kbuild: remove --include-dir MAKEFLAG from top Makefile

I added $(srctree)/ to some included Makefiles in the following commits:

 - 3204a7fb98 ("kbuild: prefix $(srctree)/ to some included Makefiles")
 - d828563955 ("kbuild: do not require sub-make for separate output tree builds")

They were a preparation for removing --include-dir flag.

I have never thought --include-dir useful. Rather, it _is_ harmful.

For example, run the following commands:

  $ make -s ARCH=x86 mrproper defconfig
  $ make ARCH=arm O=foo dtbs
  make[1]: Entering directory '/tmp/linux/foo'
    HOSTCC  scripts/basic/fixdep
  Error: kernelrelease not valid - run 'make prepare' to update it
    UPD     include/config/kernel.release
  make[1]: Leaving directory '/tmp/linux/foo'

The first command configures the source tree for x86. The next command
tries to build ARM device trees in the separate foo/ directory - this
must stop because the directory foo/ has not been configured yet.

However, due to --include-dir=$(abs_srctree), the top Makefile includes
the wrong include/config/auto.conf from the source tree and continues
building. Kbuild traverses the directory tree, but of course it does
not work correctly. The Error message is also pointless - 'make prepare'
does not help at all for fixing the issue.

This commit fixes more arch Makefile, and finally removes --include-dir
from the top Makefile.

There are more breakages under drivers/, but I do not volunteer to fix
them all. I just moved --include-dir to drivers/Makefile.

With this commit, the second command will stop with a sensible message.

  $ make -s ARCH=x86 mrproper defconfig
  $ make ARCH=arm O=foo dtbs
  make[1]: Entering directory '/tmp/linux/foo'
    SYNC    include/config/auto.conf.cmd
  ***
  *** The source tree is not clean, please run 'make ARCH=arm mrproper'
  *** in /tmp/linux
  ***
  make[2]: *** [../Makefile:646: outputmakefile] Error 1
  /tmp/linux/Makefile:770: include/config/auto.conf.cmd: No such file or directory
  make[1]: *** [/tmp/linux/Makefile:793: include/config/auto.conf.cmd] Error 2
  make[1]: Leaving directory '/tmp/linux/foo'
  make: *** [Makefile:226: __sub-make] Error 2

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

Makefile

@@ -203,14 +203,6 @@ ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
 $(error source directory cannot contain spaces or colons)
 endif
 
-ifneq ($(abs_srctree),$(abs_objtree))
-# Look for make include files relative to root of kernel src
-#
-# --included-dir is added for backward compatibility, but you should not rely on
-# it. Please add $(srctree)/ prefix to include Makefiles in the source tree.
-MAKEFLAGS += --include-dir=$(abs_srctree)
-endif
-
 ifneq ($(filter 3.%,$(MAKE_VERSION)),)
 # 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x
 # We need to invoke sub-make to avoid implicit rules in the top Makefile.

arch/arm/mach-s3c/Makefile

@@ -3,11 +3,11 @@
 # Copyright 2009 Simtec Electronics
 
 ifdef CONFIG_ARCH_S3C24XX
-include $(src)/Makefile.s3c24xx
+include $(srctree)/$(src)/Makefile.s3c24xx
 endif
 
 ifdef CONFIG_ARCH_S3C64XX
-include $(src)/Makefile.s3c64xx
+include $(srctree)/$(src)/Makefile.s3c64xx
 endif
 
 # Objects we always build independent of SoC choice

arch/ia64/kernel/Makefile

@@ -43,4 +43,4 @@ obj-$(CONFIG_ELF_CORE)		+= elfcore.o
 CFLAGS_traps.o  += -mfixed-range=f2-f5,f16-f31
 
 # The gate DSO image is built using a special linker script.
-include $(src)/Makefile.gate
+include $(srctree)/$(src)/Makefile.gate

arch/mips/Kbuild

@@ -7,7 +7,7 @@ subdir-ccflags-y := -Werror
 endif
 
 # platform specific definitions
-include arch/mips/Kbuild.platforms
+include $(srctree)/arch/mips/Kbuild.platforms
 obj-y := $(platform-y)
 
 # make clean traverses $(obj-) without having included .config, so

arch/mips/Makefile.postlink

@@ -10,7 +10,7 @@ PHONY := __archpost
 __archpost:
 
 -include include/config/auto.conf
-include scripts/Kbuild.include
+include $(srctree)/scripts/Kbuild.include
 
 CMD_LS3_LLSC = arch/mips/tools/loongson3-llsc-check
 quiet_cmd_ls3_llsc = LLSCCHK $@

arch/powerpc/Makefile.postlink

@@ -9,7 +9,7 @@ PHONY := __archpost
 __archpost:
 
 -include include/config/auto.conf
-include scripts/Kbuild.include
+include $(srctree)/scripts/Kbuild.include
 
 quiet_cmd_head_check = CHKHEAD $@
       cmd_head_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/head_check.sh "$(NM)" "$@"

arch/um/drivers/Makefile

@@ -72,4 +72,4 @@ CFLAGS_null.o = -DDEV_NULL=$(DEV_NULL_PATH)
 
 CFLAGS_xterm.o += '-DCONFIG_XTERM_CHAN_DEFAULT_EMULATOR="$(CONFIG_XTERM_CHAN_DEFAULT_EMULATOR)"'
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/um/kernel/Makefile

@@ -29,7 +29,7 @@ obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
 
 USER_OBJS := config.o
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules
 
 targets := config.c config.tmp capflags.c
 

arch/um/kernel/skas/Makefile

@@ -14,4 +14,4 @@ UNPROFILE_OBJS := clone.o
 
 KCOV_INSTRUMENT := n
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/um/os-Linux/Makefile

@@ -18,4 +18,4 @@ USER_OBJS := $(user-objs-y) elf_aux.o execvp.o file.o helper.o irq.o \
 	main.o mem.o process.o registers.o sigio.o signal.o start_up.o time.o \
 	tty.o umid.o util.o
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/um/os-Linux/drivers/Makefile

@@ -10,4 +10,4 @@ obj-y =
 obj-$(CONFIG_UML_NET_ETHERTAP) += ethertap.o
 obj-$(CONFIG_UML_NET_TUNTAP) += tuntap.o
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/um/os-Linux/skas/Makefile

@@ -7,4 +7,4 @@ obj-y := mem.o process.o
 
 USER_OBJS := $(obj-y)
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/x86/Makefile.um

@@ -17,7 +17,7 @@ LDS_EXTRA		:= -Ui386
 export LDS_EXTRA
 
 # First of all, tune CFLAGS for the specific CPU. This actually sets cflags-y.
-include arch/x86/Makefile_32.cpu
+include $(srctree)/arch/x86/Makefile_32.cpu
 
 # prevent gcc from keeping the stack 16 byte aligned. Taken from i386.
 cflags-y += $(call cc-option,-mpreferred-stack-boundary=2)

arch/x86/um/Makefile

@@ -48,4 +48,4 @@ include/generated/user_constants.h: $(obj)/user-offsets.s FORCE
 UNPROFILE_OBJS := stub_segv.o
 CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

arch/x86/um/os-Linux/Makefile

@@ -10,4 +10,4 @@ obj-$(CONFIG_64BIT) += prctl.o
 
 USER_OBJS := $(obj-y)
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules

drivers/Makefile

@@ -6,6 +6,11 @@
 # Rewritten to use lists instead of if-statements.
 #
 
+# Some driver Makefiles miss $(srctree)/ for include directive.
+ifdef building_out_of_srctree
+MAKEFLAGS += --include-dir=$(srctree)
+endif
+
 obj-y				+= irqchip/
 obj-y				+= bus/
 

fs/hostfs/Makefile

@@ -8,4 +8,4 @@ hostfs-objs := hostfs_kern.o hostfs_user.o
 obj-y :=
 obj-$(CONFIG_HOSTFS) += hostfs.o
 
-include arch/um/scripts/Makefile.rules
+include $(srctree)/arch/um/scripts/Makefile.rules