Stepping down

[Joseph Myers]

On Thu, 11 Jun 2015, Rich Felker wrote:

> > There is no no-MMU support in glibc (though I see no reason in principle 
> > it shouldn't be possible to support it cleanly enough to get accepted if 
> > anyone wishes to contribute patches - ELF no-MMU binaries not FLT, that 
> > is).
> 
> I have a preliminary patch (possibly some small cleanup needed) posted
> on the musl list (http://www.openwall.com/lists/musl/2015/06/10/1)
> that makes it so the fdpic elf loader in the kernel can load normal,
> non-fdpic ELF files too. In principle this makes it possible to use
> glibc with minimal/no modification, but without fdpic I think the
> per-process memory usage (and time spent memcpy'ing it in mmap) from
> glibc would be prohibitive for most applications.

And it's quite likely there are things relying on fork that could usefully 
be supported on no-MMU, but would need different implementations there 
(possibly in sysdeps/nommu).

> Yes, I was wondering about where it disappeared to. I found where the
> binutils-side patches were upstreamed, but couldn't find even the
> proposed patches for GCC. This really should be revived and
> upstreamed.

Googling for 'site:gcc.gnu.org gcc-patches sh fdpic' finds them easily 
enough.  It looks like the SH-specific part 
<https://gcc.gnu.org/ml/gcc-patches/2010-08/msg01464.html> was accepted, 
while it was the preparatory 
<https://gcc.gnu.org/ml/gcc-patches/2010-08/msg01462.html> that was 
problematic.

-- 
Joseph S. Myers
joseph@codesourcery.com