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tools build: Correct bpf fixdep dependencies

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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])

I also need to tweak the assignment of the OUTPUT variable, so that
relative path builds work. For example, for 'make tools/lib/bpf', OUTPUT
is unset, and is usually treated as "cwd" -- but recursive make will
change cwd and so OUTPUT has a new meaning. For consistency, I ensure
OUTPUT is always an absolute path.

And $(Q) gets a backup definition in tools/build/Makefile.include,
because Makefile.include is sometimes included without
tools/build/Makefile, so the "quiet command" stuff doesn't actually work
consistently without it.

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@chromium.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20240715203325.3832977-4-briannorris@chromium.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Brian Norris 2024-07-15 13:32:44 -07:00 committed by Arnaldo Carvalho de Melo
parent ea974028a0
commit dbb2a7a986
3 changed files with 22 additions and 4 deletions
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12
tools/build/Makefile.include
View File

@ -1,8 +1,18 @@
# 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)
Q ?=
SILENT_MAKE = +$(Q)$(MAKE)
else
Q ?= @
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

1
tools/lib/bpf/.gitignore vendored
View File

@ -5,3 +5,4 @@ TAGS
tags
cscope.*
/bpf_helper_defs.h
fixdep

13
tools/lib/bpf/Makefile
View File

@ -108,6 +108,8 @@ MAKEOVERRIDES=
all:
OUTPUT ?= ./
OUTPUT := $(abspath $(OUTPUT))/
export srctree OUTPUT CC LD CFLAGS V
include $(srctree)/tools/build/Makefile.include
@ -141,7 +143,10 @@ all: fixdep
all_cmd: $(CMD_TARGETS) check
$(BPF_IN_SHARED): force $(BPF_GENERATED)
$(SHARED_OBJDIR) $(STATIC_OBJDIR):
$(Q)mkdir -p $@
$(BPF_IN_SHARED): force $(BPF_GENERATED) | $(SHARED_OBJDIR)
@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
(diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \
echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true
@ -151,9 +156,11 @@ $(BPF_IN_SHARED): force $(BPF_GENERATED)
@(test -f ../../include/uapi/linux/if_xdp.h -a -f ../../../include/uapi/linux/if_xdp.h && ( \
(diff -B ../../include/uapi/linux/if_xdp.h ../../../include/uapi/linux/if_xdp.h >/dev/null) || \
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
$(SILENT_MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= OUTPUT=$(SHARED_OBJDIR) $(SHARED_OBJDIR)fixdep
$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)"
$(BPF_IN_STATIC): force $(BPF_GENERATED)
$(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
@ -263,7 +270,7 @@ install_pkgconfig: $(PC_FILE)
install: install_lib install_pkgconfig install_headers
clean:
clean: fixdep-clean
$(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \
*~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_GENERATED) \
$(SHARED_OBJDIR) $(STATIC_OBJDIR) \