* [PATCH 1/3] kbuild: fix false-positive need-builtin
@ 2019-08-06 10:03 Masahiro Yamada
2019-08-06 10:03 ` [PATCH 2/3] kbuild: generate modules.order only in directories visited by obj-y/m Masahiro Yamada
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Masahiro Yamada @ 2019-08-06 10:03 UTC (permalink / raw)
To: linux-kbuild
Cc: Jan Kiszka, Tom Stonecypher, linux-kernel, Masahiro Yamada, Michal Marek
The current implementation of need-builtin is false-positive,
for example, in the following Makefile:
obj-m := foo/
obj-y := foo/bar/
..., where foo/built-in.a is not required.
Fixes: f7adc3124da0 ("kbuild: create built-in.o automatically if parent directory wants it")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/Makefile.build | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 0d434d0afc0b..3fe0c73e002c 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -487,7 +487,8 @@ 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)
+ $(Q)$(MAKE) $(build)=$@ \
+ need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1)
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/3] kbuild: generate modules.order only in directories visited by obj-y/m
2019-08-06 10:03 [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
@ 2019-08-06 10:03 ` Masahiro Yamada
2019-08-06 10:03 ` [PATCH 3/3] kbuild: show hint if subdir-y/m is used to visit module Makefile Masahiro Yamada
2019-08-07 15:22 ` [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
2 siblings, 0 replies; 5+ messages in thread
From: Masahiro Yamada @ 2019-08-06 10:03 UTC (permalink / raw)
To: linux-kbuild
Cc: Jan Kiszka, Tom Stonecypher, linux-kernel, Masahiro Yamada, Michal Marek
The modules.order files in directories visited by the chain of obj-y
or obj-m are merged to the upper-level ones, and become parts of the
top-level modules.order. On the other hand, there is no need to
generate modules.order in directories visited by subdir-y or subdir-m.
They would become orphan anyway.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/Makefile.build | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 3fe0c73e002c..37a1d2cd49d4 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -488,7 +488,8 @@ targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
PHONY += $(subdir-ym)
$(subdir-ym):
$(Q)$(MAKE) $(build)=$@ \
- need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1)
+ need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \
+ need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1))
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 3/3] kbuild: show hint if subdir-y/m is used to visit module Makefile
2019-08-06 10:03 [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
2019-08-06 10:03 ` [PATCH 2/3] kbuild: generate modules.order only in directories visited by obj-y/m Masahiro Yamada
@ 2019-08-06 10:03 ` Masahiro Yamada
2019-08-08 6:29 ` Masahiro Yamada
2019-08-07 15:22 ` [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
2 siblings, 1 reply; 5+ messages in thread
From: Masahiro Yamada @ 2019-08-06 10:03 UTC (permalink / raw)
To: linux-kbuild
Cc: Jan Kiszka, Tom Stonecypher, linux-kernel, Masahiro Yamada, Michal Marek
Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead
of $(MODVERDIR)/*.mod"), a module is no longer built in the following
pattern:
[Makefile]
subdir-y := some-module
[some-module/Makefile]
obj-m := some-module.o
You cannot write Makefile this way in upstream because modules.order is
not correctly generated. subdir-y is used to descend to a sub-directory
that builds tools, device trees, etc.
For external modules, the modules order does not matter. So, the
Makefile above was known to work.
I believe the Makefile should be re-written as follows:
[Makefile]
obj-m := some-module/
[some-module/Makefile]
obj-m := some-module.o
However, people will have no idea if their Makefile suddenly stops
working. In fact, I received questions from multiple people.
Show a warning if obj-m is specified in a Makefile visited by subdir-y
or subdir-m.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Tom Stonecypher <thomas.edwardx.stonecypher@intel.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/Makefile.build | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 37a1d2cd49d4..4a26c7ed9198 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -52,6 +52,13 @@ ifndef obj
$(warning kbuild: Makefile.build is included improperly)
endif
+ifeq ($(need-modorder),)
+ifneq ($(obj-m),)
+$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
+$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
+endif
+endif
+
# ===========================================================================
ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/3] kbuild: fix false-positive need-builtin
2019-08-06 10:03 [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
2019-08-06 10:03 ` [PATCH 2/3] kbuild: generate modules.order only in directories visited by obj-y/m Masahiro Yamada
2019-08-06 10:03 ` [PATCH 3/3] kbuild: show hint if subdir-y/m is used to visit module Makefile Masahiro Yamada
@ 2019-08-07 15:22 ` Masahiro Yamada
2 siblings, 0 replies; 5+ messages in thread
From: Masahiro Yamada @ 2019-08-07 15:22 UTC (permalink / raw)
To: Linux Kbuild mailing list
Cc: Jan Kiszka, Tom Stonecypher, Linux Kernel Mailing List, Michal Marek
On Tue, Aug 6, 2019 at 7:03 PM Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> The current implementation of need-builtin is false-positive,
> for example, in the following Makefile:
>
> obj-m := foo/
> obj-y := foo/bar/
>
> ..., where foo/built-in.a is not required.
>
> Fixes: f7adc3124da0 ("kbuild: create built-in.o automatically if parent directory wants it")
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
Series, applied to linux-kbuild.
>
> scripts/Makefile.build | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 0d434d0afc0b..3fe0c73e002c 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -487,7 +487,8 @@ 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)
> + $(Q)$(MAKE) $(build)=$@ \
> + need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1)
>
> # Add FORCE to the prequisites of a target to force it to be always rebuilt.
> # ---------------------------------------------------------------------------
> --
> 2.17.1
>
--
Best Regards
Masahiro Yamada
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 3/3] kbuild: show hint if subdir-y/m is used to visit module Makefile
2019-08-06 10:03 ` [PATCH 3/3] kbuild: show hint if subdir-y/m is used to visit module Makefile Masahiro Yamada
@ 2019-08-08 6:29 ` Masahiro Yamada
0 siblings, 0 replies; 5+ messages in thread
From: Masahiro Yamada @ 2019-08-08 6:29 UTC (permalink / raw)
To: Linux Kbuild mailing list
Cc: Jan Kiszka, Tom Stonecypher, Linux Kernel Mailing List, Michal Marek
On Tue, Aug 6, 2019 at 7:03 PM Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead
> of $(MODVERDIR)/*.mod"), a module is no longer built in the following
> pattern:
>
> [Makefile]
> subdir-y := some-module
>
> [some-module/Makefile]
> obj-m := some-module.o
>
> You cannot write Makefile this way in upstream because modules.order is
> not correctly generated. subdir-y is used to descend to a sub-directory
> that builds tools, device trees, etc.
>
> For external modules, the modules order does not matter. So, the
> Makefile above was known to work.
>
> I believe the Makefile should be re-written as follows:
>
> [Makefile]
> obj-m := some-module/
>
> [some-module/Makefile]
> obj-m := some-module.o
>
> However, people will have no idea if their Makefile suddenly stops
> working. In fact, I received questions from multiple people.
>
> Show a warning if obj-m is specified in a Makefile visited by subdir-y
> or subdir-m.
>
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> Cc: Tom Stonecypher <thomas.edwardx.stonecypher@intel.com>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
This produces false-positive warnings for single-targets.
I will fix up as follows:
diff --git a/Makefile b/Makefile
index 0e37ad2f77bf..fac25e279da6 100644
--- a/Makefile
+++ b/Makefile
@@ -1783,7 +1783,7 @@ PHONY += /
/: ./
%/: prepare FORCE
- $(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir)
+ $(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir) need-modorder=1
# FIXME Should go into a make.lib or something
# ===========================================================================
>
> scripts/Makefile.build | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 37a1d2cd49d4..4a26c7ed9198 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -52,6 +52,13 @@ ifndef obj
> $(warning kbuild: Makefile.build is included improperly)
> endif
>
> +ifeq ($(need-modorder),)
> +ifneq ($(obj-m),)
> +$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
> +$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
> +endif
> +endif
> +
> # ===========================================================================
>
> ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
> --
> 2.17.1
>
--
Best Regards
Masahiro Yamada
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2019-08-07 15:22 ` [PATCH 1/3] kbuild: fix false-positive need-builtin Masahiro Yamada
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