--- zzzz-none-000/linux-3.10.107/arch/x86/lib/memset_64.S 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/x86/lib/memset_64.S 2021-02-04 17:41:59.000000000 +0000 @@ -1,23 +1,33 @@ /* Copyright 2002 Andi Kleen, SuSE Labs */ #include -#include #include #include +.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 * simpler and shorter than the orignal function as well. - * + * * rdi destination - * rsi value (char) - * rdx count (bytes) - * + * rsi value (char) + * rdx count (bytes) + * * rax original destination - */ - .section .altinstr_replacement, "ax", @progbits -.Lmemset_c: + */ +ENTRY(memset) +ENTRY(__memset) + /* + * Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended + * to use it when possible. If not available, use fast string instructions. + * + * Otherwise, use original memset function. + */ + ALTERNATIVE_2 "jmp memset_orig", "", X86_FEATURE_REP_GOOD, \ + "jmp memset_erms", X86_FEATURE_ERMS + movq %rdi,%r9 movq %rdx,%rcx andl $7,%edx @@ -31,8 +41,8 @@ rep stosb movq %r9,%rax ret -.Lmemset_e: - .previous +ENDPROC(memset) +ENDPROC(__memset) /* * ISO C memset - set a memory block to a byte value. This function uses @@ -45,20 +55,16 @@ * * rax original destination */ - .section .altinstr_replacement, "ax", @progbits -.Lmemset_c_e: +ENTRY(memset_erms) movq %rdi,%r9 movb %sil,%al movq %rdx,%rcx rep stosb movq %r9,%rax ret -.Lmemset_e_e: - .previous +ENDPROC(memset_erms) -ENTRY(memset) -ENTRY(__memset) - CFI_STARTPROC +ENTRY(memset_orig) movq %rdi,%r10 /* expand byte value */ @@ -70,7 +76,6 @@ movl %edi,%r9d andl $7,%r9d jnz .Lbad_alignment - CFI_REMEMBER_STATE .Lafter_bad_alignment: movq %rdx,%rcx @@ -120,7 +125,6 @@ movq %r10,%rax ret - CFI_RESTORE_STATE .Lbad_alignment: cmpq $7,%rdx jbe .Lhandle_7 @@ -131,24 +135,4 @@ subq %r8,%rdx jmp .Lafter_bad_alignment .Lfinal: - CFI_ENDPROC -ENDPROC(memset) -ENDPROC(__memset) - - /* Some CPUs support enhanced REP MOVSB/STOSB feature. - * It is recommended to use this when possible. - * - * If enhanced REP MOVSB/STOSB feature is not available, use fast string - * instructions. - * - * Otherwise, use original memset function. - * - * In .altinstructions section, ERMS feature is placed after REG_GOOD - * feature to implement the right patch order. - */ - .section .altinstructions,"a" - altinstruction_entry memset,.Lmemset_c,X86_FEATURE_REP_GOOD,\ - .Lfinal-memset,.Lmemset_e-.Lmemset_c - altinstruction_entry memset,.Lmemset_c_e,X86_FEATURE_ERMS, \ - .Lfinal-memset,.Lmemset_e_e-.Lmemset_c_e - .previous +ENDPROC(memset_orig)