Re: [PATCH 00/36] AArch64 Linux kernel port

[Arnd Bergmann]

On Tuesday 17 July 2012, Jon Masters wrote:
> On 07/16/2012 08:16 AM, Pavel Machek wrote:
> 
> >> If an implementation supports AArch32 at EL3 there could be some
> >> physical (or some FPGA config) switch to choose between the two. But
> >> since AArch64 is mandated, I don't see why one would force AArch32 at
> >> EL3 and therefore all lower exception levels (and make a big part of the
> >> processor unused).
> > 
> > Actually I see one ... and I can bet it will happen.
> > 
> > So you create that shiny new ARMv8 compliant CPU, 8 cores, 2GHz. HTC
> > will want to use it with 1GB of RAM... and put around exiting OMAP
> > perihepals.
> 
> But that's why we have Eagle (A15). It's a very capable 32-bit design
> from ARM and far more sensible for such designs. You can easily build
> something with a few A15 clusters in it, as we're already seeing.

Right, I would say that with any CPU core more powerful than this one
or with more than a few of these, you will also have trouble coming
up with workloads that really require the CPU performance but don't
also require a 64 bit virtual address space in either user space
or kernel.

	Arnd

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/