Clang's integrated assembler does not allow assembly macros defined in one inline asm block using the .macro directive to be used across separate asm blocks. LLVM developers consider this a feature and not a bug, recommending code refactoring:
https://bugs.llvm.org/show_bug.cgi?id=19749 As binutils doesn't allow macros to be redefined, this change adds C preprocessor macros that define the assembly macros globally for binutils and locally for clang's integrated assembler. Suggested-by: Greg Hackmann <ghackm...@google.com> Suggested-by: Nick Desaulniers <ndesaulni...@google.com> Signed-off-by: Sami Tolvanen <samitolva...@google.com> --- arch/arm64/include/asm/kvm_hyp.h | 2 ++ arch/arm64/include/asm/sysreg.h | 71 ++++++++++++++++++++++++++++++---------- 2 files changed, 56 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 4572a9b560fa..6840704ea894 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -29,6 +29,7 @@ ({ \ u64 reg; \ asm volatile(ALTERNATIVE("mrs %0, " __stringify(r##nvh),\ + DEFINE_MRS_S \ "mrs_s %0, " __stringify(r##vh),\ ARM64_HAS_VIRT_HOST_EXTN) \ : "=r" (reg)); \ @@ -39,6 +40,7 @@ do { \ u64 __val = (u64)(v); \ asm volatile(ALTERNATIVE("msr " __stringify(r##nvh) ", %x0",\ + DEFINE_MSR_S \ "msr_s " __stringify(r##vh) ", %x0",\ ARM64_HAS_VIRT_HOST_EXTN) \ : : "rZ" (__val)); \ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index f707fed5886f..1588ac3f3690 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -463,21 +463,58 @@ #include <linux/types.h> -asm( -" .irp num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n" -" .equ .L__reg_num_x\\num, \\num\n" -" .endr\n" +#define ___MRS_MSR_S_REGNUM \ +" .irp num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n" \ +" .equ .L__reg_num_x\\num, \\num\n" \ +" .endr\n" \ " .equ .L__reg_num_xzr, 31\n" -"\n" -" .macro mrs_s, rt, sreg\n" - __emit_inst(0xd5200000|(\\sreg)|(.L__reg_num_\\rt)) + +#define ___MRS_S \ +" .macro mrs_s, rt, sreg\n" \ + __emit_inst(0xd5200000|(\\sreg)|(.L__reg_num_\\rt)) \ " .endm\n" -"\n" -" .macro msr_s, sreg, rt\n" - __emit_inst(0xd5000000|(\\sreg)|(.L__reg_num_\\rt)) + +#define ___MSR_S \ +" .macro msr_s, sreg, rt\n" \ + __emit_inst(0xd5000000|(\\sreg)|(.L__reg_num_\\rt)) \ " .endm\n" + +/* + * llvm-as doesn't allow macros defined in an asm block to be used in other + * asm blocks, which means we cannot define them globally. + */ +#if !defined(CONFIG_CLANG_LTO) +asm( + ___MRS_MSR_S_REGNUM + ___MRS_S + ___MSR_S ); +#undef ___MRS_MSR_S_REGNUM +#define ___MRS_MSR_S_REGNUM +#undef ___MRS_S +#define ___MRS_S +#undef ___MSR_S +#define ___MSR_S +#endif + +#define DEFINE_MRS_S \ + ___MRS_MSR_S_REGNUM \ + ___MRS_S + +#define DEFINE_MSR_S \ + ___MRS_MSR_S_REGNUM \ + ___MSR_S + + +#define __mrs_s(r, v) \ + DEFINE_MRS_S \ +" mrs_s %0, " __stringify(r) : "=r" (v) + +#define __msr_s(r, v) \ + DEFINE_MSR_S \ +" msr_s " __stringify(r) ", %0" : : "r" (v) + /* * Unlike read_cpuid, calls to read_sysreg are never expected to be * optimized away or replaced with synthetic values. @@ -502,15 +539,15 @@ asm( * For registers without architectural names, or simply unsupported by * GAS. */ -#define read_sysreg_s(r) ({ \ - u64 __val; \ - asm volatile("mrs_s %0, " __stringify(r) : "=r" (__val)); \ - __val; \ +#define read_sysreg_s(r) ({ \ + u64 __val; \ + asm volatile(__mrs_s(r, __val)); \ + __val; \ }) -#define write_sysreg_s(v, r) do { \ - u64 __val = (u64)(v); \ - asm volatile("msr_s " __stringify(r) ", %x0" : : "rZ" (__val)); \ +#define write_sysreg_s(v, r) do { \ + u64 __val = (u64)(v); \ + asm volatile(__msr_s(r, __val)); \ } while (0) static inline void config_sctlr_el1(u32 clear, u32 set) -- 2.15.0.403.gc27cc4dac6-goog
