kbuild: enable 'make AFLAGS=...' to add additional options to AS

The variable AFLAGS is a wellknown variable and the usage by
kbuild may result in unexpected behaviour.
On top of that several people over time has asked for a way to
pass in additional flags to gcc.

This patch replace use of AFLAGS with KBUILD_AFLAGS all over
the tree.

Patch was tested on following architectures:
alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k, s390
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

arch/um/Makefile-i386

@@ -16,7 +16,7 @@ OBJCOPYFLAGS  		:= -O binary -R .note -R .comment -S
 ifeq ("$(origin SUBARCH)", "command line")
 ifneq ("$(shell uname -m | sed -e s/i.86/i386/)", "$(SUBARCH)")
 KBUILD_CFLAGS		+= $(call cc-option,-m32)
-AFLAGS			+= $(call cc-option,-m32)
+KBUILD_AFLAGS		+= $(call cc-option,-m32)
 LINK-y			+= $(call cc-option,-m32)
 UML_OBJCOPYFLAGS	+= -F $(ELF_FORMAT)
 

arch/um/Makefile-x86_64

@@ -12,7 +12,7 @@ ARCH_KERNEL_DEFINES = -U__$(SUBARCH)__
 KBUILD_CFLAGS += $(_extra_flags_)
 
 CHECKFLAGS  += -m64
-AFLAGS += -m64
+KBUILD_AFLAGS += -m64
 LDFLAGS += -m elf_x86_64
 CPPFLAGS += -m64
 

arch/um/sys-ppc/Makefile

 OBJ = built-in.o
 
 .S.o:
-	$(CC) $(AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
+	$(CC) $(KBUILD_AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
 
 OBJS = ptrace.o sigcontext.o semaphore.o checksum.o miscthings.o misc.o \
 	ptrace_user.o sysrq.o
@@ -57,13 +57,13 @@ ppc_defs.h: mk_defs.c ppc_defs.head \
 checksum.o: checksum.S
 	rm -f asm
 	ln -s $(TOPDIR)/include/asm-ppc asm
-	$(CC) $(EXTRA_AFLAGS) $(AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
+	$(CC) $(EXTRA_AFLAGS) $(KBUILD_AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
 	rm -f asm
 
 misc.o: misc.S ppc_defs.h
 	rm -f asm
 	ln -s $(TOPDIR)/include/asm-ppc asm
-	$(CC) $(EXTRA_AFLAGS) $(AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
+	$(CC) $(EXTRA_AFLAGS) $(KBUILD_AFLAGS) -D__ASSEMBLY__ -D__UM_PPC__ -c $< -o $*.o
 	rm -f asm
 
 clean-files := $(OBJS) ppc_defs.h checksum.S semaphore.c mk_defs.c

arch/x86/boot/Makefile

@@ -61,7 +61,7 @@ KBUILD_CFLAGS	:= $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
 			$(call cc-option, -fno-unit-at-a-time)) \
 		   $(call cc-option, -fno-stack-protector) \
 		   $(call cc-option, -mpreferred-stack-boundary=2)
-AFLAGS		:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
+KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 
 $(obj)/zImage:  IMAGE_OFFSET := 0x1000
 $(obj)/zImage:  EXTRA_AFLAGS := $(SVGA_MODE) $(RAMDISK)

arch/x86/boot/compressed/Makefile_64

@@ -10,7 +10,7 @@ KBUILD_CFLAGS := -m64 -D__KERNEL__ $(LINUXINCLUDE) -O2  \
 	  -fno-strict-aliasing -fPIC -mcmodel=small \
 	   $(call cc-option, -ffreestanding) \
 	   $(call cc-option, -fno-stack-protector)
-AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
+KBUILD_AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
 LDFLAGS := -m elf_x86_64
 
 LDFLAGS_vmlinux := -T

arch/x86_64/Makefile

@@ -61,18 +61,18 @@ cflags-y += -maccumulate-outgoing-args
 
 # do binutils support CFI?
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_rel_offset rsp${comma}0\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
-AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_rel_offset rsp${comma}0\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
+KBUILD_AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_rel_offset rsp${comma}0\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
 
 # is .cfi_signal_frame supported too?
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
-AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
+KBUILD_AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
 
 cflags-$(CONFIG_CC_STACKPROTECTOR) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh "$(CC)" -fstack-protector )
 cflags-$(CONFIG_CC_STACKPROTECTOR_ALL) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh "$(CC)" -fstack-protector-all )
 
 KBUILD_CFLAGS += $(cflags-y)
 CFLAGS_KERNEL += $(cflags-kernel-y)
-AFLAGS += -m64
+KBUILD_AFLAGS += -m64
 
 head-y := arch/x86/kernel/head_64.o arch/x86/kernel/head64.o arch/x86/kernel/init_task_64.o
 

scripts/Kbuild.include

@@ -81,7 +81,7 @@ as-option = $(call try-run,\
 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
 
 as-instr = $(call try-run,\
-	echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
+	echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 
 # cc-option
 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)

scripts/Makefile.lib

@@ -85,7 +85,7 @@ modname_flags  = $(if $(filter 1,$(words $(modname))),\
                  -D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
 
 _c_flags       = $(KBUILD_CFLAGS) $(EXTRA_CFLAGS) $(CFLAGS_$(basetarget).o)
-_a_flags       = $(AFLAGS) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
+_a_flags       = $(KBUILD_AFLAGS) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
 _cpp_flags     = $(CPPFLAGS) $(EXTRA_CPPFLAGS) $(CPPFLAGS_$(@F))
 
 # If building the kernel in a separate objtree expand all occurrences