svn commit: r356113 - in head: libexec/rtld-elf sys/kern sys/sys

[Justin Hibbits]

On Fri, 27 Dec 2019 10:43:16 -0800
John Baldwin <jhb at FreeBSD.org> wrote:

> On 12/26/19 8:07 PM, Justin Hibbits wrote:
> > Author: jhibbits
> > Date: Fri Dec 27 04:07:03 2019
> > New Revision: 356113
> > URL: https://svnweb.freebsd.org/changeset/base/356113
> > 
> > Log:
> >   Eliminate the last MI difference in AT_* definitions (for
> > powerpc). 
> >   Summary:
> >   As a transition aide, implement an alternative elfN_freebsd_fixup
> > which is called for old powerpc binaries.  Similarly, add a
> > translation to rtld to convert old values to new ones (as expected
> > by a new rtld). 
> >   Translation of old<->new values  is incomplete, but sufficient to
> > allow an installworld of a new userspace from an old one when a new
> > kernel is running. 
> >   Test Plan:
> >   Someone needs to see how a new kernel/rtld/libc works with an old
> >   binary.  If if works we can probalby ship this.  If not we
> > probalby need some more compat bits.
> >   
> >   Submitted by:	brooks
> >   Reviewed by:	jhibbits
> >   Differential Revision:	https://reviews.freebsd.org/D20799  
> 
> This would be much simpler as a 'sv_copyout_auxargs()' hook instead.
> You could even set it directly in the ELFv1 sysvec instead of needing
> a runtime check. You could also move it purely into the powerpc code
> at that point and not need to stick it in the MI file.
> 
> It probably should also be under COMPAT_FREEBSD12.
> 

Already addressed in r356129.  Not under COMPAT_FREEBSD12 just because
it's needed for 13 before "today", but I'll probably put it under
COMPAT_FREEBSD12 in a month or two, after some soak time.

- Justin