[PATCH 0/5] kbuild: allow big modules to sub-divide Makefiles

[PATCH 0/5] kbuild: allow big modules to sub-divide Makefiles

[Masahiro Yamada]

Recently, Jani Nikula requests a better build system support
for drivers spanning multiple directories.
(better kbuild support for drivers spanning multiple directories?)

I implemented it, so please take a look at it.

Note:
The single targets do not work correctly.

The single targets have never worked correctly:

[1] For instance, "make drivers/foo/bar/baz.o" will descend into
    drivers/foo/bar/Makefile, which may not necessarily specify
    the build rule of baz.o

    It is possible for drivers/foo/Makefile having
        obj-$(CONFIG_BAZ) += bar/baz.o

[2] subdir-ccflags-y does not work.

    The single targets directly descend into the directory of
    that file resides.

    It missed subdir-ccflags-y if it is specifies in parent
    Makefiles.

Perhaps, I will have to manage correct implementation of single targets.



Masahiro Yamada (5):
  kbuild: treat an object as multi-used when $(foo-) is set
  kbuild: clean up modname calculation
  kbuild: rename cmd_ar_builtin to cmd_ar_no_sym
  kbuild: support composite objects spanning across multiple Makefiles
  drm: i915: hierachize Makefiles

 drivers/gpu/drm/i915/Makefile               | 126 ++------------------
 drivers/gpu/drm/i915/display/Makefile       |  64 ++++++++++
 drivers/gpu/drm/i915/gem/Makefile           |  27 +++++
 drivers/gpu/drm/i915/gem/selftests/Makefile |   3 +
 drivers/gpu/drm/i915/gt/Makefile            |  16 +++
 drivers/gpu/drm/i915/gvt/Makefile           |  32 ++++-
 drivers/gpu/drm/i915/selftests/Makefile     |   9 ++
 scripts/Makefile.build                      |  39 +++---
 scripts/Makefile.lib                        |  66 ++++++----
 9 files changed, 218 insertions(+), 164 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/gem/selftests/Makefile
 create mode 100644 drivers/gpu/drm/i915/selftests/Makefile

-- 
2.17.1

[PATCH 1/5] kbuild: treat an object as multi-used when $(foo-) is set

[Masahiro Yamada]

Currently, Kbuild treats an object as multi-used when any of
$(foo-objs), $(foo-y), $(foo-m) is set. It makes more sense to
check $(foo-) as well.

In the context of foo-$(CONFIG_FOO_FEATURE1), CONFIG_FOO_FEATURE1
could be unset.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 scripts/Makefile.lib | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 41c50f9461e5..0a540599823e 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -41,9 +41,9 @@ obj-m		:= $(filter-out %/, $(obj-m))
 # Subdirectories we need to descend into
 subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
 
-# if $(foo-objs), $(foo-y), or $(foo-m) exists, foo.o is a composite object
-multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
-multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))), $(m))))
+# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
+multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))), $(m))))
+multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))), $(m))))
 multi-used   := $(multi-used-y) $(multi-used-m)
 
 # $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
@@ -52,8 +52,8 @@ subdir-obj-y := $(filter %/built-in.a, $(obj-y))
 
 # Replace multi-part objects by their individual parts,
 # including built-in.a from subdirectories
-real-obj-y := $(foreach m, $(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
-real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))
+real-obj-y := $(foreach m, $(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
+real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))
 
 # DTB
 # If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
-- 
2.17.1

Re: [PATCH 1/5] kbuild: treat an object as multi-used when $(foo-) is set

[Masahiro Yamada]

On Tue, Aug 6, 2019 at 3:40 PM Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> Currently, Kbuild treats an object as multi-used when any of
> $(foo-objs), $(foo-y), $(foo-m) is set. It makes more sense to
> check $(foo-) as well.
>
> In the context of foo-$(CONFIG_FOO_FEATURE1), CONFIG_FOO_FEATURE1
> could be unset.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Only this patch applied for now.


> ---
>
>  scripts/Makefile.lib | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 41c50f9461e5..0a540599823e 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -41,9 +41,9 @@ obj-m         := $(filter-out %/, $(obj-m))
>  # Subdirectories we need to descend into
>  subdir-ym      := $(sort $(subdir-y) $(subdir-m))
>
> -# if $(foo-objs), $(foo-y), or $(foo-m) exists, foo.o is a composite object
> -multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
> -multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))), $(m))))
> +# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
> +multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))), $(m))))
> +multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))), $(m))))
>  multi-used   := $(multi-used-y) $(multi-used-m)
>
>  # $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
> @@ -52,8 +52,8 @@ subdir-obj-y := $(filter %/built-in.a, $(obj-y))
>
>  # Replace multi-part objects by their individual parts,
>  # including built-in.a from subdirectories
> -real-obj-y := $(foreach m, $(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
> -real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))
> +real-obj-y := $(foreach m, $(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
> +real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))
>
>  # DTB
>  # If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
> --
> 2.17.1
>


-- 
Best Regards
Masahiro Yamada

[PATCH 2/5] kbuild: clean up modname calculation

[Masahiro Yamada]

'multi-used' is used for computing the modname. Improve the code
readability by removing the .o suffix before the foreach loop.

I renamed multi-used-m to modules-multi.

No functional change intended.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 scripts/Makefile.build |  6 +++---
 scripts/Makefile.lib   | 15 +++++++++------
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 0d434d0afc0b..b0ff60ac0c42 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -460,11 +460,11 @@ endif
 quiet_cmd_link_multi-m = LD [M]  $@
       cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
 
-$(multi-used-m): FORCE
+$(modules-multi): FORCE
 	$(call if_changed,link_multi-m)
-$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
+$(call multi_depend, $(modules-multi), .o, -objs -y -m)
 
-targets += $(multi-used-m)
+targets += $(modules-multi)
 targets := $(filter-out $(PHONY), $(targets))
 
 # Add intermediate targets:
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 0a540599823e..e503f12e8e9c 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -41,10 +41,13 @@ obj-m		:= $(filter-out %/, $(obj-m))
 # Subdirectories we need to descend into
 subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
 
-# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
-multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))), $(m))))
-multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))), $(m))))
-multi-used   := $(multi-used-y) $(multi-used-m)
+# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo is multi-used
+multi-used-y := $(sort $(foreach m, $(patsubst %.o,%,$(obj-y)), $(if $(strip $($(m)-objs) $($(m)-y) $($(m)-)), $(m))))
+multi-used-m := $(sort $(foreach m, $(patsubst %.o,%,$(obj-m)), $(if $(strip $($(m)-objs) $($(m)-y) $($(m)-m) $($(m)-)), $(m))))
+
+modules-multi := $(addsuffix .o, $(multi-used-m))
+
+multi-used := $(multi-used-y) $(multi-used-m)
 
 # $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
 # tell kbuild to descend
@@ -90,14 +93,14 @@ lib-y		:= $(addprefix $(obj)/,$(lib-y))
 subdir-obj-y	:= $(addprefix $(obj)/,$(subdir-obj-y))
 real-obj-y	:= $(addprefix $(obj)/,$(real-obj-y))
 real-obj-m	:= $(addprefix $(obj)/,$(real-obj-m))
-multi-used-m	:= $(addprefix $(obj)/,$(multi-used-m))
+modules-multi	:= $(addprefix $(obj)/,$(modules-multi))
 subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
 
 # Finds the multi-part object the current object will be linked into.
 # If the object belongs to two or more multi-part objects, all of them are
 # concatenated with a colon separator.
 modname-multi = $(subst $(space),:,$(sort $(foreach m,$(multi-used),\
-		$(if $(filter $*.o, $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))),$(m:.o=)))))
+		$(if $(filter $*.o, $($(m)-objs) $($(m)-y) $($(m)-m)),$(m)))))
 
 modname = $(if $(modname-multi),$(modname-multi),$(basetarget))
 
-- 
2.17.1

[PATCH 3/5] kbuild: rename cmd_ar_builtin to cmd_ar_no_sym

[Masahiro Yamada]

In the next commit, I will re-use this for thin-archives of objects
liked into modules.

Rename cmd_ar_builtin to a more generic cmd_ar_no_sym.
(cmd_ar is already defined in scripts/Makefile.lib)

I removed unneeded ifdef builtin-target.

No functional change intended.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 scripts/Makefile.build | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index b0ff60ac0c42..68622cbdfda5 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -404,16 +404,14 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ;
 #
 # Rule to compile a set of .o files into one .a file (without symbol table)
 #
-ifdef builtin-target
 
-quiet_cmd_ar_builtin = AR      $@
-      cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
+quiet_cmd_ar_no_sym = AR      $@
+      cmd_ar_no_sym = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
 
 $(builtin-target): $(real-obj-y) FORCE
-	$(call if_changed,ar_builtin)
+	$(call if_changed,ar_no_sym)
 
 targets += $(builtin-target)
-endif # builtin-target
 
 #
 # Rule to create modules.order file
-- 
2.17.1

[PATCH 4/5] kbuild: support composite objects spanning across multiple Makefiles

[Masahiro Yamada]

For a module that consists of multiple objects, the Makefile typically
looks like this:

 obj-$(CONFIG_FOO)          += foo.o
 foo-y                      += foo-main.o
 foo-$(CONFIG_FOO_FEATURE1) += foo-feature1.o
 foo-$(CONFIG_FOO_FEATURE2) += foo-feature2.o

Since other Makefiles do not understand foo-y, all modules must have
a flat structure.

As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can
handle files that are spread over several sub-directories, but the
top Makefile of a module must specify everything.

Some modules (drm, fs, etc.) have grown quite big, and the current
limitation is getting more and more painful.

This commit allows modules to recurse into sub-directories. The
child Makefiles inherit composite object names from the parent.

TODO:
Add documentation for this syntax.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 scripts/Makefile.build | 27 ++++++++++++++++------
 scripts/Makefile.lib   | 51 +++++++++++++++++++++++++-----------------
 2 files changed, 51 insertions(+), 27 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 68622cbdfda5..cea2bb25787a 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -70,7 +70,7 @@ endif
 mod-targets := $(patsubst %.o, %.mod, $(obj-m))
 
 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
-	 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \
+	 $(if $(KBUILD_MODULES),$(obj-m) $(ar-m) $(mod-targets) $(modorder-target)) \
 	 $(subdir-ym) $(always)
 	@:
 
@@ -274,7 +274,10 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 	$(call if_changed_rule,cc_o_c)
 
 cmd_mod = { \
-	echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
+	echo $(if $($*-objs)$($*-y)$($*-m), \
+		$(foreach m, $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), \
+			$(if $(filter %.a, $(m)), $(shell $(AR) t $(m)), $(m))), \
+		$(@:.mod=.o)); \
 	$(cmd_undef_syms); \
 	} > $@
 
@@ -399,19 +402,24 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 # ---------------------------------------------------------------------------
 
 # To build objects in subdirs, we need to descend into the directories
-$(sort $(subdir-obj-y)): $(subdir-ym) ;
+$(sort $(subdir-obj-y) $(subdir-ar-m)): $(subdir-ym);
 
 #
 # Rule to compile a set of .o files into one .a file (without symbol table)
 #
 
-quiet_cmd_ar_no_sym = AR      $@
+quiet_cmd_ar_no_sym = AR $(quiet_modtag)  $@
       cmd_ar_no_sym = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
 
 $(builtin-target): $(real-obj-y) FORCE
 	$(call if_changed,ar_no_sym)
 
-targets += $(builtin-target)
+$(ar-m): part-of-module := y
+$(ar-m): FORCE
+	$(call if_changed,ar_no_sym)
+$(call multi_depend, $(ar-m), .a, -objs -y -m)
+
+targets += $(builtin-target) $(ar-m)
 
 #
 # Rule to create modules.order file
@@ -456,7 +464,7 @@ endif
 # module is turned into a multi object module, $^ will contain header file
 # dependencies recorded in the .*.cmd file.
 quiet_cmd_link_multi-m = LD [M]  $@
-      cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
+      cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ --whole-archive $(filter %.o %a,$^) --no-whole-archive
 
 $(modules-multi): FORCE
 	$(call if_changed,link_multi-m)
@@ -485,7 +493,12 @@ targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
 
 PHONY += $(subdir-ym)
 $(subdir-ym):
-	$(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
+	$(MAKE) $(build)=$@ \
+	need-builtin=$(if $(filter $@/built-in.a,$(subdir-obj-y)),1) \
+	multi-used2-y="$(sort $(foreach m, $(subdir-multi-used-y), \
+			$(if $(filter $@/,$(dir $(m))), $(notdir $m))))" \
+	multi-used2-m="$(sort $(foreach m, $(subdir-multi-used-m), \
+			$(if $(filter $@/,$(dir $(m))), $(notdir $m))))"
 
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index e503f12e8e9c..e4e4ed869cad 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -25,38 +25,44 @@ lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
 # and -m subdirs.  Just put -y's first.
 modorder	:= $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m:.o=.ko))
 
-# Handle objects in subdirs
-# ---------------------------------------------------------------------------
-# o if we encounter foo/ in $(obj-y), replace it by foo/built-in.a
-#   and add the directory to the list of dirs to descend into: $(subdir-y)
-# o if we encounter foo/ in $(obj-m), remove it from $(obj-m)
-#   and add the directory to the list of dirs to descend into: $(subdir-m)
-__subdir-y	:= $(patsubst %/,%,$(filter %/, $(obj-y)))
-subdir-y	+= $(__subdir-y)
-__subdir-m	:= $(patsubst %/,%,$(filter %/, $(obj-m)))
-subdir-m	+= $(__subdir-m)
-obj-y		:= $(patsubst %/, %/built-in.a, $(obj-y))
-obj-m		:= $(filter-out %/, $(obj-m))
+
+# Replace multi-part objects by their individual parts,
+# including built-in.a from subdirectories
+real-obj-y := $(foreach m, $(obj-y),$(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))), $($(m:.o=-objs)) $($(m:.o=-y)), $(m)))
+real-obj-y += $(foreach m, $(multi-used2-y),$(if $(strip $($(m)-objs) $($(m)-y) $($(m)-)),$($(m)-objs) $($(m)-y)))
+real-obj-m := $(foreach m, $(obj-m),$(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)), $(m)))
+real-obj-m += $(foreach m, $(multi-used2-m),$(if $(strip $($(m)-objs) $($(m)-y) $($(m)-m) $($(m)-)), $($(m)-objs) $($(m)-y) $($(m)-m)))
+
+# all objects and thin archives combined into built-in.a in this directory
 
 # Subdirectories we need to descend into
-subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
+subdir-ym := $(sort $(subdir-y) $(subdir-m) \
+		$(patsubst %/,%,$(filter %/,$(real-obj-y) $(real-obj-m))))
+
+real-obj-y := $(patsubst %/, %/built-in.a, $(real-obj-y))
+subdir-obj-y := $(filter %/built-in.a, $(real-obj-y))
+
+obj-m 	   := $(filter-out %/, $(obj-m))
+real-obj-m := $(filter-out %/, $(real-obj-m))
 
 # If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo is multi-used
 multi-used-y := $(sort $(foreach m, $(patsubst %.o,%,$(obj-y)), $(if $(strip $($(m)-objs) $($(m)-y) $($(m)-)), $(m))))
 multi-used-m := $(sort $(foreach m, $(patsubst %.o,%,$(obj-m)), $(if $(strip $($(m)-objs) $($(m)-y) $($(m)-m) $($(m)-)), $(m))))
 
 modules-multi := $(addsuffix .o, $(multi-used-m))
+ar-m          := $(addsuffix .a, $(multi-used2-m))
+
+multi-used-y += $(multi-used2-y)
+multi-used-m += $(multi-used2-m)
 
 multi-used := $(multi-used-y) $(multi-used-m)
 
-# $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
-# tell kbuild to descend
-subdir-obj-y := $(filter %/built-in.a, $(obj-y))
+# multi-used (composite) objects propagated to sub-directories
+subdir-multi-used-y := $(foreach m, $(multi-used-y), $(addsuffix $(m), $(filter %/, $($(m)-objs) $($(m)-y))))
+subdir-multi-used-m := $(foreach m, $(multi-used-m), $(addsuffix $(m), $(filter %/, $($(m)-objs) $($(m)-y) $($(m)-m))))
 
-# Replace multi-part objects by their individual parts,
-# including built-in.a from subdirectories
-real-obj-y := $(foreach m, $(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
-real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)) $($(m:.o=-))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))
+$(foreach m, $(patsubst %.o,%,$(multi-used-m) $(multi-used2-m)), $(foreach s, -objs -y -m, \
+	$(eval $(m)$(s) := $(patsubst %/,%/$(m).a, $($(m)$(s))))))
 
 # DTB
 # If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
@@ -95,6 +101,11 @@ real-obj-y	:= $(addprefix $(obj)/,$(real-obj-y))
 real-obj-m	:= $(addprefix $(obj)/,$(real-obj-m))
 modules-multi	:= $(addprefix $(obj)/,$(modules-multi))
 subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
+ar-m		:= $(addprefix $(obj)/,$(ar-m))
+subdir-multi-used-y := $(addprefix $(obj)/,$(subdir-multi-used-y))
+subdir-multi-used-m := $(addprefix $(obj)/,$(subdir-multi-used-m))
+
+subdir-ar-m	:= $(addsuffix .a, $(subdir-multi-used-m))
 
 # Finds the multi-part object the current object will be linked into.
 # If the object belongs to two or more multi-part objects, all of them are
-- 
2.17.1

[PATCH 5/5] drm: i915: hierachize Makefiles

[Masahiro Yamada]

You can use the <modname>-y syntax in sub-directory Makefiles
of modules.

Demonstrate how it works.

PLEASE DO NOT APPLY FOR NOW: this is only for comments.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 drivers/gpu/drm/i915/Makefile               | 126 ++------------------
 drivers/gpu/drm/i915/display/Makefile       |  64 ++++++++++
 drivers/gpu/drm/i915/gem/Makefile           |  27 +++++
 drivers/gpu/drm/i915/gem/selftests/Makefile |   3 +
 drivers/gpu/drm/i915/gt/Makefile            |  16 +++
 drivers/gpu/drm/i915/gvt/Makefile           |  32 ++++-
 drivers/gpu/drm/i915/selftests/Makefile     |   9 ++
 7 files changed, 153 insertions(+), 124 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/gem/selftests/Makefile
 create mode 100644 drivers/gpu/drm/i915/selftests/Makefile

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 8cace65f50ce..6319c670bfb8 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -63,56 +63,16 @@ i915-y += \
 	i915_user_extensions.o
 
 i915-$(CONFIG_COMPAT)   += i915_ioc32.o
-i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o display/intel_pipe_crc.o
+i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o
 i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o
 
 # "Graphics Technology" (aka we talk to the gpu)
-obj-y += gt/
-gt-y += \
-	gt/intel_breadcrumbs.o \
-	gt/intel_context.o \
-	gt/intel_engine_cs.o \
-	gt/intel_engine_pm.o \
-	gt/intel_gt_pm.o \
-	gt/intel_hangcheck.o \
-	gt/intel_lrc.o \
-	gt/intel_reset.o \
-	gt/intel_ringbuffer.o \
-	gt/intel_mocs.o \
-	gt/intel_sseu.o \
-	gt/intel_workarounds.o
-gt-$(CONFIG_DRM_I915_SELFTEST) += \
-	gt/mock_engine.o
-i915-y += $(gt-y)
+i915-y += gt/
 
 # GEM (Graphics Execution Management) code
-obj-y += gem/
-gem-y += \
-	gem/i915_gem_busy.o \
-	gem/i915_gem_clflush.o \
-	gem/i915_gem_client_blt.o \
-	gem/i915_gem_context.o \
-	gem/i915_gem_dmabuf.o \
-	gem/i915_gem_domain.o \
-	gem/i915_gem_execbuffer.o \
-	gem/i915_gem_fence.o \
-	gem/i915_gem_internal.o \
-	gem/i915_gem_object.o \
-	gem/i915_gem_object_blt.o \
-	gem/i915_gem_mman.o \
-	gem/i915_gem_pages.o \
-	gem/i915_gem_phys.o \
-	gem/i915_gem_pm.o \
-	gem/i915_gem_shmem.o \
-	gem/i915_gem_shrinker.o \
-	gem/i915_gem_stolen.o \
-	gem/i915_gem_throttle.o \
-	gem/i915_gem_tiling.o \
-	gem/i915_gem_userptr.o \
-	gem/i915_gem_wait.o \
-	gem/i915_gemfs.o
+i915-y += gem/
+
 i915-y += \
-	  $(gem-y) \
 	  i915_active.o \
 	  i915_cmd_parser.o \
 	  i915_gem_batch_pool.o \
@@ -148,78 +108,11 @@ i915-y += intel_renderstate_gen6.o \
 	  intel_renderstate_gen8.o \
 	  intel_renderstate_gen9.o
 
-# modesetting core code
-obj-y += display/
-i915-y += \
-	display/intel_atomic.o \
-	display/intel_atomic_plane.o \
-	display/intel_audio.o \
-	display/intel_bios.o \
-	display/intel_bw.o \
-	display/intel_cdclk.o \
-	display/intel_color.o \
-	display/intel_combo_phy.o \
-	display/intel_connector.o \
-	display/intel_display.o \
-	display/intel_display_power.o \
-	display/intel_dpio_phy.o \
-	display/intel_dpll_mgr.o \
-	display/intel_fbc.o \
-	display/intel_fifo_underrun.o \
-	display/intel_frontbuffer.o \
-	display/intel_hdcp.o \
-	display/intel_hotplug.o \
-	display/intel_lpe_audio.o \
-	display/intel_overlay.o \
-	display/intel_psr.o \
-	display/intel_quirks.o \
-	display/intel_sprite.o
-i915-$(CONFIG_ACPI) += \
-	display/intel_acpi.o \
-	display/intel_opregion.o
-i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
-	display/intel_fbdev.o
-
-# modesetting output/encoder code
-i915-y += \
-	display/dvo_ch7017.o \
-	display/dvo_ch7xxx.o \
-	display/dvo_ivch.o \
-	display/dvo_ns2501.o \
-	display/dvo_sil164.o \
-	display/dvo_tfp410.o \
-	display/icl_dsi.o \
-	display/intel_crt.o \
-	display/intel_ddi.o \
-	display/intel_dp.o \
-	display/intel_dp_aux_backlight.o \
-	display/intel_dp_link_training.o \
-	display/intel_dp_mst.o \
-	display/intel_dsi.o \
-	display/intel_dsi_dcs_backlight.o \
-	display/intel_dsi_vbt.o \
-	display/intel_dvo.o \
-	display/intel_gmbus.o \
-	display/intel_hdmi.o \
-	display/intel_lspcon.o \
-	display/intel_lvds.o \
-	display/intel_panel.o \
-	display/intel_sdvo.o \
-	display/intel_tv.o \
-	display/intel_vdsc.o \
-	display/vlv_dsi.o \
-	display/vlv_dsi_pll.o
+i915-y += display/
 
 # Post-mortem debug and GPU hang state capture
 i915-$(CONFIG_DRM_I915_CAPTURE_ERROR) += i915_gpu_error.o
-i915-$(CONFIG_DRM_I915_SELFTEST) += \
-	gem/selftests/igt_gem_utils.o \
-	selftests/i915_random.o \
-	selftests/i915_selftest.o \
-	selftests/igt_flush_test.o \
-	selftests/igt_live_test.o \
-	selftests/igt_reset.o \
-	selftests/igt_spinner.o
+i915-$(CONFIG_DRM_I915_SELFTEST) += selftests/
 
 # virtual gpu code
 i915-y += i915_vgpu.o
@@ -241,10 +134,7 @@ i915-y += i915_perf.o \
 	  i915_oa_cnl.o \
 	  i915_oa_icl.o
 
-ifeq ($(CONFIG_DRM_I915_GVT),y)
-i915-y += intel_gvt.o
-include $(src)/gvt/Makefile
-endif
+i915-$(CONFIG_DRM_I915_GVT) += intel_gvt.o gvt/
 
 obj-$(CONFIG_DRM_I915) += i915.o
-obj-$(CONFIG_DRM_I915_GVT_KVMGT) += gvt/kvmgt.o
+obj-$(CONFIG_DRM_I915_GVT_KVMGT) += gvt/
diff --git a/drivers/gpu/drm/i915/display/Makefile b/drivers/gpu/drm/i915/display/Makefile
index 1c75b5c9790c..1fd26c5e68b5 100644
--- a/drivers/gpu/drm/i915/display/Makefile
+++ b/drivers/gpu/drm/i915/display/Makefile
@@ -1,2 +1,66 @@
 # Extra header tests
 include $(src)/Makefile.header-test
+
+i915-$(CONFIG_DEBUG_FS) += \
+	intel_pipe_crc.o
+
+# modesetting core code
+i915-y += \
+	intel_atomic.o \
+	intel_atomic_plane.o \
+	intel_audio.o \
+	intel_bios.o \
+	intel_bw.o \
+	intel_cdclk.o \
+	intel_color.o \
+	intel_combo_phy.o \
+	intel_connector.o \
+	intel_display.o \
+	intel_display_power.o \
+	intel_dpio_phy.o \
+	intel_dpll_mgr.o \
+	intel_fbc.o \
+	intel_fifo_underrun.o \
+	intel_frontbuffer.o \
+	intel_hdcp.o \
+	intel_hotplug.o \
+	intel_lpe_audio.o \
+	intel_overlay.o \
+	intel_psr.o \
+	intel_quirks.o \
+	intel_sprite.o
+i915-$(CONFIG_ACPI) += \
+	intel_acpi.o \
+	intel_opregion.o
+i915-$(CONFIG_DRM_FBDEV_EMULATION) += \
+	intel_fbdev.o
+
+# modesetting output/encoder code
+i915-y += \
+	dvo_ch7017.o \
+	dvo_ch7xxx.o \
+	dvo_ivch.o \
+	dvo_ns2501.o \
+	dvo_sil164.o \
+	dvo_tfp410.o \
+	icl_dsi.o \
+	intel_crt.o \
+	intel_ddi.o \
+	intel_dp.o \
+	intel_dp_aux_backlight.o \
+	intel_dp_link_training.o \
+	intel_dp_mst.o \
+	intel_dsi.o \
+	intel_dsi_dcs_backlight.o \
+	intel_dsi_vbt.o \
+	intel_dvo.o \
+	intel_gmbus.o \
+	intel_hdmi.o \
+	intel_lspcon.o \
+	intel_lvds.o \
+	intel_panel.o \
+	intel_sdvo.o \
+	intel_tv.o \
+	intel_vdsc.o \
+	vlv_dsi.o \
+	vlv_dsi_pll.o
diff --git a/drivers/gpu/drm/i915/gem/Makefile b/drivers/gpu/drm/i915/gem/Makefile
index 07e7b8b840ea..1d9da1287bef 100644
--- a/drivers/gpu/drm/i915/gem/Makefile
+++ b/drivers/gpu/drm/i915/gem/Makefile
@@ -1 +1,28 @@
 include $(src)/Makefile.header-test # Extra header tests
+
+i915-y += \
+	i915_gem_busy.o \
+	i915_gem_clflush.o \
+	i915_gem_client_blt.o \
+	i915_gem_context.o \
+	i915_gem_dmabuf.o \
+	i915_gem_domain.o \
+	i915_gem_execbuffer.o \
+	i915_gem_fence.o \
+	i915_gem_internal.o \
+	i915_gem_object.o \
+	i915_gem_object_blt.o \
+	i915_gem_mman.o \
+	i915_gem_pages.o \
+	i915_gem_phys.o \
+	i915_gem_pm.o \
+	i915_gem_shmem.o \
+	i915_gem_shrinker.o \
+	i915_gem_stolen.o \
+	i915_gem_throttle.o \
+	i915_gem_tiling.o \
+	i915_gem_userptr.o \
+	i915_gem_wait.o \
+	i915_gemfs.o
+
+i915-$(CONFIG_DRM_I915_SELFTEST) += selftests/
diff --git a/drivers/gpu/drm/i915/gem/selftests/Makefile b/drivers/gpu/drm/i915/gem/selftests/Makefile
new file mode 100644
index 000000000000..80f96f51b623
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/selftests/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+i915-y += igt_gem_utils.o
diff --git a/drivers/gpu/drm/i915/gt/Makefile b/drivers/gpu/drm/i915/gt/Makefile
index 1c75b5c9790c..1a3401e7dde5 100644
--- a/drivers/gpu/drm/i915/gt/Makefile
+++ b/drivers/gpu/drm/i915/gt/Makefile
@@ -1,2 +1,18 @@
 # Extra header tests
 include $(src)/Makefile.header-test
+
+i915-y += \
+	intel_breadcrumbs.o \
+	intel_context.o \
+	intel_engine_cs.o \
+	intel_engine_pm.o \
+	intel_gt_pm.o \
+	intel_hangcheck.o \
+	intel_lrc.o \
+	intel_reset.o \
+	intel_ringbuffer.o \
+	intel_mocs.o \
+	intel_sseu.o \
+	intel_workarounds.o
+i915-$(CONFIG_DRM_I915_SELFTEST) += \
+	mock_engine.o
diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
index ea8324abc784..2bd07b7935d3 100644
--- a/drivers/gpu/drm/i915/gvt/Makefile
+++ b/drivers/gpu/drm/i915/gvt/Makefile
@@ -1,9 +1,29 @@
 # SPDX-License-Identifier: GPL-2.0
-GVT_DIR := gvt
-GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
-	interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
-	execlist.o scheduler.o sched_policy.o mmio_context.o cmd_parser.o debugfs.o \
-	fb_decoder.o dmabuf.o page_track.o
 
 ccflags-y				+= -I $(srctree)/$(src) -I $(srctree)/$(src)/$(GVT_DIR)/
-i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
+
+i915-y += \
+	gvt.o \
+	aperture_gm.o \
+	handlers.o \
+	vgpu.o \
+	trace_points.o \
+	firmware.o \
+	interrupt.o \
+	gtt.o \
+	cfg_space.o \
+	opregion.o \
+	mmio.o \
+	display.o \
+	edid.o \
+	execlist.o \
+	scheduler.o \
+	sched_policy.o \
+	mmio_context.o \
+	cmd_parser.o \
+	debugfs.o \
+	fb_decoder.o \
+	dmabuf.o \
+	page_track.o
+
+obj-$(CONFIG_DRM_I915_GVT_KVMGT) += kvmgt.o
diff --git a/drivers/gpu/drm/i915/selftests/Makefile b/drivers/gpu/drm/i915/selftests/Makefile
new file mode 100644
index 000000000000..19ca8e7b3b80
--- /dev/null
+++ b/drivers/gpu/drm/i915/selftests/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+i915-y += \
+	i915_random.o \
+	i915_selftest.o \
+	igt_flush_test.o \
+	igt_live_test.o \
+	igt_reset.o \
+	igt_spinner.o
-- 
2.17.1

Re: [PATCH 0/5] kbuild: allow big modules to sub-divide Makefiles

[Sam Ravnborg]

Hi Masahiro

On Tue, Aug 06, 2019 at 03:39:18PM +0900, Masahiro Yamada wrote:
> 
> Recently, Jani Nikula requests a better build system support
> for drivers spanning multiple directories.
> (better kbuild support for drivers spanning multiple directories?)
> 
> I implemented it, so please take a look at it.
> 
> Note:
> The single targets do not work correctly.
> 
> The single targets have never worked correctly:

It works in most cases, but now always.
I dunno how much it is used.
Myself I almost always do make /drivers/foo/bar/
> 
> [1] For instance, "make drivers/foo/bar/baz.o" will descend into
>     drivers/foo/bar/Makefile, which may not necessarily specify
>     the build rule of baz.o
> 
>     It is possible for drivers/foo/Makefile having
>         obj-$(CONFIG_BAZ) += bar/baz.o
> 
> [2] subdir-ccflags-y does not work.
> 
>     The single targets directly descend into the directory of
>     that file resides.
> 
>     It missed subdir-ccflags-y if it is specifies in parent
>     Makefiles.
> 
> Perhaps, I will have to manage correct implementation of single targets.
The day that kbuild has a separate step to read all Makefiles
and then without using recursive make can build the kernel we can have
this fixed.
Until then we can accpet it as is - as fixing this may not be simple.

	Sam