glibc/sysdeps/x86_64/dl-trampoline.S
H.J. Lu f82a6fc223 x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve [BZ #21265]
In _dl_runtime_resolve, use fxsave/xsave/xsavec to preserve all vector,
mask and bound registers.  It simplifies _dl_runtime_resolve and supports
different calling conventions.  ld.so code size is reduced by more than
1 KB.  However, use fxsave/xsave/xsavec takes a little bit more cycles
than saving and restoring vector and bound registers individually.

Latency for _dl_runtime_resolve to lookup the function, foo, from one
shared library plus libc.so:

                             Before    After     Change

Westmere (SSE)/fxsave         345      866       151%
IvyBridge (AVX)/xsave         420      643       53%
Haswell (AVX)/xsave           713      1252      75%
Skylake (AVX+MPX)/xsavec      559      719       28%
Skylake (AVX512+MPX)/xsavec   145      272       87%
Ryzen (AVX)/xsavec            280      553       97%

This is the worst case where portion of time spent for saving and
restoring registers is bigger than majority of cases.  With smaller
_dl_runtime_resolve code size, overall performance impact is negligible.

On IvyBridge, differences in build and test time of binutils with lazy
binding GCC and binutils are noises.  On Westmere, differences in
bootstrap and "makc check" time of GCC 7 with lazy binding GCC and
binutils are also noises.

	[BZ #21265]
	* sysdeps/x86/cpu-features-offsets.sym (XSAVE_STATE_SIZE_OFFSET):
	New.
	* sysdeps/x86/cpu-features.c: Include <libc-pointer-arith.h>.
	(get_common_indeces): Set xsave_state_size, xsave_state_full_size
	and bit_arch_XSAVEC_Usable if needed.
	(init_cpu_features): Remove bit_arch_Use_dl_runtime_resolve_slow
	and bit_arch_Use_dl_runtime_resolve_opt.
	* sysdeps/x86/cpu-features.h (bit_arch_Use_dl_runtime_resolve_opt):
	Removed.
	(bit_arch_Use_dl_runtime_resolve_slow): Likewise.
	(bit_arch_Prefer_No_AVX512): Updated.
	(bit_arch_MathVec_Prefer_No_AVX512): Likewise.
	(bit_arch_XSAVEC_Usable): New.
	(STATE_SAVE_OFFSET): Likewise.
	(STATE_SAVE_MASK): Likewise.
	[__ASSEMBLER__]: Include <cpu-features-offsets.h>.
	(cpu_features): Add xsave_state_size and xsave_state_full_size.
	(index_arch_Use_dl_runtime_resolve_opt): Removed.
	(index_arch_Use_dl_runtime_resolve_slow): Likewise.
	(index_arch_XSAVEC_Usable): New.
	* sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)):
	Support XSAVEC_Usable.  Remove Use_dl_runtime_resolve_slow.
	* sysdeps/x86_64/Makefile (tst-x86_64-1-ENV): New if tunables
	is enabled.
	* sysdeps/x86_64/dl-machine.h (elf_machine_runtime_setup):
	Replace _dl_runtime_resolve_sse, _dl_runtime_resolve_avx,
	_dl_runtime_resolve_avx_slow, _dl_runtime_resolve_avx_opt,
	_dl_runtime_resolve_avx512 and _dl_runtime_resolve_avx512_opt
	with _dl_runtime_resolve_fxsave, _dl_runtime_resolve_xsave and
	_dl_runtime_resolve_xsavec.
	* sysdeps/x86_64/dl-trampoline.S (DL_RUNTIME_UNALIGNED_VEC_SIZE):
	Removed.
	(DL_RUNTIME_RESOLVE_REALIGN_STACK): Check STATE_SAVE_ALIGNMENT
	instead of VEC_SIZE.
	(REGISTER_SAVE_BND0): Removed.
	(REGISTER_SAVE_BND1): Likewise.
	(REGISTER_SAVE_BND3): Likewise.
	(REGISTER_SAVE_RAX): Always defined to 0.
	(VMOV): Removed.
	(_dl_runtime_resolve_avx): Likewise.
	(_dl_runtime_resolve_avx_slow): Likewise.
	(_dl_runtime_resolve_avx_opt): Likewise.
	(_dl_runtime_resolve_avx512): Likewise.
	(_dl_runtime_resolve_avx512_opt): Likewise.
	(_dl_runtime_resolve_sse): Likewise.
	(_dl_runtime_resolve_sse_vex): Likewise.
	(USE_FXSAVE): New.
	(_dl_runtime_resolve_fxsave): Likewise.
	(USE_XSAVE): Likewise.
	(_dl_runtime_resolve_xsave): Likewise.
	(USE_XSAVEC): Likewise.
	(_dl_runtime_resolve_xsavec): Likewise.
	* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve_avx512):
	Removed.
	(_dl_runtime_resolve_avx512_opt): Likewise.
	(_dl_runtime_resolve_avx): Likewise.
	(_dl_runtime_resolve_avx_opt): Likewise.
	(_dl_runtime_resolve_sse): Likewise.
	(_dl_runtime_resolve_sse_vex): Likewise.
	(_dl_runtime_resolve_fxsave): New.
	(_dl_runtime_resolve_xsave): Likewise.
	(_dl_runtime_resolve_xsavec): Likewise.

(cherry picked from commit b52b0d793d)
2017-10-22 07:41:00 -07:00

119 lines
3.5 KiB
ArmAsm

/* PLT trampolines. x86-64 version.
Copyright (C) 2004-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <config.h>
#include <sysdep.h>
#include <cpu-features.h>
#include <link-defines.h>
#ifndef DL_STACK_ALIGNMENT
/* Due to GCC bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
__tls_get_addr may be called with 8-byte stack alignment. Although
this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't assume
that stack will be always aligned at 16 bytes. We use unaligned
16-byte move to load and store SSE registers, which has no penalty
on modern processors if stack is 16-byte aligned. */
# define DL_STACK_ALIGNMENT 8
#endif
/* True if _dl_runtime_resolve should align stack for STATE_SAVE or align
stack to 16 bytes before calling _dl_fixup. */
#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
(STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
|| 16 > DL_STACK_ALIGNMENT)
/* Area on stack to save and restore registers used for parameter
passing when calling _dl_fixup. */
#ifdef __ILP32__
# define PRESERVE_BND_REGS_PREFIX
#else
# ifdef HAVE_MPX_SUPPORT
# define PRESERVE_BND_REGS_PREFIX bnd
# else
# define PRESERVE_BND_REGS_PREFIX .byte 0xf2
# endif
#endif
#define REGISTER_SAVE_RAX 0
#define REGISTER_SAVE_RCX (REGISTER_SAVE_RAX + 8)
#define REGISTER_SAVE_RDX (REGISTER_SAVE_RCX + 8)
#define REGISTER_SAVE_RSI (REGISTER_SAVE_RDX + 8)
#define REGISTER_SAVE_RDI (REGISTER_SAVE_RSI + 8)
#define REGISTER_SAVE_R8 (REGISTER_SAVE_RDI + 8)
#define REGISTER_SAVE_R9 (REGISTER_SAVE_R8 + 8)
#define RESTORE_AVX
#define VEC_SIZE 64
#define VMOVA vmovdqa64
#define VEC(i) zmm##i
#define _dl_runtime_profile _dl_runtime_profile_avx512
#include "dl-trampoline.h"
#undef _dl_runtime_profile
#undef VEC
#undef VMOVA
#undef VEC_SIZE
#define VEC_SIZE 32
#define VMOVA vmovdqa
#define VEC(i) ymm##i
#define _dl_runtime_profile _dl_runtime_profile_avx
#include "dl-trampoline.h"
#undef _dl_runtime_profile
#undef VEC
#undef VMOVA
#undef VEC_SIZE
/* movaps/movups is 1-byte shorter. */
#define VEC_SIZE 16
#define VMOVA movaps
#define VEC(i) xmm##i
#define _dl_runtime_profile _dl_runtime_profile_sse
#undef RESTORE_AVX
#include "dl-trampoline.h"
#undef _dl_runtime_profile
#undef VEC
#undef VMOVA
#undef VEC_SIZE
#define USE_FXSAVE
#define STATE_SAVE_ALIGNMENT 16
#define _dl_runtime_resolve _dl_runtime_resolve_fxsave
#include "dl-trampoline.h"
#undef _dl_runtime_resolve
#undef USE_FXSAVE
#undef STATE_SAVE_ALIGNMENT
#define USE_XSAVE
#define STATE_SAVE_ALIGNMENT 64
#define _dl_runtime_resolve _dl_runtime_resolve_xsave
#include "dl-trampoline.h"
#undef _dl_runtime_resolve
#undef USE_XSAVE
#undef STATE_SAVE_ALIGNMENT
#define USE_XSAVEC
#define STATE_SAVE_ALIGNMENT 64
#define _dl_runtime_resolve _dl_runtime_resolve_xsavec
#include "dl-trampoline.h"
#undef _dl_runtime_resolve
#undef USE_XSAVEC
#undef STATE_SAVE_ALIGNMENT