svn commit: r249734 - stable/9/sys/kern

[Jeremie Le Hen]

On Thu, Apr 25, 2013 at 09:20:20AM +0300, Mikolaj Golub wrote:
> On Thu, Apr 25, 2013 at 12:07:52AM +0200, Jeremie Le Hen wrote:
> > Hi Mikolaj,
> > 
> > On Sun, Apr 21, 2013 at 05:14:50PM +0000, Mikolaj Golub wrote:
> > > Author: trociny
> > > Date: Sun Apr 21 17:14:50 2013
> > > New Revision: 249734
> > > URL: http://svnweb.freebsd.org/changeset/base/249734
> > > 
> > > Log:
> > >   MFC r249238, r249239:
> > >   
> > >   r249238:
> > >   
> > >   Use 4-byte padding for core dump notes on both 32 and 64bit archs.
> > >   
> > >   Although native word padding (i.e. 8-byte on 64bit arch) looks to be
> > >   in agreement with standards, other parts of our code and other OSes
> > >   use 4-byte alignment.
> > >   
> > >   This is not expected to change alignment for currently generated core
> > >   dump notes, as the notes look to consist of structures with sizes
> > >   multiple of 8 on 64-bit archs. But there are plans to add additional
> > >   notes, where 4-byte vs 8-byte alignment makes difference.
> > >   
> > 
> > Sorry, I'm a little late, trying to catch up on emails.
> > 
> > I'd say this deserves a comment.  Even if you commit log clearly states
> > the reason for this change, a casual reader may think it would be
> > preferable to have native alignment and fix it without thinking of
> > checking the SVN metadata.
> 
> Note, there are several places in this file where the padding is
> used. Their amount has increased after r249486.
> 
> I thought about adding a constant
> 
>   #define ELF_NOTE_ROUNDSIZE	4
> 
> to imgactl_elf.c and using it throghthout the file. I think using '4'
> explicetly (instead of sizeof(Elf32_Size)) should diminish confusion
> about native alignment and the comment is not needed then.
> 
> What do you think about this?

Yes, sounds good.  Thanks!

-- 
Jeremie Le Hen

Scientists say the world is made up of Protons, Neutrons and Electrons.
They forgot to mention Morons.