kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

5 files changed, 5 insertions, 6 deletions

diff --git a/arch/arm/Kbuild b/arch/arm/Kbuild
index b506622e7e23..69de6b6243c7 100644
--- a/arch/arm/Kbuild
+++ b/arch/arm/Kbuild
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_FPE_NWFPE)		+= nwfpe/
 # Put arch/arm/fastfpe/ to use this.
-obj-$(CONFIG_FPE_FASTFPE)	+= $(patsubst $(srctree)/$(src)/%,%,$(wildcard $(srctree)/$(src)/fastfpe/))
+obj-$(CONFIG_FPE_FASTFPE)	+= $(patsubst $(src)/%,%,$(wildcard $(src)/fastfpe/))
 obj-$(CONFIG_VFP)		+= vfp/
 obj-$(CONFIG_XEN)		+= xen/
 obj-$(CONFIG_VDSO)		+= vdso/
diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
index abd6a2889fd0..ba9b9a802469 100644
--- a/arch/arm/boot/Makefile
+++ b/arch/arm/boot/Makefile
@@ -25,8 +25,7 @@ targets := Image zImage xipImage bootpImage uImage
 
 ifeq ($(CONFIG_XIP_KERNEL),y)
 
-cmd_deflate_xip_data = $(CONFIG_SHELL) -c \
-	'$(srctree)/$(src)/deflate_xip_data.sh $< $@'
+cmd_deflate_xip_data = $(CONFIG_SHELL) -c '$(src)/deflate_xip_data.sh $< $@'
 
 ifeq ($(CONFIG_XIP_DEFLATED_DATA),y)
 quiet_cmd_mkxip = XIPZ    $@
diff --git a/arch/arm/mach-s3c/Makefile b/arch/arm/mach-s3c/Makefile
index 713827bef831..988c49672715 100644
--- a/arch/arm/mach-s3c/Makefile
+++ b/arch/arm/mach-s3c/Makefile
@@ -2,7 +2,7 @@
 #
 # Copyright 2009 Simtec Electronics
 
-include $(srctree)/$(src)/Makefile.s3c64xx
+include $(src)/Makefile.s3c64xx
 
 # Objects we always build independent of SoC choice
 
diff --git a/arch/arm/plat-orion/Makefile b/arch/arm/plat-orion/Makefile
index 830b0be038c6..e8c7580df8ca 100644
--- a/arch/arm/plat-orion/Makefile
+++ b/arch/arm/plat-orion/Makefile
@@ -2,7 +2,7 @@
 #
 # Makefile for the linux kernel.
 #
-ccflags-y := -I$(srctree)/$(src)/include
+ccflags-y := -I$(src)/include
 
 orion-gpio-$(CONFIG_GPIOLIB)      += gpio.o
 obj-$(CONFIG_PLAT_ORION_LEGACY)   += irq.o pcie.o time.o common.o mpp.o
diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
index 81f13bdf32f2..28b6da8ac5f6 100644
--- a/arch/arm/tools/Makefile
+++ b/arch/arm/tools/Makefile
@@ -9,7 +9,7 @@ gen := arch/$(ARCH)/include/generated
 kapi := $(gen)/asm
 uapi := $(gen)/uapi/asm
 syshdr := $(srctree)/scripts/syscallhdr.sh
-sysnr := $(srctree)/$(src)/syscallnr.sh
+sysnr := $(src)/syscallnr.sh
 systbl := $(srctree)/scripts/syscalltbl.sh
 syscall := $(src)/syscall.tbl