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ubuntu-linux-kernel/arch/tile/lib/memcpy_64.c

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/*
* Copyright 2011 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
/* EXPORT_SYMBOL() is in arch/tile/lib/exports.c since this should be asm. */
/* Must be 8 bytes in size. */
#define op_t uint64_t
/* Threshold value for when to enter the unrolled loops. */
#define OP_T_THRES 16
#if CHIP_L2_LINE_SIZE() != 64
#error "Assumes 64 byte line size"
#endif
/* How many cache lines ahead should we prefetch? */
#define PREFETCH_LINES_AHEAD 4
/*
* Provide "base versions" of load and store for the normal code path.
* The kernel provides other versions for userspace copies.
*/
#define ST(p, v) (*(p) = (v))
#define LD(p) (*(p))
#ifndef USERCOPY_FUNC
#define ST1 ST
#define ST2 ST
#define ST4 ST
#define ST8 ST
#define LD1 LD
#define LD2 LD
#define LD4 LD
#define LD8 LD
#define RETVAL dstv
void *memcpy(void *__restrict dstv, const void *__restrict srcv, size_t n)
#else
/*
* Special kernel version will provide implementation of the LDn/STn
* macros to return a count of uncopied bytes due to mm fault.
*/
#define RETVAL 0
int __attribute__((optimize("omit-frame-pointer")))
USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n)
#endif
{
char *__restrict dst1 = (char *)dstv;
const char *__restrict src1 = (const char *)srcv;
const char *__restrict src1_end;
const char *__restrict prefetch;
op_t *__restrict dst8; /* 8-byte pointer to destination memory. */
op_t final; /* Final bytes to write to trailing word, if any */
long i;
if (n < 16) {
for (; n; n--)
ST1(dst1++, LD1(src1++));
return RETVAL;
}
/*
* Locate the end of source memory we will copy. Don't
* prefetch past this.
*/
src1_end = src1 + n - 1;
/* Prefetch ahead a few cache lines, but not past the end. */
prefetch = src1;
for (i = 0; i < PREFETCH_LINES_AHEAD; i++) {
__insn_prefetch(prefetch);
prefetch += CHIP_L2_LINE_SIZE();
prefetch = (prefetch < src1_end) ? prefetch : src1;
}
/* Copy bytes until dst is word-aligned. */
for (; (uintptr_t)dst1 & (sizeof(op_t) - 1); n--)
ST1(dst1++, LD1(src1++));
/* 8-byte pointer to destination memory. */
dst8 = (op_t *)dst1;
if (__builtin_expect((uintptr_t)src1 & (sizeof(op_t) - 1), 0)) {
/* Unaligned copy. */
op_t tmp0 = 0, tmp1 = 0, tmp2, tmp3;
const op_t *src8 = (const op_t *) ((uintptr_t)src1 &
-sizeof(op_t));
const void *srci = (void *)src1;
int m;
m = (CHIP_L2_LINE_SIZE() << 2) -
(((uintptr_t)dst8) & ((CHIP_L2_LINE_SIZE() << 2) - 1));
m = (n < m) ? n : m;
m /= sizeof(op_t);
/* Copy until 'dst' is cache-line-aligned. */
n -= (sizeof(op_t) * m);
switch (m % 4) {
case 0:
if (__builtin_expect(!m, 0))
goto _M0;
tmp1 = LD8(src8++);
tmp2 = LD8(src8++);
goto _8B3;
case 2:
m += 2;
tmp3 = LD8(src8++);
tmp0 = LD8(src8++);
goto _8B1;
case 3:
m += 1;
tmp2 = LD8(src8++);
tmp3 = LD8(src8++);
goto _8B2;
case 1:
m--;
tmp0 = LD8(src8++);
tmp1 = LD8(src8++);
if (__builtin_expect(!m, 0))
goto _8B0;
}
do {
tmp2 = LD8(src8++);
tmp0 = __insn_dblalign(tmp0, tmp1, srci);
ST8(dst8++, tmp0);
_8B3:
tmp3 = LD8(src8++);
tmp1 = __insn_dblalign(tmp1, tmp2, srci);
ST8(dst8++, tmp1);
_8B2:
tmp0 = LD8(src8++);
tmp2 = __insn_dblalign(tmp2, tmp3, srci);
ST8(dst8++, tmp2);
_8B1:
tmp1 = LD8(src8++);
tmp3 = __insn_dblalign(tmp3, tmp0, srci);
ST8(dst8++, tmp3);
m -= 4;
} while (m);
_8B0:
tmp0 = __insn_dblalign(tmp0, tmp1, srci);
ST8(dst8++, tmp0);
src8--;
_M0:
if (__builtin_expect(n >= CHIP_L2_LINE_SIZE(), 0)) {
op_t tmp4, tmp5, tmp6, tmp7, tmp8;
prefetch = ((const char *)src8) +
CHIP_L2_LINE_SIZE() * PREFETCH_LINES_AHEAD;
for (tmp0 = LD8(src8++); n >= CHIP_L2_LINE_SIZE();
n -= CHIP_L2_LINE_SIZE()) {
/* Prefetch and advance to next line to
prefetch, but don't go past the end. */
__insn_prefetch(prefetch);
/* Make sure prefetch got scheduled
earlier. */
__asm__ ("" : : : "memory");
prefetch += CHIP_L2_LINE_SIZE();
prefetch = (prefetch < src1_end) ? prefetch :
(const char *) src8;
tmp1 = LD8(src8++);
tmp2 = LD8(src8++);
tmp3 = LD8(src8++);
tmp4 = LD8(src8++);
tmp5 = LD8(src8++);
tmp6 = LD8(src8++);
tmp7 = LD8(src8++);
tmp8 = LD8(src8++);
tmp0 = __insn_dblalign(tmp0, tmp1, srci);
tmp1 = __insn_dblalign(tmp1, tmp2, srci);
tmp2 = __insn_dblalign(tmp2, tmp3, srci);
tmp3 = __insn_dblalign(tmp3, tmp4, srci);
tmp4 = __insn_dblalign(tmp4, tmp5, srci);
tmp5 = __insn_dblalign(tmp5, tmp6, srci);
tmp6 = __insn_dblalign(tmp6, tmp7, srci);
tmp7 = __insn_dblalign(tmp7, tmp8, srci);
__insn_wh64(dst8);
ST8(dst8++, tmp0);
ST8(dst8++, tmp1);
ST8(dst8++, tmp2);
ST8(dst8++, tmp3);
ST8(dst8++, tmp4);
ST8(dst8++, tmp5);
ST8(dst8++, tmp6);
ST8(dst8++, tmp7);
tmp0 = tmp8;
}
src8--;
}
/* Copy the rest 8-byte chunks. */
if (n >= sizeof(op_t)) {
tmp0 = LD8(src8++);
for (; n >= sizeof(op_t); n -= sizeof(op_t)) {
tmp1 = LD8(src8++);
tmp0 = __insn_dblalign(tmp0, tmp1, srci);
ST8(dst8++, tmp0);
tmp0 = tmp1;
}
src8--;
}
if (n == 0)
return RETVAL;
tmp0 = LD8(src8++);
tmp1 = ((const char *)src8 <= src1_end)
? LD8((op_t *)src8) : 0;
final = __insn_dblalign(tmp0, tmp1, srci);
} else {
/* Aligned copy. */
const op_t *__restrict src8 = (const op_t *)src1;
/* src8 and dst8 are both word-aligned. */
if (n >= CHIP_L2_LINE_SIZE()) {
/* Copy until 'dst' is cache-line-aligned. */
for (; (uintptr_t)dst8 & (CHIP_L2_LINE_SIZE() - 1);
n -= sizeof(op_t))
ST8(dst8++, LD8(src8++));
for (; n >= CHIP_L2_LINE_SIZE(); ) {
op_t tmp0, tmp1, tmp2, tmp3;
op_t tmp4, tmp5, tmp6, tmp7;
/*
* Prefetch and advance to next line
* to prefetch, but don't go past the
* end.
*/
__insn_prefetch(prefetch);
/* Make sure prefetch got scheduled
earlier. */
__asm__ ("" : : : "memory");
prefetch += CHIP_L2_LINE_SIZE();
prefetch = (prefetch < src1_end) ? prefetch :
(const char *)src8;
/*
* Do all the loads before wh64. This
* is necessary if [src8, src8+7] and
* [dst8, dst8+7] share the same cache
* line and dst8 <= src8, as can be
* the case when called from memmove,
* or with code tested on x86 whose
* memcpy always works with forward
* copies.
*/
tmp0 = LD8(src8++);
tmp1 = LD8(src8++);
tmp2 = LD8(src8++);
tmp3 = LD8(src8++);
tmp4 = LD8(src8++);
tmp5 = LD8(src8++);
tmp6 = LD8(src8++);
tmp7 = LD8(src8++);
/* wh64 and wait for tmp7 load completion. */
__asm__ ("move %0, %0; wh64 %1\n"
: : "r"(tmp7), "r"(dst8));
ST8(dst8++, tmp0);
ST8(dst8++, tmp1);
ST8(dst8++, tmp2);
ST8(dst8++, tmp3);
ST8(dst8++, tmp4);
ST8(dst8++, tmp5);
ST8(dst8++, tmp6);
ST8(dst8++, tmp7);
n -= CHIP_L2_LINE_SIZE();
}
#if CHIP_L2_LINE_SIZE() != 64
# error "Fix code that assumes particular L2 cache line size."
#endif
}
for (; n >= sizeof(op_t); n -= sizeof(op_t))
ST8(dst8++, LD8(src8++));
if (__builtin_expect(n == 0, 1))
return RETVAL;
final = LD8(src8);
}
/* n != 0 if we get here. Write out any trailing bytes. */
dst1 = (char *)dst8;
#ifndef __BIG_ENDIAN__
if (n & 4) {
ST4((uint32_t *)dst1, final);
dst1 += 4;
final >>= 32;
n &= 3;
}
if (n & 2) {
ST2((uint16_t *)dst1, final);
dst1 += 2;
final >>= 16;
n &= 1;
}
if (n)
ST1((uint8_t *)dst1, final);
#else
if (n & 4) {
ST4((uint32_t *)dst1, final >> 32);
dst1 += 4;
}
else
{
final >>= 32;
}
if (n & 2) {
ST2((uint16_t *)dst1, final >> 16);
dst1 += 2;
}
else
{
final >>= 16;
}
if (n & 1)
ST1((uint8_t *)dst1, final >> 8);
#endif
return RETVAL;
}
#ifdef USERCOPY_FUNC
#undef ST1
#undef ST2
#undef ST4
#undef ST8
#undef LD1
#undef LD2
#undef LD4
#undef LD8
#undef USERCOPY_FUNC
#endif
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