From: Sam Tebbs <sam.te...@arm.com> Import the latest version of Cortex Strings' memmove function.
The upstream source is src/aarch64/memmove.S as of commit 99b01ddb8e41 in https://git.linaro.org/toolchain/cortex-strings.git. Signed-off-by: Sam Tebbs <sam.te...@arm.com> [ rm: update attribution, expand commit message ] Signed-off-by: Robin Murphy <robin.mur...@arm.com> Signed-off-by: Oliver Swede <oli.sw...@arm.com> --- arch/arm64/lib/memmove.S | 232 +++++++++++++-------------------------- 1 file changed, 78 insertions(+), 154 deletions(-) diff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S index 02cda2e33bde..d0977d0ad745 100644 --- a/arch/arm64/lib/memmove.S +++ b/arch/arm64/lib/memmove.S @@ -1,13 +1,12 @@ /* SPDX-License-Identifier: GPL-2.0-only */ /* - * Copyright (C) 2013 ARM Ltd. - * Copyright (C) 2013 Linaro. + * Copyright (c) 2013 Linaro Limited. All rights reserved. + * Copyright (c) 2015 ARM Ltd. All rights reserved. * - * This code is based on glibc cortex strings work originally authored by Linaro - * be found @ + * This code is based on glibc Cortex Strings work originally authored by + * Linaro, found at: * - * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ - * files/head:/src/aarch64/ + * https://git.linaro.org/toolchain/cortex-strings.git */ #include <linux/linkage.h> @@ -25,165 +24,90 @@ * Returns: * x0 - dest */ -dstin .req x0 -src .req x1 -count .req x2 -tmp1 .req x3 -tmp1w .req w3 -tmp2 .req x4 -tmp2w .req w4 -tmp3 .req x5 -tmp3w .req w5 -dst .req x6 +/* Parameters and result. */ +#define dstin x0 +#define src x1 +#define count x2 +#define srcend x3 +#define dstend x4 +#define tmp1 x5 +#define A_l x6 +#define A_h x7 +#define B_l x8 +#define B_h x9 +#define C_l x10 +#define C_h x11 +#define D_l x12 +#define D_h x13 +#define E_l count +#define E_h tmp1 -A_l .req x7 -A_h .req x8 -B_l .req x9 -B_h .req x10 -C_l .req x11 -C_h .req x12 -D_l .req x13 -D_h .req x14 +/* All memmoves up to 96 bytes are done by memcpy as it supports overlaps. + Larger backwards copies are also handled by memcpy. The only remaining + case is forward large copies. The destination is aligned, and an + unrolled loop processes 64 bytes per iteration. +*/ - .weak memmove + .weak memmove SYM_FUNC_START_ALIAS(__memmove) SYM_FUNC_START_PI(memmove) - cmp dstin, src - b.lo __memcpy - add tmp1, src, count - cmp dstin, tmp1 - b.hs __memcpy /* No overlap. */ + sub tmp1, dstin, src + cmp count, 96 + ccmp tmp1, count, 2, hi + b.hs __memcpy - add dst, dstin, count - add src, src, count - cmp count, #16 - b.lo .Ltail15 /*probably non-alignment accesses.*/ + cbz tmp1, 3f + add dstend, dstin, count + add srcend, src, count - ands tmp2, src, #15 /* Bytes to reach alignment. */ - b.eq .LSrcAligned - sub count, count, tmp2 - /* - * process the aligned offset length to make the src aligned firstly. - * those extra instructions' cost is acceptable. It also make the - * coming accesses are based on aligned address. - */ - tbz tmp2, #0, 1f - ldrb tmp1w, [src, #-1]! - strb tmp1w, [dst, #-1]! -1: - tbz tmp2, #1, 2f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -2: - tbz tmp2, #2, 3f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! -3: - tbz tmp2, #3, .LSrcAligned - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! - -.LSrcAligned: - cmp count, #64 - b.ge .Lcpy_over64 + /* Align dstend to 16 byte alignment so that we don't cross cache line + boundaries on both loads and stores. There are at least 96 bytes + to copy, so copy 16 bytes unaligned and then align. The loop + copies 64 bytes per iteration and prefetches one iteration ahead. */ - /* - * Deal with small copies quickly by dropping straight into the - * exit block. - */ -.Ltail63: - /* - * Copy up to 48 bytes of data. At this point we only need the - * bottom 6 bits of count to be accurate. - */ - ands tmp1, count, #0x30 - b.eq .Ltail15 - cmp tmp1w, #0x20 - b.eq 1f - b.lt 2f - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! + and tmp1, dstend, 15 + ldp D_l, D_h, [srcend, -16] + sub srcend, srcend, tmp1 + sub count, count, tmp1 + ldp A_l, A_h, [srcend, -16] + stp D_l, D_h, [dstend, -16] + ldp B_l, B_h, [srcend, -32] + ldp C_l, C_h, [srcend, -48] + ldp D_l, D_h, [srcend, -64]! + sub dstend, dstend, tmp1 + subs count, count, 128 + b.ls 2f + nop 1: - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! -2: - ldp A_l, A_h, [src, #-16]! - stp A_l, A_h, [dst, #-16]! + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [srcend, -16] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [srcend, -32] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [srcend, -48] + stp D_l, D_h, [dstend, -64]! + ldp D_l, D_h, [srcend, -64]! + subs count, count, 64 + b.hi 1b -.Ltail15: - tbz count, #3, 1f - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! -1: - tbz count, #2, 2f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! + /* Write the last full set of 64 bytes. The remainder is at most 64 + bytes, so it is safe to always copy 64 bytes from the start even if + there is just 1 byte left. */ 2: - tbz count, #1, 3f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -3: - tbz count, #0, .Lexitfunc - ldrb tmp1w, [src, #-1] - strb tmp1w, [dst, #-1] - -.Lexitfunc: - ret - -.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]! + ldp E_l, E_h, [src, 48] + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [src, 32] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [src, 16] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [src] + stp D_l, D_h, [dstend, -64] + stp E_l, E_h, [dstin, 48] + stp A_l, A_h, [dstin, 32] + stp B_l, B_h, [dstin, 16] + stp C_l, C_h, [dstin] +3: ret - tst count, #0x3f - b.ne .Ltail63 - ret SYM_FUNC_END_PI(memmove) EXPORT_SYMBOL(memmove) SYM_FUNC_END_ALIAS(__memmove) -- 2.17.1
