Re: [9fans] xen3: fresh build 9xenpccpuf dies on boot

[erik quanstrom <quanstro@quanstro.net>]

On Thu Sep 12 09:49:19 EDT 2013, yarikos@gmail.com wrote:
> > The crash seems to be in init, not the kernel.  Are you sure
> > your file system image is good?
>
> it doesn't get far enough for "root from:", so it seems to fail
> somewhere in the initcode blob

this may be related to the change put in for the routerboard.

it increased the size of Tos, and thus shifted everything around
on the stack.  but the old pc kernel didn't account for this, and
386 kernels failed with bad arg in syscall.  this never affected the
pae kernel, or the other architectures.  here's the fix as it went
into 9atom.

; 9fs atom
; cd /n/atom/plan9/sys/src/9/pc
; history -D main.c
Aug  3 15:30:45 EDT 2013 main.c 16439 [quanstro]
Aug  3 15:30:45 EDT 2013 /n/atomdump/2013/0912/plan9/sys/src/9/pc/main.c 16439 [quanstro]
10a11
> #include	<tos.h>
25a27,31
> enum {
> 	/* space for syscall args, return PC, top-of-stack struct */
> 	Ustkheadroom	= sizeof(Sargs) + sizeof(uintptr) + sizeof(Tos),
> };
>
294c300
< 	sp = (uchar*)base + BY2PG - MAXSYSARG*BY2WD;
---
> 	sp = (uchar*)base + BY2PG - Ustkheadroom;

- erik