arm64: Import latest memcpy()/memmove() implementation
Import the latest implementation of memcpy(), based on the upstream code of string/aarch64/memcpy.S at commit afd6244 from https://github.com/ARM-software/optimized-routines, and subsuming memmove() in the process. Note that for simplicity Arm have chosen to contribute this code to Linux under GPLv2 rather than the original MIT license. Note also that the needs of the usercopy routines vs. regular memcpy() have now diverged so far that we abandon the shared template idea and the damage which that incurred to the tuning of LDP/STP loops. We'll be back to tackle those routines separately in future. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/3c953af43506581b2422f61952261e76949ba711.1622128527.git.robin.murphy@arm.com Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Robin Murphy
Will Deacon
parent
b6c4ea4841
commit
285133040e
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@ -1,7 +1,7 @@
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# SPDX-License-Identifier: GPL-2.0
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lib-y := clear_user.o delay.o copy_from_user.o \
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copy_to_user.o copy_in_user.o copy_page.o \
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clear_page.o csum.o memchr.o memcpy.o memmove.o \
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clear_page.o csum.o memchr.o memcpy.o \
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memset.o memcmp.o strcmp.o strncmp.o strlen.o \
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strnlen.o strchr.o strrchr.o tishift.o
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@ -1,66 +1,252 @@
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2013 ARM Ltd.
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* Copyright (C) 2013 Linaro.
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* Copyright (c) 2012-2020, Arm Limited.
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*
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* This code is based on glibc cortex strings work originally authored by Linaro
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* be found @
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*
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* http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/
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* files/head:/src/aarch64/
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* Adapted from the original at:
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* https://github.com/ARM-software/optimized-routines/blob/master/string/aarch64/memcpy.S
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/cache.h>
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/*
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* Copy a buffer from src to dest (alignment handled by the hardware)
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/* Assumptions:
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*
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* ARMv8-a, AArch64, unaligned accesses.
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*
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* Parameters:
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* x0 - dest
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* x1 - src
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* x2 - n
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* Returns:
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* x0 - dest
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*/
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.macro ldrb1 reg, ptr, val
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ldrb \reg, [\ptr], \val
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.endm
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.macro strb1 reg, ptr, val
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strb \reg, [\ptr], \val
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.endm
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#define L(label) .L ## label
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.macro ldrh1 reg, ptr, val
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ldrh \reg, [\ptr], \val
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.endm
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#define dstin x0
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#define src x1
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#define count x2
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#define dst x3
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#define srcend x4
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#define dstend x5
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#define A_l x6
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#define A_lw w6
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#define A_h x7
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#define B_l x8
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#define B_lw w8
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#define B_h x9
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#define C_l x10
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#define C_lw w10
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#define C_h x11
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#define D_l x12
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#define D_h x13
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#define E_l x14
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#define E_h x15
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#define F_l x16
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#define F_h x17
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#define G_l count
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#define G_h dst
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#define H_l src
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#define H_h srcend
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#define tmp1 x14
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.macro strh1 reg, ptr, val
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strh \reg, [\ptr], \val
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.endm
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/* This implementation handles overlaps and supports both memcpy and memmove
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from a single entry point. It uses unaligned accesses and branchless
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sequences to keep the code small, simple and improve performance.
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.macro ldr1 reg, ptr, val
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ldr \reg, [\ptr], \val
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.endm
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Copies are split into 3 main cases: small copies of up to 32 bytes, medium
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copies of up to 128 bytes, and large copies. The overhead of the overlap
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check is negligible since it is only required for large copies.
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.macro str1 reg, ptr, val
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str \reg, [\ptr], \val
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.endm
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.macro ldp1 reg1, reg2, ptr, val
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ldp \reg1, \reg2, [\ptr], \val
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.endm
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.macro stp1 reg1, reg2, ptr, val
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stp \reg1, \reg2, [\ptr], \val
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.endm
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Large copies use a software pipelined loop processing 64 bytes per iteration.
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The destination pointer is 16-byte aligned to minimize unaligned accesses.
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The loop tail is handled by always copying 64 bytes from the end.
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*/
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SYM_FUNC_START_ALIAS(__memmove)
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SYM_FUNC_START_WEAK_ALIAS_PI(memmove)
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SYM_FUNC_START_ALIAS(__memcpy)
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SYM_FUNC_START_WEAK_PI(memcpy)
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#include "copy_template.S"
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add srcend, src, count
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add dstend, dstin, count
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cmp count, 128
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b.hi L(copy_long)
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cmp count, 32
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b.hi L(copy32_128)
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/* Small copies: 0..32 bytes. */
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cmp count, 16
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b.lo L(copy16)
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ldp A_l, A_h, [src]
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ldp D_l, D_h, [srcend, -16]
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stp A_l, A_h, [dstin]
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stp D_l, D_h, [dstend, -16]
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ret
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/* Copy 8-15 bytes. */
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L(copy16):
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tbz count, 3, L(copy8)
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ldr A_l, [src]
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ldr A_h, [srcend, -8]
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str A_l, [dstin]
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str A_h, [dstend, -8]
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ret
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.p2align 3
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/* Copy 4-7 bytes. */
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L(copy8):
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tbz count, 2, L(copy4)
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ldr A_lw, [src]
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ldr B_lw, [srcend, -4]
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str A_lw, [dstin]
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str B_lw, [dstend, -4]
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ret
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/* Copy 0..3 bytes using a branchless sequence. */
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L(copy4):
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cbz count, L(copy0)
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lsr tmp1, count, 1
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ldrb A_lw, [src]
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ldrb C_lw, [srcend, -1]
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ldrb B_lw, [src, tmp1]
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strb A_lw, [dstin]
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strb B_lw, [dstin, tmp1]
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strb C_lw, [dstend, -1]
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L(copy0):
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ret
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.p2align 4
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/* Medium copies: 33..128 bytes. */
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L(copy32_128):
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ldp A_l, A_h, [src]
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ldp B_l, B_h, [src, 16]
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ldp C_l, C_h, [srcend, -32]
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ldp D_l, D_h, [srcend, -16]
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cmp count, 64
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b.hi L(copy128)
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stp A_l, A_h, [dstin]
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stp B_l, B_h, [dstin, 16]
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stp C_l, C_h, [dstend, -32]
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stp D_l, D_h, [dstend, -16]
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ret
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.p2align 4
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/* Copy 65..128 bytes. */
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L(copy128):
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ldp E_l, E_h, [src, 32]
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ldp F_l, F_h, [src, 48]
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cmp count, 96
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b.ls L(copy96)
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ldp G_l, G_h, [srcend, -64]
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ldp H_l, H_h, [srcend, -48]
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stp G_l, G_h, [dstend, -64]
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stp H_l, H_h, [dstend, -48]
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L(copy96):
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stp A_l, A_h, [dstin]
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stp B_l, B_h, [dstin, 16]
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stp E_l, E_h, [dstin, 32]
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stp F_l, F_h, [dstin, 48]
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stp C_l, C_h, [dstend, -32]
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stp D_l, D_h, [dstend, -16]
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ret
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.p2align 4
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/* Copy more than 128 bytes. */
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L(copy_long):
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/* Use backwards copy if there is an overlap. */
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sub tmp1, dstin, src
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cbz tmp1, L(copy0)
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cmp tmp1, count
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b.lo L(copy_long_backwards)
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/* Copy 16 bytes and then align dst to 16-byte alignment. */
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ldp D_l, D_h, [src]
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and tmp1, dstin, 15
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bic dst, dstin, 15
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sub src, src, tmp1
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add count, count, tmp1 /* Count is now 16 too large. */
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ldp A_l, A_h, [src, 16]
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stp D_l, D_h, [dstin]
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ldp B_l, B_h, [src, 32]
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ldp C_l, C_h, [src, 48]
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ldp D_l, D_h, [src, 64]!
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subs count, count, 128 + 16 /* Test and readjust count. */
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b.ls L(copy64_from_end)
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L(loop64):
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stp A_l, A_h, [dst, 16]
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ldp A_l, A_h, [src, 16]
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stp B_l, B_h, [dst, 32]
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ldp B_l, B_h, [src, 32]
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stp C_l, C_h, [dst, 48]
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ldp C_l, C_h, [src, 48]
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stp D_l, D_h, [dst, 64]!
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ldp D_l, D_h, [src, 64]!
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subs count, count, 64
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b.hi L(loop64)
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/* Write the last iteration and copy 64 bytes from the end. */
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L(copy64_from_end):
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ldp E_l, E_h, [srcend, -64]
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stp A_l, A_h, [dst, 16]
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ldp A_l, A_h, [srcend, -48]
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stp B_l, B_h, [dst, 32]
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ldp B_l, B_h, [srcend, -32]
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stp C_l, C_h, [dst, 48]
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ldp C_l, C_h, [srcend, -16]
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stp D_l, D_h, [dst, 64]
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stp E_l, E_h, [dstend, -64]
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stp A_l, A_h, [dstend, -48]
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stp B_l, B_h, [dstend, -32]
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stp C_l, C_h, [dstend, -16]
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ret
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.p2align 4
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/* Large backwards copy for overlapping copies.
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Copy 16 bytes and then align dst to 16-byte alignment. */
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L(copy_long_backwards):
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ldp D_l, D_h, [srcend, -16]
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and tmp1, dstend, 15
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sub srcend, srcend, tmp1
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sub count, count, tmp1
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ldp A_l, A_h, [srcend, -16]
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stp D_l, D_h, [dstend, -16]
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ldp B_l, B_h, [srcend, -32]
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ldp C_l, C_h, [srcend, -48]
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ldp D_l, D_h, [srcend, -64]!
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sub dstend, dstend, tmp1
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subs count, count, 128
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b.ls L(copy64_from_start)
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L(loop64_backwards):
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stp A_l, A_h, [dstend, -16]
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ldp A_l, A_h, [srcend, -16]
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stp B_l, B_h, [dstend, -32]
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ldp B_l, B_h, [srcend, -32]
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stp C_l, C_h, [dstend, -48]
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ldp C_l, C_h, [srcend, -48]
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stp D_l, D_h, [dstend, -64]!
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ldp D_l, D_h, [srcend, -64]!
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subs count, count, 64
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b.hi L(loop64_backwards)
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/* Write the last iteration and copy 64 bytes from the start. */
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L(copy64_from_start):
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ldp G_l, G_h, [src, 48]
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stp A_l, A_h, [dstend, -16]
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ldp A_l, A_h, [src, 32]
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stp B_l, B_h, [dstend, -32]
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ldp B_l, B_h, [src, 16]
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stp C_l, C_h, [dstend, -48]
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ldp C_l, C_h, [src]
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stp D_l, D_h, [dstend, -64]
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stp G_l, G_h, [dstin, 48]
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stp A_l, A_h, [dstin, 32]
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stp B_l, B_h, [dstin, 16]
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stp C_l, C_h, [dstin]
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ret
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SYM_FUNC_END_PI(memcpy)
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EXPORT_SYMBOL(memcpy)
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SYM_FUNC_END_ALIAS(__memcpy)
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EXPORT_SYMBOL(__memcpy)
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SYM_FUNC_END_ALIAS_PI(memmove)
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EXPORT_SYMBOL(memmove)
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SYM_FUNC_END_ALIAS(__memmove)
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EXPORT_SYMBOL(__memmove)
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@ -1,189 +0,0 @@
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2013 ARM Ltd.
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* Copyright (C) 2013 Linaro.
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*
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* This code is based on glibc cortex strings work originally authored by Linaro
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* be found @
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*
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* http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/
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* files/head:/src/aarch64/
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/cache.h>
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/*
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* Move a buffer from src to test (alignment handled by the hardware).
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* If dest <= src, call memcpy, otherwise copy in reverse order.
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*
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* Parameters:
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* x0 - dest
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* x1 - src
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* x2 - n
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* Returns:
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* x0 - dest
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*/
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dstin .req x0
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src .req x1
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count .req x2
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tmp1 .req x3
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tmp1w .req w3
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tmp2 .req x4
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tmp2w .req w4
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tmp3 .req x5
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tmp3w .req w5
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dst .req x6
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A_l .req x7
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A_h .req x8
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B_l .req x9
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B_h .req x10
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C_l .req x11
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C_h .req x12
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D_l .req x13
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D_h .req x14
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SYM_FUNC_START_ALIAS(__memmove)
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SYM_FUNC_START_WEAK_PI(memmove)
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cmp dstin, src
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b.lo __memcpy
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add tmp1, src, count
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cmp dstin, tmp1
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b.hs __memcpy /* No overlap. */
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add dst, dstin, count
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add src, src, count
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cmp count, #16
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b.lo .Ltail15 /*probably non-alignment accesses.*/
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ands tmp2, src, #15 /* Bytes to reach alignment. */
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b.eq .LSrcAligned
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sub count, count, tmp2
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/*
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* process the aligned offset length to make the src aligned firstly.
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* those extra instructions' cost is acceptable. It also make the
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* coming accesses are based on aligned address.
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*/
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tbz tmp2, #0, 1f
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ldrb tmp1w, [src, #-1]!
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strb tmp1w, [dst, #-1]!
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1:
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tbz tmp2, #1, 2f
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ldrh tmp1w, [src, #-2]!
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strh tmp1w, [dst, #-2]!
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2:
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tbz tmp2, #2, 3f
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ldr tmp1w, [src, #-4]!
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str tmp1w, [dst, #-4]!
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3:
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tbz tmp2, #3, .LSrcAligned
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ldr tmp1, [src, #-8]!
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str tmp1, [dst, #-8]!
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.LSrcAligned:
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cmp count, #64
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b.ge .Lcpy_over64
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/*
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* Deal with small copies quickly by dropping straight into the
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* exit block.
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*/
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.Ltail63:
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/*
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* Copy up to 48 bytes of data. At this point we only need the
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* bottom 6 bits of count to be accurate.
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*/
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ands tmp1, count, #0x30
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b.eq .Ltail15
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cmp tmp1w, #0x20
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b.eq 1f
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b.lt 2f
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ldp A_l, A_h, [src, #-16]!
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stp A_l, A_h, [dst, #-16]!
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1:
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ldp A_l, A_h, [src, #-16]!
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stp A_l, A_h, [dst, #-16]!
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2:
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ldp A_l, A_h, [src, #-16]!
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stp A_l, A_h, [dst, #-16]!
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.Ltail15:
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tbz count, #3, 1f
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ldr tmp1, [src, #-8]!
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str tmp1, [dst, #-8]!
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1:
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tbz count, #2, 2f
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ldr tmp1w, [src, #-4]!
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str tmp1w, [dst, #-4]!
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2:
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tbz count, #1, 3f
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ldrh tmp1w, [src, #-2]!
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strh tmp1w, [dst, #-2]!
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3:
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tbz count, #0, .Lexitfunc
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ldrb tmp1w, [src, #-1]
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strb tmp1w, [dst, #-1]
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.Lexitfunc:
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ret
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||||
|
||||
.Lcpy_over64:
|
||||
subs count, count, #128
|
||||
b.ge .Lcpy_body_large
|
||||
/*
|
||||
* Less than 128 bytes to copy, so handle 64 bytes here and then jump
|
||||
* to the tail.
|
||||
*/
|
||||
ldp A_l, A_h, [src, #-16]
|
||||
stp A_l, A_h, [dst, #-16]
|
||||
ldp B_l, B_h, [src, #-32]
|
||||
ldp C_l, C_h, [src, #-48]
|
||||
stp B_l, B_h, [dst, #-32]
|
||||
stp C_l, C_h, [dst, #-48]
|
||||
ldp D_l, D_h, [src, #-64]!
|
||||
stp D_l, D_h, [dst, #-64]!
|
||||
|
||||
tst count, #0x3f
|
||||
b.ne .Ltail63
|
||||
ret
|
||||
|
||||
/*
|
||||
* Critical loop. Start at a new cache line boundary. Assuming
|
||||
* 64 bytes per line this ensures the entire loop is in one line.
|
||||
*/
|
||||
.p2align L1_CACHE_SHIFT
|
||||
.Lcpy_body_large:
|
||||
/* pre-load 64 bytes data. */
|
||||
ldp A_l, A_h, [src, #-16]
|
||||
ldp B_l, B_h, [src, #-32]
|
||||
ldp C_l, C_h, [src, #-48]
|
||||
ldp D_l, D_h, [src, #-64]!
|
||||
1:
|
||||
/*
|
||||
* interlace the load of next 64 bytes data block with store of the last
|
||||
* loaded 64 bytes data.
|
||||
*/
|
||||
stp A_l, A_h, [dst, #-16]
|
||||
ldp A_l, A_h, [src, #-16]
|
||||
stp B_l, B_h, [dst, #-32]
|
||||
ldp B_l, B_h, [src, #-32]
|
||||
stp C_l, C_h, [dst, #-48]
|
||||
ldp C_l, C_h, [src, #-48]
|
||||
stp D_l, D_h, [dst, #-64]!
|
||||
ldp D_l, D_h, [src, #-64]!
|
||||
subs count, count, #64
|
||||
b.ge 1b
|
||||
stp A_l, A_h, [dst, #-16]
|
||||
stp B_l, B_h, [dst, #-32]
|
||||
stp C_l, C_h, [dst, #-48]
|
||||
stp D_l, D_h, [dst, #-64]!
|
||||
|
||||
tst count, #0x3f
|
||||
b.ne .Ltail63
|
||||
ret
|
||||
SYM_FUNC_END_PI(memmove)
|
||||
EXPORT_SYMBOL(memmove)
|
||||
SYM_FUNC_END_ALIAS(__memmove)
|
||||
EXPORT_SYMBOL(__memmove)
|
||||
Loading…
Reference in New Issue