| Message ID | a651d5eaf312c771c9d2e0160ddd905550bbd4e3.1585507235.git.stefan@agner.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ARM: warn if pre-UAL assembler syntax is used | expand |
On Sun, Mar 29, 2020 at 11:43 AM Stefan Agner <stefan@agner.ch> wrote: > > Remove the -mno-warn-deprecated assembler flag to make sure the GNU > assembler warns in case non-unified syntax is used. > > This also prevents a warning when building with Clang and enabling its > integrated assembler: > clang-10: error: unsupported argument '-mno-warn-deprecated' to option 'Wa,' > > GCC before 5.1 emits pre-UAL assembler. This can lead to warnings if > inline assembler explicitly switches to unified syntax by using the > ".syntax unified" directive (e.g. arch/arm/include/asm/unified.h). > Hence keep the flag for GCC versions before 5.1. > > This is a second attempt of commit e8c24bbda7d5 ("ARM: 8846/1: warn if > divided syntax assembler is used") which has subsequently been reverted > with commit b752bb405a13 ("Revert "ARM: 8846/1: warn if divided syntax > assembler is used""). > > Signed-off-by: Stefan Agner <stefan@agner.ch> Thanks for the added context. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > Changes in v2: > - Reference revert commit b752bb405a13 ("Revert "ARM: 8846/1: warn if > divided syntax assembler is used"") > - Reword commit message > > arch/arm/Makefile | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index 1fc32b611f8a..b37bb985a3c2 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -119,21 +119,25 @@ ifeq ($(CONFIG_CC_IS_CLANG),y) > CFLAGS_ABI += -meabi gnu > endif > > -# Accept old syntax despite ".syntax unified" > -AFLAGS_NOWARN :=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) > - > ifeq ($(CONFIG_THUMB2_KERNEL),y) > -CFLAGS_ISA :=-mthumb -Wa,-mimplicit-it=always $(AFLAGS_NOWARN) > +CFLAGS_ISA :=-mthumb -Wa,-mimplicit-it=always > AFLAGS_ISA :=$(CFLAGS_ISA) -Wa$(comma)-mthumb > # Work around buggy relocation from gas if requested: > ifeq ($(CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11),y) > KBUILD_CFLAGS_MODULE +=-fno-optimize-sibling-calls > endif > else > -CFLAGS_ISA :=$(call cc-option,-marm,) $(AFLAGS_NOWARN) > +CFLAGS_ISA :=$(call cc-option,-marm,) > AFLAGS_ISA :=$(CFLAGS_ISA) > endif > > +ifeq ($(CONFIG_CC_IS_GCC),y) > +ifeq ($(call cc-ifversion, -lt, 0501, y), y) > +# GCC <5.1 emits pre-UAL code and causes assembler warnings, suppress them > +CFLAGS_ISA +=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) > +endif > +endif > + > # Need -Uarm for gcc < 3.x > 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) $(tune-y) -include asm/unified.h -msoft-float > -- > 2.25.1 >
diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 1fc32b611f8a..b37bb985a3c2 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -119,21 +119,25 @@ ifeq ($(CONFIG_CC_IS_CLANG),y) CFLAGS_ABI += -meabi gnu endif -# Accept old syntax despite ".syntax unified" -AFLAGS_NOWARN :=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) - ifeq ($(CONFIG_THUMB2_KERNEL),y) -CFLAGS_ISA :=-mthumb -Wa,-mimplicit-it=always $(AFLAGS_NOWARN) +CFLAGS_ISA :=-mthumb -Wa,-mimplicit-it=always AFLAGS_ISA :=$(CFLAGS_ISA) -Wa$(comma)-mthumb # Work around buggy relocation from gas if requested: ifeq ($(CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11),y) KBUILD_CFLAGS_MODULE +=-fno-optimize-sibling-calls endif else -CFLAGS_ISA :=$(call cc-option,-marm,) $(AFLAGS_NOWARN) +CFLAGS_ISA :=$(call cc-option,-marm,) AFLAGS_ISA :=$(CFLAGS_ISA) endif +ifeq ($(CONFIG_CC_IS_GCC),y) +ifeq ($(call cc-ifversion, -lt, 0501, y), y) +# GCC <5.1 emits pre-UAL code and causes assembler warnings, suppress them +CFLAGS_ISA +=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) +endif +endif + # Need -Uarm for gcc < 3.x 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
Remove the -mno-warn-deprecated assembler flag to make sure the GNU assembler warns in case non-unified syntax is used. This also prevents a warning when building with Clang and enabling its integrated assembler: clang-10: error: unsupported argument '-mno-warn-deprecated' to option 'Wa,' GCC before 5.1 emits pre-UAL assembler. This can lead to warnings if inline assembler explicitly switches to unified syntax by using the ".syntax unified" directive (e.g. arch/arm/include/asm/unified.h). Hence keep the flag for GCC versions before 5.1. This is a second attempt of commit e8c24bbda7d5 ("ARM: 8846/1: warn if divided syntax assembler is used") which has subsequently been reverted with commit b752bb405a13 ("Revert "ARM: 8846/1: warn if divided syntax assembler is used""). Signed-off-by: Stefan Agner <stefan@agner.ch> --- Changes in v2: - Reference revert commit b752bb405a13 ("Revert "ARM: 8846/1: warn if divided syntax assembler is used"") - Reword commit message arch/arm/Makefile | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)