cvs commit: src/lib/libthr/arch/alpha/alpha _curthread.c

[Marcel Moolenaar]

On Thu, Jul 24, 2003 at 03:08:32PM -0400, John Baldwin wrote:
> 
> On 24-Jul-2003 Marcel Moolenaar wrote:
> > marcel      2003/07/24 00:51:49 PDT
> > 
> >   FreeBSD src repository
> > 
> >   Modified files:
> >     lib/libthr/arch/alpha/alpha _curthread.c 
> >   Log:
> >   Implement _get_curthread and _set_curthread. We use GCCs builtin
> >   function this, which expands to PAL calls (rduniq and wruniq).
> >   This needs adjustment when TLS is implemented.
> 
> This trashes SMP since we use the per-CPU unique value already
> to maintain the per-cpu data pointer.

Writing to the per-CPU unique value is an unprivileged operation.
You cannot possibly use that for in-kernel use without saving and
restoring it on kernel exit/entry. Which is what needs to be done.

-- 
 Marcel Moolenaar	  USPA: A-39004		 marcel at xcllnt.net