| Message ID | 20200827203608.1225689-1-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 1764c3edc66880778604f5053fe2dda7b3ddd2c1 |
| Headers | show |
| Series | [v2] arm64: use a common .arch preamble for inline assembly | expand |
On Thu, Aug 27, 2020 at 01:36:08PM -0700, Sami Tolvanen wrote: > Commit 7c78f67e9bd9 ("arm64: enable tlbi range instructions") breaks > LLVM's integrated assembler, because -Wa,-march is only passed to > external assemblers and therefore, the new instructions are not enabled > when IAS is used. > > This change adds a common architecture version preamble, which can be > used in inline assembly blocks that contain instructions that require > a newer architecture version, and uses it to fix __TLBI_0 and __TLBI_1 > with ARM64_TLB_RANGE. > > Fixes: 7c78f67e9bd9 ("arm64: enable tlbi range instructions") > Link: https://github.com/ClangBuiltLinux/linux/issues/1106 > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> I have verified that this fixes the build with LLVM_IAS=1. Additionally, I have booted a kernel with this patch on my Raspberry Pi and saw no adverse affects through a compilation workload. Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> > --- > Changes in v2: > - Switched to a standard preamble for the architecture version. > > --- > arch/arm64/Makefile | 11 ++++++++--- > arch/arm64/include/asm/compiler.h | 6 ++++++ > arch/arm64/include/asm/tlbflush.h | 6 ++++-- > 3 files changed, 18 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile > index b45f0124cc16..20ab5c9375a5 100644 > --- a/arch/arm64/Makefile > +++ b/arch/arm64/Makefile > @@ -82,8 +82,8 @@ endif > # compiler to generate them and consequently to break the single image contract > # we pass it only to the assembler. This option is utilized only in case of non > # integrated assemblers. > -ifneq ($(CONFIG_AS_HAS_ARMV8_4), y) > -branch-prot-flags-$(CONFIG_AS_HAS_PAC) += -Wa,-march=armv8.3-a > +ifeq ($(CONFIG_AS_HAS_PAC), y) > +asm-arch := armv8.3-a > endif > endif > > @@ -91,7 +91,12 @@ KBUILD_CFLAGS += $(branch-prot-flags-y) > > ifeq ($(CONFIG_AS_HAS_ARMV8_4), y) > # make sure to pass the newest target architecture to -march. > -KBUILD_CFLAGS += -Wa,-march=armv8.4-a > +asm-arch := armv8.4-a > +endif > + > +ifdef asm-arch > +KBUILD_CFLAGS += -Wa,-march=$(asm-arch) \ > + -DARM64_ASM_ARCH='"$(asm-arch)"' > endif > > ifeq ($(CONFIG_SHADOW_CALL_STACK), y) > diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h > index 51a7ce87cdfe..6fb2e6bcc392 100644 > --- a/arch/arm64/include/asm/compiler.h > +++ b/arch/arm64/include/asm/compiler.h > @@ -2,6 +2,12 @@ > #ifndef __ASM_COMPILER_H > #define __ASM_COMPILER_H > > +#ifdef ARM64_ASM_ARCH > +#define ARM64_ASM_PREAMBLE ".arch " ARM64_ASM_ARCH "\n" > +#else > +#define ARM64_ASM_PREAMBLE > +#endif > + > /* > * The EL0/EL1 pointer bits used by a pointer authentication code. > * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply. > diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h > index d493174415db..cc3f5a33ff9c 100644 > --- a/arch/arm64/include/asm/tlbflush.h > +++ b/arch/arm64/include/asm/tlbflush.h > @@ -28,14 +28,16 @@ > * not. The macros handles invoking the asm with or without the > * register argument as appropriate. > */ > -#define __TLBI_0(op, arg) asm ("tlbi " #op "\n" \ > +#define __TLBI_0(op, arg) asm (ARM64_ASM_PREAMBLE \ > + "tlbi " #op "\n" \ > ALTERNATIVE("nop\n nop", \ > "dsb ish\n tlbi " #op, \ > ARM64_WORKAROUND_REPEAT_TLBI, \ > CONFIG_ARM64_WORKAROUND_REPEAT_TLBI) \ > : : ) > > -#define __TLBI_1(op, arg) asm ("tlbi " #op ", %0\n" \ > +#define __TLBI_1(op, arg) asm (ARM64_ASM_PREAMBLE \ > + "tlbi " #op ", %0\n" \ > ALTERNATIVE("nop\n nop", \ > "dsb ish\n tlbi " #op ", %0", \ > ARM64_WORKAROUND_REPEAT_TLBI, \ > > base-commit: 15bc20c6af4ceee97a1f90b43c0e386643c071b4 > -- > 2.28.0.297.g1956fa8f8d-goog >
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index b45f0124cc16..20ab5c9375a5 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -82,8 +82,8 @@ endif # compiler to generate them and consequently to break the single image contract # we pass it only to the assembler. This option is utilized only in case of non # integrated assemblers. -ifneq ($(CONFIG_AS_HAS_ARMV8_4), y) -branch-prot-flags-$(CONFIG_AS_HAS_PAC) += -Wa,-march=armv8.3-a +ifeq ($(CONFIG_AS_HAS_PAC), y) +asm-arch := armv8.3-a endif endif @@ -91,7 +91,12 @@ KBUILD_CFLAGS += $(branch-prot-flags-y) ifeq ($(CONFIG_AS_HAS_ARMV8_4), y) # make sure to pass the newest target architecture to -march. -KBUILD_CFLAGS += -Wa,-march=armv8.4-a +asm-arch := armv8.4-a +endif + +ifdef asm-arch +KBUILD_CFLAGS += -Wa,-march=$(asm-arch) \ + -DARM64_ASM_ARCH='"$(asm-arch)"' endif ifeq ($(CONFIG_SHADOW_CALL_STACK), y) diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index 51a7ce87cdfe..6fb2e6bcc392 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -2,6 +2,12 @@ #ifndef __ASM_COMPILER_H #define __ASM_COMPILER_H +#ifdef ARM64_ASM_ARCH +#define ARM64_ASM_PREAMBLE ".arch " ARM64_ASM_ARCH "\n" +#else +#define ARM64_ASM_PREAMBLE +#endif + /* * The EL0/EL1 pointer bits used by a pointer authentication code. * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply. diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h index d493174415db..cc3f5a33ff9c 100644 --- a/arch/arm64/include/asm/tlbflush.h +++ b/arch/arm64/include/asm/tlbflush.h @@ -28,14 +28,16 @@ * not. The macros handles invoking the asm with or without the * register argument as appropriate. */ -#define __TLBI_0(op, arg) asm ("tlbi " #op "\n" \ +#define __TLBI_0(op, arg) asm (ARM64_ASM_PREAMBLE \ + "tlbi " #op "\n" \ ALTERNATIVE("nop\n nop", \ "dsb ish\n tlbi " #op, \ ARM64_WORKAROUND_REPEAT_TLBI, \ CONFIG_ARM64_WORKAROUND_REPEAT_TLBI) \ : : ) -#define __TLBI_1(op, arg) asm ("tlbi " #op ", %0\n" \ +#define __TLBI_1(op, arg) asm (ARM64_ASM_PREAMBLE \ + "tlbi " #op ", %0\n" \ ALTERNATIVE("nop\n nop", \ "dsb ish\n tlbi " #op ", %0", \ ARM64_WORKAROUND_REPEAT_TLBI, \
Commit 7c78f67e9bd9 ("arm64: enable tlbi range instructions") breaks LLVM's integrated assembler, because -Wa,-march is only passed to external assemblers and therefore, the new instructions are not enabled when IAS is used. This change adds a common architecture version preamble, which can be used in inline assembly blocks that contain instructions that require a newer architecture version, and uses it to fix __TLBI_0 and __TLBI_1 with ARM64_TLB_RANGE. Fixes: 7c78f67e9bd9 ("arm64: enable tlbi range instructions") Link: https://github.com/ClangBuiltLinux/linux/issues/1106 Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- Changes in v2: - Switched to a standard preamble for the architecture version. --- arch/arm64/Makefile | 11 ++++++++--- arch/arm64/include/asm/compiler.h | 6 ++++++ arch/arm64/include/asm/tlbflush.h | 6 ++++-- 3 files changed, 18 insertions(+), 5 deletions(-) base-commit: 15bc20c6af4ceee97a1f90b43c0e386643c071b4