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  3. [PATCH v4 0/3] tools build: Incorrect fixdep dependencies
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[PATCH v4 3/3] tools build: Correct bpf fixdep dependencies

Brian Norris posted 3 patches 1 year, 5 months ago
[PATCH v4 3/3] tools build: Correct bpf fixdep dependencies
Posted by Brian Norris 1 year, 5 months ago 
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: Jiri Olsa <jolsa@kernel.org>
---

Changes in v4:
 - update tools/lib/bpf/.gitignore to exclude 'fixdep'
 - update tools/lib/bpf `make clean` target for fixdep
 - combine $(SHARED_OBJDIR) and $(STATIC_OBJDIR) rules

Changes in v3:
 - add Jiri's Acked-by

Changes in v2:
 - also fix libbpf shared library rules
 - ensure OUTPUT is always set, and always an absolute path
 - add backup $(Q) definition in tools/build/Makefile.include

 tools/build/Makefile.include | 12 +++++++++++-
 tools/lib/bpf/.gitignore     |  1 +
 tools/lib/bpf/Makefile       | 13 ++++++++++---
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/tools/build/Makefile.include b/tools/build/Makefile.include
index 8dadaa0fbb43..0e4de83400ac 100644
--- a/tools/build/Makefile.include
+++ b/tools/build/Makefile.include
@@ -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
diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
index 0da84cb9e66d..f02725b123b3 100644
--- a/tools/lib/bpf/.gitignore
+++ b/tools/lib/bpf/.gitignore
@@ -5,3 +5,4 @@ TAGS
 tags
 cscope.*
 /bpf_helper_defs.h
+fixdep
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 2cf892774346..1b22f0f37288 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -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)			     \
-- 
2.45.2.993.g49e7a77208-goog
Re: [PATCH v4 3/3] tools build: Correct bpf fixdep dependencies
Posted by Andrii Nakryiko 1 year, 5 months ago 
On Mon, Jul 15, 2024 at 1:37 PM Brian Norris <briannorris@chromium.org> wrote:
>
> 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: Jiri Olsa <jolsa@kernel.org>
> ---
>

LGTM

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

> Changes in v4:
>  - update tools/lib/bpf/.gitignore to exclude 'fixdep'
>  - update tools/lib/bpf `make clean` target for fixdep
>  - combine $(SHARED_OBJDIR) and $(STATIC_OBJDIR) rules
>
> Changes in v3:
>  - add Jiri's Acked-by
>
> Changes in v2:
>  - also fix libbpf shared library rules
>  - ensure OUTPUT is always set, and always an absolute path
>  - add backup $(Q) definition in tools/build/Makefile.include
>
>  tools/build/Makefile.include | 12 +++++++++++-
>  tools/lib/bpf/.gitignore     |  1 +
>  tools/lib/bpf/Makefile       | 13 ++++++++++---
>  3 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/tools/build/Makefile.include b/tools/build/Makefile.include
> index 8dadaa0fbb43..0e4de83400ac 100644
> --- a/tools/build/Makefile.include
> +++ b/tools/build/Makefile.include
> @@ -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
> diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
> index 0da84cb9e66d..f02725b123b3 100644
> --- a/tools/lib/bpf/.gitignore
> +++ b/tools/lib/bpf/.gitignore
> @@ -5,3 +5,4 @@ TAGS
>  tags
>  cscope.*
>  /bpf_helper_defs.h
> +fixdep
> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> index 2cf892774346..1b22f0f37288 100644
> --- a/tools/lib/bpf/Makefile
> +++ b/tools/lib/bpf/Makefile
> @@ -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)                            \
> --
> 2.45.2.993.g49e7a77208-goog
>
>

Patchew 2.1-devel-b67e4c2

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