Messages in this thread | | | Date | Mon, 16 Nov 2020 14:02:11 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf bench: Update arch/x86/lib/mem{cpy,set}_64.S |
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Em Tue, Nov 03, 2020 at 04:56:09PM -0800, Fangrui Song escreveu: > 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-maskray@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
Sorry, I noticed this just now and I have done this update already, will send to Linus soon.
- Arnaldo
> 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-maskray@google.com > Signed-off-by: Fangrui Song <maskray@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 >
--
- Arnaldo
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