cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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memcpy.c (2641B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * arch/openrisc/lib/memcpy.c
      4 *
      5 * Optimized memory copy routines for openrisc.  These are mostly copied
      6 * from ohter sources but slightly entended based on ideas discuassed in
      7 * #openrisc.
      8 *
      9 * The word unroll implementation is an extension to the arm byte
     10 * unrolled implementation, but using word copies (if things are
     11 * properly aligned)
     12 *
     13 * The great arm loop unroll algorithm can be found at:
     14 *  arch/arm/boot/compressed/string.c
     15 */
     16
     17#include <linux/export.h>
     18
     19#include <linux/string.h>
     20
     21#ifdef CONFIG_OR1K_1200
     22/*
     23 * Do memcpy with word copies and loop unrolling. This gives the
     24 * best performance on the OR1200 and MOR1KX archirectures
     25 */
     26void *memcpy(void *dest, __const void *src, __kernel_size_t n)
     27{
     28	int i = 0;
     29	unsigned char *d, *s;
     30	uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
     31
     32	/* If both source and dest are word aligned copy words */
     33	if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
     34		/* Copy 32 bytes per loop */
     35		for (i = n >> 5; i > 0; i--) {
     36			*dest_w++ = *src_w++;
     37			*dest_w++ = *src_w++;
     38			*dest_w++ = *src_w++;
     39			*dest_w++ = *src_w++;
     40			*dest_w++ = *src_w++;
     41			*dest_w++ = *src_w++;
     42			*dest_w++ = *src_w++;
     43			*dest_w++ = *src_w++;
     44		}
     45
     46		if (n & 1 << 4) {
     47			*dest_w++ = *src_w++;
     48			*dest_w++ = *src_w++;
     49			*dest_w++ = *src_w++;
     50			*dest_w++ = *src_w++;
     51		}
     52
     53		if (n & 1 << 3) {
     54			*dest_w++ = *src_w++;
     55			*dest_w++ = *src_w++;
     56		}
     57
     58		if (n & 1 << 2)
     59			*dest_w++ = *src_w++;
     60
     61		d = (unsigned char *)dest_w;
     62		s = (unsigned char *)src_w;
     63
     64	} else {
     65		d = (unsigned char *)dest_w;
     66		s = (unsigned char *)src_w;
     67
     68		for (i = n >> 3; i > 0; i--) {
     69			*d++ = *s++;
     70			*d++ = *s++;
     71			*d++ = *s++;
     72			*d++ = *s++;
     73			*d++ = *s++;
     74			*d++ = *s++;
     75			*d++ = *s++;
     76			*d++ = *s++;
     77		}
     78
     79		if (n & 1 << 2) {
     80			*d++ = *s++;
     81			*d++ = *s++;
     82			*d++ = *s++;
     83			*d++ = *s++;
     84		}
     85	}
     86
     87	if (n & 1 << 1) {
     88		*d++ = *s++;
     89		*d++ = *s++;
     90	}
     91
     92	if (n & 1)
     93		*d++ = *s++;
     94
     95	return dest;
     96}
     97#else
     98/*
     99 * Use word copies but no loop unrolling as we cannot assume there
    100 * will be benefits on the archirecture
    101 */
    102void *memcpy(void *dest, __const void *src, __kernel_size_t n)
    103{
    104	unsigned char *d, *s;
    105	uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
    106
    107	/* If both source and dest are word aligned copy words */
    108	if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
    109		for (; n >= 4; n -= 4)
    110			*dest_w++ = *src_w++;
    111	}
    112
    113	d = (unsigned char *)dest_w;
    114	s = (unsigned char *)src_w;
    115
    116	/* For remaining or if not aligned, copy bytes */
    117	for (; n >= 1; n -= 1)
    118		*d++ = *s++;
    119
    120	return dest;
    121
    122}
    123#endif
    124
    125EXPORT_SYMBOL(memcpy);