[PATCH] D19272: [ELF] - linkerscript AT keyword (in output section description) implemented.

[Davide Italiano via llvm-commits]

davide added a comment.

In https://reviews.llvm.org/D19272#513530, @grimar wrote:

> In https://reviews.llvm.org/D19272#512904, @emaste wrote:
>
> > FYI the linker script parser now handles all of the FreeBSD kernel linker script except for `AT`. Now the only kernel linker script workaround in my test FreeBSD tree is:
> >
> >   diff --git a/sys/conf/ldscript.amd64 b/sys/conf/ldscript.amd64
> >   index d445857..3efca9a 100644
> >   --- a/sys/conf/ldscript.amd64
> >   +++ b/sys/conf/ldscript.amd64
> >   @@ -8,12 +8,7 @@ SECTIONS
> >      /* Read-only sections, merged into text segment: */
> >      kernphys = CONSTANT (MAXPAGESIZE);
> >      . = kernbase + kernphys + SIZEOF_HEADERS;
> >   -  /*
> >   -   * Use the AT keyword in order to set the right LMA that contains
> >   -   * the physical address where the section should be loaded. This is
> >   -   * needed for the Xen loader which honours the LMA.
> >   -   */
> >   -  .interp         : AT (kernphys + SIZEOF_HEADERS) { *(.interp) }
> >   +  .interp         : { *(.interp) }
> >      .hash           : { *(.hash) }
> >      .gnu.hash       : { *(.gnu.hash) }
> >      .dynsym         : { *(.dynsym) }
> >
>
>
> Yes, I know. I am testing it with the same "change". I think 10.3 release sources head does not contain AT and I using them.
>
> I am not sure how to test properly that AT implementation is correct ? Since it is not important to have for FreeBSD.


As far as I can tell the Xen loader in FreeBSD loader uses it. Eventually we might want to try (or ask somebody to try).
I think that getting X86-64 (and maybe other tier1 or tier2-almost-1 arches) to run is an higher priority (at least it is for me:))


https://reviews.llvm.org/D19272