Re: ARM defconfig files

From: Nicolas Pitre
Date: Thu Jun 03 2010 - 18:45:45 EST


On Fri, 4 Jun 2010, Tony Lindgren wrote:

> * Russell King <rmk@xxxxxxxxxxxxxxxx> [100603 21:07]:
> > On Thu, Jun 03, 2010 at 07:46:23PM +0300, Tony Lindgren wrote:
> > > Compiling in multiple ARM platforms is trickier, we would have to get
> > > rid of the duplicate defines like NR_IRQS, then have some common clock
> > > framework etc. Then figure out some way to get rid of Makefile.boot.
> > > Russell probably has some other things in mind that would have to be
> > > changed to make this happen.
> >
> > - Find someway to handle the wide variety of interrupt controllers.

Eric Miao posted a patch series for that already.

> > - Be able to handle any multitude of V:P translations, including non-linear
> > alongside linear transations.

Some effort is being deployed at my $job to do that. Initially only the
linear translation will be supported, which should cover the vast
majority of the cases already. The odd targets will simply require a
build of their own like it is done today.

> > - Different PAGE_OFFSETs

Again, a majority of targets may simply share the default one.

> > - Different kernel VM layouts allowing for a variety of different ioremap
> > region sizes

VMALLOC_END should only need to become a per machine class variable
initialized at run time.

> Some of these could be handled by allowing building a seprate instance
> for each platform compiled in. Maybe we could set them up with symlinks.

We already have runtime selectable machine instances. Building multiple
machine class could extend on that.

> How about a minimal generic relocatable ARM kernel and then we load the
> platform support as a module from ramdisk? :)

Pity... Nah.

> > and so the list goes on...
>
> Yeah..

Like I said, there is an effort to gradually overcome those issues one
by one.


Nicolas
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