diff options
Diffstat (limited to 'arch/arm64/lib/memset.S')
| -rw-r--r-- | arch/arm64/lib/memset.S | 207 |
1 files changed, 185 insertions, 22 deletions
diff --git a/arch/arm64/lib/memset.S b/arch/arm64/lib/memset.S index 87e4a68fbbbc..7c72dfd36b63 100644 --- a/arch/arm64/lib/memset.S +++ b/arch/arm64/lib/memset.S @@ -1,5 +1,13 @@ /* * Copyright (C) 2013 ARM Ltd. + * Copyright (C) 2013 Linaro. + * + * This code is based on glibc cortex strings work originally authored by Linaro + * and re-licensed under GPLv2 for the Linux kernel. The original code can + * be found @ + * + * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ + * files/head:/src/aarch64/ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -16,6 +24,7 @@ #include <linux/linkage.h> #include <asm/assembler.h> +#include <asm/cache.h> /* * Fill in the buffer with character c (alignment handled by the hardware) @@ -27,27 +36,181 @@ * Returns: * x0 - buf */ + +dstin .req x0 +val .req w1 +count .req x2 +tmp1 .req x3 +tmp1w .req w3 +tmp2 .req x4 +tmp2w .req w4 +zva_len_x .req x5 +zva_len .req w5 +zva_bits_x .req x6 + +A_l .req x7 +A_lw .req w7 +dst .req x8 +tmp3w .req w9 +tmp3 .req x9 + ENTRY(memset) - mov x4, x0 - and w1, w1, #0xff - orr w1, w1, w1, lsl #8 - orr w1, w1, w1, lsl #16 - orr x1, x1, x1, lsl #32 - subs x2, x2, #8 - b.mi 2f -1: str x1, [x4], #8 - subs x2, x2, #8 - b.pl 1b -2: adds x2, x2, #4 - b.mi 3f - sub x2, x2, #4 - str w1, [x4], #4 -3: adds x2, x2, #2 - b.mi 4f - sub x2, x2, #2 - strh w1, [x4], #2 -4: adds x2, x2, #1 - b.mi 5f - strb w1, [x4] -5: ret + mov dst, dstin /* Preserve return value. */ + and A_lw, val, #255 + orr A_lw, A_lw, A_lw, lsl #8 + orr A_lw, A_lw, A_lw, lsl #16 + orr A_l, A_l, A_l, lsl #32 + + cmp count, #15 + b.hi .Lover16_proc + /*All store maybe are non-aligned..*/ + tbz count, #3, 1f + str A_l, [dst], #8 +1: + tbz count, #2, 2f + str A_lw, [dst], #4 +2: + tbz count, #1, 3f + strh A_lw, [dst], #2 +3: + tbz count, #0, 4f + strb A_lw, [dst] +4: + ret + +.Lover16_proc: + /*Whether the start address is aligned with 16.*/ + neg tmp2, dst + ands tmp2, tmp2, #15 + b.eq .Laligned +/* +* The count is not less than 16, we can use stp to store the start 16 bytes, +* then adjust the dst aligned with 16.This process will make the current +* memory address at alignment boundary. +*/ + stp A_l, A_l, [dst] /*non-aligned store..*/ + /*make the dst aligned..*/ + sub count, count, tmp2 + add dst, dst, tmp2 + +.Laligned: + cbz A_l, .Lzero_mem + +.Ltail_maybe_long: + cmp count, #64 + b.ge .Lnot_short +.Ltail63: + ands tmp1, count, #0x30 + b.eq 3f + cmp tmp1w, #0x20 + b.eq 1f + b.lt 2f + stp A_l, A_l, [dst], #16 +1: + stp A_l, A_l, [dst], #16 +2: + stp A_l, A_l, [dst], #16 +/* +* The last store length is less than 16,use stp to write last 16 bytes. +* It will lead some bytes written twice and the access is non-aligned. +*/ +3: + ands count, count, #15 + cbz count, 4f + add dst, dst, count + stp A_l, A_l, [dst, #-16] /* Repeat some/all of last store. */ +4: + 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 +.Lnot_short: + sub dst, dst, #16/* Pre-bias. */ + sub count, count, #64 +1: + stp A_l, A_l, [dst, #16] + stp A_l, A_l, [dst, #32] + stp A_l, A_l, [dst, #48] + stp A_l, A_l, [dst, #64]! + subs count, count, #64 + b.ge 1b + tst count, #0x3f + add dst, dst, #16 + b.ne .Ltail63 +.Lexitfunc: + ret + + /* + * For zeroing memory, check to see if we can use the ZVA feature to + * zero entire 'cache' lines. + */ +.Lzero_mem: + cmp count, #63 + b.le .Ltail63 + /* + * For zeroing small amounts of memory, it's not worth setting up + * the line-clear code. + */ + cmp count, #128 + b.lt .Lnot_short /*count is at least 128 bytes*/ + + mrs tmp1, dczid_el0 + tbnz tmp1, #4, .Lnot_short + mov tmp3w, #4 + and zva_len, tmp1w, #15 /* Safety: other bits reserved. */ + lsl zva_len, tmp3w, zva_len + + ands tmp3w, zva_len, #63 + /* + * ensure the zva_len is not less than 64. + * It is not meaningful to use ZVA if the block size is less than 64. + */ + b.ne .Lnot_short +.Lzero_by_line: + /* + * Compute how far we need to go to become suitably aligned. We're + * already at quad-word alignment. + */ + cmp count, zva_len_x + b.lt .Lnot_short /* Not enough to reach alignment. */ + sub zva_bits_x, zva_len_x, #1 + neg tmp2, dst + ands tmp2, tmp2, zva_bits_x + b.eq 2f /* Already aligned. */ + /* Not aligned, check that there's enough to copy after alignment.*/ + sub tmp1, count, tmp2 + /* + * grantee the remain length to be ZVA is bigger than 64, + * avoid to make the 2f's process over mem range.*/ + cmp tmp1, #64 + ccmp tmp1, zva_len_x, #8, ge /* NZCV=0b1000 */ + b.lt .Lnot_short + /* + * We know that there's at least 64 bytes to zero and that it's safe + * to overrun by 64 bytes. + */ + mov count, tmp1 +1: + stp A_l, A_l, [dst] + stp A_l, A_l, [dst, #16] + stp A_l, A_l, [dst, #32] + subs tmp2, tmp2, #64 + stp A_l, A_l, [dst, #48] + add dst, dst, #64 + b.ge 1b + /* We've overrun a bit, so adjust dst downwards.*/ + add dst, dst, tmp2 +2: + sub count, count, zva_len_x +3: + dc zva, dst + add dst, dst, zva_len_x + subs count, count, zva_len_x + b.ge 3b + ands count, count, zva_bits_x + b.ne .Ltail_maybe_long + ret ENDPROC(memset) |