linux-kernel - Re: Inflation of vmlinux by linker on x86

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Date:	Fri, 26 Sep 2008 11:52:24 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Joris van Rantwijk <jorispubl@...all.nl>
CC:	linux-kernel@...r.kernel.org
Subject: Re: Inflation of vmlinux by linker on x86_64

Joris van Rantwijk wrote:
>  #endif
> -			memcpy(dest,
> -			       output + phdr->p_offset,
> -			       phdr->p_filesz);
> +			src = output + phdr->p_offset;
> +
> +			/* order the copying to avoid overwriting */
> +			if ((direction == 1  && dest <= src) ||
> +			    (direction == -1 && dest > src)) {
> +				/* note: unlike standard memcpy, this one
> +				 * is safe to use when dest and src overlap.
> +				 */
> +				memcpy(dest, src, phdr->p_filesz);
> +			}
> +
>  			break;

Instead of adding a comment like this, we should simply rename it memmove().

Furthermore, we probably spend enough time copying that using a real 
memmove() implementation, using string instructions, would be good.

	-hpa
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