On Fri, Jun 21, 2002 at 12:23:19AM -0400, Pete Zaitcev wrote:
PER appears to be used, I am not sure if that's actually the case.
PER is definately used. PTRACE. DProbes uses it as well for single
stepping the original instruction after a probe point is handled.
Thanks
Mike
]
Reply-To: Linux on 390 Port [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Putting current in register
Date: Fri, 21 Jun 2002 00:23:19 -0400
Since interrupt stacks were split, current sits in the prefix page.
Did anyone think about returning it into a register? I am not
sufficiently familiar
[...]
However, what's the point? Loading current from the prefix page
costs one cycle (assuming it is in L1 cache); on our platform
register-register operations and memory-register operations
from L1 usually take the same time.
I am trying to unmap the prefix page, if I do so the
Pete Zaitcev wrote:
I am trying to unmap the prefix page, if I do so the get_current
has to be modified.
Er, it would seem that if you unmap the prefix page, get_current
would be the least of your problems ;-( What about all the other
uses of the lowcore (including those demanded by the
Since interrupt stacks were split, current sits in the prefix page.
Did anyone think about returning it into a register? I am not
sufficiently familiar with the architecture to figure it out.
Candidates include control 10 (PER start), control 15 (Linkage),
and GPR 12. Possibly I missed something.
