Re: [PATCH 1/6] MIPS: remove cpu_has_64bit_gp_regs and cpu_has_64bit_addresses

Christoph Hellwig
2020-03-25T08:30:20Z

On Wed, Mar 25, 2020 at 02:36:57AM +0000, Maciej W. Rozycki wrote:
> On Tue, 24 Mar 2020, Christoph Hellwig wrote:
>
> > Both macros are always identical to CONFIG_64BIT.
>
> I think this abstraction makes sense, especially if we want to support
> 64-bit CPUs that only support 32-bit segments, i.e. MIPS architecture
> processors whose CP0.Config.AT=1, or legacy MIPS processors that had a
> similar limitation, such as the R5900 currently under review.

The only use of cpu_has_64bit_addresses is the choice of the ioremap
code base. Which ioremap code does the R5900 want to use? If it
doesn't match CONFIG_64BIT having a config option for the ioremap
implementation seems much more sensible, and can be added with the
R5900 patch set (do you have a link to it?).