Re: RFC: Map GNU attributes section to PT_GNU_STACK segment

[Nick Clifton <nickc at redhat dot com>]

Hi H.J.

> We keep GNU attributes section in executable and shared library. Also
> There is a PT_GNU_STACK segment. But only its segment type is used.
> This patch maps GNU attributes section to PT_GNU_STACK segment and
> makes PT_GNU_ATTRIBUTES an alias of PT_GNU_STACK so that GNU attributes
> section is available to ELF loader.

Why do you want to do this ?  In particular why do you want to overload the 
PT_GNU_STACK segment ?  Why not create a new PT_GNU_ATTR segment ?  Is space in 
the header the only reason ?

It seems to me that overloading the PT_GNU_STACK segment in the way you propose 
is prone to confusing the user, and I think that we ought to try to avoid this.

On the other hand, if you are trying to tidy up the program headers then maybe 
it would be cleaner to have a new name (eg PT_GNU_STUFF) and then define an 
*extendable* scheme for putting loader-accessible information into this 
segment.  Using this scheme you can then define a replacement for the current 
PT_GNU_STACK segment and a home for the GNU attributes section.  Ideally this 
new segment would be backwards compatible with the current PT_GNU_STACK segment 
(same type, same flags) so that older loaders can still use it.

Cheers
  Nick