/* SPDX-License-Identifier: GPL-2.0-only */
/*
- * Copyright (C) 2013 ARM Ltd.
- * Copyright (C) 2013 Linaro.
+ * Copyright (c) 2012-2020, Arm Limited.
*
- * This code is based on glibc cortex strings work originally authored by Linaro
- * be found @
- *
- * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/
- * files/head:/src/aarch64/
+ * Adapted from the original at:
+ * https://github.com/ARM-software/optimized-routines/blob/master/string/aarch64/memcpy.S
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
-#include <asm/cache.h>
-/*
- * Copy a buffer from src to dest (alignment handled by the hardware)
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64, unaligned accesses.
*
- * Parameters:
- * x0 - dest
- * x1 - src
- * x2 - n
- * Returns:
- * x0 - dest
*/
- .macro ldrb1 reg, ptr, val
- ldrb \reg, [\ptr], \val
- .endm
-
- .macro strb1 reg, ptr, val
- strb \reg, [\ptr], \val
- .endm
- .macro ldrh1 reg, ptr, val
- ldrh \reg, [\ptr], \val
- .endm
+#define L(label) .L ## label
- .macro strh1 reg, ptr, val
- strh \reg, [\ptr], \val
- .endm
+#define dstin x0
+#define src x1
+#define count x2
+#define dst x3
+#define srcend x4
+#define dstend x5
+#define A_l x6
+#define A_lw w6
+#define A_h x7
+#define B_l x8
+#define B_lw w8
+#define B_h x9
+#define C_l x10
+#define C_lw w10
+#define C_h x11
+#define D_l x12
+#define D_h x13
+#define E_l x14
+#define E_h x15
+#define F_l x16
+#define F_h x17
+#define G_l count
+#define G_h dst
+#define H_l src
+#define H_h srcend
+#define tmp1 x14
- .macro ldr1 reg, ptr, val
- ldr \reg, [\ptr], \val
- .endm
+/* This implementation handles overlaps and supports both memcpy and memmove
+ from a single entry point. It uses unaligned accesses and branchless
+ sequences to keep the code small, simple and improve performance.
- .macro str1 reg, ptr, val
- str \reg, [\ptr], \val
- .endm
+ Copies are split into 3 main cases: small copies of up to 32 bytes, medium
+ copies of up to 128 bytes, and large copies. The overhead of the overlap
+ check is negligible since it is only required for large copies.
- .macro ldp1 reg1, reg2, ptr, val
- ldp \reg1, \reg2, [\ptr], \val
- .endm
-
- .macro stp1 reg1, reg2, ptr, val
- stp \reg1, \reg2, [\ptr], \val
- .endm
+ Large copies use a software pipelined loop processing 64 bytes per iteration.
+ The destination pointer is 16-byte aligned to minimize unaligned accesses.
+ The loop tail is handled by always copying 64 bytes from the end.
+*/
+SYM_FUNC_START_ALIAS(__memmove)
+SYM_FUNC_START_WEAK_ALIAS_PI(memmove)
SYM_FUNC_START_ALIAS(__memcpy)
SYM_FUNC_START_WEAK_PI(memcpy)
-#include "copy_template.S"
+ add srcend, src, count
+ add dstend, dstin, count
+ cmp count, 128
+ b.hi L(copy_long)
+ cmp count, 32
+ b.hi L(copy32_128)
+
+ /* Small copies: 0..32 bytes. */
+ cmp count, 16
+ b.lo L(copy16)
+ ldp A_l, A_h, [src]
+ ldp D_l, D_h, [srcend, -16]
+ stp A_l, A_h, [dstin]
+ stp D_l, D_h, [dstend, -16]
+ ret
+
+ /* Copy 8-15 bytes. */
+L(copy16):
+ tbz count, 3, L(copy8)
+ ldr A_l, [src]
+ ldr A_h, [srcend, -8]
+ str A_l, [dstin]
+ str A_h, [dstend, -8]
+ ret
+
+ .p2align 3
+ /* Copy 4-7 bytes. */
+L(copy8):
+ tbz count, 2, L(copy4)
+ ldr A_lw, [src]
+ ldr B_lw, [srcend, -4]
+ str A_lw, [dstin]
+ str B_lw, [dstend, -4]
+ ret
+
+ /* Copy 0..3 bytes using a branchless sequence. */
+L(copy4):
+ cbz count, L(copy0)
+ lsr tmp1, count, 1
+ ldrb A_lw, [src]
+ ldrb C_lw, [srcend, -1]
+ ldrb B_lw, [src, tmp1]
+ strb A_lw, [dstin]
+ strb B_lw, [dstin, tmp1]
+ strb C_lw, [dstend, -1]
+L(copy0):
+ ret
+
+ .p2align 4
+ /* Medium copies: 33..128 bytes. */
+L(copy32_128):
+ ldp A_l, A_h, [src]
+ ldp B_l, B_h, [src, 16]
+ ldp C_l, C_h, [srcend, -32]
+ ldp D_l, D_h, [srcend, -16]
+ cmp count, 64
+ b.hi L(copy128)
+ stp A_l, A_h, [dstin]
+ stp B_l, B_h, [dstin, 16]
+ stp C_l, C_h, [dstend, -32]
+ stp D_l, D_h, [dstend, -16]
ret
+
+ .p2align 4
+ /* Copy 65..128 bytes. */
+L(copy128):
+ ldp E_l, E_h, [src, 32]
+ ldp F_l, F_h, [src, 48]
+ cmp count, 96
+ b.ls L(copy96)
+ ldp G_l, G_h, [srcend, -64]
+ ldp H_l, H_h, [srcend, -48]
+ stp G_l, G_h, [dstend, -64]
+ stp H_l, H_h, [dstend, -48]
+L(copy96):
+ stp A_l, A_h, [dstin]
+ stp B_l, B_h, [dstin, 16]
+ stp E_l, E_h, [dstin, 32]
+ stp F_l, F_h, [dstin, 48]
+ stp C_l, C_h, [dstend, -32]
+ stp D_l, D_h, [dstend, -16]
+ ret
+
+ .p2align 4
+ /* Copy more than 128 bytes. */
+L(copy_long):
+ /* Use backwards copy if there is an overlap. */
+ sub tmp1, dstin, src
+ cbz tmp1, L(copy0)
+ cmp tmp1, count
+ b.lo L(copy_long_backwards)
+
+ /* Copy 16 bytes and then align dst to 16-byte alignment. */
+
+ ldp D_l, D_h, [src]
+ and tmp1, dstin, 15
+ bic dst, dstin, 15
+ sub src, src, tmp1
+ add count, count, tmp1 /* Count is now 16 too large. */
+ ldp A_l, A_h, [src, 16]
+ stp D_l, D_h, [dstin]
+ ldp B_l, B_h, [src, 32]
+ ldp C_l, C_h, [src, 48]
+ ldp D_l, D_h, [src, 64]!
+ subs count, count, 128 + 16 /* Test and readjust count. */
+ b.ls L(copy64_from_end)
+
+L(loop64):
+ 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.hi L(loop64)
+
+ /* Write the last iteration and copy 64 bytes from the end. */
+L(copy64_from_end):
+ ldp E_l, E_h, [srcend, -64]
+ stp A_l, A_h, [dst, 16]
+ ldp A_l, A_h, [srcend, -48]
+ stp B_l, B_h, [dst, 32]
+ ldp B_l, B_h, [srcend, -32]
+ stp C_l, C_h, [dst, 48]
+ ldp C_l, C_h, [srcend, -16]
+ stp D_l, D_h, [dst, 64]
+ stp E_l, E_h, [dstend, -64]
+ stp A_l, A_h, [dstend, -48]
+ stp B_l, B_h, [dstend, -32]
+ stp C_l, C_h, [dstend, -16]
+ ret
+
+ .p2align 4
+
+ /* Large backwards copy for overlapping copies.
+ Copy 16 bytes and then align dst to 16-byte alignment. */
+L(copy_long_backwards):
+ ldp D_l, D_h, [srcend, -16]
+ and tmp1, dstend, 15
+ 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 L(copy64_from_start)
+
+L(loop64_backwards):
+ 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 L(loop64_backwards)
+
+ /* Write the last iteration and copy 64 bytes from the start. */
+L(copy64_from_start):
+ ldp G_l, G_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 G_l, G_h, [dstin, 48]
+ stp A_l, A_h, [dstin, 32]
+ stp B_l, B_h, [dstin, 16]
+ stp C_l, C_h, [dstin]
+ ret
+
SYM_FUNC_END_PI(memcpy)
EXPORT_SYMBOL(memcpy)
SYM_FUNC_END_ALIAS(__memcpy)
EXPORT_SYMBOL(__memcpy)
+SYM_FUNC_END_ALIAS_PI(memmove)
+EXPORT_SYMBOL(memmove)
+SYM_FUNC_END_ALIAS(__memmove)
+EXPORT_SYMBOL(__memmove)
\ No newline at end of file
+++ /dev/null
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2013 ARM Ltd.
- * Copyright (C) 2013 Linaro.
- *
- * This code is based on glibc cortex strings work originally authored by Linaro
- * be found @
- *
- * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/
- * files/head:/src/aarch64/
- */
-
-#include <linux/linkage.h>
-#include <asm/assembler.h>
-#include <asm/cache.h>
-
-/*
- * Move a buffer from src to test (alignment handled by the hardware).
- * If dest <= src, call memcpy, otherwise copy in reverse order.
- *
- * Parameters:
- * x0 - dest
- * x1 - src
- * x2 - n
- * 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
-
-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
-
-SYM_FUNC_START_ALIAS(__memmove)
-SYM_FUNC_START_WEAK_PI(memmove)
- cmp dstin, src
- b.lo __memcpy
- add tmp1, src, count
- cmp dstin, tmp1
- b.hs __memcpy /* No overlap. */
-
- add dst, dstin, count
- add src, src, count
- cmp count, #16
- b.lo .Ltail15 /*probably non-alignment accesses.*/
-
- 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
-
- /*
- * 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]!
-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]!
-
-.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]!
-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]!
-
- tst count, #0x3f
- b.ne .Ltail63
- ret
-SYM_FUNC_END_PI(memmove)
-EXPORT_SYMBOL(memmove)
-SYM_FUNC_END_ALIAS(__memmove)
-EXPORT_SYMBOL(__memmove)
projects / platform / kernel / linux-starfive.git / commitdiff