tree b31b08a67de28433232370862cfd128707a10838
parent ec233ede4c8654894610ea54f4dae7adc954ac62
author Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> 1510107834 -0800
committer Michael Ellerman <mpe@ellerman.id.au> 1510437789 +1100

powerpc: Define set_thread_uses_vas()

A CP_ABORT instruction is required in processes that have mapped a VAS
"paste address" with the intention of using COPY/PASTE instructions.
But since CP_ABORT is expensive, we want to restrict it to only
processes that use/intend to use COPY/PASTE.

Define an interface, set_thread_uses_vas(), that VAS can use to
indicate that the current process opened a send window. During context
switch, issue CP_ABORT only for processes that have the flag set.

Thanks for input from Nick Piggin, Michael Ellerman.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
[mpe: Fix to not use new_thread after _switch() returns]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>