[PATCH] powerpc/64: interrupt return in C

[Nicholas Piggin]

Nicholas Piggin's on August 28, 2019 7:06 pm:
> This is a work in progress that goes on top of the syscalls in C patch.
> It's not quite complete, 64e low level exit is not taken care of, and
> the new return is hacked into the existing interrupt handlers pretty
> quickly (e.g., full gprs handling is still ugly and could be cleaned),

In performance testing on a POWER9, page fault latency is about 1.1%
faster with interrupt returns in C which always saves NVGPRs. So I
think the plan will be to rip out all the NVGPR save optimisation from
the 64-bit code.

Thanks,
Nick