treewide: prefix header search paths with $(srctree)/

Currently, the Kbuild core manipulates header search paths in a crazy
way [1].

To fix this mess, I want all Makefiles to add explicit $(srctree)/ to
the search paths in the srctree. Some Makefiles are already written in
that way, but not all. The goal of this work is to make the notation
consistent, and finally get rid of the gross hacks.

Having whitespaces after -I does not matter since commit 48f6e3cf
("kbuild: do not drop -I without parameter").

[1]: https://patchwork.kernel.org/patch/9632347/Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

arch/mips/pnx833x/Platform

 # NXP STB225
 platform-$(CONFIG_SOC_PNX833X)	+= pnx833x/
-cflags-$(CONFIG_SOC_PNX833X)	+= -Iarch/mips/include/asm/mach-pnx833x
+cflags-$(CONFIG_SOC_PNX833X)	+= -I $(srctree)/arch/mips/include/asm/mach-pnx833x
 load-$(CONFIG_NXP_STB220)	+= 0xffffffff80001000
 load-$(CONFIG_NXP_STB225)	+= 0xffffffff80001000

arch/powerpc/Makefile

@@ -211,7 +211,7 @@ endif
 
 asinstr := $(call as-instr,lis 9$(comma)foo@high,-DHAVE_AS_ATHIGH=1)
 
-KBUILD_CPPFLAGS	+= -Iarch/$(ARCH) $(asinstr)
+KBUILD_CPPFLAGS	+= -I $(srctree)/arch/$(ARCH) $(asinstr)
 KBUILD_AFLAGS	+= $(AFLAGS-y)
 KBUILD_CFLAGS	+= $(call cc-option,-msoft-float)
 KBUILD_CFLAGS	+= -pipe $(CFLAGS-y)

arch/sh/Makefile

@@ -191,8 +191,8 @@ cpuincdir-y			+= cpu-common	# Must be last
 drivers-y			+= arch/sh/drivers/
 drivers-$(CONFIG_OPROFILE)	+= arch/sh/oprofile/
 
-cflags-y	+= $(foreach d, $(cpuincdir-y), -Iarch/sh/include/$(d)) \
-		   $(foreach d, $(machdir-y), -Iarch/sh/include/$(d))
+cflags-y	+= $(foreach d, $(cpuincdir-y), -I $(srctree)/arch/sh/include/$(d)) \
+		   $(foreach d, $(machdir-y), -I $(srctree)/arch/sh/include/$(d))
 
 KBUILD_CFLAGS		+= -pipe $(cflags-y)
 KBUILD_CPPFLAGS		+= $(cflags-y)

arch/x86/kernel/Makefile

@@ -42,7 +42,7 @@ endif
 # non-deterministic coverage.
 KCOV_INSTRUMENT		:= n
 
-CFLAGS_irq.o := -I$(src)/../include/asm/trace
+CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
 
 obj-y			:= process_$(BITS).o signal.o
 obj-$(CONFIG_COMPAT)	+= signal_compat.o

arch/x86/mm/Makefile

@@ -21,7 +21,7 @@ CFLAGS_physaddr.o		:= $(nostackp)
 CFLAGS_setup_nx.o		:= $(nostackp)
 CFLAGS_mem_encrypt_identity.o	:= $(nostackp)
 
-CFLAGS_fault.o := -I$(src)/../include/asm/trace
+CFLAGS_fault.o := -I $(srctree)/$(src)/../include/asm/trace
 
 obj-$(CONFIG_X86_PAT)		+= pat_rbtree.o
 

arch/xtensa/boot/lib/Makefile

@@ -7,7 +7,7 @@ zlib	:= inffast.c inflate.c inftrees.c
 
 lib-y	+= $(zlib:.c=.o) zmem.o
 
-ccflags-y	:= -Ilib/zlib_inflate
+ccflags-y	:= -I $(srctree)/lib/zlib_inflate
 ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_inflate.o = -pg
 CFLAGS_REMOVE_zmem.o = -pg

drivers/hid/intel-ish-hid/Makefile

@@ -23,4 +23,4 @@ intel-ishtp-hid-objs += ishtp-hid-client.o
 obj-$(CONFIG_INTEL_ISH_FIRMWARE_DOWNLOADER) += intel-ishtp-loader.o
 intel-ishtp-loader-objs += ishtp-fw-loader.o
 
-ccflags-y += -Idrivers/hid/intel-ish-hid/ishtp
+ccflags-y += -I $(srctree)/$(src)/ishtp

drivers/net/ethernet/chelsio/libcxgb/Makefile

-ccflags-y := -Idrivers/net/ethernet/chelsio/cxgb4
+ccflags-y := -I $(srctree)/$(src)/../cxgb4
 
 obj-$(CONFIG_CHELSIO_LIB) += libcxgb.o
 

drivers/target/iscsi/cxgbit/Makefile

 # SPDX-License-Identifier: GPL-2.0
-ccflags-y := -Idrivers/net/ethernet/chelsio/cxgb4
-ccflags-y += -Idrivers/net/ethernet/chelsio/libcxgb
-ccflags-y += -Idrivers/target/iscsi
+ccflags-y := -I $(srctree)/drivers/net/ethernet/chelsio/cxgb4
+ccflags-y += -I $(srctree)/drivers/net/ethernet/chelsio/libcxgb
+ccflags-y += -I $(srctree)/drivers/target/iscsi
 
 obj-$(CONFIG_ISCSI_TARGET_CXGB4)  += cxgbit.o
 

drivers/usb/storage/Makefile

@@ -6,7 +6,7 @@
 # Rewritten to use lists instead of if-statements.
 #
 
-ccflags-y := -Idrivers/scsi
+ccflags-y := -I $(srctree)/drivers/scsi
 
 obj-$(CONFIG_USB_UAS)		+= uas.o
 obj-$(CONFIG_USB_STORAGE)	+= usb-storage.o

fs/ocfs2/dlm/Makefile

-ccflags-y := -I$(src)/..
+ccflags-y := -I $(srctree)/$(src)/..
 
 obj-$(CONFIG_OCFS2_FS_O2CB) += ocfs2_dlm.o
 
 ocfs2_dlm-objs := dlmdomain.o dlmdebug.o dlmthread.o dlmrecovery.o \
 	dlmmaster.o dlmast.o dlmconvert.o dlmlock.o dlmunlock.o
-

fs/ocfs2/dlmfs/Makefile

-ccflags-y := -I$(src)/..
+ccflags-y := -I $(srctree)/$(src)/..
 
 obj-$(CONFIG_OCFS2_FS) += ocfs2_dlmfs.o
 

fs/xfs/Makefile

@@ -4,8 +4,8 @@
 # All Rights Reserved.
 #
 
-ccflags-y += -I$(src)			# needed for trace events
-ccflags-y += -I$(src)/libxfs
+ccflags-y += -I $(srctree)/$(src)		# needed for trace events
+ccflags-y += -I $(srctree)/$(src)/libxfs
 
 ccflags-$(CONFIG_XFS_DEBUG) += -g
 

net/bpfilter/Makefile

@@ -5,7 +5,7 @@
 
 hostprogs-y := bpfilter_umh
 bpfilter_umh-objs := main.o
-KBUILD_HOSTCFLAGS += -Itools/include/ -Itools/include/uapi
+KBUILD_HOSTCFLAGS += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
 HOSTCC := $(CC)
 
 ifeq ($(CONFIG_BPFILTER_UMH), y)

scripts/dtc/Makefile

@@ -9,7 +9,7 @@ dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
 dtc-objs	+= dtc-lexer.lex.o dtc-parser.tab.o
 
 # Source files need to get at the userspace version of libfdt_env.h to compile
-HOST_EXTRACFLAGS := -I$(src)/libfdt
+HOST_EXTRACFLAGS := -I $(srctree)/$(src)/libfdt
 
 ifeq ($(wildcard /usr/include/yaml.h),)
 ifneq ($(CHECK_DTBS),)
@@ -23,8 +23,8 @@ HOSTLDLIBS_dtc	:= -lyaml
 endif
 
 # Generated files need one more search path to include headers in source tree
-HOSTCFLAGS_dtc-lexer.lex.o := -I$(src)
-HOSTCFLAGS_dtc-parser.tab.o := -I$(src)
+HOSTCFLAGS_dtc-lexer.lex.o := -I $(srctree)/$(src)
+HOSTCFLAGS_dtc-parser.tab.o := -I $(srctree)/$(src)
 
 # dependencies on generated files need to be listed explicitly
 $(obj)/dtc-lexer.lex.o: $(obj)/dtc-parser.tab.h

scripts/genksyms/Makefile

@@ -31,8 +31,8 @@ $(obj)/parse.tab.h: $(src)/parse.y FORCE
 endif
 
 # -I needed for generated C source (shipped source)
-HOSTCFLAGS_parse.tab.o := -I$(src)
-HOSTCFLAGS_lex.lex.o := -I$(src)
+HOSTCFLAGS_parse.tab.o := -I $(srctree)/$(src)
+HOSTCFLAGS_lex.lex.o := -I $(srctree)/$(src)
 
 # dependencies on generated files need to be listed explicitly
 $(obj)/lex.lex.o: $(obj)/parse.tab.h

scripts/kconfig/Makefile

@@ -147,8 +147,8 @@ common-objs	:= confdata.o expr.o lexer.lex.o parser.tab.o preprocess.o \
 		   symbol.o
 
 $(obj)/lexer.lex.o: $(obj)/parser.tab.h
-HOSTCFLAGS_lexer.lex.o	:= -I$(src)
-HOSTCFLAGS_parser.tab.o	:= -I$(src)
+HOSTCFLAGS_lexer.lex.o	:= -I $(srctree)/$(src)
+HOSTCFLAGS_parser.tab.o	:= -I $(srctree)/$(src)
 
 # conf: Used for defconfig, oldconfig and related targets
 hostprogs-y	+= conf