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From: hupu <hupu.gm@gmail.com>
To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	namhyung@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,
	hupu.gm@gmail.com
Subject: [RFC 1/2] perf build: Allow passing extra Clang flags via EXTRA_BPF_FLAGS
Date: Tue, 23 Dec 2025 16:43:34 +0800	[thread overview]
Message-ID: <20251223084337.3789-2-hupu.gm@gmail.com> (raw)
In-Reply-To: <20251223084337.3789-1-hupu.gm@gmail.com>

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>
---
 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


  reply	other threads:[~2025-12-23  8:44 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 ` hupu [this message]
2025-12-23 18:20   ` [RFC 1/2] perf build: Allow passing extra Clang flags via EXTRA_BPF_FLAGS Namhyung Kim
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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