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([202.43.239.100]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29034f070basm126638635ad.77.2025.10.13.01.06.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Oct 2025 01:06:25 -0700 (PDT) From: hupu To: namhyung@kernel.org, irogers@google.com, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, nathan@kernel.org, nick.desaulniers+lkml@gmail.com, morbo@google.com, justinstitt@google.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: hupu.gm@gmail.com Subject: [RFC] perf build: Allow passing extra Clang flags via EXTRA_CLANG_FLAGS Date: Mon, 13 Oct 2025 16:06:09 +0800 Message-ID: <20251013080609.2070555-1-hupu.gm@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When cross-compiling perf with the BPF option enabled, Clang is used during the build process. Some environments may require additional compiler options such as `--sysroot` or custom include paths. This patch adds a new make variable, `EXTRA_CLANG_FLAGS`, which appends user-specified options to `CLANG_OPTIONS` during BPF skeleton builds. Example: EXTRA_CLANG_FLAGS=3D"--sysroot=3D$SYSROOT" make perf ARCH=3Darm64 EXTRA_CLANG_FLAGS=3D"$EXTRA_CLANG_FLAGS" This enables more flexible cross-compilation setups without modifying Makefile.perf directly. Signed-off-by: hupu --- tools/perf/Makefile.perf | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 47c906b807ef..b0da7314a0d8 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -1249,6 +1249,11 @@ else $(Q)cp "$(VMLINUX_H)" $@ endif =20 +# Allow users to specify additional Clang options (e.g. --sysroot) +# when cross-compiling BPF skeletons, enabling more flexible +# build configurations. +CLANG_OPTIONS +=3D $(EXTRA_CLANG_FLAGS) + $(SKEL_TMP_OUT)/%.bpf.o: $(OUTPUT)PERF-VERSION-FILE util/bpf_skel/perf_ver= sion.h | $(SKEL_TMP_OUT) $(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) $(SKEL_OUT)/vmlin= ux.h $(QUIET_CLANG)$(CLANG) -g -O2 -fno-stack-protector --target=3Dbpf \ --=20 2.43.0