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91cc803d27
commit 3ec5d83d2a
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sat Jan 25 14:19:40 2020 -0800
x86-64: Avoid rep movsb with short distance [BZ #27130]
introduced some regressions on Intel processors without Fast Short REP
MOV (FSRM). Add Avoid_Short_Distance_REP_MOVSB to avoid rep movsb with
short distance only on Intel processors with FSRM. bench-memmove-large
on Skylake server shows that cycles of __memmove_evex_unaligned_erms
improves for the following data size:
before after Improvement
length=4127, align1=3, align2=0: 479.38 349.25 27%
length=4223, align1=9, align2=5: 405.62 333.25 18%
length=8223, align1=3, align2=0: 786.12 496.38 37%
length=8319, align1=9, align2=5: 727.50 501.38 31%
length=16415, align1=3, align2=0: 1436.88 840.00 41%
length=16511, align1=9, align2=5: 1375.50 836.38 39%
length=32799, align1=3, align2=0: 2890.00 1860.12 36%
length=32895, align1=9, align2=5: 2891.38 1931.88 33%
119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/* Assembler macros for x86.
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Copyright (C) 2017-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _X86_SYSDEP_H
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#define _X86_SYSDEP_H 1
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#include <sysdeps/generic/sysdep.h>
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/* __CET__ is defined by GCC with Control-Flow Protection values:
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enum cf_protection_level
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{
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CF_NONE = 0,
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CF_BRANCH = 1 << 0,
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CF_RETURN = 1 << 1,
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CF_FULL = CF_BRANCH | CF_RETURN,
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CF_SET = 1 << 2
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};
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*/
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/* Set if CF_BRANCH (IBT) is enabled. */
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#define X86_FEATURE_1_IBT (1U << 0)
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/* Set if CF_RETURN (SHSTK) is enabled. */
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#define X86_FEATURE_1_SHSTK (1U << 1)
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#ifdef __CET__
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# define CET_ENABLED 1
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# define IBT_ENABLED (__CET__ & X86_FEATURE_1_IBT)
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# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
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#else
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# define CET_ENABLED 0
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# define IBT_ENABLED 0
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# define SHSTK_ENABLED 0
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#endif
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/* Offset for fxsave/xsave area used by _dl_runtime_resolve. Also need
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space to preserve RCX, RDX, RSI, RDI, R8, R9 and RAX. It must be
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aligned to 16 bytes for fxsave and 64 bytes for xsave. */
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#define STATE_SAVE_OFFSET (8 * 7 + 8)
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/* Save SSE, AVX, AVX512, mask and bound registers. */
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#define STATE_SAVE_MASK \
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((1 << 1) | (1 << 2) | (1 << 3) | (1 << 5) | (1 << 6) | (1 << 7))
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/* Constants for bits in __x86_string_control: */
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/* Avoid short distance REP MOVSB. */
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#define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB (1 << 0)
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#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
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#ifdef _CET_ENDBR
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# define _CET_NOTRACK notrack
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#else
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# define _CET_ENDBR
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# define _CET_NOTRACK
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#endif
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/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
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#define ALIGNARG(log2) 1<<log2
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
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/* Define an entry point visible from C. */
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#define ENTRY(name) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),@function; \
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.align ALIGNARG(4); \
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C_LABEL(name) \
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cfi_startproc; \
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_CET_ENDBR; \
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CALL_MCOUNT
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#undef END
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#define END(name) \
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cfi_endproc; \
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ASM_SIZE_DIRECTIVE(name)
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#define ENTRY_CHK(name) ENTRY (name)
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#define END_CHK(name) END (name)
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/* Since C identifiers are not normally prefixed with an underscore
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on this system, the asm identifier `syscall_error' intrudes on the
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C name space. Make sure we use an innocuous name. */
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#define syscall_error __syscall_error
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#define mcount _mcount
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#undef PSEUDO_END
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#define PSEUDO_END(name) \
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END (name)
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/* Local label name for asm code. */
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#ifndef L
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/* ELF-like local names start with `.L'. */
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# define L(name) .L##name
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#endif
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#define atom_text_section .section ".text.atom", "ax"
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#endif /* __ASSEMBLER__ */
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#endif /* _X86_SYSDEP_H */
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