[RFC PATCH v2 13/13] powerpc/kernel: Do not use READ_ONCE() to access current thread_info flags

[Nicholas Piggin]

Christophe Leroy's on April 6, 2020 3:44 am:
> current is a volatile pointer hold by r2 register.
> 
> READ_ONCE() is not required.
> 
> Before: 327 cycles on null_syscall
> Before: 325 cycles on null_syscall

Patches against Michael's next-test branch have a few small changes 
here. I need to look at the fallout on 64-bit code, although most
likely it's not measurable so if it saves you a few cycles we can
lean toward what ppc32 prefers.

Same with the compat test.

Thanks,
Nick