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 <khickey@xxxxxxxxxxx> 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 [1] 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. [1] : http://www.linux-mips.org/git?p=linux-bcm63xx.git;a=blob;f=arch/mips/bcm63xx/cpu.c;h=0a403dd07cf48109c904486cc1106d99ce036aad;hb=30c20e2899bbf31069aee0bdc4258c211f7a3d0f -- Best regards, Florian Fainelli Email : florian@xxxxxxxxxxx http://openwrt.org -------------------------------
