Re: [patch 07/15] Basic x86_64 support

[Tom Rini <trini@kernel.crashing.org>]

On Thu, Aug 04, 2005 at 08:56:32PM +0200, Andi Kleen wrote:
> On Thu, Aug 04, 2005 at 08:06:36AM -0700, Tom Rini wrote:
> > > 
> > > Why can't you run on x86-64 early? 
> > 
> > As I said earlier:
> > "
> > > If you want to run gdb earlier you need to do it without a tasklet.
> > 
> > We really would like to try again once stacks are setup (IOW, once
> > if ((&__get_cpu_var(init_tss))[0].ist[0])) is true).
> > "
> > 
> > IOW, when we parse the params on x86_64 this isn't true (or rather it
> > wasn't true as of 2.6.9'ish, if this has changed I'd be glad to retest
> > things).
> 
> The ISTs are set up for the boot processor extremly early - even
> before start_kernel. But they are useless before trap_init()
> runs because you won't get any exceptions that need an IDT (or rather
> they will all still point to the early exception handler that just panics) 

I wonder if there was a reason we couldn't do what we did with i386 and
make an early_trap_init() so that we can get what we care about that
early at least.  I'll have to poke at this a bit more, thanks!

-- 
Tom Rini
http://gate.crashing.org/~trini/