* [PATCH v1 1/2] perf build: Support building BPF skeletons with bpf-gcc
2026-10-13 22:16 [PATCH v1 0/2] perf build: Support building BPF skeletons with bpf-gcc Ian Rogers
@ 2026-10-13 22:16 ` Ian Rogers
2026-10-13 22:27 ` sashiko-bot
2026-10-13 22:16 ` [PATCH v1 2/2] perf test make: Add BPF skeleton build tests for clang and bpf-gcc Ian Rogers
1 sibling, 1 reply; 4+ messages in thread
From: Ian Rogers @ 2026-10-13 22:16 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo, Namhyung Kim, Jose E . Marchesi,
David Faust, Cupertino Miranda
Cc: Peter Zijlstra, Ingo Molnar, Jiri Olsa, Ian Rogers, Adrian Hunter,
James Clark, Andrii Nakryiko, Eduard Zingerman, Yonghong Song,
linux-perf-users, bpf, linux-kernel
Support building perf BPF skeletons with bpf-gcc (>= 14.0.0) in addition
to clang (>= 12.0.1), similar to tools/testing/selftests/bpf/Makefile.
When building perf with GCC (CC_NO_CLANG=1), prefer bpf-gcc and fall
back to clang if bpf-gcc is unavailable or too old. When building with
Clang/LLVM (CC_NO_CLANG=0), prefer clang and fall back to bpf-gcc.
Explicit command-line overrides via BPF_GCC=... or CLANG=... are
respected, and setting BPF_GCC= or CLANG= to empty disables that
compiler.
In bpf_skel.mak, pass the bpf-gcc flags (-mcpu=v3, -fno-ident,
-DBPF_NO_PRESERVE_ACCESS_INDEX, -Wno-attributes,
-D__TARGET_ARCH_$(SRCARCH), and target endianness) and query system
include paths from $(CC).
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/Makefile.config | 81 +++++++++++++++++++++++++++-------
tools/perf/Makefile.perf | 8 +++-
tools/perf/bpf_skel.mak | 36 ++++++++++-----
tools/scripts/Makefile.include | 1 +
4 files changed, 97 insertions(+), 29 deletions(-)
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index cafc7be79643..6aee2665b64c 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -662,27 +662,76 @@ ifeq ($(BUILD_BPF_SKEL),1)
else ifeq ($(filter -DHAVE_LIBOPENSSL_SUPPORT, $(CFLAGS)),)
$(warning Warning: Disabled BPF skeletons as libopenssl is required)
BUILD_BPF_SKEL := 0
- else ifeq ($(call get-executable,$(CLANG)),)
- $(warning Warning: Disabled BPF skeletons as clang ($(CLANG)) is missing)
- BUILD_BPF_SKEL := 0
- else
- CLANG_VERSION := $(shell $(CLANG) --version | head -1 | sed 's/.*clang version \([[:digit:]]\+.[[:digit:]]\+.[[:digit:]]\+\).*/\1/g')
- ifeq ($(call version-lt3,$(CLANG_VERSION),12.0.1),1)
- $(warning Warning: Disabled BPF skeletons as reliable BTF generation needs at least $(CLANG) version 12.0.1)
- BUILD_BPF_SKEL := 0
- endif
endif
ifeq ($(BUILD_BPF_SKEL),1)
- $(call feature_check,clang-bpf-co-re)
- ifeq ($(feature-clang-bpf-co-re), 0)
- $(warning Warning: Disabled BPF skeletons as clang is too old)
+ # Prefer bpf-gcc when building with gcc (CC_NO_CLANG=1) and clang when
+ # building with clang, unless CLANG or BPF_GCC was explicitly specified on
+ # the command line. Fall back to whichever compiler is available.
+ prefer_bpf_gcc := $(CC_NO_CLANG)
+ ifeq ($(origin BPF_GCC),command line)
+ ifneq ($(BPF_GCC),)
+ prefer_bpf_gcc := 1
+ endif
+ else ifeq ($(origin CLANG),command line)
+ ifneq ($(CLANG),)
+ prefer_bpf_gcc := 0
+ endif
+ endif
+
+ have_bpf_gcc := 0
+ have_clang_bpf := 0
+
+ define check_bpf_gcc
+ ifneq ($$(call get-executable,$$(BPF_GCC)),)
+ BPF_GCC_VERSION := $$(shell $$(BPF_GCC) -dumpfullversion -dumpversion 2>/dev/null)
+ ifneq ($$(call version-lt3,$$(BPF_GCC_VERSION),14.0.0),1)
+ have_bpf_gcc := 1
+ endif
+ endif
+ endef
+
+ ifeq ($(prefer_bpf_gcc),1)
+ $(eval $(check_bpf_gcc))
+ endif
+
+ ifeq ($(have_bpf_gcc),0)
+ ifneq ($(call get-executable,$(CLANG)),)
+ CLANG_VERSION := $(shell $(CLANG) --version | head -1 | sed 's/.*clang version \([[:digit:]]\+.[[:digit:]]\+.[[:digit:]]\+\).*/\1/g')
+ ifneq ($(call version-lt3,$(CLANG_VERSION),12.0.1),1)
+ $(call feature_check,clang-bpf-co-re)
+ ifeq ($(feature-clang-bpf-co-re), 1)
+ have_clang_bpf := 1
+ endif
+ endif
+ endif
+ endif
+
+ ifeq ($(prefer_bpf_gcc)$(have_clang_bpf),00)
+ $(eval $(check_bpf_gcc))
+ endif
+
+ ifeq ($(have_bpf_gcc),1)
+ $(call detected,CONFIG_PERF_BPF_SKEL_BPF_GCC)
+ $(call detected,CONFIG_PERF_BPF_SKEL)
+ CFLAGS += -DHAVE_BPF_SKEL
+ else ifeq ($(have_clang_bpf),1)
+ $(call detected,CONFIG_PERF_BPF_SKEL)
+ CFLAGS += -DHAVE_BPF_SKEL
+ else
+ ifeq ($(call get-executable,$(CLANG))$(call get-executable,$(BPF_GCC)),)
+ $(warning Warning: Disabled BPF skeletons as clang ($(CLANG)) and bpf-gcc ($(BPF_GCC)) are missing)
+ else ifneq ($(call get-executable,$(CLANG)),)
+ ifeq ($(call version-lt3,$(CLANG_VERSION),12.0.1),1)
+ $(warning Warning: Disabled BPF skeletons as reliable BTF generation needs at least $(CLANG) version 12.0.1)
+ else
+ $(warning Warning: Disabled BPF skeletons as clang is too old)
+ endif
+ else
+ $(warning Warning: Disabled BPF skeletons as bpf-gcc ($(BPF_GCC)) needs at least version 14.0.0)
+ endif
BUILD_BPF_SKEL := 0
endif
endif
- ifeq ($(BUILD_BPF_SKEL),1)
- $(call detected,CONFIG_PERF_BPF_SKEL)
- CFLAGS += -DHAVE_BPF_SKEL
- endif
endif
ifndef GEN_VMLINUX_H
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 2d9379fea267..4061a79cae54 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -37,6 +37,9 @@ include ../scripts/utilities.mak
# Define EXTRA_BPF_FLAGS="--sysroot=<path>" or other custom include paths for
# cross-compiling BPF skeletons
#
+# Define BPF_GCC to point to the bpf-gcc binary if the default `bpf-gcc' is not
+# correct, or set BPF_GCC= to disable using bpf-gcc for BPF skeletons.
+#
# Define EXCLUDE_EXTLIBS=-lmylib to exclude libmylib from the auto-generated
# EXTLIBS.
#
@@ -208,6 +211,7 @@ FIND = find
INSTALL = install
FLEX ?= flex
BISON ?= bison
+BPF_GCC ?= bpf-gcc
AWK = awk
# include Makefile.config by default and rule out
@@ -321,8 +325,8 @@ ifneq ($(force_fixdep),1)
endif
endif
-export srctree OUTPUT RM CC CXX RUSTC CLANG LD AR CFLAGS CXXFLAGS RUST_FLAGS V BISON FLEX AWK LIBBPF READELF
-export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK MYPY PYLINT CONFIG_PERF_BPF_SKEL
+export srctree OUTPUT RM CC CXX RUSTC CLANG BPF_GCC LD AR CFLAGS CXXFLAGS RUST_FLAGS V BISON FLEX AWK LIBBPF READELF
+export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK MYPY PYLINT CONFIG_PERF_BPF_SKEL CONFIG_PERF_BPF_SKEL_BPF_GCC
include $(srctree)/tools/build/Makefile.include
diff --git a/tools/perf/bpf_skel.mak b/tools/perf/bpf_skel.mak
index f2559de39f96..7b7edf506509 100644
--- a/tools/perf/bpf_skel.mak
+++ b/tools/perf/bpf_skel.mak
@@ -22,21 +22,35 @@ bpf-skel-prepare: $(BPFTOOL) $(VMLINUX_H)
define get_sys_includes
$(shell $(1) $(2) -v -E - </dev/null 2>&1 \
| sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
-$(shell $(1) $(2) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}')
+$(shell $(1) $(2) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}') \
+$(shell $(1) $(2) -dM -E - </dev/null | grep '__loongarch_grlen ' | awk '{printf("-D__BITS_PER_LONG=%d", $$3)}') \
+$(shell $(1) $(2) -dM -E - </dev/null | grep -E 'MIPS(EL|EB)|_MIPS_SZ(PTR|LONG) |_MIPS_SIM |_ABI(O32|N32|64) ' | awk '{printf("-D%s=%s ", $$2, $$3)}')
endef
-ifneq ($(CROSS_COMPILE),)
-CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
+ifeq ($(CONFIG_PERF_BPF_SKEL_BPF_GCC),y)
+ BPF_CC := $(BPF_GCC)
+ QUIET_BPF_CC = $(QUIET_BPF_GCC)
+ IS_LITTLE_ENDIAN := $(shell $(CC) -dM -E - </dev/null | \
+ grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
+ BPF_OPTIONS = -Wall -mcpu=v3 -fno-ident -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes \
+ -D__TARGET_ARCH_$(SRCARCH) $(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
+ BPF_SYS_INCLUDES = $(call get_sys_includes,$(CC),)
+else
+ BPF_CC := $(CLANG)
+ QUIET_BPF_CC = $(QUIET_CLANG)
+ ifneq ($(CROSS_COMPILE),)
+ CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
+ endif
+ BPF_OPTIONS = -Wall -mcpu=v3 -fno-stack-protector --target=bpf -Wno-microsoft-anon-tag
+ BPF_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
endif
-CLANG_OPTIONS = -Wall -mcpu=v3
-CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
LIBBPF_INCLUDE := $(abspath $(or $(OUTPUT),.))/libbpf/include
-BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(SKEL_TOOL_OUT) -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES)
+BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(SKEL_TOOL_OUT) -I$(LIBBPF_INCLUDE) $(BPF_SYS_INCLUDES)
TOOLS_UAPI_INCLUDE := -I$(srctree)/tools/include/uapi
ifneq ($(WERROR),0)
- CLANG_OPTIONS += -Werror
+ BPF_OPTIONS += -Werror
endif
$(BPFTOOL):
@@ -83,11 +97,11 @@ endif
# Consolidated Pattern rule for $(dir)/bpf_skel/
$(SKEL_TMP_OUT)/%.bpf.o: $(srctree)/tools/perf/$(dir)/bpf_skel/%.bpf.c $(LIBBPF) $(VMLINUX_H) $(OUTPUT)PERF-VERSION-FILE util/bpf_skel/perf_version.h
$(call rule_mkdir)
- $(QUIET_CLANG)
- $(Q)$(CLANG) -g -O2 -fno-stack-protector --target=bpf \
- $(CLANG_OPTIONS) $(EXTRA_BPF_FLAGS) $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
+ $(QUIET_BPF_CC)
+ $(Q)$(BPF_CC) -g -O2 \
+ $(BPF_OPTIONS) $(EXTRA_BPF_FLAGS) $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
-include $(OUTPUT)PERF-VERSION-FILE -include util/bpf_skel/perf_version.h \
- -fms-extensions -Wno-microsoft-anon-tag \
+ -fms-extensions \
-c $< -o $@
$(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o $(BPFTOOL)
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 378387f62960..9967210b2928 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -217,6 +217,7 @@ ifneq ($(silent),1)
QUIET_CC = @echo ' CC '$@;
QUIET_CC_FPIC = @echo ' CC FPIC '$@;
QUIET_CLANG = @echo ' CLANG '$@;
+ QUIET_BPF_GCC = @echo ' BPF_GCC '$@;
QUIET_AR = @echo ' AR '$@;
QUIET_LINK = @echo ' LINK '$@;
QUIET_MKDIR = @echo ' MKDIR '$@;
--
2.56.0.385.gd3acb90ef8-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v1 2/2] perf test make: Add BPF skeleton build tests for clang and bpf-gcc
2026-10-13 22:16 [PATCH v1 0/2] perf build: Support building BPF skeletons with bpf-gcc Ian Rogers
2026-10-13 22:16 ` [PATCH v1 1/2] " Ian Rogers
@ 2026-10-13 22:16 ` Ian Rogers
1 sibling, 0 replies; 4+ messages in thread
From: Ian Rogers @ 2026-10-13 22:16 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo, Namhyung Kim, Jose E . Marchesi,
David Faust, Cupertino Miranda
Cc: Peter Zijlstra, Ingo Molnar, Jiri Olsa, Ian Rogers, Adrian Hunter,
James Clark, Andrii Nakryiko, Eduard Zingerman, Yonghong Song,
linux-perf-users, bpf, linux-kernel
Add make_bpf_skel_clang (CLANG=clang BPF_GCC=) and make_bpf_skel_bpf_gcc
(BPF_GCC=bpf-gcc CLANG=) targets to tools/perf/tests/make when the
corresponding compiler and BPF skeleton dependencies are available on
the host. Verify with 'perf check -q feature bpf_skeletons' that BPF
skeleton support is enabled for both targets and disabled for
make_no_bpf_skel.
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/tests/make | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index 7524de522802..4e66b93cf12c 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -78,6 +78,8 @@ make_extra_tests := EXTRA_TESTS=1
make_no_jevents := NO_JEVENTS=1
make_jevents_all := JEVENTS_ARCH=all
make_no_bpf_skel := BUILD_BPF_SKEL=0
+make_bpf_skel_clang := CLANG=clang BPF_GCC=
+make_bpf_skel_bpf_gcc := BPF_GCC=bpf-gcc CLANG=
make_gen_vmlinux_h := GEN_VMLINUX_H=1
make_no_python_module := NO_PYTHON_MODULE=1
make_no_scripts := NO_PYTHON_MODULE=1
@@ -142,6 +144,20 @@ have_libllvm := $(shell printf '#include <llvm/Support/ManagedStatic.h>\n#includ
$(shell $(LLVM_CONFIG) --system-libs 2>/dev/null) >/dev/null 2>&1 && echo y)
endif
+have_bpf_skel_deps := $(shell printf '#include <libelf.h>\n#include <zlib.h>\n#include <linux/bpf.h>\n#include <openssl/opensslv.h>\nint main(){return 0;}\n' | \
+ $(CC) -x c -I$(srctree)/tools/include/uapi - -o /dev/null -lelf -lz -lcrypto >/dev/null 2>&1 && echo y)
+
+ifneq ($(have_bpf_skel_deps),)
+ifneq ($(call has,clang),)
+have_clang_bpf := $(shell printf '#if (__clang_major__ < 12) || (__clang_major__ == 12 && __clang_minor__ == 0 && __clang_patchlevel__ < 1)\n#error "old"\n#endif\n' | \
+ clang -S -g --target=bpf -x c - -o /dev/null >/dev/null 2>&1 && echo y)
+endif
+ifneq ($(call has,bpf-gcc),)
+have_bpf_gcc := $(shell printf '#if __GNUC__ < 14\n#error "old"\n#endif\n' | \
+ bpf-gcc -E -x c - >/dev/null 2>&1 && echo y)
+endif
+endif
+
# $(run) contains all available tests
run := make_pure
# Targets 'clean all' can be run together only through top level
@@ -173,6 +189,12 @@ run += make_extra_tests
run += make_no_jevents
run += make_jevents_all
run += make_no_bpf_skel
+ifneq ($(have_clang_bpf),)
+run += make_bpf_skel_clang
+endif
+ifneq ($(have_bpf_gcc),)
+run += make_bpf_skel_bpf_gcc
+endif
run += make_gen_vmlinux_h
run += make_no_python_module
run += make_no_scripts
@@ -313,6 +335,13 @@ test_make_clang_nondistro := $(test_make_clang)
test_make_clang_nondistro_O := $(test_make_clang_O)
endif
+test_make_no_bpf_skel := test -x $(PERF_O)/perf && ! $(PERF_O)/perf check -q feature bpf_skeletons
+test_make_no_bpf_skel_O := test -x $$TMP_O/perf && ! $$TMP_O/perf check -q feature bpf_skeletons
+test_make_bpf_skel_clang := test -x $(PERF_O)/perf && $(PERF_O)/perf check -q feature bpf_skeletons
+test_make_bpf_skel_clang_O := test -x $$TMP_O/perf && $$TMP_O/perf check -q feature bpf_skeletons
+test_make_bpf_skel_bpf_gcc := test -x $(PERF_O)/perf && $(PERF_O)/perf check -q feature bpf_skeletons
+test_make_bpf_skel_bpf_gcc_O := test -x $$TMP_O/perf && $$TMP_O/perf check -q feature bpf_skeletons
+
test_make_python_perf_so_O := test -f $$TMP_O/python/perf.so
test_make_perf_o_O := test -f $$TMP_O/perf.o
test_make_util_map_o_O := test -f $$TMP_O/util/map.o
--
2.56.0.385.gd3acb90ef8-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread