| Message ID | 20220516210954.1660716-1-ndesaulniers@google.com |
|---|---|
| Headers | show |
| Series | pass -march= only to compiler | expand |
+ Ard (I messed up my command line invocation of git send-email, sorry for more noise) https://lore.kernel.org/llvm/20220516210954.1660716-1-ndesaulniers@google.com/ On Mon, May 16, 2022 at 2:10 PM Nick Desaulniers <ndesaulniers@google.com> wrote: > > When both -march= and -Wa,-march= are specified for assembler or > assembler-with-cpp sources, GCC and Clang will prefer the -Wa,-march= > value but Clang will warn that -march= is unused. > > warning: argument unused during compilation: '-march=armv6k' > [-Wunused-command-line-argument] > > This is the top group of warnings we observe when using clang to > assemble the kernel via `ARCH=arm make LLVM=1`. > > Arnd sent a v2 of my previous patch > https://lore.kernel.org/linux-arm-kernel/20210928154143.2106903-14-arnd@kernel.org/ > I added yet a few more instances I found since then. > > Fixing this will allow us to enable > -Werror=unused-command-line-argument for clang builds. > > Nick Desaulniers (4): > ARM: remove lazy evaluation in Makefile > ARM: use .arch directives instead of assembler command line flags > ARM: only use -mtp=cp15 for the compiler > ARM: pass -march= only to compiler > > arch/arm/Makefile | 76 ++++++++++++++++------------- > arch/arm/boot/compressed/Makefile | 1 - > arch/arm/common/Makefile | 2 - > arch/arm/common/mcpm_head.S | 2 + > arch/arm/common/vlock.S | 2 + > arch/arm/kernel/Makefile | 2 - > arch/arm/kernel/hyp-stub.S | 2 + > arch/arm/kernel/swp_emulate.c | 1 + > arch/arm/lib/Makefile | 4 -- > arch/arm/lib/delay-loop.S | 4 ++ > arch/arm/mach-at91/Makefile | 3 -- > arch/arm/mach-at91/pm_suspend.S | 4 ++ > arch/arm/mach-imx/Makefile | 3 -- > arch/arm/mach-imx/headsmp.S | 2 + > arch/arm/mach-imx/resume-imx6.S | 2 + > arch/arm/mach-imx/suspend-imx6.S | 2 + > arch/arm/mach-mvebu/Makefile | 3 -- > arch/arm/mach-mvebu/coherency_ll.S | 1 + > arch/arm/mach-mvebu/pmsu.c | 1 + > arch/arm/mach-npcm/Makefile | 2 - > arch/arm/mach-npcm/headsmp.S | 2 + > arch/arm/mach-tegra/Makefile | 2 - > arch/arm/mach-tegra/reset-handler.S | 2 + > arch/arm/mach-tegra/sleep-tegra20.S | 2 + > arch/arm/mach-tegra/sleep-tegra30.S | 2 + > arch/arm/mm/Makefile | 15 ------ > arch/arm/mm/abort-ev6.S | 1 + > arch/arm/mm/abort-ev7.S | 1 + > arch/arm/mm/cache-v6.S | 2 + > arch/arm/mm/cache-v7.S | 2 + > arch/arm/mm/cache-v7m.S | 2 + > arch/arm/mm/copypage-feroceon.c | 1 + > arch/arm/mm/proc-v6.S | 2 + > arch/arm/mm/proc-v7-2level.S | 2 + > arch/arm/mm/proc-v7.S | 2 + > arch/arm/mm/tlb-v6.S | 2 + > arch/arm/mm/tlb-v7.S | 2 + > drivers/memory/Makefile | 2 - > drivers/memory/ti-emif-sram-pm.S | 1 + > drivers/soc/bcm/brcmstb/pm/Makefile | 1 - > drivers/soc/bcm/brcmstb/pm/s2-arm.S | 1 + > 41 files changed, 94 insertions(+), 74 deletions(-) > > > base-commit: 0ac824f379fba2c2b17b75fd5ada69cd68c66348 > -- > 2.36.0.550.gb090851708-goog >
+ Ard (I messed up my command line invocation of git send-email, sorry for more noise) https://lore.kernel.org/llvm/20220516210954.1660716-1-ndesaulniers@google.com/ On Mon, May 16, 2022 at 2:10 PM Nick Desaulniers <ndesaulniers@google.com> wrote: > > arch-y and tune-y used lazy evaluation since they used to contain > cc-option checks. They don't any longer, so just eagerly evaluate these > command line flags. > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/arm/Makefile | 60 +++++++++++++++++++++-------------------------- > 1 file changed, 27 insertions(+), 33 deletions(-) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index a2391b8de5a5..99a7ed7e9f09 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -60,44 +60,38 @@ KBUILD_CFLAGS += $(call cc-option,-fno-ipa-sra) > # Note that GCC does not numerically define an architecture version > # macro, but instead defines a whole series of macros which makes > # testing for a specific architecture or later rather impossible. > -arch-$(CONFIG_CPU_32v7M) =-D__LINUX_ARM_ARCH__=7 -march=armv7-m > -arch-$(CONFIG_CPU_32v7) =-D__LINUX_ARM_ARCH__=7 -march=armv7-a > -arch-$(CONFIG_CPU_32v6) =-D__LINUX_ARM_ARCH__=6 -march=armv6 > -# Only override the compiler option if ARMv6. The ARMv6K extensions are > +arch-$(CONFIG_CPU_32v7M) :=-D__LINUX_ARM_ARCH__=7 -march=armv7-m > +arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 -march=armv7-a > +arch-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 -march=armv6 > +# Only override the compiler opt:ion if ARMv6. The ARMv6K extensions are > # always available in ARMv7 > ifeq ($(CONFIG_CPU_32v6),y) > -arch-$(CONFIG_CPU_32v6K) =-D__LINUX_ARM_ARCH__=6 -march=armv6k > +arch-$(CONFIG_CPU_32v6K) :=-D__LINUX_ARM_ARCH__=6 -march=armv6k > endif > -arch-$(CONFIG_CPU_32v5) =-D__LINUX_ARM_ARCH__=5 -march=armv5te > -arch-$(CONFIG_CPU_32v4T) =-D__LINUX_ARM_ARCH__=4 -march=armv4t > -arch-$(CONFIG_CPU_32v4) =-D__LINUX_ARM_ARCH__=4 -march=armv4 > -arch-$(CONFIG_CPU_32v3) =-D__LINUX_ARM_ARCH__=3 -march=armv3m > - > -# Evaluate arch cc-option calls now > -arch-y := $(arch-y) > +arch-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 -march=armv5te > +arch-$(CONFIG_CPU_32v4T) :=-D__LINUX_ARM_ARCH__=4 -march=armv4t > +arch-$(CONFIG_CPU_32v4) :=-D__LINUX_ARM_ARCH__=4 -march=armv4 > +arch-$(CONFIG_CPU_32v3) :=-D__LINUX_ARM_ARCH__=3 -march=armv3m > > # This selects how we optimise for the processor. > -tune-$(CONFIG_CPU_ARM7TDMI) =-mtune=arm7tdmi > -tune-$(CONFIG_CPU_ARM720T) =-mtune=arm7tdmi > -tune-$(CONFIG_CPU_ARM740T) =-mtune=arm7tdmi > -tune-$(CONFIG_CPU_ARM9TDMI) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_ARM940T) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_ARM946E) =-mtune=arm9e > -tune-$(CONFIG_CPU_ARM920T) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_ARM922T) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_ARM925T) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_ARM926T) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_FA526) =-mtune=arm9tdmi > -tune-$(CONFIG_CPU_SA110) =-mtune=strongarm110 > -tune-$(CONFIG_CPU_SA1100) =-mtune=strongarm1100 > -tune-$(CONFIG_CPU_XSCALE) =-mtune=xscale > -tune-$(CONFIG_CPU_XSC3) =-mtune=xscale > -tune-$(CONFIG_CPU_FEROCEON) =-mtune=xscale > -tune-$(CONFIG_CPU_V6) =-mtune=arm1136j-s > -tune-$(CONFIG_CPU_V6K) =-mtune=arm1136j-s > - > -# Evaluate tune cc-option calls now > -tune-y := $(tune-y) > +tune-$(CONFIG_CPU_ARM7TDMI) :=-mtune=arm7tdmi > +tune-$(CONFIG_CPU_ARM720T) :=-mtune=arm7tdmi > +tune-$(CONFIG_CPU_ARM740T) :=-mtune=arm7tdmi > +tune-$(CONFIG_CPU_ARM9TDMI) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_ARM940T) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_ARM946E) :=-mtune=arm9e > +tune-$(CONFIG_CPU_ARM920T) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_ARM922T) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_ARM925T) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_ARM926T) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_FA526) :=-mtune=arm9tdmi > +tune-$(CONFIG_CPU_SA110) :=-mtune=strongarm110 > +tune-$(CONFIG_CPU_SA1100) :=-mtune=strongarm1100 > +tune-$(CONFIG_CPU_XSCALE) :=-mtune=xscale > +tune-$(CONFIG_CPU_XSC3) :=-mtune=xscale > +tune-$(CONFIG_CPU_FEROCEON) :=-mtune=xscale > +tune-$(CONFIG_CPU_V6) :=-mtune=arm1136j-s > +tune-$(CONFIG_CPU_V6K) :=-mtune=arm1136j-s > > ifeq ($(CONFIG_AEABI),y) > CFLAGS_ABI :=-mabi=aapcs-linux -mfpu=vfp > -- > 2.36.0.550.gb090851708-goog >
+ Ard (I messed up my command line invocation of git send-email, sorry for more noise) https://lore.kernel.org/llvm/20220516210954.1660716-1-ndesaulniers@google.com/ On Mon, May 16, 2022 at 2:10 PM Nick Desaulniers <ndesaulniers@google.com> wrote: > > Avoids an error from the assembler for CONFIG_THUMB2 kernels: > > clang-15: error: hardware TLS register is not supported for the thumbv4t > sub-architecture > > This flag only makes sense to pass to the compiler, not the assembler. > > Perhaps CFLAGS_ABI can be renamed to CPPFLAGS_ABI to reflect that they > will be passed to both the compiler and assembler for sources that > require pre-processing. > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/arm/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index 99a7ed7e9f09..1029c2503aef 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -108,7 +108,7 @@ CFLAGS_ABI += -meabi gnu > endif > > ifeq ($(CONFIG_CURRENT_POINTER_IN_TPIDRURO),y) > -CFLAGS_ABI += -mtp=cp15 > +KBUILD_CFLAGS += -mtp=cp15 > endif > > # Accept old syntax despite ".syntax unified" > -- > 2.36.0.550.gb090851708-goog >
+ Ard (I messed up my command line invocation of git send-email, sorry for more noise) https://lore.kernel.org/llvm/20220516210954.1660716-1-ndesaulniers@google.com/ On Mon, May 16, 2022 at 2:10 PM Nick Desaulniers <ndesaulniers@google.com> wrote: > > When both -march= and -Wa,-march= are specified for assembler or > assembler-with-cpp sources, GCC and Clang will prefer the -Wa,-march= > value but Clang will warn that -march= is unused. > > warning: argument unused during compilation: '-march=armv6k' > [-Wunused-command-line-argument] > > This is the top group of warnings we observe when using clang to > assemble the kernel via `ARCH=arm make LLVM=1`. > > Split the arch-y make variable into two, so that -march= flags only get > passed to the compiler, not the assembler. -D flags are added to > KBUILD_CPPFLAGS which is used for both C and assembler-with-cpp sources. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1315 > Link: https://github.com/ClangBuiltLinux/linux/issues/1587 > Link: https://lore.kernel.org/llvm/628249e8.1c69fb81.d20fd.02ea@mx.google.com/ > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/arm/Makefile | 34 ++++++++++++++++++++++++---------- > 1 file changed, 24 insertions(+), 10 deletions(-) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index 1029c2503aef..47a300f6f99c 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -57,21 +57,34 @@ endif > KBUILD_CFLAGS += $(call cc-option,-fno-ipa-sra) > > # This selects which instruction set is used. > +arch-$(CONFIG_CPU_32v7M) :=-march=armv7-m > +arch-$(CONFIG_CPU_32v7) :=-march=armv7-a > +arch-$(CONFIG_CPU_32v6) :=-march=armv6 > +# Only override the compiler option if ARMv6. The ARMv6K extensions are > +# always available in ARMv7 > +ifeq ($(CONFIG_CPU_32v6),y) > +arch-$(CONFIG_CPU_32v6K) :=-march=armv6k > +endif > +arch-$(CONFIG_CPU_32v5) :=-march=armv5te > +arch-$(CONFIG_CPU_32v4T) :=-march=armv4t > +arch-$(CONFIG_CPU_32v4) :=-march=armv4 > +arch-$(CONFIG_CPU_32v3) :=-march=armv3m > + > # Note that GCC does not numerically define an architecture version > # macro, but instead defines a whole series of macros which makes > # testing for a specific architecture or later rather impossible. > -arch-$(CONFIG_CPU_32v7M) :=-D__LINUX_ARM_ARCH__=7 -march=armv7-m > -arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 -march=armv7-a > -arch-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 -march=armv6 > -# Only override the compiler opt:ion if ARMv6. The ARMv6K extensions are > +cpp-$(CONFIG_CPU_32v7M) :=-D__LINUX_ARM_ARCH__=7 > +cpp-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 > +cpp-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 > +# Only override the compiler option if ARMv6. The ARMv6K extensions are > # always available in ARMv7 > ifeq ($(CONFIG_CPU_32v6),y) > -arch-$(CONFIG_CPU_32v6K) :=-D__LINUX_ARM_ARCH__=6 -march=armv6k > +cpp-$(CONFIG_CPU_32v6K) :=-D__LINUX_ARM_ARCH__=6 > endif > -arch-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 -march=armv5te > -arch-$(CONFIG_CPU_32v4T) :=-D__LINUX_ARM_ARCH__=4 -march=armv4t > -arch-$(CONFIG_CPU_32v4) :=-D__LINUX_ARM_ARCH__=4 -march=armv4 > -arch-$(CONFIG_CPU_32v3) :=-D__LINUX_ARM_ARCH__=3 -march=armv3m > +cpp-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 > +cpp-$(CONFIG_CPU_32v4T) :=-D__LINUX_ARM_ARCH__=4 > +cpp-$(CONFIG_CPU_32v4) :=-D__LINUX_ARM_ARCH__=4 > +cpp-$(CONFIG_CPU_32v3) :=-D__LINUX_ARM_ARCH__=3 > > # This selects how we optimise for the processor. > tune-$(CONFIG_CPU_ARM7TDMI) :=-mtune=arm7tdmi > @@ -123,8 +136,9 @@ AFLAGS_ISA :=$(CFLAGS_ISA) > endif > > # Need -Uarm for gcc < 3.x > +KBUILD_CPPFLAGS +=$(cpp-y) > 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) $(tune-y) -include asm/unified.h -msoft-float > +KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) -Wa,$(arch-y) $(tune-y) -include asm/unified.h -msoft-float > > CHECKFLAGS += -D__arm__ > > -- > 2.36.0.550.gb090851708-goog >