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ad2fac552c
Add a framework for selecting from one of multiple implementations of a function based on amd64 architecture level (cf. amd64 SysV ABI supplement). Sponsored by: The FreeBSD Foundation Approved by: kib Reviewed by: jrtc27 Differential Revision: https://reviews.freebsd.org/D40693
91 lines
3.4 KiB
C
91 lines
3.4 KiB
C
/*-
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* Copyright (c) 2023 The FreeBSD Foundation
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*
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* This software was developed by Robert Clausecker <fuz@FreeBSD.org>
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ''AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE
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*/
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/* must be macros so they can be accessed from assembly */
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#define X86_64_SCALAR 0 /* disable SIMD optimisations */
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#define X86_64_BASELINE 1 /* CMOV, CX8, FPU, FXSR, MMX, OSFXSR, SSE, SSE2 */
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#define X86_64_V2 2 /* CMPXCHG16B, LAHF-SAHF, POPCNT, SSE3, SSSE3, SSE4_1, SSE4_2 */
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#define X86_64_V3 3 /* AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, OSXSAVE */
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#define X86_64_V4 4 /* AVX512F, AVX512BW, AVX512CD, AVX512DQ, AVX512VL */
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#define X86_64_MAX X86_64_V4 /* highest supported architecture level */
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#define X86_64_UNDEFINED -1 /* architecture level not set yet */
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#ifndef __ASSEMBLER__
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#include <dlfcn.h>
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dlfunc_t __archlevel_resolve(u_int, u_int, u_int, u_int,
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int32_t[X86_64_MAX + 1]) __hidden;
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#else
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#include <machine/asm.h>
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#define ARCHRESOLVE(func) \
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.globl CNAME(func); \
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.type CNAME(func), @gnu_indirect_function; \
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.set CNAME(func), __CONCAT(func,_resolver); \
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ARCHENTRY(func, resolver); \
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lea __CONCAT(func,_funcs)(%rip), %r8; \
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jmp CNAME(__archlevel_resolve); \
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ARCHEND(func, resolver)
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/*
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* The func_funcs array stores the location of the implementations
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* as the distance from the func_funcs array to the function. Due
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* to compiling for the medium code model, a 32 bit integer suffices
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* to hold the distance.
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*
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* Doing it this way both saves storage and avoids giving rtld
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* relocations to process at load time.
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*/
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#define ARCHFUNCS(func) \
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ARCHRESOLVE(func); \
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.section .rodata; \
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.align 4; \
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__CONCAT(func,_funcs):
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#define NOARCHFUNC \
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.4byte 0
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#define ARCHFUNC(func, level) \
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.4byte __CONCAT(__CONCAT(func,_),level) - __CONCAT(func,_funcs)
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#define ENDARCHFUNCS(func) \
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.zero 4*(X86_64_MAX+1)-(.-__CONCAT(func,_funcs)); \
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.size __CONCAT(func,_funcs), .-__CONCAT(func,_funcs)
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#define ARCHENTRY(func, level) \
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_START_ENTRY; \
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.type __CONCAT(__CONCAT(func,_),level), @function; \
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__CONCAT(__CONCAT(func,_),level):; \
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.cfi_startproc
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#define ARCHEND(func, level) \
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END(__CONCAT(__CONCAT(func,_),level))
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#endif /* __ASSEMBLER__ */
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