Subject: Re: [PATCH] powerpc xmon: drop the option `i` in cacheflush

From: Michael Ellerman <[email-masked]>
Date: Tue, 24 Mar 2020 14:52:21 +1100

"Naveen N. Rao" <[email-masked]> writes:
> Segher Boessenkool wrote:
>> On Mon, Mar 23, 2020 at 04:55:48PM +0530, Balamuruhan S wrote:
>>> Data Cache Block Invalidate (dcbi) instruction implemented in 32-bit
>>> designs prior to PowerPC architecture version 2.01 and got obsolete
>>> from version 2.01.

We still support 32-bit ...

>> It was added back in 2.03.  It also exists in 64-bit designs (using
>> category embedded), in 2.07 still even.
>
> Indeed, it has been part of Book3e.
>
> It isn't clear if this is still useful in this context (xmon) though, 
> since 'dcbf' seems to be equivalent in most respects. At the very least, 
> we should restrict this to Book3e, if it is of value there.

Looking at the ISA it looks like dcbf is more or less equivalent and we
could probably drop the explicit invalidate command.

But the simplest option is probably to just ifdef it out for
PPC_BOOK3S_64.

cheers