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kernel-ark/arch/tile/lib/memcpy_64.c
Chris Metcalf 49cf78ef7b tile: support FRAME_POINTER 
Allow enabling frame pointer support; this makes it easier to hook
into the various kernel features that claim they require it without
having to add Kconfig conditionals everywhere (a la mips, ppc, s390,
and microblaze).  When enabled, it basically eliminates leaf functions
as such, and stops optimizing tail and sibling calls.  It adds around
3% to the size of the kernel when enabled.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2013-09-03 14:52:09 -04:00

368 lines
8.4 KiB
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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