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

[Marcel Moolenaar]

On Thu, Jul 24, 2003 at 05:00:13PM -0400, John Baldwin wrote:
> 
> There is a chicken and egg problem.  We use the unique value to
> initialize the per-cpu pointer on kernel entry.  We only have one
> such beast, and in the kernel we cache it in a register that userland
> gets to clobber (and frequently does).  If you can think of a better
> way to store the per-cpu pointer such that kernel entry can load it
> into the register go for it.

I see where the confusion is:

>         pcpup = (struct pcpu *) alpha_pal_rdval();
				^^^^^^^^^^^^^^^^^^^^^^

This is not the per-CPU unique value. I had to add alpha_pal_rdunique()
in order to access it. In numbers:

PAL_rdval = PAL_OSF1_rdval = 0x0032
PAL_rdunique = 0x009e

PAL_rdval is a privileged operation PAL_rdunique isn't.

There is no fundamental problem (although my alpha does reboot
when I run a 1:1-threaded application, so there is a problem :-)

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