[PATCH v3 1/3] kbuild: unexport abs_srctree and abs_objtree

[PATCH v3 1/3] kbuild: unexport abs_srctree and abs_objtree

[Masahiro Yamada]

'make rpm-pkg' builds the kernel in rpmbuild/BUILD, but $(abs_srctree)
and $(abs_objtree) point to the directory path where make was started,
not the kernel is actually being built. Fix it.

In hindsight, there was no need to export abs_srctree and abs_objtree.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Changes in v3:
 - New patch

 Makefile | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index f18d59c81241..6f9bbb0d9172 100644
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,10 @@ __all:
 # descending is started. They are now explicitly listed as the
 # prepare rule.
 
+this-makefile := $(lastword $(MAKEFILE_LIST))
+abs_srctree := $(realpath $(dir $(this-makefile)))
+abs_objtree := $(CURDIR)
+
 ifneq ($(sub_make_done),1)
 
 # Do not use make's built-in rules and variables
@@ -185,8 +189,6 @@ $(if $(abs_objtree),, \
 
 # $(realpath ...) resolves symlinks
 abs_objtree := $(realpath $(abs_objtree))
-else
-abs_objtree := $(CURDIR)
 endif # ifneq ($(KBUILD_OUTPUT),)
 
 ifeq ($(abs_objtree),$(CURDIR))
@@ -196,9 +198,6 @@ else
 need-sub-make := 1
 endif
 
-this-makefile := $(lastword $(MAKEFILE_LIST))
-abs_srctree := $(realpath $(dir $(this-makefile)))
-
 ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
 $(error source directory cannot contain spaces or colons)
 endif
@@ -211,7 +210,6 @@ need-sub-make := 1
 $(this-makefile): ;
 endif
 
-export abs_srctree abs_objtree
 export sub_make_done := 1
 
 ifeq ($(need-sub-make),1)
-- 
2.39.2

[PATCH v3 2/3] kbuild: revive "Entering directory" for Make >= 4.4.1

[Masahiro Yamada]

With commit 9da0763bdd82 ("kbuild: Use relative path when building in
a subdir of the source tree"), compiler messages in out-of-tree builds
include relative paths, which are relative to the build directory, not
the directory where make was started.

To help IDEs/editors find the source files, Kbuild lets GNU Make print
"Entering directory ..." when it changes the working directory. It has
been working fine for a long time, but David reported it is broken with
the latest GNU Make.

The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537]
Fix setting -w in makefiles"). Previously, setting --no-print-directory
to MAKEFLAGS only affected child makes, but it is now interpreted in
the current make as soon as it is set.

[test code]

  $ cat /tmp/Makefile
  ifneq ($(SUBMAKE),1)
  MAKEFLAGS += --no-print-directory
  all: ; $(MAKE) SUBMAKE=1
  else
  all: ; :
  endif

[before 8f9e7722ff0f]

  $ make -C /tmp
  make: Entering directory '/tmp'
  make SUBMAKE=1
  :
  make: Leaving directory '/tmp'

[after 8f9e7722ff0f]

  $ make -C /tmp
  make SUBMAKE=1
  :

Previously, the effect of --no-print-directory was delayed until Kbuild
started the directory descending, but it is no longer true with GNU Make
4.4.1.

This commit adds one more recursion to cater to GNU Make >= 4.4.1.

When Kbuild needs to change the working directory, __submake will be
executed twice.

  __submake without --no-print-directory  --> show "Entering directory ..."
  __submake with    --no-print-directory  --> parse the rest of Makefile

We end up with one more recursion than needed for GNU Make < 4.4.1, but
I do not want to complicate the version check.

Reported-by: David Howells <dhowells@redhat.com>
Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nicolas Schier <n.schier@avm.de>
---

Changes in v3:
  - Fix build breakage of 'make rpm-pkg'.

Changes in v2:
  - Fix the code. V1 did not work.
  - Remove the version check to simplify the code

 Makefile | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/Makefile b/Makefile
index 6f9bbb0d9172..0663c99e050b 100644
--- a/Makefile
+++ b/Makefile
@@ -191,13 +191,6 @@ $(if $(abs_objtree),, \
 abs_objtree := $(realpath $(abs_objtree))
 endif # ifneq ($(KBUILD_OUTPUT),)
 
-ifeq ($(abs_objtree),$(CURDIR))
-# Suppress "Entering directory ..." unless we are changing the work directory.
-MAKEFLAGS += --no-print-directory
-else
-need-sub-make := 1
-endif
-
 ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
 $(error source directory cannot contain spaces or colons)
 endif
@@ -212,6 +205,23 @@ endif
 
 export sub_make_done := 1
 
+endif # sub_make_done
+
+ifeq ($(abs_objtree),$(CURDIR))
+# Suppress "Entering directory ..." if we are at the final work directory.
+no-print-directory := --no-print-directory
+else
+# Recursion to show "Entering directory ..."
+need-sub-make := 1
+endif
+
+ifeq ($(filter --no-print-directory, $(MAKEFLAGS)),)
+# If --no-print-directory is unset, recurse once again to set it.
+# You may end up recursing into __sub-make twice. This is needed due to the
+# behavior change in GNU Make 4.4.1.
+need-sub-make := 1
+endif
+
 ifeq ($(need-sub-make),1)
 
 PHONY += $(MAKECMDGOALS) __sub-make
@@ -221,18 +231,12 @@ $(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make
 
 # Invoke a second make in the output directory, passing relevant variables
 __sub-make:
-	$(Q)$(MAKE) -C $(abs_objtree) -f $(abs_srctree)/Makefile $(MAKECMDGOALS)
+	$(Q)$(MAKE) $(no-print-directory) -C $(abs_objtree) \
+	-f $(abs_srctree)/Makefile $(MAKECMDGOALS)
 
-endif # need-sub-make
-endif # sub_make_done
+else # need-sub-make
 
 # We process the rest of the Makefile if this is the final invocation of make
-ifeq ($(need-sub-make),)
-
-# Do not print "Entering directory ...",
-# but we want to display it when entering to the output directory
-# so that IDEs/editors are able to understand relative filenames.
-MAKEFLAGS += --no-print-directory
 
 ifeq ($(abs_srctree),$(abs_objtree))
         # building in the source tree
-- 
2.39.2

[PATCH v3 3/3] kbuild: respect GNU Make -w flag

[Masahiro Yamada]

Currently, -w (--print-directory) option is ignored, but it is better
to respect the user's choice.

This commit changes the behavior of "Entering directory ..." logging.

If -w (or --print-directory) is given via the command line or the
MAKEFLAGS environment variable, print "Entering directory ..." for every
sub make.

If --no-print-directory is given via the command line or the MAKEFLAGS
environment variable, suppress "Entering directory ..." completely.

If none of them is given, print "Entering directory ..." when Kbuild
changes the working directory at the start of building. (default)

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nicolas Schier <n.schier@avm.de>
---

Changes in v3:
  - new patch

 Makefile | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 0663c99e050b..aab8e149feec 100644
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,12 @@ __all:
 # descending is started. They are now explicitly listed as the
 # prepare rule.
 
+ifeq ($(filter 3.%,$(MAKE_VERSION)),)
+short-opts := $(firstword -$(MAKEFLAGS))
+else
+short-opts := $(filter-out --%,$(MAKEFLAGS))
+endif
+
 this-makefile := $(lastword $(MAKEFILE_LIST))
 abs_srctree := $(realpath $(dir $(this-makefile)))
 abs_objtree := $(CURDIR)
@@ -95,12 +101,6 @@ endif
 # commands
 # make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
 
-ifeq ($(filter 3.%,$(MAKE_VERSION)),)
-short-opts := $(firstword -$(MAKEFLAGS))
-else
-short-opts := $(filter-out --%,$(MAKEFLAGS))
-endif
-
 ifneq ($(findstring s,$(short-opts)),)
 quiet=silent_
 override KBUILD_VERBOSE :=
@@ -215,12 +215,16 @@ else
 need-sub-make := 1
 endif
 
+ifeq ($(findstring w, $(short-opts)),)
 ifeq ($(filter --no-print-directory, $(MAKEFLAGS)),)
 # If --no-print-directory is unset, recurse once again to set it.
 # You may end up recursing into __sub-make twice. This is needed due to the
 # behavior change in GNU Make 4.4.1.
 need-sub-make := 1
 endif
+else
+no-print-directory :=
+endif
 
 ifeq ($(need-sub-make),1)
 
-- 
2.39.2

Re: [PATCH v3 1/3] kbuild: unexport abs_srctree and abs_objtree

[Masahiro Yamada]

On Sun, Jun 25, 2023 at 11:06 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> 'make rpm-pkg' builds the kernel in rpmbuild/BUILD, but $(abs_srctree)
> and $(abs_objtree) point to the directory path where make was started,
> not the kernel is actually being built. Fix it.
>
> In hindsight, there was no need to export abs_srctree and abs_objtree.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---

Tools Makefiles rely on abs_*.
I will keep them exported. Sigh.





-- 
Best Regards
Masahiro Yamada