[RFC PATCH bpf-next v2 0/3] selftests/bpf: restructure the Makefile as a layered build

[RFC PATCH bpf-next v2 0/3] selftests/bpf: restructure the Makefile as a layered build

[Mykola Lysenko]

The BPF selftests Makefile has grown to ~1,100 lines, with much of the
complexity concentrated in the DEFINE_TEST_RUNNER double-expansion
machinery: the per-runner rules are written in $$-escaped make and
eval'd once per flavor, so the rules that actually run never appear in
the source, are invisible to make's own debugging facilities, and are
easy to break for one flavor while testing another.

This series restructures the build in three steps, each independently
buildable and each producing byte-identical artifacts:

  1) the four near-identical skeleton generation recipes move into a
     parameterized helper script (gen_bpf_skel.sh);
  2) shared (non-rule) definitions move into Makefile.buildvars;
  3) each test runner instance (test_progs, test_progs-<flavor>,
     test_maps) becomes its own plain-make sub-make (Makefile.runner),
     replacing the eval/escaping layer.

After the series the top Makefile owns everything that exists once
(toolchain setup, the libbpf/bpftool/resolve_btfids sub-builds,
vmlinux.h, shared helper objects, standalone binaries, and the lib.mk
run/install contract), while every runner instance is an ordinary
single-flavor makefile with no escaping. Total line count is roughly a
wash; the point is the structure, not the size.

Sent as RFC to gather feedback on the overall direction.

Validation (each patch, x86_64, identical toolchains, clean builds):
2,948/2,948 BPF objects, 5,352/5,352 skeleton headers and 1,413/1,413
userspace objects byte-identical to the current Makefile's output. For
the end state additionally: 20/22 binaries byte-identical, and the two
exceptions (bench, test_maps) differ only in object link order, proven
by relinking the current Makefile's objects in the new order and
comparing bytes; emit_tests output and the installed tree identical;
BPF CI green on a manual pre-submission run across x86_64 gcc/llvm,
aarch64 and s390x (including GCC-BPF, ASAN and veristat jobs); and all
76 benchmarks produce identical outcomes on old- and new-built bench
binaries.

v1 -> v2:
- rebased onto current bpf-next: ported the semantics of commit
  0b236ac75d04 ("selftests/bpf: Fix make install target") - bpftool
  installed under tools/sbin/, *.BTF files installed - into the new
  install rule (resolves the CI apply conflict against v1)
- gen_bpf_skel.sh is a prerequisite of every skeleton rule, so editing
  the script regenerates the headers (reported by Sashiko AI review)
- the shared helper objects the top Makefile pre-builds now depend on
  a superset of the prerequisites the runner-side object rule uses
  (libarena skeletons, both generated tests.h headers), closing a
  window where the unflavored test_progs and test_maps sub-makes could
  both consider a shared helper object stale and recompile it
  concurrently in the shared output directory (reported by Sashiko AI
  review)
- v1: https://lore.kernel.org/bpf/20260721174909.8044-1-nickolay.lysenko@gmail.com/

Mykola Lysenko (3):
  selftests/bpf: extract BPF skeleton generation into a helper script
  selftests/bpf: move shared build definitions into Makefile.buildvars
  selftests/bpf: build each test runner instance in its own sub-make

 tools/testing/selftests/bpf/Makefile          | 950 +++++-------------
 .../testing/selftests/bpf/Makefile.buildvars  | 204 ++++
 tools/testing/selftests/bpf/Makefile.runner   | 316 ++++++
 tools/testing/selftests/bpf/gen_bpf_skel.sh   |  97 ++
 4 files changed, 886 insertions(+), 681 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/Makefile.buildvars
 create mode 100644 tools/testing/selftests/bpf/Makefile.runner
 create mode 100755 tools/testing/selftests/bpf/gen_bpf_skel.sh


base-commit: 5eb8921371c6fd117d4a328b6053dfda38707df8
-- 
2.43.0

[RFC PATCH bpf-next v2 1/3] selftests/bpf: extract BPF skeleton generation into a helper script

[Mykola Lysenko]

The four skeleton generation recipes (regular, light, signed light and
linked) are near-identical five-step pipelines - link via "bpftool gen
object" three times, compare the second and third results as a
regression test for bpftool's determinism, generate the skeleton (and
possibly subskeleton), remove intermediates - duplicated with small
variations inside DEFINE_TEST_RUNNER_RULES, where every line pays the
double-expansion escaping tax.

Move the pipeline into gen_bpf_skel.sh; the differences between the four
variants become flags (--lskel, --sign, --subskel, --infix). The
distinct linked/llinked intermediate infixes are kept: tests listed in
LSKELS_EXTRA generate both a .skel.h and a .lskel.h from the same
.bpf.o, and distinct intermediate names are what keeps parallel builds
from racing. The determinism check gets an escape hatch
(--no-determinism-check) but remains on by default; behavior is
unchanged.

Generated skeletons are byte-identical to the previous recipes' output.

The script is a prerequisite of every skeleton rule, so editing it
regenerates the headers.

Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Assisted-by: Claude:claude-fable-5 shellcheck
Signed-off-by: Mykola Lysenko <nickolay.lysenko@gmail.com>
---
 tools/testing/selftests/bpf/Makefile        | 99 ++++++---------------
 tools/testing/selftests/bpf/gen_bpf_skel.sh | 97 ++++++++++++++++++++
 2 files changed, 125 insertions(+), 71 deletions(-)
 create mode 100755 tools/testing/selftests/bpf/gen_bpf_skel.sh

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 55d394438..09e5be201 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -628,82 +628,39 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.bpf.o:				\
 					  $$($$<-CFLAGS)		\
 					  $$($$<-$2-CFLAGS),$(TRUNNER_BINARY))
 
-$(TRUNNER_BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
-		$$(RM) $$@ $$(@:.skel.h=.subskel.h);			\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-		exit 0;							\
-	fi;)								\
-	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2; \
-	$$(BPFTOOL) gen object $$(<:.o=.linked1.o) $$< &&		\
-	$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o) && \
-	$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o) && \
-	diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o) &&		\
-	$$(BPFTOOL) gen skeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$@ && \
-	$$(BPFTOOL) gen subskeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$(@:.skel.h=.subskel.h) $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@ $$(@:.skel.h=.subskel.h); \
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-	}) && \
-	rm -f $$(<:.o=.linked1.o) $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
-
-$(TRUNNER_BPF_LSKELS): %.lskel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
-		$$(RM) $$@;						\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-		exit 0;							\
-	fi;)								\
-	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2; \
-	$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$< &&		\
-	$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o) && \
-	$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o) && \
-	diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o) &&		\
-	$$(BPFTOOL) gen skeleton -L $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@ $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@; \
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-	}) && \
-	rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
-
-$(TRUNNER_BPF_LSKELS_SIGNED): %.lskel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
-		$$(RM) $$@;						\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-		exit 0;							\
-	fi;)								\
-	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY) (signed)] $$(notdir $$@)' 1>&2; \
-	$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$< &&		\
-	$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o) && \
-	$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o) && \
-	diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o) &&		\
-	$$(BPFTOOL) gen skeleton $(LSKEL_SIGN) $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@ $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@; \
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-	}) && \
-	rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
+$(TRUNNER_BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
+	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
+		--name $$(notdir $$(<:.bpf.o=)) --infix linked			\
+		--skel $$@ --subskel $$(@:.skel.h=.subskel.h) $$< $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@ $$(@:.skel.h=.subskel.h);				\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
+
+$(TRUNNER_BPF_LSKELS): %.lskel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
+	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
+		--name $$(notdir $$(<:.bpf.o=_lskel)) --infix llinked --lskel	\
+		--skel $$@ $$< $(if $(PERMISSIVE),|| {				\
+		$$(RM) $$@;							\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
+
+$(TRUNNER_BPF_LSKELS_SIGNED): %.lskel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
+	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY) (signed)' \
+		--name $$(notdir $$(<:.bpf.o=_lskel)) --infix llinked		\
+		--sign '$(LSKEL_SIGN)'						\
+		--skel $$@ $$< $(if $(PERMISSIVE),|| {				\
+		$$(RM) $$@;							\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
 
 $(LINKED_BPF_OBJS): %: $(TRUNNER_OUTPUT)/%
 
 # .SECONDEXPANSION here allows to correctly expand %-deps variables as prerequisites
 .SECONDEXPANSION:
-$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_OUTPUT)/%: $$$$(%-deps) $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$(Q)$(if $(PERMISSIVE),for f in $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)); do \
-		if [ ! -f $$$$f ]; then						\
-			$$(RM) $$@ $$(@:.skel.h=.subskel.h);		\
-			printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-			exit 0;							\
-		fi;								\
-	done;)									\
-	printf '  %-12s %s\n' 'LINK-BPF' '[$(TRUNNER_BINARY)] $$(notdir $$(@:.skel.h=.bpf.o))' 1>&2; \
-	$$(BPFTOOL) gen object $$(@:.skel.h=.linked1.o) $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)) && \
-	$$(BPFTOOL) gen object $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked1.o) && \
-	$$(BPFTOOL) gen object $$(@:.skel.h=.linked3.o) $$(@:.skel.h=.linked2.o) && \
-	diff $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o) &&	\
-	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2 && \
-	$$(BPFTOOL) gen skeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$@ && \
-	$$(BPFTOOL) gen subskeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$(@:.skel.h=.subskel.h) $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@ $$(@:.skel.h=.subskel.h);			\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
-	}) &&									\
-	rm -f $$(@:.skel.h=.linked1.o) $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o)
+$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_OUTPUT)/%: $$$$(%-deps) $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
+	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
+		--name $$(notdir $$(@:.skel.h=)) --infix linked			\
+		--skel $$@ --subskel $$(@:.skel.h=.subskel.h)			\
+		$$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)) $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@ $$(@:.skel.h=.subskel.h);				\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
 
 # When the compiler generates a %.d file, only skel basenames (not
 # full paths) are specified as prerequisites for corresponding %.o
diff --git a/tools/testing/selftests/bpf/gen_bpf_skel.sh b/tools/testing/selftests/bpf/gen_bpf_skel.sh
new file mode 100755
index 000000000..0b237f639
--- /dev/null
+++ b/tools/testing/selftests/bpf/gen_bpf_skel.sh
@@ -0,0 +1,97 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Link BPF object file(s) with "bpftool gen object" and generate a
+# skeleton (or light skeleton) header from the result.
+#
+# Usage:
+#   BPFTOOL=<bpftool> gen_bpf_skel.sh --name NAME --skel OUT [options] OBJ...
+#
+#   --name NAME       skeleton object name ("name NAME" for bpftool)
+#   --skel OUT        output header ("foo.skel.h" or "foo.lskel.h")
+#   --subskel OUT     also generate a subskeleton header into OUT
+#   --lskel           generate a light skeleton (bpftool gen skeleton -L)
+#   --sign 'ARGS'     extra "gen skeleton" args for signing (-S -k .. -i ..)
+#   --tag TAG         build-log tag, e.g. "test_progs-no_alu32"
+#   --infix STR       intermediate file infix (default: linked). Callers
+#                     generating both a .skel.h and a .lskel.h from the
+#                     same .bpf.o MUST use distinct infixes, or parallel
+#                     builds race on the intermediate files.
+#   --no-determinism-check
+#                     link the inputs once instead of three times.
+#                     By default the object is re-linked twice more and
+#                     the 2nd and 3rd results compared, as a regression
+#                     test for the determinism of "bpftool gen object".
+#
+# The bpftool binary is taken from $BPFTOOL (default: bpftool from PATH).
+# On failure all outputs and intermediates are removed and the script
+# exits non-zero; permissive-mode skipping is the caller's business
+# (see skip_on_fail in Makefile.buildvars).
+
+set -u
+
+bpftool=${BPFTOOL:-bpftool}
+name='' skel='' subskel='' tag='' sign_args='' infix=linked
+lskel=0 det_check=1
+
+while [ $# -gt 0 ]; do
+	case "$1" in
+	--name)		name=$2; shift 2 ;;
+	--skel)		skel=$2; shift 2 ;;
+	--subskel)	subskel=$2; shift 2 ;;
+	--tag)		tag=$2; shift 2 ;;
+	--infix)	infix=$2; shift 2 ;;
+	--sign)		sign_args=$2; shift 2 ;;
+	--lskel)	lskel=1; shift ;;
+	--no-determinism-check) det_check=0; shift ;;
+	--)		shift; break ;;
+	-*)		echo "$0: unknown option: $1" >&2; exit 1 ;;
+	*)		break ;;
+	esac
+done
+
+if [ -z "$name" ] || [ -z "$skel" ] || [ $# -eq 0 ]; then
+	echo "usage: $0 --name NAME --skel OUT [options] OBJ..." >&2
+	exit 1
+fi
+
+base=${skel%.skel.h}
+base=${base%.lskel.h}
+t1=$base.${infix}1.o
+t2=$base.${infix}2.o
+t3=$base.${infix}3.o
+
+fail() {
+	rm -f "$skel" ${subskel:+"$subskel"} "$t1" "$t2" "$t3"
+	exit 1
+}
+
+if [ $# -gt 1 ]; then
+	printf '  %-12s %s\n' 'LINK-BPF' "${tag:+[$tag] }$(basename "$base").bpf.o" >&2
+fi
+printf '  %-12s %s\n' 'GEN-SKEL' "${tag:+[$tag] }$(basename "$skel")" >&2
+
+"$bpftool" gen object "$t1" "$@" || fail
+final=$t1
+if [ "$det_check" -eq 1 ]; then
+	"$bpftool" gen object "$t2" "$t1" || fail
+	"$bpftool" gen object "$t3" "$t2" || fail
+	if ! cmp -s "$t2" "$t3"; then
+		echo "$0: bpftool gen object is not deterministic for $skel" >&2
+		fail
+	fi
+	final=$t3
+fi
+
+flags=
+[ "$lskel" -eq 1 ] && flags=-L
+# $sign_args intentionally unquoted: it is a list of bpftool arguments
+# shellcheck disable=SC2086
+"$bpftool" gen skeleton $sign_args $flags "$final" name "$name" > "$skel" || fail
+
+if [ -n "$subskel" ]; then
+	"$bpftool" gen subskeleton "$final" name "$name" > "$subskel" || fail
+fi
+
+rm -f "$t1" "$t2" "$t3"
+exit 0
-- 
2.43.0

[RFC PATCH bpf-next v2 2/3] selftests/bpf: move shared build definitions into Makefile.buildvars

[Mykola Lysenko]

Move the toolchain, path, flag, probe and knob definitions that are not
rules into Makefile.buildvars: output-tree layout, libbpf/bpftool binary
locations, BPF_CFLAGS/COMMON_CFLAGS assembly, libelf/libpcap probes,
endianness and clang feature detection, the vmlinux BTF search list,
signing key paths, permissive-mode knob and the libarena skeleton names.

This is preparation for building each test runner instance in its own
sub-make: the definitions become includable by more than one makefile.
No rules or recipes are changed. One deliberate nuance: the include
sits after ../lib.mk, so CFLAGS is now assembled by *prepending*
COMMON_CFLAGS (keeping the include-search order identical to before,
where the definitions preceded lib.mk's additions).

Build artifacts are byte-identical before and after this change.

Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Assisted-by: Claude:claude-fable-5 shellcheck
Signed-off-by: Mykola Lysenko <nickolay.lysenko@gmail.com>
---
 tools/testing/selftests/bpf/Makefile          | 165 +--------------
 .../testing/selftests/bpf/Makefile.buildvars  | 196 ++++++++++++++++++
 2 files changed, 203 insertions(+), 158 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/Makefile.buildvars

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 09e5be201..2ddcb812d 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -3,93 +3,24 @@ include ../../../build/Build.include
 include ../../../scripts/Makefile.arch
 include ../../../scripts/Makefile.include
 
-CXX ?= $(CROSS_COMPILE)g++
-OBJCOPY ?= $(CROSS_COMPILE)objcopy
-
-CURDIR := $(abspath .)
-TOOLSDIR := $(abspath ../../..)
-LIBDIR := $(TOOLSDIR)/lib
-BPFDIR := $(LIBDIR)/bpf
-TOOLSINCDIR := $(TOOLSDIR)/include
-TOOLSARCHINCDIR := $(TOOLSDIR)/arch/$(SRCARCH)/include
-BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool
-APIDIR := $(TOOLSINCDIR)/uapi
-ifneq ($(O),)
-GENDIR := $(O)/include/generated
-else
-GENDIR := $(abspath ../../../../include/generated)
-endif
-GENHDR := $(GENDIR)/autoconf.h
-PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
 
-ifneq ($(wildcard $(GENHDR)),)
-  GENFLAGS := -DHAVE_GENHDR
+# These probes gate the flavor list, which must be final before lib.mk is
+# included; keep values consistent with Makefile.buildvars.
+ifeq ($(origin BPF_GCC),undefined)
+BPF_GCC := $(shell command -v bpf-gcc;)
 endif
 
-BPF_GCC		?= $(shell command -v bpf-gcc;)
-ifdef ASAN
-SAN_CFLAGS 	?= -fsanitize=address -fno-omit-frame-pointer
-else
-SAN_CFLAGS	?=
-endif
-SAN_LDFLAGS	?= $(SAN_CFLAGS)
-RELEASE		?=
-OPT_FLAGS	?= $(if $(RELEASE),-O2,-O0)
-
-LIBELF_CFLAGS	:= $(shell $(PKG_CONFIG) libelf --cflags 2>/dev/null)
-LIBELF_LIBS	:= $(shell $(PKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
-
-SKIP_DOCS	?=
-SKIP_LLVM	?=
-SKIP_LIBBFD	?=
-SKIP_CRYPTO	?=
-
-# When BPF_STRICT_BUILD is 1, any BPF object, skeleton, test object, or
-# benchmark compilation failure is fatal. Set to 0 to tolerate failures
-# and continue building the remaining tests.
-BPF_STRICT_BUILD ?= 1
-PERMISSIVE := $(filter 0,$(BPF_STRICT_BUILD))
-
-ifeq ($(srctree),)
-srctree := $(patsubst %/,%,$(dir $(CURDIR)))
-srctree := $(patsubst %/,%,$(dir $(srctree)))
-srctree := $(patsubst %/,%,$(dir $(srctree)))
-srctree := $(patsubst %/,%,$(dir $(srctree)))
-endif
 
-COMMON_CFLAGS = -g $(OPT_FLAGS) -rdynamic -std=gnu11				\
-	  -Wall -Werror -fno-omit-frame-pointer				\
-	  -Wno-unused-but-set-variable					\
-	  $(GENFLAGS) $(SAN_CFLAGS) $(LIBELF_CFLAGS)			\
-	  -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR)		\
-	  -I$(TOOLSINCDIR) -I$(TOOLSARCHINCDIR) -I$(APIDIR) -I$(OUTPUT)	\
-	  -I$(CURDIR)/libarena/include
-LDFLAGS += $(SAN_LDFLAGS)
-LDLIBS += $(LIBELF_LIBS) -lz -lrt -lpthread
-
-PCAP_CFLAGS	:= $(shell $(PKG_CONFIG) --cflags libpcap 2>/dev/null && echo "-DTRAFFIC_MONITOR=1")
-PCAP_LIBS	:= $(shell $(PKG_CONFIG) --libs libpcap 2>/dev/null)
-LDLIBS += $(PCAP_LIBS)
-CFLAGS += $(COMMON_CFLAGS) $(PCAP_CFLAGS)
 
 # Some utility functions use LLVM libraries
 jit_disasm_helpers.c-CFLAGS = $(LLVM_CFLAGS)
 
-ifneq ($(LLVM),)
-# Silence some warnings when compiled with clang
-CFLAGS += -Wno-unused-command-line-argument
-endif
 
 # Check whether bpf cpu=v4 is supported or not by clang
 ifneq ($(shell $(CLANG) --target=bpf -mcpu=help 2>&1 | grep 'v4'),)
 CLANG_CPUV4 := 1
 endif
 
-# Check whether clang supports BPF address sanitizer (requires LLVM 22+)
-CLANG_HAS_ARENA_ASAN := $(shell echo 'int x;' | \
-	$(CLANG) --target=bpf -fsanitize=kernel-address \
-	-mllvm -asan-shadow-addr-space=1 \
-	-x c -c - -o /dev/null 2>/dev/null && echo 1)
 
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_progs \
@@ -132,9 +63,8 @@ TEST_PROGS := test_kmod.sh \
 TEST_PROGS_EXTENDED := \
 	ima_setup.sh verify_sig_setup.sh
 
-TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
+TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
 	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
-TEST_KMOD_TARGETS = $(addprefix $(OUTPUT)/,$(TEST_KMODS))
 
 # Compile but not part of 'make run_tests'
 TEST_GEN_PROGS_EXTENDED = \
@@ -150,9 +80,6 @@ TEST_GEN_PROGS_EXTENDED = \
 
 TEST_GEN_FILES += $(TEST_KMODS) liburandom_read.so urandom_read sign-file uprobe_multi
 
-ifneq ($(V),1)
-submake_extras := feature_display=0
-endif
 
 # override lib.mk's default rules
 OVERRIDE_TARGETS := 1
@@ -188,6 +115,8 @@ override OUTPUT := $(patsubst %/,%,$(OUTPUT))
 endif
 endif
 
+include Makefile.buildvars
+
 ifneq ($(SKIP_LLVM),1)
 ifeq ($(feature-llvm),1)
   LLVM_CFLAGS  += -DHAVE_LLVM_SUPPORT
@@ -213,30 +142,6 @@ ifeq ($(feature-llvm),1)
 endif
 endif
 
-SCRATCH_DIR := $(OUTPUT)/tools
-BUILD_DIR := $(SCRATCH_DIR)/build
-INCLUDE_DIR := $(SCRATCH_DIR)/include
-BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
-ifneq ($(CROSS_COMPILE),)
-HOST_BUILD_DIR		:= $(BUILD_DIR)/host
-HOST_SCRATCH_DIR	:= $(OUTPUT)/host-tools
-HOST_INCLUDE_DIR	:= $(HOST_SCRATCH_DIR)/include
-else
-HOST_BUILD_DIR		:= $(BUILD_DIR)
-HOST_SCRATCH_DIR	:= $(SCRATCH_DIR)
-HOST_INCLUDE_DIR	:= $(INCLUDE_DIR)
-endif
-HOST_BPFOBJ := $(HOST_BUILD_DIR)/libbpf/libbpf.a
-RESOLVE_BTFIDS := $(HOST_BUILD_DIR)/resolve_btfids/resolve_btfids
-VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
-		     $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)	\
-		     ../../../../vmlinux				\
-		     /sys/kernel/btf/vmlinux				\
-		     /boot/vmlinux-$(shell uname -r)
-VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
-ifeq ($(VMLINUX_BTF),)
-$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
-endif
 
 # Define simple and short `make test_progs`, `make test_maps`, etc targets
 # to build individual tests.
@@ -314,15 +219,6 @@ $(TEST_KMOD_TARGETS): $(addprefix test_kmods/,$(TEST_KMODS))
 	$(Q)$(if $(PERMISSIVE),if [ -f test_kmods/$(@F) ]; then )cp test_kmods/$(@F) $@$(if $(PERMISSIVE),; fi)
 
 
-DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool
-ifneq ($(CROSS_COMPILE),)
-CROSS_BPFTOOL := $(SCRATCH_DIR)/sbin/bpftool
-TRUNNER_BPFTOOL := $(CROSS_BPFTOOL)
-USE_BOOTSTRAP := ""
-else
-TRUNNER_BPFTOOL := $(DEFAULT_BPFTOOL)
-USE_BOOTSTRAP := "bootstrap/"
-endif
 
 $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(BPFOBJ)
 
@@ -344,7 +240,6 @@ $(OUTPUT)/test_maps: $(TESTING_HELPERS)
 $(OUTPUT)/test_verifier: $(TESTING_HELPERS) $(CAP_HELPERS) $(UNPRIV_HELPERS)
 $(OUTPUT)/xsk.o: $(BPFOBJ)
 
-BPFTOOL ?= $(DEFAULT_BPFTOOL)
 $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)    \
 		    $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
 	$(Q)$(MAKE) $(submake_extras)  -C $(BPFTOOLDIR)			       \
@@ -437,45 +332,6 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids	\
 		HOSTPKG_CONFIG='$(PKG_CONFIG)' \
 		OUTPUT=$(HOST_BUILD_DIR)/resolve_btfids/ BPFOBJ=$(HOST_BPFOBJ)
 
-# Get Clang's default includes on this system, as opposed to those seen by
-# '--target=bpf'. This fixes "missing" files on some architectures/distros,
-# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
-#
-# Use '-idirafter': Don't interfere with include mechanics except where the
-# build would have failed anyways.
-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 '__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
-
-# Determine target endianness.
-IS_LITTLE_ENDIAN := $(shell $(CC) -dM -E - </dev/null | \
-			grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
-MENDIAN:=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
-BPF_TARGET_ENDIAN:=$(if $(IS_LITTLE_ENDIAN),--target=bpfel,--target=bpfeb)
-
-ifneq ($(CROSS_COMPILE),)
-CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
-endif
-
-CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
-BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN)	\
-	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR)			\
-	     -I$(CURDIR)/libarena/include				\
-	     -I$(abspath $(OUTPUT)/../usr/include)			\
-	     -std=gnu11		 					\
-	     -fno-strict-aliasing 					\
-	     -Wno-microsoft-anon-tag					\
-	     -fms-extensions						\
-	     -Wno-compare-distinct-pointer-types			\
-	     -Wno-initializer-overrides					\
-	     #
-# TODO: enable me -Wsign-compare
-
-CLANG_CFLAGS = $(CLANG_SYS_INCLUDES)
 
 $(OUTPUT)/test_l4lb_noinline.o: BPF_CFLAGS += -fno-inline
 $(OUTPUT)/test_xdp_noinline.o: BPF_CFLAGS += -fno-inline
@@ -756,10 +612,6 @@ $(OUTPUT)/$(TRUNNER_BINARY): $(if $(filter test_progs%,$1),$(if $(PERMISSIVE),$$
 
 endef
 
-VERIFY_SIG_SETUP := $(CURDIR)/verify_sig_setup.sh
-VERIFY_SIG_HDR := verification_cert.h
-VERIFICATION_CERT   := $(BUILD_DIR)/signing_key.der
-PRIVATE_KEY := $(BUILD_DIR)/signing_key.pem
 
 $(VERIFICATION_CERT) $(PRIVATE_KEY): $(VERIFY_SIG_SETUP)
 	$(Q)mkdir -p $(BUILD_DIR)
@@ -790,14 +642,11 @@ LIBARENA_BPF_DEPS := $(wildcard libarena/Makefile		\
 				 libarena/selftests/*		\
 				 libarena/*.bpf.o)
 
-LIBARENA_SKEL := libarena/libarena.skel.h
 
 $(LIBARENA_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS)
 	+$(MAKE) -C libarena libarena.skel.h $(LIBARENA_MAKE_ARGS)
 
 ifneq ($(CLANG_HAS_ARENA_ASAN),)
-LIBARENA_ASAN_SKEL := libarena/libarena_asan.skel.h
-CFLAGS += -DHAS_BPF_ARENA_ASAN
 
 $(LIBARENA_ASAN_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS)
 	+$(MAKE) -C libarena libarena_asan.skel.h $(LIBARENA_MAKE_ARGS)
diff --git a/tools/testing/selftests/bpf/Makefile.buildvars b/tools/testing/selftests/bpf/Makefile.buildvars
new file mode 100644
index 000000000..2a7efe6d1
--- /dev/null
+++ b/tools/testing/selftests/bpf/Makefile.buildvars
@@ -0,0 +1,196 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Shared toolchain, path and flag definitions for the BPF selftests build.
+# Included by both Makefile (the top level) and Makefile.runner (one
+# test-runner instance).
+#
+# Requirements at include time:
+#   - $(OUTPUT) is set to an absolute path
+#   - tools/build/Build.include, tools/scripts/Makefile.arch and
+#     tools/scripts/Makefile.include have been included (for SRCARCH etc.)
+
+CXX ?= $(CROSS_COMPILE)g++
+PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
+
+TOOLSDIR := $(abspath ../../..)
+LIBDIR := $(TOOLSDIR)/lib
+BPFDIR := $(LIBDIR)/bpf
+TOOLSINCDIR := $(TOOLSDIR)/include
+TOOLSARCHINCDIR := $(TOOLSDIR)/arch/$(SRCARCH)/include
+BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool
+APIDIR := $(TOOLSINCDIR)/uapi
+ifneq ($(O),)
+GENDIR := $(O)/include/generated
+else
+GENDIR := $(abspath ../../../../include/generated)
+endif
+GENHDR := $(GENDIR)/autoconf.h
+
+ifneq ($(wildcard $(GENHDR)),)
+  GENFLAGS := -DHAVE_GENHDR
+endif
+
+ifeq ($(srctree),)
+srctree := $(abspath ../../../..)
+endif
+
+# Immediate (with an override-preserving guard): a plain ?= stays
+# recursively expanded and would re-run 'command -v' on every expansion.
+ifeq ($(origin BPF_GCC),undefined)
+BPF_GCC		:= $(shell command -v bpf-gcc;)
+endif
+ifdef ASAN
+SAN_CFLAGS	?= -fsanitize=address -fno-omit-frame-pointer
+else
+SAN_CFLAGS	?=
+endif
+SAN_LDFLAGS	?= $(SAN_CFLAGS)
+RELEASE		?=
+OPT_FLAGS	?= $(if $(RELEASE),-O2,-O0)
+
+LIBELF_CFLAGS	:= $(shell $(PKG_CONFIG) libelf --cflags 2>/dev/null)
+LIBELF_LIBS	:= $(shell $(PKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
+
+SKIP_DOCS	?=
+SKIP_LLVM	?=
+SKIP_LIBBFD	?=
+SKIP_CRYPTO	?=
+
+# When BPF_STRICT_BUILD is 1, any BPF object, skeleton, test object, or
+# benchmark compilation failure is fatal. Set to 0 to tolerate failures
+# and continue building the remaining tests.
+BPF_STRICT_BUILD ?= 1
+PERMISSIVE := $(filter 0,$(BPF_STRICT_BUILD))
+
+# Kernel test modules; TEST_KMODS= on the command line disables them.
+TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
+	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
+TEST_KMOD_TARGETS = $(addprefix $(OUTPUT)/,$(TEST_KMODS))
+
+# Output-tree layout. Defined before COMMON_CFLAGS on purpose: CFLAGS
+# below is expanded immediately and references $(INCLUDE_DIR).
+SCRATCH_DIR := $(OUTPUT)/tools
+BUILD_DIR := $(SCRATCH_DIR)/build
+INCLUDE_DIR := $(SCRATCH_DIR)/include
+BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
+ifneq ($(CROSS_COMPILE),)
+HOST_BUILD_DIR		:= $(BUILD_DIR)/host
+HOST_SCRATCH_DIR	:= $(OUTPUT)/host-tools
+HOST_INCLUDE_DIR	:= $(HOST_SCRATCH_DIR)/include
+else
+HOST_BUILD_DIR		:= $(BUILD_DIR)
+HOST_SCRATCH_DIR	:= $(SCRATCH_DIR)
+HOST_INCLUDE_DIR	:= $(INCLUDE_DIR)
+endif
+HOST_BPFOBJ := $(HOST_BUILD_DIR)/libbpf/libbpf.a
+RESOLVE_BTFIDS := $(HOST_BUILD_DIR)/resolve_btfids/resolve_btfids
+
+DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool
+ifneq ($(CROSS_COMPILE),)
+CROSS_BPFTOOL := $(SCRATCH_DIR)/sbin/bpftool
+TRUNNER_BPFTOOL := $(CROSS_BPFTOOL)
+USE_BOOTSTRAP :=
+else
+TRUNNER_BPFTOOL := $(DEFAULT_BPFTOOL)
+USE_BOOTSTRAP := bootstrap/
+endif
+BPFTOOL ?= $(DEFAULT_BPFTOOL)
+
+COMMON_CFLAGS = -g $(OPT_FLAGS) -rdynamic -std=gnu11			\
+	  -Wall -Werror -fno-omit-frame-pointer				\
+	  -Wno-unused-but-set-variable					\
+	  $(GENFLAGS) $(SAN_CFLAGS) $(LIBELF_CFLAGS)			\
+	  -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR)		\
+	  -I$(TOOLSINCDIR) -I$(TOOLSARCHINCDIR) -I$(APIDIR) -I$(OUTPUT)	\
+	  -I$(CURDIR)/libarena/include
+LDFLAGS += $(SAN_LDFLAGS)
+LDLIBS += $(LIBELF_LIBS) -lz -lrt -lpthread
+
+PCAP_CFLAGS	:= $(shell $(PKG_CONFIG) --cflags libpcap 2>/dev/null && echo "-DTRAFFIC_MONITOR=1")
+PCAP_LIBS	:= $(shell $(PKG_CONFIG) --libs libpcap 2>/dev/null)
+LDLIBS += $(PCAP_LIBS)
+# Prepend rather than append: the include-search order must stay
+# "$(COMMON_CFLAGS) first, lib.mk additions after" regardless of whether
+# lib.mk was included before this file (top level) or not at all (runner).
+CFLAGS := $(COMMON_CFLAGS) $(PCAP_CFLAGS) $(CFLAGS)
+
+ifneq ($(LLVM),)
+# Silence some warnings when compiled with clang
+CFLAGS += -Wno-unused-command-line-argument
+endif
+
+# Check whether clang supports BPF address sanitizer (requires LLVM 22+)
+CLANG_HAS_ARENA_ASAN := $(shell echo 'int x;' | \
+	$(CLANG) --target=bpf -fsanitize=kernel-address \
+	-mllvm -asan-shadow-addr-space=1 \
+	-x c -c - -o /dev/null 2>/dev/null && echo 1)
+ifneq ($(CLANG_HAS_ARENA_ASAN),)
+CFLAGS += -DHAS_BPF_ARENA_ASAN
+endif
+
+VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
+		     $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)	\
+		     ../../../../vmlinux				\
+		     /sys/kernel/btf/vmlinux				\
+		     /boot/vmlinux-$(shell uname -r)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+ifeq ($(VMLINUX_BTF),)
+$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
+endif
+
+# Get Clang's default includes on this system, as opposed to those seen by
+# '--target=bpf'. This fixes "missing" files on some architectures/distros,
+# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
+#
+# Use '-idirafter': Don't interfere with include mechanics except where the
+# build would have failed anyways.
+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 '__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
+
+# Determine target endianness.
+IS_LITTLE_ENDIAN := $(shell $(CC) -dM -E - </dev/null | \
+			grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
+MENDIAN := $(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
+BPF_TARGET_ENDIAN := $(if $(IS_LITTLE_ENDIAN),--target=bpfel,--target=bpfeb)
+
+ifneq ($(CROSS_COMPILE),)
+CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
+endif
+
+CLANG_SYS_INCLUDES := $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
+BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN)	\
+	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR)			\
+	     -I$(CURDIR)/libarena/include				\
+	     -I$(abspath $(OUTPUT)/../usr/include)			\
+	     -std=gnu11		 					\
+	     -fno-strict-aliasing 					\
+	     -Wno-microsoft-anon-tag					\
+	     -fms-extensions						\
+	     -Wno-compare-distinct-pointer-types			\
+	     -Wno-initializer-overrides					\
+	     #
+# TODO: enable me -Wsign-compare
+
+CLANG_CFLAGS = $(CLANG_SYS_INCLUDES)
+
+# Signing key/cert shared by the signed light skeletons and test_progs.
+VERIFY_SIG_SETUP := $(CURDIR)/verify_sig_setup.sh
+VERIFY_SIG_HDR := verification_cert.h
+VERIFICATION_CERT := $(BUILD_DIR)/signing_key.der
+PRIVATE_KEY := $(BUILD_DIR)/signing_key.pem
+
+# libarena skeletons, built by the libarena/ sub-make (driven by the top
+# level Makefile); test_progs and its flavors depend on the headers.
+LIBARENA_SKEL := libarena/libarena.skel.h
+ifneq ($(CLANG_HAS_ARENA_ASAN),)
+LIBARENA_ASAN_SKEL := libarena/libarena_asan.skel.h
+endif
+
+ifneq ($(V),1)
+submake_extras := feature_display=0
+endif
-- 
2.43.0

[RFC PATCH bpf-next v2 3/3] selftests/bpf: build each test runner instance in its own sub-make

[Mykola Lysenko]

Replace the DEFINE_TEST_RUNNER/DEFINE_TEST_RUNNER_RULES double-expansion
machinery with Makefile.runner: one sub-make invocation per test runner
instance (test_progs, test_progs-no_alu32, test_progs-cpuv4,
test_progs-bpf_gcc, test_maps), each in its own single-flavor namespace
written in plain make - no $$-escaping, no per-flavor eval guards, no
accumulating vpath directives.

The main Makefile keeps everything that exists once - tool sub-builds,
vmlinux.h, signing keys, tests.h generation, shared helper objects,
standalone binaries and the kselftest lib.mk contract - and delegates to
the runner through explicit per-instance rules. Light-skeleton demand
lists are derived from the tests' own '#include "*.lskel.h"' lines; the
bench object list is derived from $(wildcard benchs/bench_*.c). The ~20
inline $(if $(PERMISSIVE),...) fragments collapse into one skip_on_fail
helper in Makefile.buildvars.

This also fixes a latent parallel-build race (objects including libbpf
internal headers now order against the bpftool sub-build that installs
them) and makes the signing key generation rule properly grouped (the
two-target form ran genkey twice concurrently under -j).

Validation is as for the whole series: BPF objects, skeleton headers,
userspace objects and 21/22 binaries byte-identical with the previous
Makefile (bench differs only in object link order); emit_tests and the
installed tree identical; BPF CI green on x86_64 gcc/llvm, aarch64 and
s390x including GCC-BPF, ASAN and veristat jobs; all 76 benchmarks
produce identical outcomes.

The shared helper objects the main Makefile pre-builds depend on a
superset of the prerequisites the runner's uniform object rule uses,
so the unflavored test_progs and test_maps sub-makes always see them
as up to date and never race to recompile them in the shared output
directory.

Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Assisted-by: Claude:claude-fable-5 shellcheck
Signed-off-by: Mykola Lysenko <nickolay.lysenko@gmail.com>
---
 tools/testing/selftests/bpf/Makefile          | 738 ++++++------------
 .../testing/selftests/bpf/Makefile.buildvars  |   8 +
 tools/testing/selftests/bpf/Makefile.runner   | 316 ++++++++
 3 files changed, 584 insertions(+), 478 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/Makefile.runner

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 2ddcb812d..329f3cbbe 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -1,27 +1,44 @@
 # SPDX-License-Identifier: GPL-2.0
+#
+# BPF selftests build.
+#
+# The build is split in two layers:
+#
+#   Makefile (this file)
+#       Everything that exists once: knobs and toolchain setup, libbpf /
+#       bpftool / resolve_btfids sub-builds, vmlinux.h, signing keys,
+#       generated tests.h headers, shared helper objects, standalone test
+#       binaries (bench, veristat, test_verifier, xsk*, ...), kernel test
+#       modules, docs, and the kselftest lib.mk run/install/clean
+#       contract.
+#
+#   Makefile.runner
+#       One test-runner instance (test_progs, test_progs-<flavor>,
+#       test_maps): BPF objects, skeleton headers, test objects and the
+#       final runner binary. Invoked from here once per instance; each
+#       invocation is an independent single-flavor namespace, so the
+#       runner is plain make without $$-escaping or eval.
+#
+#   gen_bpf_skel.sh
+#       Links BPF objects via bpftool and generates (light) skeletons;
+#       one script instead of four near-identical make recipes.
+#
+# Shared definitions (paths, flags, permissive-mode helpers) live in
+# Makefile.buildvars, included by both layers.
+
 include ../../../build/Build.include
 include ../../../scripts/Makefile.arch
 include ../../../scripts/Makefile.include
 
-
 # These probes gate the flavor list, which must be final before lib.mk is
 # included; keep values consistent with Makefile.buildvars.
 ifeq ($(origin BPF_GCC),undefined)
 BPF_GCC := $(shell command -v bpf-gcc;)
 endif
-
-
-
-# Some utility functions use LLVM libraries
-jit_disasm_helpers.c-CFLAGS = $(LLVM_CFLAGS)
-
-
-# Check whether bpf cpu=v4 is supported or not by clang
 ifneq ($(shell $(CLANG) --target=bpf -mcpu=help 2>&1 | grep 'v4'),)
 CLANG_CPUV4 := 1
 endif
 
-
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_progs \
 	test_sockmap \
@@ -33,16 +50,6 @@ TEST_INST_SUBDIRS := no_alu32
 ifneq ($(BPF_GCC),)
 TEST_GEN_PROGS += test_progs-bpf_gcc
 TEST_INST_SUBDIRS += bpf_gcc
-
-# The following tests contain C code that, although technically legal,
-# triggers GCC warnings that cannot be disabled: declaration of
-# anonymous struct types in function parameter lists.
-progs/btf_dump_test_case_bitfields.c-bpf_gcc-CFLAGS := -Wno-error
-progs/btf_dump_test_case_namespacing.c-bpf_gcc-CFLAGS := -Wno-error
-progs/btf_dump_test_case_packing.c-bpf_gcc-CFLAGS := -Wno-error
-progs/btf_dump_test_case_padding.c-bpf_gcc-CFLAGS := -Wno-error
-progs/btf_dump_test_case_syntax.c-bpf_gcc-CFLAGS := -Wno-error
-
 endif
 
 ifneq ($(CLANG_CPUV4),)
@@ -63,9 +70,6 @@ TEST_PROGS := test_kmod.sh \
 TEST_PROGS_EXTENDED := \
 	ima_setup.sh verify_sig_setup.sh
 
-TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
-	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
-
 # Compile but not part of 'make run_tests'
 TEST_GEN_PROGS_EXTENDED = \
 	bench \
@@ -78,8 +82,10 @@ TEST_GEN_PROGS_EXTENDED = \
 	xdp_synproxy \
 	xskxceiver
 
-TEST_GEN_FILES += $(TEST_KMODS) liburandom_read.so urandom_read sign-file uprobe_multi
+TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
+	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
 
+TEST_GEN_FILES += $(TEST_KMODS) liburandom_read.so urandom_read sign-file uprobe_multi
 
 # override lib.mk's default rules
 OVERRIDE_TARGETS := 1
@@ -98,7 +104,7 @@ endef
 include ../lib.mk
 
 NON_CHECK_FEAT_TARGETS := clean docs-clean emit_tests
-CHECK_FEAT := $(filter-out $(NON_CHECK_FEAT_TARGETS),$(or $(MAKECMDGOALS), "none"))
+CHECK_FEAT := $(filter-out $(NON_CHECK_FEAT_TARGETS),$(or $(MAKECMDGOALS),all))
 ifneq ($(CHECK_FEAT),)
 FEATURE_USER := .selftests
 FEATURE_TESTS := llvm
@@ -142,12 +148,11 @@ ifeq ($(feature-llvm),1)
 endif
 endif
 
-
 # Define simple and short `make test_progs`, `make test_maps`, etc targets
 # to build individual tests.
 # NOTE: Semicolon at the end is critical to override lib.mk's default static
 # rule for binaries.
-$(notdir $(TEST_GEN_PROGS) $(TEST_KMODS)				\
+$(notdir $(TEST_GEN_PROGS) $(TEST_KMOD_TARGETS)				\
 	 $(TEST_GEN_PROGS_EXTENDED)): %: $(OUTPUT)/% ;
 
 # sort removes libbpf duplicates when not cross-building
@@ -161,11 +166,14 @@ $(MAKE_DIRS):
 
 $(OUTPUT)/%.o: %.c
 	$(call msg,CC,,$@)
-	$(Q)$(CC) $(CFLAGS) -c $(filter %.c,$^) $(LDLIBS) -o $@
+	$(Q)$(CC) $(CFLAGS) -c $(filter %.c,$^) -o $@
 
+# Headers may appear among the prerequisites for dependency tracking;
+# they must not reach the clang/gcc command line (clang treats a bare .h
+# argument as a precompiled-header job and refuses -o).
 $(OUTPUT)/%:%.c
 	$(call msg,BINARY,,$@)
-	$(Q)$(LINK.c) $^ $(LDLIBS) -o $@
+	$(Q)$(LINK.c) $(filter-out %.h,$^) $(LDLIBS) -o $@
 
 # LLVM's ld.lld doesn't support all the architectures, so use it only on x86
 ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 riscv))
@@ -202,6 +210,13 @@ $(OUTPUT)/sign-file: ../../../../scripts/sign-file.c
 		  $< -o $@ \
 		  $(shell $(PKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto)
 
+# Linking uprobe_multi can fail due to relocation overflows on mips.
+$(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot)
+$(OUTPUT)/uprobe_multi: uprobe_multi.c uprobe_multi.ld
+	$(call msg,BINARY,,$@)
+	$(Q)$(CC) $(CFLAGS) -Wl,-T,uprobe_multi.ld -O0 $(LDFLAGS) 	\
+		$(filter-out %.ld,$^) $(LDLIBS) -o $@
+
 # This should really be a grouped target, but make versions before 4.3 don't
 # support that for regular rules. However, pattern matching rules are implicitly
 # treated as grouped even with older versions of make, so as a workaround, the
@@ -219,26 +234,15 @@ $(TEST_KMOD_TARGETS): $(addprefix test_kmods/,$(TEST_KMODS))
 	$(Q)$(if $(PERMISSIVE),if [ -f test_kmods/$(@F) ]; then )cp test_kmods/$(@F) $@$(if $(PERMISSIVE),; fi)
 
 
-
 $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(BPFOBJ)
 
-TESTING_HELPERS	:= $(OUTPUT)/testing_helpers.o
-CGROUP_HELPERS	:= $(OUTPUT)/cgroup_helpers.o
-UNPRIV_HELPERS  := $(OUTPUT)/unpriv_helpers.o
-TRACE_HELPERS	:= $(OUTPUT)/trace_helpers.o
-JSON_WRITER		:= $(OUTPUT)/json_writer.o
-CAP_HELPERS	:= $(OUTPUT)/cap_helpers.o
-NETWORK_HELPERS := $(OUTPUT)/network_helpers.o
-
-$(OUTPUT)/test_sockmap: $(CGROUP_HELPERS) $(TESTING_HELPERS)
-$(OUTPUT)/test_tcpnotify_user: $(CGROUP_HELPERS) $(TESTING_HELPERS) $(TRACE_HELPERS)
-$(OUTPUT)/test_sock_fields: $(CGROUP_HELPERS) $(TESTING_HELPERS)
-$(OUTPUT)/test_tag: $(TESTING_HELPERS)
-$(OUTPUT)/test_lirc_mode2_user: $(TESTING_HELPERS)
-$(OUTPUT)/flow_dissector_load: $(TESTING_HELPERS)
-$(OUTPUT)/test_maps: $(TESTING_HELPERS)
-$(OUTPUT)/test_verifier: $(TESTING_HELPERS) $(CAP_HELPERS) $(UNPRIV_HELPERS)
-$(OUTPUT)/xsk.o: $(BPFOBJ)
+# ---------------------------------------------------------------------
+# Tool sub-builds: bpftool and libbpf (host and, when cross-compiling,
+# target variants) and resolve_btfids.
+#
+# Note the deliberate asymmetry: the host libbpf builds without
+# sanitizers and with the host toolchain.
+# ---------------------------------------------------------------------
 
 $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)    \
 		    $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
@@ -270,20 +274,6 @@ $(CROSS_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)	\
 		    prefix= DESTDIR=$(SCRATCH_DIR)/ install-bin
 endif
 
-ifneq ($(SKIP_DOCS),1)
-all: docs
-endif
-
-docs:
-	$(Q)RST2MAN_OPTS="--exit-status=1" $(MAKE) $(submake_extras)	\
-	            -f Makefile.docs					\
-	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
-
-docs-clean:
-	$(Q)$(MAKE) $(submake_extras)					\
-	            -f Makefile.docs					\
-	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
-
 $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 	   $(APIDIR)/linux/bpf.h					       \
 	   | $(BUILD_DIR)/libbpf
@@ -305,19 +295,6 @@ $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 		    DESTDIR=$(HOST_SCRATCH_DIR)/ prefix= all install_headers
 endif
 
-# vmlinux.h is first dumped to a temporary file and then compared to
-# the previous version. This helps to avoid unnecessary re-builds of
-# $(TRUNNER_BPF_OBJS)
-$(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
-ifeq ($(VMLINUX_H),)
-	$(call msg,GEN,,$@)
-	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $(INCLUDE_DIR)/.vmlinux.h.tmp
-	$(Q)cmp -s $(INCLUDE_DIR)/.vmlinux.h.tmp $@ || mv $(INCLUDE_DIR)/.vmlinux.h.tmp $@
-else
-	$(call msg,CP,,$@)
-	$(Q)cp "$(VMLINUX_H)" $@
-endif
-
 $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids	\
 		       $(TOOLSDIR)/bpf/resolve_btfids/main.c	\
 		       $(TOOLSDIR)/lib/rbtree.c			\
@@ -332,288 +309,38 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids	\
 		HOSTPKG_CONFIG='$(PKG_CONFIG)' \
 		OUTPUT=$(HOST_BUILD_DIR)/resolve_btfids/ BPFOBJ=$(HOST_BPFOBJ)
 
-
-$(OUTPUT)/test_l4lb_noinline.o: BPF_CFLAGS += -fno-inline
-$(OUTPUT)/test_xdp_noinline.o: BPF_CFLAGS += -fno-inline
-
-$(OUTPUT)/flow_dissector_load.o: flow_dissector_load.h
-$(OUTPUT)/cgroup_getset_retval_hooks.o: cgroup_getset_retval_hooks.h
-
-# Build BPF object using Clang
-# $1 - input .c file
-# $2 - output .o file
-# $3 - CFLAGS
-# $4 - binary name
-define CLANG_BPF_BUILD_RULE
-	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v3 -o $2 $(if $(PERMISSIVE),|| \
-		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
-endef
-# Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32
-define CLANG_NOALU32_BPF_BUILD_RULE
-	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v2 -o $2 $(if $(PERMISSIVE),|| \
-		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
-endef
-# Similar to CLANG_BPF_BUILD_RULE, but with cpu-v4
-define CLANG_CPUV4_BPF_BUILD_RULE
-	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v4 -o $2 $(if $(PERMISSIVE),|| \
-		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
-endef
-# Build BPF object using GCC
-define GCC_BPF_BUILD_RULE
-	$(call msg,GCC-BPF,$4,$2)
-	$(Q)$(BPF_GCC) $3 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -c $1 -o $2 $(if $(PERMISSIVE),|| \
-		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
-endef
-
-SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c
-
-LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
-		linked_vars.skel.h linked_maps.skel.h 			\
-		test_subskeleton.skel.h test_subskeleton_lib.skel.h	\
-		test_usdt.skel.h tracing_multi.skel.h			\
-		tracing_multi_module.skel.h				\
-		tracing_multi_intersect.skel.h				\
-		tracing_multi_session.skel.h
-
-LSKELS := fexit_sleep.c trace_printk.c trace_vprintk.c map_ptr_kern.c 	\
-	core_kern.c core_kern_overflow.c test_ringbuf.c			\
-	test_ringbuf_n.c test_ringbuf_map_key.c test_ringbuf_write.c    \
-	test_ringbuf_overwrite.c
-
-LSKELS_SIGNED := fentry_test.c fexit_test.c atomics.c
-
-# Generate both light skeleton and libbpf skeleton for these
-LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \
-	kfunc_call_test_subprog.c
-SKEL_BLACKLIST += $$(LSKELS) $$(LSKELS_SIGNED)
-
-test_static_linked.skel.h-deps := test_static_linked1.bpf.o test_static_linked2.bpf.o
-linked_funcs.skel.h-deps := linked_funcs1.bpf.o linked_funcs2.bpf.o
-linked_vars.skel.h-deps := linked_vars1.bpf.o linked_vars2.bpf.o
-linked_maps.skel.h-deps := linked_maps1.bpf.o linked_maps2.bpf.o
-# In the subskeleton case, we want the test_subskeleton_lib.subskel.h file
-# but that's created as a side-effect of the skel.h generation.
-test_subskeleton.skel.h-deps := test_subskeleton_lib2.bpf.o test_subskeleton_lib.bpf.o test_subskeleton.bpf.o
-test_subskeleton_lib.skel.h-deps := test_subskeleton_lib2.bpf.o test_subskeleton_lib.bpf.o
-test_usdt.skel.h-deps := test_usdt.bpf.o test_usdt_multispec.bpf.o
-xsk_xdp_progs.skel.h-deps := xsk_xdp_progs.bpf.o
-xdp_hw_metadata.skel.h-deps := xdp_hw_metadata.bpf.o
-xdp_features.skel.h-deps := xdp_features.bpf.o
-tracing_multi.skel.h-deps := tracing_multi_attach.bpf.o tracing_multi_check.bpf.o
-tracing_multi_module.skel.h-deps := tracing_multi_attach_module.bpf.o tracing_multi_check.bpf.o
-tracing_multi_intersect.skel.h-deps := tracing_multi_intersect_attach.bpf.o tracing_multi_check.bpf.o
-tracing_multi_session.skel.h-deps := tracing_multi_session_attach.bpf.o tracing_multi_check.bpf.o
-
-LINKED_BPF_OBJS := $(foreach skel,$(LINKED_SKELS),$($(skel)-deps))
-LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(LINKED_BPF_OBJS))
-
-HEADERS_FOR_BPF_OBJS := $(wildcard $(BPFDIR)/*.bpf.h)		\
-			$(wildcard $(CURDIR)/libarena/include/*.[ch])	\
-			$(addprefix $(BPFDIR)/,	bpf_core_read.h	\
-			                        bpf_endian.h	\
-						bpf_helpers.h	\
-			                        bpf_tracing.h)
-
-# Set up extra TRUNNER_XXX "temporary" variables in the environment (relies on
-# $eval()) and pass control to DEFINE_TEST_RUNNER_RULES.
-# Parameters:
-# $1 - test runner base binary name (e.g., test_progs)
-# $2 - test runner extra "flavor" (e.g., no_alu32, cpuv4, bpf_gcc, etc)
-define DEFINE_TEST_RUNNER
-
-LSKEL_SIGN := -S -k $(PRIVATE_KEY) -i $(VERIFICATION_CERT)
-TRUNNER_OUTPUT := $(OUTPUT)$(if $2,/)$2
-TRUNNER_BINARY := $1$(if $2,-)$2
-TRUNNER_TEST_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.test.o,	\
-				 $$(notdir $$(wildcard $(TRUNNER_TESTS_DIR)/*.c)))
-TRUNNER_EXTRA_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o,		\
-				 $$(filter %.c,$(TRUNNER_EXTRA_SOURCES)))
-TRUNNER_LIB_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o,		\
-				 $$(filter %.c,$(TRUNNER_LIB_SOURCES)))
-TRUNNER_EXTRA_HDRS := $$(filter %.h,$(TRUNNER_EXTRA_SOURCES))
-TRUNNER_TESTS_HDR := $(TRUNNER_TESTS_DIR)/tests.h
-TRUNNER_BPF_SRCS := $$(notdir $$(wildcard $(TRUNNER_BPF_PROGS_DIR)/*.c))
-TRUNNER_BPF_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.bpf.o, $$(TRUNNER_BPF_SRCS))
-TRUNNER_BPF_SKELS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.skel.h,	\
-				 $$(filter-out $(SKEL_BLACKLIST) $(LINKED_BPF_SRCS),\
-					       $$(TRUNNER_BPF_SRCS)))
-TRUNNER_BPF_LSKELS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.lskel.h, $$(LSKELS) $$(LSKELS_EXTRA))
-TRUNNER_BPF_SKELS_LINKED := $$(addprefix $$(TRUNNER_OUTPUT)/,$(LINKED_SKELS))
-TRUNNER_BPF_LSKELS_SIGNED := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.lskel.h, $$(LSKELS_SIGNED))
-TEST_GEN_FILES += $$(TRUNNER_BPF_OBJS)
-
-# Evaluate rules now with extra TRUNNER_XXX variables above already defined
-$$(eval $$(call DEFINE_TEST_RUNNER_RULES,$1,$2))
-
-endef
-
-# Using TRUNNER_XXX variables, provided by callers of DEFINE_TEST_RUNNER and
-# set up by DEFINE_TEST_RUNNER itself, create test runner build rules with:
-# $1 - test runner base binary name (e.g., test_progs)
-# $2 - test runner extra "flavor" (e.g., no_alu32, cpuv4, bpf_gcc, etc)
-define DEFINE_TEST_RUNNER_RULES
-
-# Permissive build behaviour (skip-on-failure compile, partial-link) only
-# applies to test_progs and its flavors; runners that use strong cross-object
-# references (e.g. test_maps) keep strict semantics even when permissive.
-# The check is inlined per-runner so $1 is substituted at $(call) time and
-# the result is baked into each rule's recipe.
-
-ifeq ($($(TRUNNER_OUTPUT)-dir),)
-$(TRUNNER_OUTPUT)-dir := y
-$(TRUNNER_OUTPUT):
-	$$(call msg,MKDIR,,$$@)
-	$(Q)mkdir -p $$@
-endif
-
-# ensure we set up BPF objects generation rule just once for a given
-# input/output directory combination
-ifeq ($($(TRUNNER_BPF_PROGS_DIR)$(if $2,-)$2-bpfobjs),)
-$(TRUNNER_BPF_PROGS_DIR)$(if $2,-)$2-bpfobjs := y
-$(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.bpf.o:				\
-		     $(TRUNNER_BPF_PROGS_DIR)/%.c			\
-		     $(TRUNNER_BPF_PROGS_DIR)/*.h			\
-		     $$(INCLUDE_DIR)/vmlinux.h				\
-		     $(HEADERS_FOR_BPF_OBJS)				\
-		     | $(TRUNNER_OUTPUT) $$(BPFOBJ)
-	$$(call $(TRUNNER_BPF_BUILD_RULE),$$<,$$@,			\
-					  $(TRUNNER_BPF_CFLAGS)         \
-					  $$($$<-CFLAGS)		\
-					  $$($$<-$2-CFLAGS),$(TRUNNER_BINARY))
-
-$(TRUNNER_BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
-	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
-		--name $$(notdir $$(<:.bpf.o=)) --infix linked			\
-		--skel $$@ --subskel $$(@:.skel.h=.subskel.h) $$< $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@ $$(@:.skel.h=.subskel.h);				\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
-
-$(TRUNNER_BPF_LSKELS): %.lskel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
-	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
-		--name $$(notdir $$(<:.bpf.o=_lskel)) --infix llinked --lskel	\
-		--skel $$@ $$< $(if $(PERMISSIVE),|| {				\
-		$$(RM) $$@;							\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
-
-$(TRUNNER_BPF_LSKELS_SIGNED): %.lskel.h: %.bpf.o $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
-	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY) (signed)' \
-		--name $$(notdir $$(<:.bpf.o=_lskel)) --infix llinked		\
-		--sign '$(LSKEL_SIGN)'						\
-		--skel $$@ $$< $(if $(PERMISSIVE),|| {				\
-		$$(RM) $$@;							\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
-
-$(LINKED_BPF_OBJS): %: $(TRUNNER_OUTPUT)/%
-
-# .SECONDEXPANSION here allows to correctly expand %-deps variables as prerequisites
-.SECONDEXPANSION:
-$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_OUTPUT)/%: $$$$(%-deps) $(BPFTOOL) gen_bpf_skel.sh | $(TRUNNER_OUTPUT)
-	$(Q)BPFTOOL=$$(BPFTOOL) ./gen_bpf_skel.sh --tag '$(TRUNNER_BINARY)'	\
-		--name $$(notdir $$(@:.skel.h=)) --infix linked			\
-		--skel $$@ --subskel $$(@:.skel.h=.subskel.h)			\
-		$$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)) $(if $(PERMISSIVE),|| { \
-		$$(RM) $$@ $$(@:.skel.h=.subskel.h);				\
-		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; })
-
-# When the compiler generates a %.d file, only skel basenames (not
-# full paths) are specified as prerequisites for corresponding %.o
-# file. vpath directives below instruct make to search for skel files
-# in TRUNNER_OUTPUT, if they are not present in the working directory.
-vpath %.skel.h $(TRUNNER_OUTPUT)
-vpath %.lskel.h $(TRUNNER_OUTPUT)
-vpath %.subskel.h $(TRUNNER_OUTPUT)
-
+ifneq ($(SKIP_DOCS),1)
+all: docs
 endif
 
-# ensure we set up tests.h header generation rule just once
-ifeq ($($(TRUNNER_TESTS_DIR)-tests-hdr),)
-$(TRUNNER_TESTS_DIR)-tests-hdr := y
-$(TRUNNER_TESTS_HDR): $(TRUNNER_TESTS_DIR)/*.c
-	$$(call msg,TEST-HDR,$(TRUNNER_BINARY),$$@)
-	$$(shell (echo '/* Generated header, do not edit */';					\
-		  sed -n -E 's/^void (serial_)?test_([a-zA-Z0-9_]+)\((void)?\).*/DEFINE_TEST(\2)/p'	\
-			$(TRUNNER_TESTS_DIR)/*.c | sort ;	\
-		 ) > $$@)
-endif
+docs:
+	$(Q)RST2MAN_OPTS="--exit-status=1" $(MAKE) $(submake_extras)	\
+	            -f Makefile.docs					\
+	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
 
-$(TRUNNER_OUTPUT)/resolve_btfids.test.o: $(RESOLVE_BTFIDS) $(TRUNNER_OUTPUT)/btf_data.bpf.o
-$(TRUNNER_OUTPUT)/resolve_btfids.test.o: private TEST_NEEDS_BTFIDS = 1
-
-# compile individual test files
-# Note: we cd into output directory to ensure embedded BPF object is found
-$(TRUNNER_TEST_OBJS): $(TRUNNER_OUTPUT)/%.test.o:			\
-		      $(TRUNNER_TESTS_DIR)/%.c				\
-		      | $(TRUNNER_OUTPUT)/%.test.d
-	$$(call msg,TEST-OBJ,$(TRUNNER_BINARY),$$@)
-	$(Q)(cd $$(@D) && $$(CC) -I. $$(CFLAGS) -MMD -MT $$@ -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F)) $(if $(filter test_progs%,$1),$(if $(PERMISSIVE),|| \
-		($(RM) $$@; printf '  %-12s %s\n' 'SKIP-TEST' '$$(notdir $$@)' 1>&2)))
-	$$(if $$(TEST_NEEDS_BTFIDS),						\
-		$(Q)if [ -f $$@ ]; then						\
-		$(if $(filter 1,$(V)),true,printf '  %-8s%s %s\n' "BTFIDS" " [$(TRUNNER_BINARY)]" "$$(notdir $$@)"); \
-		$(RESOLVE_BTFIDS) --btf $(TRUNNER_OUTPUT)/btf_data.bpf.o $$@;	\
-		$(RESOLVE_BTFIDS) --patch_btfids $$@.BTF_ids $$@;		\
-		fi)
-
-$(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d:			\
-			    $(TRUNNER_TESTS_DIR)/%.c			\
-			    $(TRUNNER_EXTRA_HDRS)			\
-			    $$(BPFOBJ) | $(TRUNNER_OUTPUT)		\
-			    $(TRUNNER_BPF_SKELS)			\
-			    $(TRUNNER_BPF_LSKELS)			\
-			    $(TRUNNER_BPF_LSKELS_SIGNED)		\
-			    $(TRUNNER_BPF_SKELS_LINKED)
-
-ifeq ($(filter clean docs-clean emit_tests,$(MAKECMDGOALS)),)
-include $(wildcard $(TRUNNER_TEST_OBJS:.o=.d))
-endif
+docs-clean:
+	$(Q)$(MAKE) $(submake_extras)					\
+	            -f Makefile.docs					\
+	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
 
-# add per extra obj CFGLAGS definitions
-$(foreach N,$(patsubst $(TRUNNER_OUTPUT)/%.o,%,$(TRUNNER_EXTRA_OBJS)),	\
-	$(eval $(TRUNNER_OUTPUT)/$(N).o: CFLAGS += $($(N).c-CFLAGS)))
-
-$(TRUNNER_EXTRA_OBJS): $(TRUNNER_OUTPUT)/%.o:				\
-		       %.c						\
-		       $(TRUNNER_EXTRA_HDRS)				\
-		       $(VERIFY_SIG_HDR)				\
-		       $(TRUNNER_TESTS_HDR)				\
-		       $$(BPFOBJ) | $(TRUNNER_OUTPUT)
-	$$(call msg,EXT-OBJ,$(TRUNNER_BINARY),$$@)
-	$(Q)$$(CC) $$(CFLAGS) -c $$< $$(LDLIBS) -o $$@
-
-$(TRUNNER_LIB_OBJS): $(TRUNNER_OUTPUT)/%.o:$(TOOLSDIR)/lib/%.c
-	$$(call msg,LIB-OBJ,$(TRUNNER_BINARY),$$@)
-	$(Q)$$(CC) $$(CFLAGS) -c $$< $$(LDLIBS) -o $$@
-
-# non-flavored in-srctree builds receive special treatment, in particular, we
-# do not need to copy extra resources (see e.g. test_btf_dump_case())
-$(TRUNNER_BINARY)-extras: $(TRUNNER_EXTRA_FILES) | $(TRUNNER_OUTPUT)
-ifneq ($2:$(OUTPUT),:$(shell pwd))
-	$$(call msg,EXT-COPY,$(TRUNNER_BINARY),$(TRUNNER_EXTRA_FILES))
-	$(Q)rsync -aq $(if $(PERMISSIVE),--ignore-missing-args) $$^ $(TRUNNER_OUTPUT)/
+# vmlinux.h is first dumped to a temporary file and then compared to
+# the previous version. This helps to avoid unnecessary re-builds of
+# BPF objects.
+$(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
+ifeq ($(VMLINUX_H),)
+	$(call msg,GEN,,$@)
+	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $(INCLUDE_DIR)/.vmlinux.h.tmp
+	$(Q)cmp -s $(INCLUDE_DIR)/.vmlinux.h.tmp $@ || mv $(INCLUDE_DIR)/.vmlinux.h.tmp $@
+else
+	$(call msg,CP,,$@)
+	$(Q)cp "$(VMLINUX_H)" $@
 endif
 
-# some X.test.o files have runtime dependencies on Y.bpf.o files
-$(OUTPUT)/$(TRUNNER_BINARY): | $(TRUNNER_BPF_OBJS)
-
-$(OUTPUT)/$(TRUNNER_BINARY): $(if $(filter test_progs%,$1),$(if $(PERMISSIVE),$$(wildcard $(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS))	\
-			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
-			     $(TRUNNER_LIB_OBJS)			\
-			     $(TRUNNER_BPFTOOL)				\
-			     $(OUTPUT)/veristat				\
-			     | $(TRUNNER_BINARY)-extras			\
-			     $(if $(filter test_progs%,$1),$(if $(PERMISSIVE),$(TRUNNER_TEST_OBJS)))
-	$$(call msg,BINARY,,$$@)
-	$(Q)$$(CC) $$(CFLAGS) $(if $(filter test_progs%,$1),$(if $(PERMISSIVE),$$(filter %.a %.o,$$(wildcard $(TRUNNER_TEST_OBJS)) $$(filter-out $(TRUNNER_TEST_OBJS),$$^)),$$(filter %.a %.o,$$^)),$$(filter %.a %.o,$$^)) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
-	$(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)bpftool \
-		   $(OUTPUT)/$(if $2,$2/)bpftool
-
-endef
-
-
-$(VERIFICATION_CERT) $(PRIVATE_KEY): $(VERIFY_SIG_SETUP)
+# One genkey run produces both files. A plain two-target rule is not
+# grouped - under -j make would run genkey twice concurrently and the
+# openssl invocations race; the pattern form is implicitly grouped even
+# with make < 4.3 (same workaround as the test_kmods rule).
+$(BUILD_DIR)/%.pem $(BUILD_DIR)/%.der: $(VERIFY_SIG_SETUP)
 	$(Q)mkdir -p $(BUILD_DIR)
 	$(Q)$(VERIFY_SIG_SETUP) genkey $(BUILD_DIR)
 
@@ -642,113 +369,192 @@ LIBARENA_BPF_DEPS := $(wildcard libarena/Makefile		\
 				 libarena/selftests/*		\
 				 libarena/*.bpf.o)
 
-
 $(LIBARENA_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS)
 	+$(MAKE) -C libarena libarena.skel.h $(LIBARENA_MAKE_ARGS)
 
-ifneq ($(CLANG_HAS_ARENA_ASAN),)
+libarena: $(LIBARENA_SKEL)
 
+ifneq ($(CLANG_HAS_ARENA_ASAN),)
 $(LIBARENA_ASAN_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS)
 	+$(MAKE) -C libarena libarena_asan.skel.h $(LIBARENA_MAKE_ARGS)
+
+libarena_asan: $(LIBARENA_ASAN_SKEL)
 endif
 
-# Define test_progs test runner.
-TRUNNER_TESTS_DIR := prog_tests
-TRUNNER_BPF_PROGS_DIR := progs
-TRUNNER_EXTRA_SOURCES := test_progs.c		\
-			 cgroup_helpers.c	\
-			 trace_helpers.c	\
-			 network_helpers.c	\
-			 testing_helpers.c	\
-			 btf_helpers.c		\
-			 cap_helpers.c		\
-			 unpriv_helpers.c 	\
-			 sysctl_helpers.c	\
-			 netlink_helpers.c	\
-			 jit_disasm_helpers.c	\
-			 io_helpers.c		\
-			 test_loader.c		\
-			 xsk.c			\
-			 disasm.c		\
-			 disasm_helpers.c	\
-			 json_writer.c 		\
-			 $(VERIFY_SIG_HDR)		\
-			 flow_dissector_load.h	\
-			 ip_check_defrag_frags.h	\
-			 bpftool_helpers.c	\
-			 usdt_1.c usdt_2.c	\
-			 $(LIBARENA_SKEL)	\
-			 $(LIBARENA_ASAN_SKEL)
-TRUNNER_LIB_SOURCES := find_bit.c
-TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read				\
-		       $(OUTPUT)/liburandom_read.so			\
-		       $(OUTPUT)/xdp_synproxy				\
-		       $(OUTPUT)/sign-file				\
-		       $(OUTPUT)/uprobe_multi				\
-		       $(TEST_KMOD_TARGETS)				\
-		       ima_setup.sh 					\
-		       $(VERIFY_SIG_SETUP)				\
-		       $(wildcard progs/btf_dump_test_case_*.c)		\
-		       $(wildcard progs/*.bpf.o)
-TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
-TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS) -DENABLE_ATOMICS_TESTS
-$(eval $(call DEFINE_TEST_RUNNER,test_progs))
-
-# Define test_progs-no_alu32 test runner.
-TRUNNER_BPF_BUILD_RULE := CLANG_NOALU32_BPF_BUILD_RULE
-TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS)
-$(eval $(call DEFINE_TEST_RUNNER,test_progs,no_alu32))
-
-# Define test_progs-cpuv4 test runner.
+# ---------------------------------------------------------------------
+# Generated test list headers
+# ---------------------------------------------------------------------
+
+define gen_tests_hdr
+	$(call msg,TEST-HDR,,$@)
+	$(Q)(echo '/* Generated header, do not edit */';		\
+	     sed -n -E 's/^void (serial_)?test_([a-zA-Z0-9_]+)\((void)?\).*/DEFINE_TEST(\2)/p' \
+		$(@D)/*.c | sort) > $@
+endef
+
+prog_tests/tests.h: $(wildcard prog_tests/*.c)
+	$(gen_tests_hdr)
+
+map_tests/tests.h: $(wildcard map_tests/*.c)
+	$(gen_tests_hdr)
+
+verifier/tests.h: verifier/*.c
+	$(Q)( cd verifier/; \
+	      echo '/* Generated header, do not edit */'; \
+	      echo '#ifdef FILL_ARRAY'; \
+	      ls *.c 2> /dev/null | sed -e 's@\(.*\)@#include \"\1\"@'; \
+	      echo '#endif' \
+	    ) > verifier/tests.h
+
+# ---------------------------------------------------------------------
+# Shared helper objects, used by the standalone binaries below and (as
+# prebuilt inputs) by the unflavored test_progs runner.
+# ---------------------------------------------------------------------
+
+# Some utility functions use LLVM libraries
+$(OUTPUT)/jit_disasm_helpers.o: CFLAGS += $(LLVM_CFLAGS)
+
+HELPER_OBJS := $(addprefix $(OUTPUT)/,testing_helpers.o cgroup_helpers.o \
+	       trace_helpers.o network_helpers.o json_writer.o		\
+	       cap_helpers.o unpriv_helpers.o usdt_1.o usdt_2.o xsk.o)
+
+# $(BPFTOOL) is a prerequisite because its sub-make is what installs
+# libbpf's internal headers (bpf/hashmap.h, bpf/libbpf_internal.h) into
+# $(INCLUDE_DIR); without it, helpers including those headers race the
+# install and can silently pick up the source-tree copies instead.
+#
+# Invariant: this list must be a superset of every prerequisite the
+# runner's EXTRA_OBJS rule attaches to these same objects (EXTRA_HDRS,
+# both tests.h flavors, $(BPFOBJ)). It guarantees the helpers built
+# here are never older than a runner-side prerequisite, so the
+# unflavored test_progs and test_maps sub-makes, which share $(OUTPUT),
+# treat them as up to date instead of both recompiling the same object
+# file concurrently.
+$(HELPER_OBJS): flow_dissector_load.h ip_check_defrag_frags.h		\
+		$(VERIFY_SIG_HDR) $(LIBARENA_SKEL) $(LIBARENA_ASAN_SKEL)\
+		prog_tests/tests.h map_tests/tests.h $(BPFOBJ) $(BPFTOOL)
+
+$(OUTPUT)/test_sockmap: $(OUTPUT)/cgroup_helpers.o $(OUTPUT)/testing_helpers.o
+$(OUTPUT)/test_tcpnotify_user: $(OUTPUT)/cgroup_helpers.o		\
+			       $(OUTPUT)/testing_helpers.o		\
+			       $(OUTPUT)/trace_helpers.o
+$(OUTPUT)/test_tag: $(OUTPUT)/testing_helpers.o
+$(OUTPUT)/test_lirc_mode2_user: $(OUTPUT)/testing_helpers.o
+$(OUTPUT)/flow_dissector_load: flow_dissector_load.h $(OUTPUT)/testing_helpers.o
+
+# ---------------------------------------------------------------------
+# Test runner instances, one sub-make each (see Makefile.runner).
+# ---------------------------------------------------------------------
+
+# The LLVM feature-probe results are exported to the runner sub-makes.
+# CC is passed explicitly instead: exporting it would also leak lib.mk's
+# CC into the libbpf/bpftool/resolve_btfids sub-builds, which compute
+# their own.
+export LLVM_CFLAGS LLVM_LDLIBS LLVM_LDFLAGS
+
+RUNNER_MAKE := $(MAKE) -f Makefile.runner OUTPUT=$(OUTPUT) CC='$(CC)'
+
+# Everything a runner instance references but does not know how to build.
+RUNNER_PREREQS := $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(BPFTOOL)		\
+		  $(TRUNNER_BPFTOOL) $(RESOLVE_BTFIDS)			\
+		  $(OUTPUT)/veristat					\
+		  $(VERIFY_SIG_HDR) $(PRIVATE_KEY) $(VERIFICATION_CERT)	\
+		  $(LIBARENA_SKEL) $(LIBARENA_ASAN_SKEL)		\
+		  prog_tests/tests.h					\
+		  $(HELPER_OBJS)					\
+		  $(OUTPUT)/urandom_read $(OUTPUT)/liburandom_read.so	\
+		  $(OUTPUT)/xdp_synproxy $(OUTPUT)/sign-file		\
+		  $(OUTPUT)/uprobe_multi $(TEST_KMOD_TARGETS)
+
+FORCE:
+
+# The default flavor's skeletons are also inputs of bench, test_maps,
+# xskxceiver, xdp_* and test_cpp; "default-skels" builds just those
+# without the test_progs test objects and binary.
+.PHONY: default-skels
+default-skels: $(RUNNER_PREREQS)
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR= TESTS_DIR=prog_tests \
+		BPF_BUILD=clang BPF_MCPU=v3 BPF_DEFINES=-DENABLE_ATOMICS_TESTS skels
+
+$(OUTPUT)/test_progs: $(RUNNER_PREREQS) default-skels FORCE
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR= TESTS_DIR=prog_tests \
+		BPF_BUILD=clang BPF_MCPU=v3 BPF_DEFINES=-DENABLE_ATOMICS_TESTS
+
+$(OUTPUT)/test_progs-no_alu32: $(RUNNER_PREREQS) FORCE
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR=no_alu32 TESTS_DIR=prog_tests \
+		BPF_BUILD=clang BPF_MCPU=v2
+
 ifneq ($(CLANG_CPUV4),)
-TRUNNER_BPF_BUILD_RULE := CLANG_CPUV4_BPF_BUILD_RULE
-TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS) -DENABLE_ATOMICS_TESTS
-$(eval $(call DEFINE_TEST_RUNNER,test_progs,cpuv4))
+$(OUTPUT)/test_progs-cpuv4: $(RUNNER_PREREQS) FORCE
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR=cpuv4 TESTS_DIR=prog_tests \
+		BPF_BUILD=clang BPF_MCPU=v4 BPF_DEFINES=-DENABLE_ATOMICS_TESTS
 endif
 
-# Define test_progs BPF-GCC-flavored test runner.
 ifneq ($(BPF_GCC),)
-TRUNNER_BPF_BUILD_RULE := GCC_BPF_BUILD_RULE
-TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(call get_sys_includes,gcc,)
-$(eval $(call DEFINE_TEST_RUNNER,test_progs,bpf_gcc))
+$(OUTPUT)/test_progs-bpf_gcc: $(RUNNER_PREREQS) FORCE
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR=bpf_gcc TESTS_DIR=prog_tests \
+		BPF_BUILD=gcc
 endif
 
-# Define test_maps test runner.
-TRUNNER_TESTS_DIR := map_tests
-TRUNNER_BPF_PROGS_DIR := progs
-TRUNNER_EXTRA_SOURCES := test_maps.c
-TRUNNER_LIB_SOURCES :=
-TRUNNER_EXTRA_FILES :=
-TRUNNER_BPF_BUILD_RULE := $$(error no BPF objects should be built)
-TRUNNER_BPF_CFLAGS :=
-$(eval $(call DEFINE_TEST_RUNNER,test_maps))
-
-# Define test_verifier test runner.
-# It is much simpler than test_maps/test_progs and sufficiently different from
-# them (e.g., test.h is using completely pattern), that it's worth just
-# explicitly defining all the rules explicitly.
-verifier/tests.h: verifier/*.c
-	$(shell ( cd verifier/; \
-		  echo '/* Generated header, do not edit */'; \
-		  echo '#ifdef FILL_ARRAY'; \
-		  ls *.c 2> /dev/null | sed -e 's@\(.*\)@#include \"\1\"@'; \
-		  echo '#endif' \
-		) > verifier/tests.h)
-$(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT)
+# test_maps compiles map_tests/*.c against the default flavor's skeletons
+$(OUTPUT)/test_maps: $(RUNNER_PREREQS) map_tests/tests.h default-skels FORCE
+	+$(Q)$(RUNNER_MAKE) RUNNER=test_maps FLAVOR= TESTS_DIR=map_tests \
+		BPF_BUILD=none
+
+# Default-flavor BPF objects and skeletons consumed by targets in this
+# Makefile (and by lib.mk's install rule) are produced by the runner
+# sub-make above; the empty recipe plus the order-only prerequisite
+# makes them available here without duplicating the runner's rules.
+DEFAULT_BPF_OBJS := $(patsubst progs/%.c,$(OUTPUT)/%.bpf.o,$(wildcard progs/*.c))
+TEST_GEN_FILES += $(DEFAULT_BPF_OBJS)
+
+BENCH_SKELS := $(addprefix $(OUTPUT)/,					\
+	       test_overhead.skel.h trigger_bench.skel.h		\
+	       ringbuf_bench.skel.h perfbuf_bench.skel.h		\
+	       bloom_filter_bench.skel.h bpf_loop_bench.skel.h		\
+	       strncmp_bench.skel.h bpf_hashmap_full_update_bench.skel.h\
+	       local_storage_bench.skel.h				\
+	       local_storage_rcu_tasks_trace_bench.skel.h		\
+	       bench_local_storage_create.skel.h			\
+	       bpf_hashmap_lookup.skel.h htab_mem_bench.skel.h		\
+	       crypto_bench.skel.h bench_sockmap_prog.skel.h		\
+	       lpm_trie_bench.skel.h lpm_trie_map.skel.h		\
+	       bpf_nop_bench.skel.h xdp_lb_bench.skel.h)
+TOP_SKELS := $(addprefix $(OUTPUT)/,xsk_xdp_progs.skel.h		\
+	     xdp_hw_metadata.skel.h xdp_features.skel.h			\
+	     test_core_extern.skel.h) $(BENCH_SKELS)
+
+# Empty-recipe delegation: "default-skels" (re)builds the file via the
+# runner sub-make, after which make re-stats the target, so dependents
+# see fresh timestamps within the same invocation. Dependents still
+# rebuild on mtime only - the phony prerequisite does not cascade.
+$(DEFAULT_BPF_OBJS) $(TOP_SKELS): default-skels ;
+
+# ---------------------------------------------------------------------
+# Standalone test binaries
+# ---------------------------------------------------------------------
+
+# test_verifier is much simpler than test_maps/test_progs and
+# sufficiently different from them (e.g., its tests.h uses a completely
+# different pattern), that it's worth just defining its rules explicitly.
+$(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ)	\
+			 $(OUTPUT)/testing_helpers.o			\
+			 $(OUTPUT)/cap_helpers.o			\
+			 $(OUTPUT)/unpriv_helpers.o
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
 # Include find_bit.c to compile xskxceiver.
 EXTRA_SRC := $(TOOLSDIR)/lib/find_bit.c prog_tests/test_xsk.c prog_tests/test_xsk.h
-$(OUTPUT)/xskxceiver: $(EXTRA_SRC) xskxceiver.c xskxceiver.h $(OUTPUT)/network_helpers.o $(OUTPUT)/xsk.o $(OUTPUT)/xsk_xdp_progs.skel.h $(BPFOBJ) | $(OUTPUT)
+$(OUTPUT)/xskxceiver: $(EXTRA_SRC) xskxceiver.c xskxceiver.h $(OUTPUT)/network_helpers.o $(OUTPUT)/xsk.o $(OUTPUT)/xsk_xdp_progs.skel.h $(BPFOBJ)
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
-$(OUTPUT)/xdp_hw_metadata: xdp_hw_metadata.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xsk.o $(OUTPUT)/xdp_hw_metadata.skel.h | $(OUTPUT)
+$(OUTPUT)/xdp_hw_metadata: xdp_hw_metadata.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xsk.o $(OUTPUT)/xdp_hw_metadata.skel.h
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
-$(OUTPUT)/xdp_features: xdp_features.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xdp_features.skel.h | $(OUTPUT)
+$(OUTPUT)/xdp_features: xdp_features.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xdp_features.skel.h
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
@@ -760,11 +566,18 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
 	$(call msg,CXX,,$@)
 	$(Q)$(CXX) $(CXXFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
 
-# Benchmark runner
-$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
+# ---------------------------------------------------------------------
+# Benchmark runner. The benchmark list is defined by the files in
+# benchs/: every benchs/bench_*.c is compiled and linked in.
+# ---------------------------------------------------------------------
+
+BENCH_OBJS := $(sort $(patsubst benchs/%.c,$(OUTPUT)/%.o,$(wildcard benchs/bench_*.c)))
+
+$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ) | default-skels
 	$(call msg,CC,,$@)
-	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
-		($(RM) $@; printf '  %-12s %s\n' 'SKIP-BENCH' '$(notdir $@)' 1>&2))
+	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) -o $@ $(call skip_on_fail,BENCH)
+
+# benchmark-specific generated-skeleton dependencies
 $(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h
 $(OUTPUT)/bench_trigger.o: $(OUTPUT)/trigger_bench.skel.h
 $(OUTPUT)/bench_ringbufs.o: $(OUTPUT)/ringbuf_bench.skel.h \
@@ -784,37 +597,19 @@ $(OUTPUT)/bench_lpm_trie_map.o: $(OUTPUT)/lpm_trie_bench.skel.h $(OUTPUT)/lpm_tr
 $(OUTPUT)/bench_bpf_nop.o: $(OUTPUT)/bpf_nop_bench.skel.h bench_bpf_timing.h
 $(OUTPUT)/bench_xdp_lb.o: $(OUTPUT)/xdp_lb_bench.skel.h bench_bpf_timing.h
 $(OUTPUT)/bench_bpf_timing.o: bench_bpf_timing.h
+
 $(OUTPUT)/bench.o: bench.h testing_helpers.h $(BPFOBJ)
 $(OUTPUT)/bench: LDLIBS += -lm
-$(OUTPUT)/bench: $(OUTPUT)/bench.o \
-		 $(TESTING_HELPERS) \
-		 $(TRACE_HELPERS) \
-		 $(CGROUP_HELPERS) \
-		 $(OUTPUT)/bench_count.o \
-		 $(OUTPUT)/bench_rename.o \
-		 $(OUTPUT)/bench_trigger.o \
-		 $(OUTPUT)/bench_ringbufs.o \
-		 $(OUTPUT)/bench_bloom_filter_map.o \
-		 $(OUTPUT)/bench_bpf_loop.o \
-		 $(OUTPUT)/bench_strncmp.o \
-		 $(OUTPUT)/bench_bpf_hashmap_full_update.o \
-		 $(OUTPUT)/bench_local_storage.o \
-		 $(OUTPUT)/bench_local_storage_rcu_tasks_trace.o \
-		 $(OUTPUT)/bench_bpf_hashmap_lookup.o \
-		 $(OUTPUT)/bench_local_storage_create.o \
-		 $(OUTPUT)/bench_htab_mem.o \
-		 $(OUTPUT)/bench_bpf_crypto.o \
-		 $(OUTPUT)/bench_sockmap.o \
-		 $(OUTPUT)/bench_lpm_trie_map.o \
-		 $(OUTPUT)/bench_bpf_timing.o \
-		 $(OUTPUT)/bench_bpf_nop.o \
-		 $(OUTPUT)/bench_xdp_lb.o \
-		 $(OUTPUT)/usdt_1.o \
-		 $(OUTPUT)/usdt_2.o \
-		 #
+$(OUTPUT)/bench: $(OUTPUT)/bench.o		\
+		 $(OUTPUT)/testing_helpers.o	\
+		 $(OUTPUT)/trace_helpers.o	\
+		 $(OUTPUT)/cgroup_helpers.o	\
+		 $(OUTPUT)/usdt_1.o		\
+		 $(OUTPUT)/usdt_2.o		\
+		 $(BENCH_OBJS)
 	$(call msg,BINARY,,$@)
-	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
-		($(RM) $@; printf '  %-12s %s\n' 'SKIP-LINK' '$(notdir $@) (some benchmarks may have been skipped)' 1>&2))
+	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ \
+		$(call skip_on_fail,LINK,,(some benchmarks may have been skipped))
 
 # This works around GCC warning about snprintf truncating strings like:
 #
@@ -826,13 +621,6 @@ $(OUTPUT)/veristat: $(OUTPUT)/veristat.o
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
 
-# Linking uprobe_multi can fail due to relocation overflows on mips.
-$(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot)
-$(OUTPUT)/uprobe_multi: uprobe_multi.c uprobe_multi.ld
-	$(call msg,BINARY,,$@)
-	$(Q)$(CC) $(CFLAGS) -Wl,-T,uprobe_multi.ld -O0 $(LDFLAGS) 	\
-		$(filter-out %.ld,$^) $(LDLIBS) -o $@
-
 EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)			\
 	prog_tests/tests.h map_tests/tests.h verifier/tests.h		\
 	feature bpftool $(TEST_KMOD_TARGETS)				\
@@ -842,7 +630,7 @@ EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)			\
 			       liburandom_read.so)			\
 	$(OUTPUT)/FEATURE-DUMP.selftests
 
-.PHONY: docs docs-clean
+.PHONY: docs docs-clean libarena libarena_asan
 
 # Delete partially updated (corrupted) files on error
 .DELETE_ON_ERROR:
@@ -869,9 +657,3 @@ override define INSTALL_RULE
 			$(INSTALL_PATH)/$$DIR;				  \
 	done
 endef
-
-libarena: $(LIBARENA_SKEL)
-
-ifneq ($(CLANG_HAS_ARENA_ASAN),)
-libarena_asan: $(LIBARENA_ASAN_SKEL)
-endif
diff --git a/tools/testing/selftests/bpf/Makefile.buildvars b/tools/testing/selftests/bpf/Makefile.buildvars
index 2a7efe6d1..ea975feef 100644
--- a/tools/testing/selftests/bpf/Makefile.buildvars
+++ b/tools/testing/selftests/bpf/Makefile.buildvars
@@ -62,6 +62,14 @@ SKIP_CRYPTO	?=
 BPF_STRICT_BUILD ?= 1
 PERMISSIVE := $(filter 0,$(BPF_STRICT_BUILD))
 
+# Permissive-mode recipe suffix: on failure, remove the target, emit a
+# SKIP marker and report success so the rest of the build continues.
+# $(1) - SKIP tag (BPF, TEST, BENCH, SKEL, LINK, ...)
+# $(2) - optional extra files to remove alongside the target
+# $(3) - optional note appended to the SKIP message
+skip_on_fail = $(if $(PERMISSIVE),|| { $(RM) $@ $(2); \
+	printf '  %-12s %s\n' 'SKIP-$(1)' '$(notdir $@)$(if $(3), $(3))' 1>&2; })
+
 # Kernel test modules; TEST_KMODS= on the command line disables them.
 TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
 	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
diff --git a/tools/testing/selftests/bpf/Makefile.runner b/tools/testing/selftests/bpf/Makefile.runner
new file mode 100644
index 000000000..63f3f19bd
--- /dev/null
+++ b/tools/testing/selftests/bpf/Makefile.runner
@@ -0,0 +1,316 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Build one BPF test-runner instance: test_progs, one of its flavors
+# (no_alu32, cpuv4, bpf_gcc), or test_maps.
+#
+# Each instance is an independent sub-make with its own output directory,
+# so everything here is written in plain make - no $$-escaping, no eval,
+# no per-flavor guards. This file is always invoked by the main Makefile,
+# never directly: all shared prerequisites (libbpf, bpftool, vmlinux.h,
+# veristat, helper objects, signing key, generated tests.h, extra
+# binaries) are built by the main Makefile *before* this one runs and are
+# referenced below as plain files.
+#
+# Parameters (all passed on the sub-make command line):
+#   OUTPUT      absolute path of the selftests output directory
+#   RUNNER      base binary name: test_progs | test_maps
+#   FLAVOR      flavor suffix: empty | no_alu32 | cpuv4 | bpf_gcc
+#   TESTS_DIR   directory with the test sources: prog_tests | map_tests
+#   BPF_BUILD   how to build progs/*.c BPF objects: clang | gcc | none
+#   BPF_MCPU    clang -mcpu= value: v2 | v3 | v4
+#   BPF_DEFINES extra defines for BPF objects (e.g. -DENABLE_ATOMICS_TESTS)
+#   CC          C compiler (as resolved by lib.mk in the main Makefile)
+#   LLVM_CFLAGS/LLVM_LDLIBS/LLVM_LDFLAGS
+#               results of the top-level LLVM feature probe
+
+include ../../../build/Build.include
+include ../../../scripts/Makefile.arch
+include ../../../scripts/Makefile.include
+
+# Same message helpers as ../lib.mk, which only the top level includes.
+ifeq ($(V),1)
+Q =
+msg =
+else
+Q = @
+msg = @printf '  %-8s%s %s%s\n' "$(1)" "$(if $(2), [$(2)])" "$(notdir $(3))" "$(if $(4), $(4))";
+MAKEFLAGS += --no-print-directory
+endif
+
+include Makefile.buildvars
+
+# Keep in sync with the CFLAGS/LDFLAGS additions in ../lib.mk.
+CFLAGS += -D_GNU_SOURCE=
+CFLAGS += -I$(srctree)/tools/testing/selftests
+CFLAGS += $(USERCFLAGS)
+LDFLAGS += $(USERLDFLAGS)
+ifneq ($(LLVM),)
+CFLAGS += -Wno-address-of-packed-member
+CFLAGS += -Wno-gnu-variable-sized-type-not-at-end
+endif
+
+BINARY := $(RUNNER)$(if $(FLAVOR),-$(FLAVOR))
+RDIR   := $(OUTPUT)$(if $(FLAVOR),/$(FLAVOR))
+
+all: $(OUTPUT)/$(BINARY)
+.PHONY: all
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR:
+
+# Permissive skip-on-failure of individual tests applies to test_progs and
+# its flavors only; test_maps uses strong cross-object references and keeps
+# strict semantics even when BPF_STRICT_BUILD=0.
+PERMISSIVE_TESTS := $(if $(filter test_progs,$(RUNNER)),$(PERMISSIVE))
+
+$(RDIR):
+	$(call msg,MKDIR,,$@)
+	$(Q)mkdir -p $@
+
+# ---------------------------------------------------------------------
+# Per-runner sources
+# ---------------------------------------------------------------------
+
+ifeq ($(RUNNER),test_progs)
+EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c		\
+		 network_helpers.c testing_helpers.c btf_helpers.c	\
+		 cap_helpers.c unpriv_helpers.c sysctl_helpers.c	\
+		 netlink_helpers.c jit_disasm_helpers.c io_helpers.c	\
+		 test_loader.c xsk.c disasm.c disasm_helpers.c		\
+		 json_writer.c bpftool_helpers.c usdt_1.c usdt_2.c
+LIB_SOURCES := find_bit.c
+EXTRA_HDRS := flow_dissector_load.h ip_check_defrag_frags.h		\
+	      $(VERIFY_SIG_HDR) $(LIBARENA_SKEL) $(LIBARENA_ASAN_SKEL)
+EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/liburandom_read.so	\
+	       $(OUTPUT)/xdp_synproxy $(OUTPUT)/sign-file		\
+	       $(OUTPUT)/uprobe_multi					\
+	       $(TEST_KMOD_TARGETS)					\
+	       ima_setup.sh $(VERIFY_SIG_SETUP)				\
+	       $(wildcard progs/btf_dump_test_case_*.c)			\
+	       $(wildcard progs/*.bpf.o)
+endif
+
+ifeq ($(RUNNER),test_maps)
+EXTRA_SOURCES := test_maps.c testing_helpers.c
+endif
+
+# Note on the unflavored runners, which share $(OUTPUT) with the main
+# Makefile: helper objects the main Makefile also uses (and lists in the
+# runner prerequisites) are already built and fresh when a runner starts,
+# so the rules below find them up to date and never write them. This
+# holds because the main Makefile's helper-object rule depends on a
+# superset of the prerequisites the EXTRA_OBJS rule uses here - keep
+# the two lists in sync (see the invariant comment there).
+
+TESTS_HDR := $(TESTS_DIR)/tests.h
+
+TEST_SRCS  := $(notdir $(wildcard $(TESTS_DIR)/*.c))
+TEST_OBJS  := $(patsubst %.c,$(RDIR)/%.test.o,$(TEST_SRCS))
+TEST_DEPS  := $(TEST_OBJS:.o=.d)
+EXTRA_OBJS := $(patsubst %.c,$(RDIR)/%.o,$(filter %.c,$(EXTRA_SOURCES)))
+LIB_OBJS   := $(patsubst %.c,$(RDIR)/%.o,$(LIB_SOURCES))
+
+# ---------------------------------------------------------------------
+# BPF objects and skeletons
+# ---------------------------------------------------------------------
+
+ifneq ($(BPF_BUILD),none)
+
+BPF_SRCS := $(notdir $(wildcard progs/*.c))
+BPF_OBJS := $(patsubst %.c,$(RDIR)/%.bpf.o,$(BPF_SRCS))
+
+# Which tests want a light skeleton is derived from the test sources
+# themselves: an '#include "foo.lskel.h"' line is the single source of
+# truth. Tests that include both foo.skel.h and foo.lskel.h get both.
+skel_includes = $(shell grep -rhoE '"[a-zA-Z0-9_]+\.$(1)"' prog_tests benchs map_tests *.c *.cpp 2>/dev/null)
+LSKEL_BASES := $(sort $(patsubst "%.lskel.h",%,$(call skel_includes,lskel.h)))
+SKEL_DEMANDED := $(sort $(patsubst "%.skel.h",%,$(call skel_includes,skel.h)))
+
+# Signing is not expressed in the include, so the signed subset stays
+# explicit.
+LSKELS_SIGNED := fentry_test fexit_test atomics
+
+# BPF objects that cannot have a regular skeleton, plus lskel-only tests
+# (light-skeleton users whose sources never include the .skel.h form).
+SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c \
+		  $(addsuffix .c,$(filter-out $(SKEL_DEMANDED),$(LSKEL_BASES)))
+
+# Skeletons made by linking multiple BPF objects together. The %-deps
+# mapping is the only hand-maintained metadata: it cannot be derived from
+# the sources.
+test_static_linked.skel.h-deps := test_static_linked1.bpf.o test_static_linked2.bpf.o
+linked_funcs.skel.h-deps := linked_funcs1.bpf.o linked_funcs2.bpf.o
+linked_vars.skel.h-deps := linked_vars1.bpf.o linked_vars2.bpf.o
+linked_maps.skel.h-deps := linked_maps1.bpf.o linked_maps2.bpf.o
+# In the subskeleton case, we want the test_subskeleton_lib.subskel.h file
+# but that's created as a side-effect of the skel.h generation.
+test_subskeleton.skel.h-deps := test_subskeleton_lib2.bpf.o test_subskeleton_lib.bpf.o test_subskeleton.bpf.o
+test_subskeleton_lib.skel.h-deps := test_subskeleton_lib2.bpf.o test_subskeleton_lib.bpf.o
+test_usdt.skel.h-deps := test_usdt.bpf.o test_usdt_multispec.bpf.o
+tracing_multi.skel.h-deps := tracing_multi_attach.bpf.o tracing_multi_check.bpf.o
+tracing_multi_module.skel.h-deps := tracing_multi_attach_module.bpf.o tracing_multi_check.bpf.o
+tracing_multi_intersect.skel.h-deps := tracing_multi_intersect_attach.bpf.o tracing_multi_check.bpf.o
+tracing_multi_session.skel.h-deps := tracing_multi_session_attach.bpf.o tracing_multi_check.bpf.o
+
+LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
+		linked_vars.skel.h linked_maps.skel.h			\
+		test_subskeleton.skel.h test_subskeleton_lib.skel.h	\
+		test_usdt.skel.h tracing_multi.skel.h			\
+		tracing_multi_module.skel.h				\
+		tracing_multi_intersect.skel.h				\
+		tracing_multi_session.skel.h
+LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
+
+SKELS := $(patsubst %.c,$(RDIR)/%.skel.h,				\
+	   $(filter-out $(SKEL_BLACKLIST) $(LINKED_BPF_SRCS),$(BPF_SRCS)))
+LSKELS_H        := $(patsubst %,$(RDIR)/%.lskel.h,$(filter-out $(LSKELS_SIGNED),$(LSKEL_BASES)))
+LSKELS_SIGNED_H := $(patsubst %,$(RDIR)/%.lskel.h,$(LSKELS_SIGNED))
+LINKED_SKELS_H  := $(addprefix $(RDIR)/,$(LINKED_SKELS))
+ALL_SKELS := $(SKELS) $(LSKELS_H) $(LSKELS_SIGNED_H) $(LINKED_SKELS_H)
+
+HEADERS_FOR_BPF_OBJS := $(wildcard $(BPFDIR)/*.bpf.h)			\
+			$(wildcard $(CURDIR)/libarena/include/*.[ch])	\
+			$(addprefix $(BPFDIR)/,	bpf_core_read.h		\
+						bpf_endian.h		\
+						bpf_helpers.h		\
+						bpf_tracing.h)
+
+# Per-source BPF compilation flag overrides ($<-CFLAGS / $<-$(FLAVOR)-CFLAGS).
+# GCC cannot disable "declaration of anonymous struct in parameter list"
+# warnings triggered by these (technically legal) test programs.
+progs/btf_dump_test_case_bitfields.c-bpf_gcc-CFLAGS := -Wno-error
+progs/btf_dump_test_case_namespacing.c-bpf_gcc-CFLAGS := -Wno-error
+progs/btf_dump_test_case_packing.c-bpf_gcc-CFLAGS := -Wno-error
+progs/btf_dump_test_case_padding.c-bpf_gcc-CFLAGS := -Wno-error
+progs/btf_dump_test_case_syntax.c-bpf_gcc-CFLAGS := -Wno-error
+
+ifeq ($(BPF_BUILD),gcc)
+BPF_CC_MSG := GCC-BPF
+# Note: sys includes come from the *host* gcc, not $(BPF_GCC) - bpf-gcc's
+# own search path lacks the host's asm-generic/ headers. Computed once
+# here: bpf_cc below is deferred and expands per compiled object.
+GCC_SYS_INCLUDES := $(call get_sys_includes,gcc,)
+bpf_cc = $(BPF_GCC) $(BPF_CFLAGS) $(GCC_SYS_INCLUDES)			\
+	 $(BPF_DEFINES) $($<-CFLAGS) $($<-$(FLAVOR)-CFLAGS)		\
+	 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -c $< -o $@
+else
+BPF_CC_MSG := CLNG-BPF
+bpf_cc = $(CLANG) $(BPF_CFLAGS) $(CLANG_CFLAGS) $(BPF_DEFINES)		\
+	 $($<-CFLAGS) $($<-$(FLAVOR)-CFLAGS)				\
+	 -O2 $(BPF_TARGET_ENDIAN) -c $< -mcpu=$(BPF_MCPU) -o $@
+endif
+
+$(BPF_OBJS): $(RDIR)/%.bpf.o: progs/%.c progs/*.h			\
+	     $(INCLUDE_DIR)/vmlinux.h $(HEADERS_FOR_BPF_OBJS)		\
+	     | $(RDIR) $(BPFOBJ)
+	$(call msg,$(BPF_CC_MSG),$(BINARY),$@)
+	$(Q)$(bpf_cc) $(call skip_on_fail,BPF)
+
+# gen_bpf_skel.sh picks the bpftool binary up from the environment.
+export BPFTOOL
+GEN_SKEL := ./gen_bpf_skel.sh
+
+$(SKELS): $(RDIR)/%.skel.h: $(RDIR)/%.bpf.o $(BPFTOOL) $(GEN_SKEL) | $(RDIR)
+	$(Q)$(GEN_SKEL) --tag '$(BINARY)' --name $* --infix linked	\
+		--skel $@ --subskel $(@:.skel.h=.subskel.h) $<		\
+		$(call skip_on_fail,SKEL,$(@:.skel.h=.subskel.h))
+
+$(LSKELS_H): $(RDIR)/%.lskel.h: $(RDIR)/%.bpf.o $(BPFTOOL) $(GEN_SKEL) | $(RDIR)
+	$(Q)$(GEN_SKEL) --tag '$(BINARY)' --name $*_lskel --infix llinked \
+		--lskel --skel $@ $< $(call skip_on_fail,SKEL)
+
+$(LSKELS_SIGNED_H): $(RDIR)/%.lskel.h: $(RDIR)/%.bpf.o $(BPFTOOL)	\
+		    $(GEN_SKEL) $(PRIVATE_KEY) $(VERIFICATION_CERT) | $(RDIR)
+	$(Q)$(GEN_SKEL) --tag '$(BINARY) (signed)' --name $*_lskel	\
+		--infix llinked						\
+		--sign '-S -k $(PRIVATE_KEY) -i $(VERIFICATION_CERT)'	\
+		--skel $@ $< $(call skip_on_fail,SKEL)
+
+.SECONDEXPANSION:
+$(LINKED_SKELS_H): $(RDIR)/%.skel.h: $$(addprefix $(RDIR)/,$$($$*.skel.h-deps)) \
+		   $(BPFTOOL) $(GEN_SKEL) | $(RDIR)
+	$(Q)$(GEN_SKEL) --tag '$(BINARY)' --name $* --infix linked	\
+		--skel $@ --subskel $(@:.skel.h=.subskel.h)		\
+		$(addprefix $(RDIR)/,$($*.skel.h-deps))			\
+		$(call skip_on_fail,SKEL,$(@:.skel.h=.subskel.h))
+
+endif # BPF_BUILD != none
+
+.PHONY: skels
+skels: $(ALL_SKELS)
+
+# When the compiler generates a %.d file, only skel basenames (not full
+# paths) are specified as prerequisites for the corresponding %.o file.
+# The vpath directives instruct make to also search for skel files in
+# $(RDIR) if they are not present in the working directory.
+vpath %.skel.h $(RDIR)
+vpath %.lskel.h $(RDIR)
+vpath %.subskel.h $(RDIR)
+
+# ---------------------------------------------------------------------
+# Test objects and runner binary
+# ---------------------------------------------------------------------
+
+$(RDIR)/resolve_btfids.test.o: $(RESOLVE_BTFIDS) $(RDIR)/btf_data.bpf.o
+$(RDIR)/resolve_btfids.test.o: private TEST_NEEDS_BTFIDS = 1
+
+# Compile individual test files.
+# Note: we cd into the output directory to ensure embedded BPF objects
+# are found. The %.test.d dependency files are a side effect of the -MMD
+# below; the separate no-recipe rule for them orders the first
+# compilation after skeleton generation and re-orders test object
+# compilation when headers change.
+$(TEST_OBJS): $(RDIR)/%.test.o: $(TESTS_DIR)/%.c | $(RDIR)/%.test.d
+	$(call msg,TEST-OBJ,$(BINARY),$@)
+	$(Q)(cd $(@D) && $(CC) -I. $(CFLAGS) -MMD -MT $@ -c $(CURDIR)/$< -o $(@F)) \
+		$(if $(PERMISSIVE_TESTS),$(call skip_on_fail,TEST))
+	$(if $(TEST_NEEDS_BTFIDS),					\
+		$(Q)if [ -f $@ ]; then					\
+		$(if $(filter 1,$(V)),true,printf '  %-8s%s %s\n' "BTFIDS" " [$(BINARY)]" "$(notdir $@)"); \
+		$(RESOLVE_BTFIDS) --btf $(RDIR)/btf_data.bpf.o $@;	\
+		$(RESOLVE_BTFIDS) --patch_btfids $@.BTF_ids $@;		\
+		fi)
+
+$(TEST_DEPS): $(RDIR)/%.test.d: $(TESTS_DIR)/%.c $(EXTRA_HDRS) $(BPFOBJ) \
+	      | $(RDIR) $(ALL_SKELS)
+
+include $(wildcard $(TEST_DEPS))
+
+$(RDIR)/jit_disasm_helpers.o: CFLAGS += $(LLVM_CFLAGS)
+
+$(EXTRA_OBJS): $(RDIR)/%.o: %.c $(EXTRA_HDRS) $(TESTS_HDR) $(BPFOBJ) | $(RDIR)
+	$(call msg,EXT-OBJ,$(BINARY),$@)
+	$(Q)$(CC) $(CFLAGS) -c $< -o $@
+
+$(LIB_OBJS): $(RDIR)/%.o: $(TOOLSDIR)/lib/%.c | $(RDIR)
+	$(call msg,LIB-OBJ,$(BINARY),$@)
+	$(Q)$(CC) $(CFLAGS) -c $< -o $@
+
+# Non-flavored in-srctree builds receive special treatment, in particular
+# we do not need to copy extra resources (see e.g. test_btf_dump_case()).
+.PHONY: extras
+extras: $(if $(PERMISSIVE),$(wildcard $(EXTRA_FILES)),$(EXTRA_FILES)) | $(RDIR)
+ifneq ($(FLAVOR):$(OUTPUT),:$(CURDIR))
+ifneq ($(strip $(EXTRA_FILES)),)
+	$(call msg,EXT-COPY,$(BINARY),$(notdir $(EXTRA_FILES)))
+	$(Q)rsync -aq $(if $(PERMISSIVE),--ignore-missing-args) $(EXTRA_FILES) $(RDIR)/
+endif
+endif
+
+# In permissive mode, link whatever test objects were successfully built
+# (their compilation may have been skipped); the wildcard in the recipe
+# picks up the survivors at link time.
+# Prerequisite order is also link order (test objects, extra objects,
+# libbpf, lib objects).
+$(OUTPUT)/$(BINARY): $(if $(PERMISSIVE_TESTS),,$(TEST_OBJS))		\
+		     $(EXTRA_OBJS) $(BPFOBJ) $(LIB_OBJS)		\
+		     $(TRUNNER_BPFTOOL) $(OUTPUT)/veristat		\
+		     | extras $(BPF_OBJS)				\
+		     $(if $(PERMISSIVE_TESTS),$(TEST_OBJS))
+	$(call msg,BINARY,,$@)
+	$(Q)$(CC) $(CFLAGS)						\
+		$(if $(PERMISSIVE_TESTS),$(wildcard $(TEST_OBJS)))	\
+		$(filter %.a %.o,$^)					\
+		$(LDLIBS) $(LLVM_LDLIBS) $(LDFLAGS) $(LLVM_LDFLAGS) -o $@
+	$(Q)ln -sf $(if $(FLAVOR),..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)bpftool \
+		   $(RDIR)/bpftool
-- 
2.43.0

Re: [RFC PATCH bpf-next v2 3/3] selftests/bpf: build each test runner instance in its own sub-make

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] In permissive mode, test objects are treated exclusively as order-only prerequisites, which completely breaks incremental test development by never relinking the test runner when test sources are modified.
--

--- Patch [3]: [RFC PATCH bpf-next v2 3/3] selftests/bpf: build each test runner instance in its own sub-make ---
commit f7cbf6f3b146270d8f7ba71d9ea0557ab2070208
Author: Mykola Lysenko <nickolay.lysenko@gmail.com>

selftests/bpf: build each test runner instance in its own sub-make

This commit refactors the bpf selftests build system to use a dedicated
Makefile.runner for each test runner instance, running them in separate
sub-makes. It aims to eliminate double-expansion complexity while fixing
parallel build races.

> diff --git a/tools/testing/selftests/bpf/Makefile.runner b/tools/testing/selftests/bpf/Makefile.runner
> new file mode 100644
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/Makefile.runner

[ ... ]

> +# In permissive mode, link whatever test objects were successfully built
> +# (their compilation may have been skipped); the wildcard in the recipe
> +# picks up the survivors at link time.
> +# Prerequisite order is also link order (test objects, extra objects,
> +# libbpf, lib objects).
> +$(OUTPUT)/$(BINARY): $(if $(PERMISSIVE_TESTS),,$(TEST_OBJS))		\
> +		     $(EXTRA_OBJS) $(BPFOBJ) $(LIB_OBJS)		\
> +		     $(TRUNNER_BPFTOOL) $(OUTPUT)/veristat		\
> +		     | extras $(BPF_OBJS)				\
> +		     $(if $(PERMISSIVE_TESTS),$(TEST_OBJS))

[Severity: Medium]
Will this break incremental test development in permissive mode?

By placing TEST_OBJS exclusively after the order-only prerequisite pipe (|)
when PERMISSIVE_TESTS is active, make is instructed to not rebuild the target
when the test objects are updated. 

If a developer modifies an existing test file while using BPF_STRICT_BUILD=0,
the test object will successfully recompile, but the test runner binary
(like test_progs) will not relink to include the new object. Does this cause
stale tests to be executed unknowingly?

> +	$(call msg,BINARY,,$@)
> +	$(Q)$(CC) $(CFLAGS)						\
> +		$(if $(PERMISSIVE_TESTS),$(wildcard $(TEST_OBJS)))	\
> +		$(filter %.a %.o,$^)					\
> +		$(LDLIBS) $(LLVM_LDLIBS) $(LDFLAGS) $(LLVM_LDFLAGS) -o $@
> +	$(Q)ln -sf $(if $(FLAVOR),..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)bpftool \
> +		   $(RDIR)/bpftool

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260721194111.334795-1-nickolay.lysenko@gmail.com?part=3

Re: [RFC PATCH bpf-next v2 2/3] selftests/bpf: move shared build definitions into Makefile.buildvars

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The variables TEST_KMODS and BPF_GCC are duplicated in both Makefile and Makefile.buildvars, creating a brittle maintenance hazard.
--

--- Patch [2]: [RFC PATCH bpf-next v2 2/3] selftests/bpf: move shared build definitions into Makefile.buildvars ---
commit 609eb873658507425701a592c055f112cedbb6b8
Author: Mykola Lysenko <nickolay.lysenko@gmail.com>

selftests/bpf: move shared build definitions into Makefile.buildvars

This commit moves toolchain, path, flag, and probe definitions from the main
Makefile into a new Makefile.buildvars file. This allows these definitions
to be included by multiple makefiles for running test instances in sub-makes.

> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 09e5be201afb5..2ddcb812dc85c 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
[ ... ]
> +# These probes gate the flavor list, which must be final before lib.mk is
> +# included; keep values consistent with Makefile.buildvars.
> +ifeq ($(origin BPF_GCC),undefined)
> +BPF_GCC := $(shell command -v bpf-gcc;)
>  endif
[ ... ]
> -TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
> +TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
>  	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko
[ ... ]
> diff --git a/tools/testing/selftests/bpf/Makefile.buildvars b/tools/testing/selftests/bpf/Makefile.buildvars
> new file mode 100644
> index 0000000000000..2a7efe6d1c795
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/Makefile.buildvars
[ ... ]
> +# Immediate (with an override-preserving guard): a plain ?= stays
> +# recursively expanded and would re-run 'command -v' on every expansion.
> +ifeq ($(origin BPF_GCC),undefined)
> +BPF_GCC		:= $(shell command -v bpf-gcc;)
> +endif
[ ... ]
> +# Kernel test modules; TEST_KMODS= on the command line disables them.
> +TEST_KMODS ?= bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
> +	bpf_test_modorder_y.ko bpf_test_rqspinlock.ko

[Severity: Medium]
Does keeping duplicate definitions of TEST_KMODS and BPF_GCC in both Makefile
and Makefile.buildvars create a maintenance hazard?

Since Makefile defines TEST_KMODS with "?=" before including
Makefile.buildvars, if a developer adds a new test module to
Makefile.buildvars but forgets to update Makefile, the new module won't
be built because the Makefile definition takes precedence and ignores the
update.

Could these definitions be consolidated into a single location to prevent
silent build failures from desynchronized lists?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260721194111.334795-1-nickolay.lysenko@gmail.com?part=2