The dependencies in tools/lib/bpf/Makefile are incorrect. Before we recurse to build $(BPF_IN_STATIC), we need to build its 'fixdep' executable. I can't use the usual shortcut from Makefile.include: <target>: <sources> fixdep because its 'fixdep' target relies on $(OUTPUT), and $(OUTPUT) differs in the parent 'make' versus the child 'make' -- so I imitate it via open-coding. I tweak a few $(MAKE) invocations while I'm at it, because 1. I'm adding a new recursive make; and 2. these recursive 'make's print spurious lines about files that are "up to date" (which isn't normally a feature in Kbuild subtargets) or "jobserver not available" (see [1]) After this change, top-level builds result in an empty grep result from: $ grep 'cannot find fixdep' $(find tools/ -name '*.cmd') [1] https://www.gnu.org/software/make/manual/html_node/MAKE-Variable.html If we're not using $(MAKE) directly, then we need to use more '+'. Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> --- tools/build/Makefile.include | 10 +++++++++- tools/lib/bpf/Makefile | 6 +++++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/tools/build/Makefile.include b/tools/build/Makefile.include index 8dadaa0fbb43..c95e4773b826 100644 --- a/tools/build/Makefile.include +++ b/tools/build/Makefile.include @@ -1,8 +1,16 @@ # SPDX-License-Identifier: GPL-2.0-only build := -f $(srctree)/tools/build/Makefile.build dir=. obj +# More than just $(Q), we sometimes want to suppress all command output from a +# recursive make -- even the 'up to date' printout. +ifeq ($(V),1) + SILENT_MAKE = +$(Q)$(MAKE) +else + SILENT_MAKE = +$(Q)$(MAKE) --silent +endif + fixdep: - $(Q)$(MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= $(OUTPUT)fixdep + $(SILENT_MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= $(OUTPUT)fixdep fixdep-clean: $(Q)$(MAKE) -C $(srctree)/tools/build clean diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 2cf892774346..0743cf653615 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -153,7 +153,11 @@ $(BPF_IN_SHARED): force $(BPF_GENERATED) echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)" -$(BPF_IN_STATIC): force $(BPF_GENERATED) +$(STATIC_OBJDIR): + $(Q)mkdir -p $@ + +$(BPF_IN_STATIC): force $(BPF_GENERATED) | $(STATIC_OBJDIR) + $(SILENT_MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= OUTPUT=$(STATIC_OBJDIR) $(STATIC_OBJDIR)fixdep $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR) $(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h -- 2.45.2.803.g4e1b14247a-goog
