In memset_64.S, the macros expand to `.weak MEMSET ... .globl MEMSET` which will produce a STB_WEAK MEMSET with GNU as but STB_GLOBAL MEMSET with LLVM's integrated assembler before LLVM 12. LLVM 12 (since https://reviews.llvm.org/D90108) will error on such an overridden symbol binding. memcpy_64.S is similar.
Port http://lore.kernel.org/r/20201103012358.168682-1-mask...@google.com ("x86_64: Change .weak to SYM_FUNC_START_WEAK for arch/x86/lib/mem*_64.S") to fix the issue. Additionally, port SYM_L_WEAK and SYM_FUNC_START_WEAK from include/linux/linkage.h to tools/perf/util/include/linux/linkage.h Fixes: 7d7d1bf1d1da ("perf bench: Copy kernel files needed to build mem{cpy,set} x86_64 benchmarks") Link: https://lore.kernel.org/r/20201103012358.168682-1-mask...@google.com Signed-off-by: Fangrui Song <mask...@google.com> --- tools/arch/x86/lib/memcpy_64.S | 4 +--- tools/arch/x86/lib/memset_64.S | 4 +--- tools/perf/util/include/linux/linkage.h | 7 +++++++ 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/tools/arch/x86/lib/memcpy_64.S b/tools/arch/x86/lib/memcpy_64.S index 0b5b8ae56bd9..9428f251df0f 100644 --- a/tools/arch/x86/lib/memcpy_64.S +++ b/tools/arch/x86/lib/memcpy_64.S @@ -16,8 +16,6 @@ * to a jmp to memcpy_erms which does the REP; MOVSB mem copy. */ -.weak memcpy - /* * memcpy - Copy a memory block. * @@ -30,7 +28,7 @@ * rax original destination */ SYM_FUNC_START_ALIAS(__memcpy) -SYM_FUNC_START_LOCAL(memcpy) +SYM_FUNC_START_WEAK(memcpy) ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \ "jmp memcpy_erms", X86_FEATURE_ERMS diff --git a/tools/arch/x86/lib/memset_64.S b/tools/arch/x86/lib/memset_64.S index fd5d25a474b7..1f9b11f9244d 100644 --- a/tools/arch/x86/lib/memset_64.S +++ b/tools/arch/x86/lib/memset_64.S @@ -5,8 +5,6 @@ #include <asm/cpufeatures.h> #include <asm/alternative-asm.h> -.weak memset - /* * ISO C memset - set a memory block to a byte value. This function uses fast * string to get better performance than the original function. The code is @@ -18,7 +16,7 @@ * * rax original destination */ -SYM_FUNC_START_ALIAS(memset) +SYM_FUNC_START_WEAK(memset) SYM_FUNC_START(__memset) /* * Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended diff --git a/tools/perf/util/include/linux/linkage.h b/tools/perf/util/include/linux/linkage.h index b8a5159361b4..0e493bf3151b 100644 --- a/tools/perf/util/include/linux/linkage.h +++ b/tools/perf/util/include/linux/linkage.h @@ -25,6 +25,7 @@ /* SYM_L_* -- linkage of symbols */ #define SYM_L_GLOBAL(name) .globl name +#define SYM_L_WEAK(name) .weak name #define SYM_L_LOCAL(name) /* nothing */ #define ALIGN __ALIGN @@ -78,6 +79,12 @@ SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) #endif +/* SYM_FUNC_START_WEAK -- use for weak functions */ +#ifndef SYM_FUNC_START_WEAK +#define SYM_FUNC_START_WEAK(name) \ + SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) +#endif + /* SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed function */ #ifndef SYM_FUNC_END_ALIAS #define SYM_FUNC_END_ALIAS(name) \ -- 2.29.1.341.ge80a0c044ae-goog
