Merge branch 'install libbpf headers when using the library'

Quentin Monnet says:

====================

Libbpf is used at several locations in the repository. Most of the time,
the tools relying on it build the library in its own directory, and include
the headers from there. This works, but this is not the cleanest approach.
It generates objects outside of the directory of the tool which is being
built, and it also increases the risk that developers include a header file
internal to libbpf, which is not supposed to be exposed to user
applications.

This set adjusts all involved Makefiles to make sure that libbpf is built
locally (with respect to the tool's directory or provided build directory),
and by ensuring that "make install_headers" is run from libbpf's Makefile
to export user headers properly.

This comes at a cost: given that the libbpf was so far mostly compiled in
its own directory by the different components using it, compiling it once
would be enough for all those components. With the new approach, each
component compiles its own version. To mitigate this cost, efforts were
made to reuse the compiled library when possible:

- Make the bpftool version in samples/bpf reuse the library previously
  compiled for the selftests.
- Make the bpftool version in BPF selftests reuse the library previously
  compiled for the selftests.
- Similarly, make resolve_btfids in BPF selftests reuse the same compiled
  library.
- Similarly, make runqslower in BPF selftests reuse the same compiled
  library; and make it rely on the bpftool version also compiled from the
  selftests (instead of compiling its own version).
- runqslower, when compiled independently, needs its own version of
  bpftool: make them share the same compiled libbpf.

As a result:

- Compiling the samples/bpf should compile libbpf just once.
- Compiling the BPF selftests should compile libbpf just once.
- Compiling the kernel (with BTF support) should now lead to compiling
  libbpf twice: one for resolve_btfids, one for kernel/bpf/preload.
- Compiling runqslower individually should compile libbpf just once. Same
  thing for bpftool, resolve_btfids, and kernel/bpf/preload/iterators.

(Not accounting for the boostrap version of libbpf required by bpftool,
which was already placed under a dedicated .../boostrap/libbpf/ directory,
and for which the count remains unchanged.)

A few commits in the series also contain drive-by clean-up changes for
bpftool includes, samples/bpf/.gitignore, or test_bpftool_build.sh. Please
refer to individual commit logs for details.

v4:
  - Make the "libbpf_hdrs" dependency an order-only dependency in
    kernel/bpf/preload/Makefile, samples/bpf/Makefile, and
    tools/bpf/runqslower/Makefile. This is to avoid to unconditionally
    recompile the targets.
  - samples/bpf/.gitignore: prefix objects with a "/" to mark that we
    ignore them when at the root of the samples/bpf/ directory.
  - libbpf: add a commit to make "install_headers" depend on the header
    files, to avoid exporting again if the sources are older than the
    targets. This ensures that applications relying on those headers are
    not rebuilt unnecessarily.
  - bpftool: uncouple the copy of nlattr.h from libbpf target, to have it
    depend on the source header itself. By avoiding to reinstall this
    header every time, we avoid unnecessary builds of bpftool.
  - samples/bpf: Add a new commit to remove the FORCE dependency for
    libbpf, and replace it with a "$(wildcard ...)" on the .c/.h files in
    libbpf's directory. This is to avoid always recompiling libbpf/bpftool.
  - Adjust prefixes in commit subjects.

v3:
  - Remove order-only dependencies on $(LIBBPF_INCLUDE) (or equivalent)
    directories, given that they are created by libbpf's Makefile.
  - Add libbpf as a dependency for bpftool/resolve_btfids/runqslower when
    they are supposed to reuse a libbpf compiled previously. This is to
    avoid having several libbpf versions being compiled simultaneously in
    the same directory with parallel builds. Even if this didn't show up
    during tests, let's remain on the safe side.
  - kernel/bpf/preload/Makefile: Rename libbpf-hdrs (dash) dependency as
    libbpf_hdrs.
  - samples/bpf/.gitignore: Add bpftool/
  - samples/bpf/Makefile: Change "/bin/rm -rf" to "$(RM) -r".
  - samples/bpf/Makefile: Add missing slashes for $(LIBBPF_OUTPUT) and
    $(LIBBPF_DESTDIR) when buildling bpftool
  - samples/bpf/Makefile: Add a dependency to libbpf's headers for
    $(TRACE_HELPERS).
  - bpftool's Makefile: Use $(LIBBPF) instead of equivalent (but longer)
    $(LIBBPF_OUTPUT)libbpf.a
  - BPF iterators' Makefile: build bpftool in .output/bpftool (instead of
    .output/), add and clean up variables.
  - runqslower's Makefile: Add an explicit dependency on libbpf's headers
    to several objects. The dependency is not required (libbpf should have
    been compiled and so the headers exported through other dependencies
    for those targets), but they better mark the logical dependency and
    should help if exporting the headers changed in the future.
  - New commit to add an "install-bin" target to bpftool, to avoid
    installing bash completion when buildling BPF iterators and selftests.

v2: Declare an additional dependency on libbpf's headers for
    iterators/iterators.o in kernel/preload/Makefile to make sure that
    these headers are exported before we compile the object file (and not
    just before we link it).
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

13 files changed, 169 insertions, 78 deletions

diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
index 1951332dd15f..469d35e890eb 100644
--- a/kernel/bpf/preload/Makefile
+++ b/kernel/bpf/preload/Makefile
@@ -1,21 +1,36 @@
 # SPDX-License-Identifier: GPL-2.0
 
 LIBBPF_SRCS = $(srctree)/tools/lib/bpf/
-LIBBPF_A = $(obj)/libbpf.a
-LIBBPF_OUT = $(abspath $(obj))
+LIBBPF_OUT = $(abspath $(obj))/libbpf
+LIBBPF_A = $(LIBBPF_OUT)/libbpf.a
+LIBBPF_DESTDIR = $(LIBBPF_OUT)
+LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
 
 # Although not in use by libbpf's Makefile, set $(O) so that the "dummy" test
 # in tools/scripts/Makefile.include always succeeds when building the kernel
 # with $(O) pointing to a relative path, as in "make O=build bindeb-pkg".
-$(LIBBPF_A):
-	$(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
+$(LIBBPF_A): | $(LIBBPF_OUT)
+	$(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/   \
+		DESTDIR=$(LIBBPF_DESTDIR) prefix=			       \
+		$(LIBBPF_OUT)/libbpf.a install_headers
+
+libbpf_hdrs: $(LIBBPF_A)
+
+.PHONY: libbpf_hdrs
+
+$(LIBBPF_OUT):
+	$(call msg,MKDIR,$@)
+	$(Q)mkdir -p $@
 
 userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
-	-I $(srctree)/tools/lib/ -Wno-unused-result
+	-I $(LIBBPF_INCLUDE) -Wno-unused-result
 
 userprogs := bpf_preload_umd
 
 clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
+clean-files += $(LIBBPF_OUT) $(LIBBPF_DESTDIR)
+
+$(obj)/iterators/iterators.o: | libbpf_hdrs
 
 bpf_preload_umd-objs := iterators/iterators.o
 bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz
diff --git a/kernel/bpf/preload/iterators/Makefile b/kernel/bpf/preload/iterators/Makefile
index 28fa8c1440f4..b8bd60511227 100644
--- a/kernel/bpf/preload/iterators/Makefile
+++ b/kernel/bpf/preload/iterators/Makefile
@@ -1,18 +1,26 @@
 # SPDX-License-Identifier: GPL-2.0
 OUTPUT := .output
+abs_out := $(abspath $(OUTPUT))
+
 CLANG ?= clang
 LLC ?= llc
 LLVM_STRIP ?= llvm-strip
+
+TOOLS_PATH := $(abspath ../../../../tools)
+BPFTOOL_SRC := $(TOOLS_PATH)/bpf/bpftool
+BPFTOOL_OUTPUT := $(abs_out)/bpftool
 DEFAULT_BPFTOOL := $(OUTPUT)/sbin/bpftool
 BPFTOOL ?= $(DEFAULT_BPFTOOL)
-LIBBPF_SRC := $(abspath ../../../../tools/lib/bpf)
-BPFOBJ := $(OUTPUT)/libbpf.a
-BPF_INCLUDE := $(OUTPUT)
-INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../../../tools/lib)        \
-       -I$(abspath ../../../../tools/include/uapi)
+
+LIBBPF_SRC := $(TOOLS_PATH)/lib/bpf
+LIBBPF_OUTPUT := $(abs_out)/libbpf
+LIBBPF_DESTDIR := $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include
+BPFOBJ := $(LIBBPF_OUTPUT)/libbpf.a
+
+INCLUDES := -I$(OUTPUT) -I$(LIBBPF_INCLUDE) -I$(TOOLS_PATH)/include/uapi
 CFLAGS := -g -Wall
 
-abs_out := $(abspath $(OUTPUT))
 ifeq ($(V),1)
 Q =
 msg =
@@ -44,14 +52,18 @@ $(OUTPUT)/iterators.bpf.o: iterators.bpf.c $(BPFOBJ) | $(OUTPUT)
 		 -c $(filter %.c,$^) -o $@ &&				      \
 	$(LLVM_STRIP) -g $@
 
-$(OUTPUT):
+$(OUTPUT) $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
 	$(call msg,MKDIR,$@)
-	$(Q)mkdir -p $(OUTPUT)
+	$(Q)mkdir -p $@
 
-$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
+$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
 	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)			       \
-		    OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
+		    OUTPUT=$(abspath $(dir $@))/ prefix=		       \
+		    DESTDIR=$(LIBBPF_DESTDIR) $(abspath $@) install_headers
 
-$(DEFAULT_BPFTOOL):
-	$(Q)$(MAKE) $(submake_extras) -C ../../../../tools/bpf/bpftool			      \
-		    prefix= OUTPUT=$(abs_out)/ DESTDIR=$(abs_out) install
+$(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC)			       \
+		    OUTPUT=$(BPFTOOL_OUTPUT)/				       \
+		    LIBBPF_OUTPUT=$(LIBBPF_OUTPUT)/			       \
+		    LIBBPF_DESTDIR=$(LIBBPF_DESTDIR)/			       \
+		    prefix= DESTDIR=$(abs_out)/ install-bin
diff --git a/samples/bpf/.gitignore b/samples/bpf/.gitignore
index fcba217f0ae2..0e7bfdbff80a 100644
--- a/samples/bpf/.gitignore
+++ b/samples/bpf/.gitignore
@@ -57,3 +57,7 @@ testfile.img
 hbm_out.log
 iperf.*
 *.out
+*.skel.h
+/vmlinux.h
+/bpftool/
+/libbpf/
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index a5783749ec15..4c5ad15f8d28 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -61,7 +61,11 @@ tprogs-y += xdp_redirect
 tprogs-y += xdp_monitor
 
 # Libbpf dependencies
-LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
+LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
+LIBBPF_OUTPUT = $(abspath $(BPF_SAMPLES_PATH))/libbpf
+LIBBPF_DESTDIR = $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
+LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
 
 CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o
 TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o
@@ -200,7 +204,7 @@ TPROGS_CFLAGS += -Wstrict-prototypes
 
 TPROGS_CFLAGS += -I$(objtree)/usr/include
 TPROGS_CFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
-TPROGS_CFLAGS += -I$(srctree)/tools/lib/
+TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE)
 TPROGS_CFLAGS += -I$(srctree)/tools/include
 TPROGS_CFLAGS += -I$(srctree)/tools/perf
 TPROGS_CFLAGS += -DHAVE_ATTR_TEST=0
@@ -270,16 +274,27 @@ all:
 clean:
 	$(MAKE) -C ../../ M=$(CURDIR) clean
 	@find $(CURDIR) -type f -name '*~' -delete
+	@$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool
 
-$(LIBBPF): FORCE
+$(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
 # Fix up variables inherited from Kbuild that tools/ build system won't like
-	$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
-		LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(BPF_SAMPLES_PATH)/../../ O=
+	$(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
+		LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(BPF_SAMPLES_PATH)/../../ \
+		O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
+		$@ install_headers
 
 BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
-BPFTOOL := $(BPFTOOLDIR)/bpftool
-$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)
-	    $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../
+BPFTOOL_OUTPUT := $(abspath $(BPF_SAMPLES_PATH))/bpftool
+BPFTOOL := $(BPFTOOL_OUTPUT)/bpftool
+$(BPFTOOL): $(LIBBPF) $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
+	    $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \
+		OUTPUT=$(BPFTOOL_OUTPUT)/ \
+		LIBBPF_OUTPUT=$(LIBBPF_OUTPUT)/ \
+		LIBBPF_DESTDIR=$(LIBBPF_DESTDIR)/
+
+$(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
+	$(call msg,MKDIR,$@)
+	$(Q)mkdir -p $@
 
 $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
 	$(call filechk,offsets,__SYSCALL_NRS_H__)
@@ -311,6 +326,11 @@ verify_target_bpf: verify_cmds
 $(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
 $(src)/*.c: verify_target_bpf $(LIBBPF)
 
+libbpf_hdrs: $(LIBBPF)
+$(obj)/$(TRACE_HELPERS): | libbpf_hdrs
+
+.PHONY: libbpf_hdrs
+
 $(obj)/xdp_redirect_cpu_user.o: $(obj)/xdp_redirect_cpu.skel.h
 $(obj)/xdp_redirect_map_multi_user.o: $(obj)/xdp_redirect_map_multi.skel.h
 $(obj)/xdp_redirect_map_user.o: $(obj)/xdp_redirect_map.skel.h
@@ -369,7 +389,7 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x
 	$(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(SRCARCH) \
 		-Wno-compare-distinct-pointer-types -I$(srctree)/include \
 		-I$(srctree)/samples/bpf -I$(srctree)/tools/include \
-		-I$(srctree)/tools/lib $(CLANG_SYS_INCLUDES) \
+		-I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \
 		-c $(filter %.bpf.c,$^) -o $@
 
 LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map_multi.skel.h \
@@ -406,7 +426,7 @@ $(obj)/%.o: $(src)/%.c
 	@echo "  CLANG-bpf " $@
 	$(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \
 		-I$(obj) -I$(srctree)/tools/testing/selftests/bpf/ \
-		-I$(srctree)/tools/lib/ \
+		-I$(LIBBPF_INCLUDE) \
 		-D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \
 		-D__TARGET_ARCH_$(SRCARCH) -Wno-compare-distinct-pointer-types \
 		-Wno-gnu-variable-sized-type-not-at-end \
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 1fcf5b01a193..9c2d13c513f0 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -17,19 +17,23 @@ endif
 BPF_DIR = $(srctree)/tools/lib/bpf/
 
 ifneq ($(OUTPUT),)
-  LIBBPF_OUTPUT = $(OUTPUT)/libbpf/
-  LIBBPF_PATH = $(LIBBPF_OUTPUT)
-  BOOTSTRAP_OUTPUT = $(OUTPUT)/bootstrap/
+  _OUTPUT := $(OUTPUT)
 else
-  LIBBPF_OUTPUT =
-  LIBBPF_PATH = $(BPF_DIR)
-  BOOTSTRAP_OUTPUT = $(CURDIR)/bootstrap/
+  _OUTPUT := $(CURDIR)
 endif
+BOOTSTRAP_OUTPUT := $(_OUTPUT)/bootstrap/
+LIBBPF_OUTPUT := $(_OUTPUT)/libbpf/
+LIBBPF_DESTDIR := $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include
 
-LIBBPF = $(LIBBPF_PATH)libbpf.a
+LIBBPF = $(LIBBPF_OUTPUT)libbpf.a
 LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/
 LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a
 
+# We need to copy nlattr.h which is not otherwise exported by libbpf, but still
+# required by bpftool.
+LIBBPF_INTERNAL_HDRS := nlattr.h
+
 ifeq ($(BPFTOOL_VERSION),)
 BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
 endif
@@ -38,7 +42,13 @@ $(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT):
 	$(QUIET_MKDIR)mkdir -p $@
 
 $(LIBBPF): FORCE | $(LIBBPF_OUTPUT)
-	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) $(LIBBPF_OUTPUT)libbpf.a
+	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) \
+		DESTDIR=$(LIBBPF_DESTDIR) prefix= $(LIBBPF) install_headers
+
+$(LIBBPF_INCLUDE)/bpf/$(LIBBPF_INTERNAL_HDRS): \
+		$(addprefix $(BPF_DIR),$(LIBBPF_INTERNAL_HDRS)) $(LIBBPF)
+	$(call QUIET_INSTALL, bpf/$(notdir $@))
+	$(Q)install -m 644 -t $(LIBBPF_INCLUDE)/bpf/ $(BPF_DIR)$(notdir $@)
 
 $(LIBBPF_BOOTSTRAP): FORCE | $(LIBBPF_BOOTSTRAP_OUTPUT)
 	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \
@@ -60,10 +70,10 @@ CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers
 CFLAGS += $(filter-out -Wswitch-enum -Wnested-externs,$(EXTRA_WARNINGS))
 CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
 	-I$(if $(OUTPUT),$(OUTPUT),.) \
+	-I$(LIBBPF_INCLUDE) \
 	-I$(srctree)/kernel/bpf/ \
 	-I$(srctree)/tools/include \
 	-I$(srctree)/tools/include/uapi \
-	-I$(srctree)/tools/lib \
 	-I$(srctree)/tools/perf
 CFLAGS += -DBPFTOOL_VERSION='"$(BPFTOOL_VERSION)"'
 ifneq ($(EXTRA_CFLAGS),)
@@ -140,7 +150,7 @@ BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o g
 $(BOOTSTRAP_OBJS): $(LIBBPF_BOOTSTRAP)
 
 OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
-$(OBJS): $(LIBBPF)
+$(OBJS): $(LIBBPF) $(LIBBPF_INCLUDE)/bpf/$(LIBBPF_INTERNAL_HDRS)
 
 VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
 		     $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)	\
@@ -167,8 +177,7 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF)
 	$(QUIET_CLANG)$(CLANG) \
 		-I$(if $(OUTPUT),$(OUTPUT),.) \
 		-I$(srctree)/tools/include/uapi/ \
-		-I$(LIBBPF_PATH) \
-		-I$(srctree)/tools/lib \
+		-I$(LIBBPF_INCLUDE) \
 		-g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@
 
 $(OUTPUT)%.skel.h: $(OUTPUT)%.bpf.o $(BPFTOOL_BOOTSTRAP)
@@ -217,10 +226,12 @@ clean: $(LIBBPF)-clean $(LIBBPF_BOOTSTRAP)-clean feature-detect-clean
 	$(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpftool
 	$(Q)$(RM) -r -- $(OUTPUT)feature/
 
-install: $(OUTPUT)bpftool
+install-bin: $(OUTPUT)bpftool
 	$(call QUIET_INSTALL, bpftool)
 	$(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(prefix)/sbin
 	$(Q)$(INSTALL) $(OUTPUT)bpftool $(DESTDIR)$(prefix)/sbin/bpftool
+
+install: install-bin
 	$(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(bash_compdir)
 	$(Q)$(INSTALL) -m 0644 bash-completion/bpftool $(DESTDIR)$(bash_compdir)
 
@@ -247,6 +258,6 @@ zdep:
 	@if [ "$(feature-zlib)" != "1" ]; then echo "No zlib found"; exit 1 ; fi
 
 .SECONDARY:
-.PHONY: all FORCE clean install uninstall zdep
+.PHONY: all FORCE clean install-bin install uninstall zdep
 .PHONY: doc doc-clean doc-install doc-uninstall
 .DEFAULT_GOAL := all
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index cc835859465b..b2ffc18eafc1 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -18,7 +18,6 @@
 #include <sys/stat.h>
 #include <sys/mman.h>
 #include <bpf/btf.h>
-#include <bpf/bpf_gen_internal.h>
 
 #include "json_writer.h"
 #include "main.h"
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index a24ea7e26aa4..277d51c4c5d9 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -25,7 +25,6 @@
 #include <bpf/bpf.h>
 #include <bpf/btf.h>
 #include <bpf/libbpf.h>
-#include <bpf/bpf_gen_internal.h>
 #include <bpf/skel_internal.h>
 
 #include "cfg.h"
diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 08b75e314ae7..751643f860b2 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -29,25 +29,30 @@ BPFOBJ     := $(OUTPUT)/libbpf/libbpf.a
 LIBBPF_OUT := $(abspath $(dir $(BPFOBJ)))/
 SUBCMDOBJ  := $(OUTPUT)/libsubcmd/libsubcmd.a
 
+LIBBPF_DESTDIR := $(LIBBPF_OUT)
+LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)include
+
 BINARY     := $(OUTPUT)/resolve_btfids
 BINARY_IN  := $(BINARY)-in.o
 
 all: $(BINARY)
 
-$(OUTPUT) $(OUTPUT)/libbpf $(OUTPUT)/libsubcmd:
+$(OUTPUT) $(OUTPUT)/libsubcmd $(LIBBPF_OUT):
 	$(call msg,MKDIR,,$@)
 	$(Q)mkdir -p $(@)
 
 $(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
 	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
 
-$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/libbpf
-	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)  OUTPUT=$(LIBBPF_OUT) $(abspath $@)
+$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT)    \
+		    DESTDIR=$(LIBBPF_DESTDIR) prefix=			       \
+		    $(abspath $@) install_headers
 
 CFLAGS := -g \
           -I$(srctree)/tools/include \
           -I$(srctree)/tools/include/uapi \
-          -I$(LIBBPF_SRC) \
+          -I$(LIBBPF_INCLUDE) \
           -I$(SUBCMD_SRC)
 
 LIBS = -lelf -lz
@@ -65,7 +70,8 @@ $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
 clean_objects := $(wildcard $(OUTPUT)/*.o                \
                             $(OUTPUT)/.*.o.cmd           \
                             $(OUTPUT)/.*.o.d             \
-                            $(OUTPUT)/libbpf             \
+                            $(LIBBPF_OUT)                \
+                            $(LIBBPF_DESTDIR)            \
                             $(OUTPUT)/libsubcmd          \
                             $(OUTPUT)/resolve_btfids)
 
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index c6c3e613858a..716e6ad1864b 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -60,8 +60,8 @@
 #include <linux/rbtree.h>
 #include <linux/zalloc.h>
 #include <linux/err.h>
-#include <btf.h>
-#include <libbpf.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
 #include <parse-options.h>
 
 #define BTF_IDS_SECTION	".BTF_ids"
diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile
index 3818ec511fd2..bbd1150578f7 100644
--- a/tools/bpf/runqslower/Makefile
+++ b/tools/bpf/runqslower/Makefile
@@ -9,9 +9,9 @@ BPFTOOL ?= $(DEFAULT_BPFTOOL)
 LIBBPF_SRC := $(abspath ../../lib/bpf)
 BPFOBJ_OUTPUT := $(OUTPUT)libbpf/
 BPFOBJ := $(BPFOBJ_OUTPUT)libbpf.a
-BPF_INCLUDE := $(BPFOBJ_OUTPUT)
-INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../lib)        \
-       -I$(abspath ../../include/uapi)
+BPF_DESTDIR := $(BPFOBJ_OUTPUT)
+BPF_INCLUDE := $(BPF_DESTDIR)/include
+INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../include/uapi)
 CFLAGS := -g -Wall
 
 # Try to detect best kernel BTF source
@@ -33,7 +33,7 @@ endif
 
 .DELETE_ON_ERROR:
 
-.PHONY: all clean runqslower
+.PHONY: all clean runqslower libbpf_hdrs
 all: runqslower
 
 runqslower: $(OUTPUT)/runqslower
@@ -46,13 +46,15 @@ clean:
 	$(Q)$(RM) $(OUTPUT)runqslower
 	$(Q)$(RM) -r .output
 
+libbpf_hdrs: $(BPFOBJ)
+
 $(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(BPFOBJ)
 	$(QUIET_LINK)$(CC) $(CFLAGS) $^ -lelf -lz -o $@
 
 $(OUTPUT)/runqslower.o: runqslower.h $(OUTPUT)/runqslower.skel.h	      \
-			$(OUTPUT)/runqslower.bpf.o
+			$(OUTPUT)/runqslower.bpf.o | libbpf_hdrs
 
-$(OUTPUT)/runqslower.bpf.o: $(OUTPUT)/vmlinux.h runqslower.h
+$(OUTPUT)/runqslower.bpf.o: $(OUTPUT)/vmlinux.h runqslower.h | libbpf_hdrs
 
 $(OUTPUT)/%.skel.h: $(OUTPUT)/%.bpf.o | $(BPFTOOL)
 	$(QUIET_GEN)$(BPFTOOL) gen skeleton $< > $@
@@ -81,8 +83,10 @@ else
 endif
 
 $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(BPFOBJ_OUTPUT)
-	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(BPFOBJ_OUTPUT) $@
+	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(BPFOBJ_OUTPUT) \
+		    DESTDIR=$(BPFOBJ_OUTPUT) prefix= $(abspath $@) install_headers
 
-$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT)
+$(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT)
 	$(Q)$(MAKE) $(submake_extras) -C ../bpftool OUTPUT=$(BPFTOOL_OUTPUT)   \
-		    CC=$(HOSTCC) LD=$(HOSTLD)
+		    LIBBPF_OUTPUT=$(BPFOBJ_OUTPUT)			       \
+		    LIBBPF_DESTDIR=$(BPF_DESTDIR) CC=$(HOSTCC) LD=$(HOSTLD)
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 41e4f78dbad5..9c6804ca5b45 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -241,15 +241,24 @@ install_lib: all_cmd
 		$(call do_install_mkdir,$(libdir_SQ)); \
 		cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ)
 
-INSTALL_HEADERS = bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h \
-		  bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h		     \
-		  bpf_endian.h bpf_core_read.h skel_internal.h		     \
-		  libbpf_version.h
-
-install_headers: $(BPF_GENERATED)
-	$(call QUIET_INSTALL, headers)					     \
-		$(foreach hdr,$(INSTALL_HEADERS),			     \
-			$(call do_install,$(hdr),$(prefix)/include/bpf,644);)
+SRC_HDRS := bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h	     \
+	    bpf_helpers.h bpf_tracing.h bpf_endian.h bpf_core_read.h	     \
+	    skel_internal.h libbpf_version.h
+GEN_HDRS := $(BPF_GENERATED)
+
+INSTALL_PFX := $(DESTDIR)$(prefix)/include/bpf
+INSTALL_SRC_HDRS := $(addprefix $(INSTALL_PFX)/, $(SRC_HDRS))
+INSTALL_GEN_HDRS := $(addprefix $(INSTALL_PFX)/, $(notdir $(GEN_HDRS)))
+
+$(INSTALL_SRC_HDRS): $(INSTALL_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(prefix)/include/bpf,644)
+
+$(INSTALL_GEN_HDRS): $(INSTALL_PFX)/%.h: $(OUTPUT)%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(prefix)/include/bpf,644)
+
+install_headers: $(BPF_GENERATED) $(INSTALL_SRC_HDRS) $(INSTALL_GEN_HDRS)
 
 install_pkgconfig: $(PC_FILE)
 	$(call QUIET_INSTALL, $(PC_FILE)) \
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index c5c9a9f50d8d..498222543c37 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -122,12 +122,15 @@ 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
+RUNQSLOWER_OUTPUT := $(BUILD_DIR)/runqslower/
 
 VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
 		     $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)	\
@@ -152,7 +155,7 @@ $(notdir $(TEST_GEN_PROGS)						\
 # sort removes libbpf duplicates when not cross-building
 MAKE_DIRS := $(sort $(BUILD_DIR)/libbpf $(HOST_BUILD_DIR)/libbpf	       \
 	       $(HOST_BUILD_DIR)/bpftool $(HOST_BUILD_DIR)/resolve_btfids      \
-	       $(INCLUDE_DIR))
+	       $(RUNQSLOWER_OUTPUT) $(INCLUDE_DIR))
 $(MAKE_DIRS):
 	$(call msg,MKDIR,,$@)
 	$(Q)mkdir -p $@
@@ -181,11 +184,13 @@ $(OUTPUT)/test_stub.o: test_stub.c $(BPFOBJ)
 
 DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool
 
-$(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL)
-	$(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/runqslower	\
-		    OUTPUT=$(SCRATCH_DIR)/ VMLINUX_BTF=$(VMLINUX_BTF)   \
-		    BPFOBJ=$(BPFOBJ) BPF_INCLUDE=$(INCLUDE_DIR) &&	\
-		    cp $(SCRATCH_DIR)/runqslower $@
+$(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL) $(RUNQSLOWER_OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/runqslower	       \
+		    OUTPUT=$(RUNQSLOWER_OUTPUT) VMLINUX_BTF=$(VMLINUX_BTF)     \
+		    BPFTOOL_OUTPUT=$(BUILD_DIR)/bpftool/		       \
+		    BPFOBJ_OUTPUT=$(BUILD_DIR)/libbpf			       \
+		    BPFOBJ=$(BPFOBJ) BPF_INCLUDE=$(INCLUDE_DIR) &&	       \
+		    cp $(RUNQSLOWER_OUTPUT)runqslower $@
 
 TEST_GEN_PROGS_EXTENDED += $(DEFAULT_BPFTOOL)
 
@@ -209,7 +214,9 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)    \
 		    CC=$(HOSTCC) LD=$(HOSTLD)				       \
 		    EXTRA_CFLAGS='-g -O0'				       \
 		    OUTPUT=$(HOST_BUILD_DIR)/bpftool/			       \
-		    prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install
+		    LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/		       \
+		    LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/			       \
+		    prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install-bin
 
 all: docs
 
@@ -225,7 +232,7 @@ docs-clean:
 
 $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 	   ../../../include/uapi/linux/bpf.h                                   \
-	   | $(INCLUDE_DIR) $(BUILD_DIR)/libbpf
+	   | $(BUILD_DIR)/libbpf
 	$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \
 		    EXTRA_CFLAGS='-g -O0'				       \
 		    DESTDIR=$(SCRATCH_DIR) prefix= all install_headers
@@ -233,7 +240,7 @@ $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 ifneq ($(BPFOBJ),$(HOST_BPFOBJ))
 $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)                \
 	   ../../../include/uapi/linux/bpf.h                                   \
-	   | $(INCLUDE_DIR) $(HOST_BUILD_DIR)/libbpf
+	   | $(HOST_BUILD_DIR)/libbpf
 	$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR)                             \
 		    EXTRA_CFLAGS='-g -O0'				       \
 		    OUTPUT=$(HOST_BUILD_DIR)/libbpf/ CC=$(HOSTCC) LD=$(HOSTLD) \
@@ -258,6 +265,7 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids	\
 		       $(TOOLSDIR)/lib/str_error_r.c
 	$(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/resolve_btfids	\
 		CC=$(HOSTCC) LD=$(HOSTLD) AR=$(HOSTAR) \
+		LIBBPF_INCLUDE=$(HOST_INCLUDE_DIR) \
 		OUTPUT=$(HOST_BUILD_DIR)/resolve_btfids/ BPFOBJ=$(HOST_BPFOBJ)
 
 # Get Clang's default includes on this system, as opposed to those seen by
diff --git a/tools/testing/selftests/bpf/test_bpftool_build.sh b/tools/testing/selftests/bpf/test_bpftool_build.sh
index b03a87571592..1453a53ed547 100755
--- a/tools/testing/selftests/bpf/test_bpftool_build.sh
+++ b/tools/testing/selftests/bpf/test_bpftool_build.sh
@@ -90,6 +90,10 @@ echo -e "... through kbuild\n"
 
 if [ -f ".config" ] ; then
 	make_and_clean tools/bpf
+	## "make tools/bpf" sets $(OUTPUT) to ...tools/bpf/runqslower for
+	## runqslower, but the default (used for the "clean" target) is .output.
+	## Let's make sure we clean runqslower's directory properly.
+	make -C tools/bpf/runqslower OUTPUT=${KDIR_ROOT_DIR}/tools/bpf/runqslower/ clean
 
 	## $OUTPUT is overwritten in kbuild Makefile, and thus cannot be passed
 	## down from toplevel Makefile to bpftool's Makefile.