Re: problems compiling xen on a crusoe

[A Streetcar Named <desire@gmail.com>]

On Mon, 15 Nov 2004 14:44:47 +0000, Keir Fraser
<keir.fraser@cl.cam.ac.uk> wrote:
> >
> > The infinite loops in x86_32.S did make a difference at the following
> > line though:
> >     128 start_paging:
> >     129         mov     $idle_pg_table-__PAGE_OFFSET,%eax
> >     130         mov     %eax,%cr3
> >     131         mov     $0x80050033,%eax /* hi-to-lo: PG,AM,WP,NE,ET,MP,PE */
> >     132         mov     %eax,%cr0
> >     133         jmp     1f
> >     134 1:      /* Install relocated selectors (FS/GS unused). */
> >     135         lgdt    gdt_descr
> >
> > Adding the 1:  jump 1b before line 132 would make it hang; adding the
> > line after 132 saw the computer rebooting continuously...  I have no
> > idea what to make of this though.
> 
> Hmm.... sounds like we don't work so well with Crusoe. :-)
> Firstly, I don't suggest that looping between lines 132 and 133 is
> very wise. The move to %cr0 and the following jump are supposed to
> happen right after one another. Put the loop immediately after line
> 134.

Only just got my hands on the notebook to test again.  I vaguely
remembered that I had tried putting the loop between lines 134 and 135
previously (with the result being that it still kept rebooting), which
led me to move the loop higher up.  Anyway, I've tried this again, and
confirmed what I remembered.  If you're interested, I've put my xen
images at the same location as previously, so xen-132-syms is for the
loop inserted between lines 131 and 132, etc.


> Then, a few possibilities that might get you further:
> 
> Change line 131 to:
>  mov %cr0,%eax ; or $0x80050023,%eax
>                              ^
>                              Note this digit changed!
> 
> Change line 133 to:
>  ljmp $(__HYPERVISOR_CS),$1f
> 
> Let me know how you get on with these changes.

I'm not clear what you mean by this.  Do you want me to change the
source to this and compile it?

   128 start_paging:
   129         mov     $idle_pg_table-__PAGE_OFFSET,%eax
   130         mov     %eax,%cr3
   131         mov %cr0,%eax ; or $0x80050023,%eax
   132         mov     %eax,%cr0
   133         ljmp $(__HYPERVISOR_CS),$1f
   134 1:      /* Install relocated selectors (FS/GS unused). */
   135         lgdt    gdt_descr


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