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Commit 91802a8e authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

ARM: pass -marm to gcc by default for both C and assembler 



The Linaro cross toolchain and probably others nowadays default to
building in THUMB2 mode. When building a kernel for a CPU that does
not support THUMB2, the compiler complains about incorrect flags.
We can work around this by setting -marm for all non-T2 builds.

-marm was passed unconditionally for C files previously, but nothing was
passed to the gcc frontend when processing .S files, resulting in a
warning.  The assembler never defaults to ARM unless -Wa,-mthumb is
supplied explicitly, so the files were still assembled correctly.

This patch makes sure that -marm is passed for .S files too, and also
avoids the redundant gcc -marm -mthumb in Thumb kernels.

Without this patch, building assabet_defconfig results in:

usr/initramfs_data.S:1:0: warning: target CPU does not support THUMB instructions [enabled by default]
arch/arm/nwfpe/entry.S:1:0: warning: target CPU does not support THUMB instructions [enabled by default]
firmware/cis/PCMLM28.cis.gen.S:1:0: warning: target CPU does not support THUMB instructions [enabled by default]
(and many more)

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Acked-by: default avatarDave Martin <dave.martin@linaro.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
parent f880b67d

arch/arm/Makefile

+7 −6
Original line number Diff line number Diff line
@@ -21,8 +21,6 @@ endif 
OBJCOPYFLAGS	:=-O binary -R .comment -S

GZFLAGS		:=-9

#KBUILD_CFLAGS	+=-pipe

# Explicitly specifiy 32-bit ARM ISA since toolchain default can be -mthumb:

KBUILD_CFLAGS	+=$(call cc-option,-marm,)



# Never generate .eh_frame

KBUILD_CFLAGS	+= $(call cc-option,-fno-dwarf2-cfi-asm)
@@ -105,17 +103,20 @@ endif 
ifeq ($(CONFIG_THUMB2_KERNEL),y)

AFLAGS_AUTOIT	:=$(call as-option,-Wa$(comma)-mimplicit-it=always,-Wa$(comma)-mauto-it)

AFLAGS_NOWARN	:=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W)

CFLAGS_THUMB2	:=-mthumb $(AFLAGS_AUTOIT) $(AFLAGS_NOWARN)

AFLAGS_THUMB2	:=$(CFLAGS_THUMB2) -Wa$(comma)-mthumb

CFLAGS_ISA	:=-mthumb $(AFLAGS_AUTOIT) $(AFLAGS_NOWARN)

AFLAGS_ISA	:=$(CFLAGS_ISA) -Wa$(comma)-mthumb

# Work around buggy relocation from gas if requested:

ifeq ($(CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11),y)

CFLAGS_MODULE	+=-fno-optimize-sibling-calls

endif

else

CFLAGS_ISA	:=$(call cc-option,-marm,)

AFLAGS_ISA	:=$(CFLAGS_ISA)

endif



# Need -Uarm for gcc < 3.x

KBUILD_CFLAGS	+=$(CFLAGS_ABI) $(CFLAGS_THUMB2) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm

KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(AFLAGS_THUMB2) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float

KBUILD_CFLAGS	+=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm

KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float



CHECKFLAGS	+= -D__arm__