cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

memset.c (2257B)

      1/*
      2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
      3 * Copyright (C) 2008-2009 PetaLogix
      4 * Copyright (C) 2007 John Williams
      5 *
      6 * Reasonably optimised generic C-code for memset on Microblaze
      7 * This is generic C code to do efficient, alignment-aware memcpy.
      8 *
      9 * It is based on demo code originally Copyright 2001 by Intel Corp, taken from
     10 * http://www.embedded.com/showArticle.jhtml?articleID=19205567
     11 *
     12 * Attempts were made, unsuccessfully, to contact the original
     13 * author of this code (Michael Morrow, Intel).  Below is the original
     14 * copyright notice.
     15 *
     16 * This software has been developed by Intel Corporation.
     17 * Intel specifically disclaims all warranties, express or
     18 * implied, and all liability, including consequential and
     19 * other indirect damages, for the use of this program, including
     20 * liability for infringement of any proprietary rights,
     21 * and including the warranties of merchantability and fitness
     22 * for a particular purpose. Intel does not assume any
     23 * responsibility for and errors which may appear in this program
     24 * not any responsibility to update it.
     25 */
     26
     27#include <linux/export.h>
     28#include <linux/types.h>
     29#include <linux/stddef.h>
     30#include <linux/compiler.h>
     31#include <linux/string.h>
     32
     33#ifdef CONFIG_OPT_LIB_FUNCTION
     34void *memset(void *v_src, int c, __kernel_size_t n)
     35{
     36	char *src = v_src;
     37	uint32_t *i_src;
     38	uint32_t w32 = 0;
     39
     40	/* Truncate c to 8 bits */
     41	c = (c & 0xFF);
     42
     43	if (unlikely(c)) {
     44		/* Make a repeating word out of it */
     45		w32 = c;
     46		w32 |= w32 << 8;
     47		w32 |= w32 << 16;
     48	}
     49
     50	if (likely(n >= 4)) {
     51		/* Align the destination to a word boundary */
     52		/* This is done in an endian independent manner */
     53		switch ((unsigned) src & 3) {
     54		case 1:
     55			*src++ = c;
     56			--n;
     57			fallthrough;
     58		case 2:
     59			*src++ = c;
     60			--n;
     61			fallthrough;
     62		case 3:
     63			*src++ = c;
     64			--n;
     65		}
     66
     67		i_src  = (void *)src;
     68
     69		/* Do as many full-word copies as we can */
     70		for (; n >= 4; n -= 4)
     71			*i_src++ = w32;
     72
     73		src  = (void *)i_src;
     74	}
     75
     76	/* Simple, byte oriented memset or the rest of count. */
     77	switch (n) {
     78	case 3:
     79		*src++ = c;
     80		fallthrough;
     81	case 2:
     82		*src++ = c;
     83		fallthrough;
     84	case 1:
     85		*src++ = c;
     86		break;
     87	default:
     88		break;
     89	}
     90
     91	return v_src;
     92}
     93EXPORT_SYMBOL(memset);
     94#endif /* CONFIG_OPT_LIB_FUNCTION */