Re: Reg Sparc memory addresses

[Ben Collins <bcollins@debian.org>]

On Thu, Sep 26, 2002 at 01:54:57PM -0400, Shanti Katta wrote:
> On Wed, 2002-09-25 at 21:56, Ben Collins wrote:
> > On Wed, Sep 25, 2002 at 10:01:15PM -0400, Shanti Katta wrote:
> > > Hi,
> > > I compiled user-mode-linux kernel on Ultrasparc with load address set to
> > > 00000000e0000000. But, when I try to debug the kernel, it just says
> > > cannot access memory at address 0xa00020b0.
> > > This error message remains the same no matter what I change the load
> > > address to. Can anyone guide me on valid memory addresses for userspace
> > > on Sparc? and how much different is that from x86 architecture?
> > 
> > You compiled it on ultrasparc, but I hope you compiled it as a "sparc"
> > target and not "sparc64".
> 
> I compiled UML as "sparc64".
> 
>  
> > I'm not familiar with how UML runs in user space, but I suspect it needs
> > to think it is sparc and not sparc64 for it to run in 32bit sparc
> > userspace (which is what ultrasparc runs at for most cases).
> > 
> So, I guess I need to compile UML as "sparc" target and debug it. I am
> not sure how much of UML code runs in kernelspace and how much in
> userspace. So, do I need to compile only the userspace code for UML as
> "sparc" target or the whole of UML?

I believe it all runs in userspace (hence the name user-mode-linux :)

Compiling for sparc64 is the problem I suspect. IIRC, UML uses the
asm-<arch> that you choose, which will break when sparc64 headers are
used for a sparc32 application.

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