On Thu, Jan 17, 2002 at 04:07:23PM -0800, Ulrich Drepper wrote:
> The time is near when we (well, I) well start a drastic move toward
> generally using thread registers. Even in non-threaded code.
>
> This means that unless all architectures get thread registers (or
> equivalent things like Alpha's special code) we'll have a two class
> society of platforms where all code written for the platforms without
> thread register can be run on the other systems, but not vice versa.
>
> >From what I see today we have thread registers only on Alpha, x86,
> IA-64, SH, and x86_64. SPARC shouldn't be too much of a problem. Sun
> is using %g6 or %g7 (forgot which one) and since they define the ABI
> no big complications are expected.
>
> Now, what is about the rest? I assume cris isn't much of a problem
> since it's a purely embedded machine.
>
>
> Arm: don't know whether this should fall in the same category.
> Philip?
>
>
> m68k: Well, maybe it's time to retire these machines. But on the
> other hand, there are those useless address registers. Andreas, Jes?
>
>
> PPC (32-bit) is known to be a problem. I've seen several proposals as
> to what register to use but haven't seen a final decision. Problems
> with the different PPC implementations are probably hindering this.
> Geoff, could you please make a decision? I hope the PPC64 ABI already
> allocated a thread register.
>
>
> S390: I have no idea. Martin, please comment and make a decision.
>
>
> MIPS: Who feels responsible? Andreas, HJ?
>
I don't see there are any registers we can use without breaking ABI.
On the other hand, can we change the mips kernel to save k0 or k1 for
user space?
>
> PA: no idea. HP has no 32-bit ELF so. But they have 64-bit ELF and
> it definitely has a thread register.
>
>
>
> Please consider this a high priority task now. I've been warning
> about this for a long time. Jakub is working on some code and once
> this is ready for me to use I'll make lots of changes to ld.so and the
> locale handling and from that point on we have the two classes of
> architectures.
>
> Oh, this now also concerns Hurd. So, Roland, how far is using LDTs on
> Hurd/x86?
>
H.J.
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