lkml.org 
[lkml]   [2014]   [Feb]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 07/11] kexec: Create a relocatable object called purgatory
On Mon, Feb 24, 2014 at 11:08:11AM -0800, H. Peter Anvin wrote:
> On 01/27/2014 10:57 AM, Vivek Goyal wrote:
> > +
> > +/**
> > + * memcpy - Copy one area of memory to another
> > + * @dest: Where to copy to
> > + * @src: Where to copy from
> > + * @count: The size of the area.
> > + */
> > +static void *memcpy(void *dest, const void *src, unsigned long count)
> > +{
> > + char *tmp = dest;
> > + const char *s = src;
> > +
> > + while (count--)
> > + *tmp++ = *s++;
> > + return dest;
> > +}
> > +
> > +static int memcmp(const void *cs, const void *ct, size_t count)
> > +{
> > + const unsigned char *su1, *su2;
> > + int res = 0;
> > +
> > + for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
> > + if ((res = *su1 - *su2) != 0)
> > + break;
> > + return res;
> > +}
> > +
>
> <bikeshed>
>
> There multiple implementations of memcpy(), memcmp() and memset() in
> this patchset, and they make my eyes want to bleed (especially
> memcmp()). Can we centralize there, and perhaps even share code with
> the stuff in arch/x86/boot already?
>
> </bikeshed>

Hi hpa,

There is multiple implementation of memcpy() only (sha256.c and
purgatory.c). I will merge the two and make them use single definition of
memcpy().

I can't see multiple implementation of memcpy() and memcmp() in purgatory
code.

W.r.t sharing the code with arch/x86/boot/, I am not sure how to do it.

I see two implementations of memcpy() under arch/x86/boot.

One is in copy.S. This is assembly code and looks like is supposed to
run in 16bit mode. (code16).

Other one is in compressed/misc.c and there are two definitions, one
for 32bit and one fore 64bit.

I am not sure why there is a need to write memcpy() in assembly when
C will do just fine for my case. I don't have to write two versions of
memcpy() and use it both for 32bit and 64bit.

So I can just make all the purgatory code share same version of memcpy(),
memcmp() and memset(), is that fine. I have taken implementations of
these functions from lib/string.c

Thanks
Vivek

>
> -hpa


\
 
 \ /
  Last update: 2014-02-25 18:21    [W:0.107 / U:0.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site