DLOPEN and Statically linked executable

[Steve Munroe]

> Jakub Jelinek wrote:
> > Steve Munroe wrote:

> > I know that PowerPC (32-bit) currently only support fixed sized
(default)
> > thread stacks.
>
> Because it lacks a thread pointer register in its ABI. AFAIK Geoff
Keating
> wants to change this soon. IA-64, Sparc*, S390* etc. have one in their
ABIs,
> Alpha, IA-32 and X86-64 use magic (be it PAL call on alpha or %gs segment
> on the other two).

The PowerPC64 ABI does not seem to support the magic allowing thread stacks
to "float". The stack frames "back chain" field, would seem to make moving
a thread stack around (in virtual memory) impractical. But there should be
a better way to set/change the thread stack size on a process wide basis
(without resorting to pthread_attr_setstacksize).

> It would be good to reserve one from the beginning.
> The tp register is not only about ability to pthread_attr_setstacksize,
but
> also thread local storage implementation depends heavily on it.

The PowerPC64 ABI states that R13 is " Reserved for use as system Thread
ID".