powerpc: Define set_thread_uses_vas()

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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>

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Sukadev Bhattiprolu 2017-11-07 18:23:54 -08:00 • committed by Michael Ellerman

parent ec233ede4c

commit 9d2a4d7133

3 changed files with 35 additions and 10 deletions

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2

arch/powerpc/include/asm/processor.h

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2

arch/powerpc/include/asm/switch_to.h

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41

arch/powerpc/kernel/process.c

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