arch/tile/lib/memcpy_64.c - kernel/quantenna - Git at Google

 /*
  * 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
	/*
	* 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