Supporting emulated tls

[Johannes Pfau]

Am Fri, 23 Mar 2012 13:05:55 +0100
schrieb "Martin Nowak" <dawg at dawgfoto.de>:

> On Fri, 23 Mar 2012 11:02:44 +0100, Johannes Pfau
> <nospam at example.com> wrote:
> 
> > For FreeBSD, this is easy again, dtv[1] contains the size of the
> > dtv. But that's probably nonstandard.
> 
> Yeah, seems to be non-standard.

> There might also be issues with outdated dtv's.

Which means we'd have to check the generation counter. And if the
counter mismatches, we'd need the C runtime to update it. I'm not sure
if we can access tls_dtv_generation on FreeBSD, but updating the
counter is easy: every call to __tls_get_addr works, so we could just
use module id 1 offset 0. AFAIK the TLS memory for the application
module is always allocated anyway.

I'll probably try this at some point, but I have to set up a FreeBSD VM
first.