclude libmylib from the auto-generated
> # EXTLIBS.
> #
> @@ -1250,7 +1253,7 @@ endif
> $(SKEL_TMP_OUT)/%.bpf.o: $(OUTPUT)PERF-VERSION-FILE util/bpf_skel/perf_version.h | $(SKEL_TMP_OUT)
> $(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) $(SKEL_OUT)/vmlinux.h
> $(QUIET_CLANG)$(CLANG) -g -O2 -fno-stack-protector --target=bpf \
> - $(CLANG_OPTIONS) $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
> + $(CLANG_OPTIONS) $(EXTRA_BPF_FLAGS) $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
> -include $(OUTPUT)PERF-VERSION-FILE -include util/bpf_skel/perf_version.h \
> -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@
>
> --
> 2.43.0
>
next prev parent reply other threads:[~2025-12-23 18:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-23 8:43 [RFC 0/2] perf build: Improve header handling for BPF skeleton cross-builds hupu
2025-12-23 8:43 ` [RFC 1/2] perf build: Allow passing extra Clang flags via EXTRA_BPF_FLAGS hupu
2025-12-23 18:20 ` Namhyung Kim [this message]
2026-02-10 5:54 ` hupu
2026-02-11 16:27 ` Arnaldo Carvalho de Melo
2025-12-23 8:43 ` [RFC 2/2] perf build: Prefer kernel source headers for BPF skeletons hupu
2026-01-12 1:46 ` hupu
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