Hi Manuel, Kevin,
Le Sunday 29 March 2009 17:52:43 Manuel Lauss, vous avez écrit :
> On Sun, 29 Mar 2009 10:27:46 -0500
> Kevin Hickey <firstname.lastname@example.org> wrote:
> > On Sun, 2009-03-29 at 17:03 +0400, Sergei Shtylyov wrote:
> > > Single kernel binary? If it's at all possible, I am all for it.
> > On some level, I agree but not at the expense of a larger kernel or
> > longer boot times. Maybe I'm just not following how your implementation
> > works but it seems to me that runtime checks will add to boot time.
> > More importantly it adds to the kernel memory footprint as the tables of
> > constants for multiple CPUs will have to be compiled in. If I'm
> > designing a board with an Au1250 in it, I don't care about the interrupt
> > numbers for Au1100 or Au1500. This problem compounds when we introduce
> > Au1300 - several of its subsystems (like the interrupt controller) are
> > new requiring not only a new table of constants but a new object as
> > well. In the desktop space I can understand this approach, but in the
> > embedded space it seems like an unnecessary resource burden.
> > Please enlighten me :)
> You're right, from a single-cpu-board POV it doesn't make sense.
> However if you have a few boards which mostly differ in the Alchemy
> chip used (and not much else difference in board support code), I find
> this to be highly beneficial. If I can have a single binary for the
> folks testing these boards, all the better!
I definitively agree, from a distribution point of view, that's even better.
For instance Maxime did an excellent job with bcm63xx  which has both
different base addresses for the SoC registers and even different offsets for
the same things inside those registers. Resulting kernel is not that slower
even though I do not have figures to show. Additionnaly you can still choose
which BCM63xx SoC you are compiling for.
> Yes, increased binary size is to be expected, but I don't expect it to
> be in the megabyte range.
> I'm primarily doing this for company-internal purposes; I just thought
> I'd share the final result, maybe someone else might find it useful.
Best regards, Florian Fainelli
Email : email@example.com