lib/uasan/mem_uasan.c

// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
/*
 * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
 */

#include <config.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <malloc.h>

/* version for uasan without check */

void *__memset(void *s, int c, size_t count)
{
	unsigned long *sl = (unsigned long *)s;
	char *s8;

#if 1
	unsigned long cl = 0;
	int i;

	/* do it one word at a time (32 bits or 64 bits) while possible */
	if (((ulong)s & (sizeof(*sl) - 1)) == 0) {
		for (i = 0; i < sizeof(*sl); i++) {
			cl <<= 8;
			cl |= c & 0xff;
		}
		while (count >= sizeof(*sl)) {
			*sl++ = cl;
			count -= sizeof(*sl);
		}
	}
#endif	/* fill 8 bits at a time */
	s8 = (char *)sl;
	while (count--)
		*s8++ = c;

	return s;
}

void *__memcpy(void *dest, const void *src, size_t count)
{
	unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
	char *d8, *s8;

	if (src == dest)
		return dest;

	/* while all data is aligned (common case), copy a word at a time */
	if ((((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
		while (count >= sizeof(*dl)) {
			*dl++ = *sl++;
			count -= sizeof(*dl);
		}
	}
	/* copy the reset one byte at a time */
	d8 = (char *)dl;
	s8 = (char *)sl;
	while (count--)
		*d8++ = *s8++;

	return dest;
}

void *__memmove(void *dest, const void *src, size_t count)
{
	char *tmp, *s;

	if (dest <= src) {
		memcpy(dest, src, count);
	} else {
		tmp = (char *)dest + count;
		s = (char *)src + count;
		while (count--)
			*--tmp = *--s;
		}

	return dest;
}