[okl4-developer] linking boot image

[Tomas Hruby]

Hi,

I only wanted to have the userspace code linked to a different virtual
address. Setting _LINKADDRESS does exactly what I want. The ELF image
is still laid out by the build system in "physical" memory, however
the virtual load address is mine :) The Openboot loads the image with
virtual addressing ON, so I need to patch the physical addresses in
the rootserver info by adding an offset. But that's OK.

Cheers, T.

On Mon, Aug 18, 2008 at 09:04:37PM +1000, Geoffrey Lee wrote:
> On Mon, Aug 18, 2008 at 02:47:40PM +1000, Tomas Hruby wrote:
> > Hi,
> > 
> > > If you look closely, the elfadorn command actually contains a call to  
> > > the linker (ld).  The -Ttext option is actually passed to the linker,  
> > > not elfadorn.  If you take a look at the linker man page, you'll find  
> > > that -Ttext determines the absolute address that the .text section will 
> > > be linked to.  This is important because the bootloader should start 
> > > execution from this very address after bootstrap.
> > 
> > Yes, that is clear. It was probably a wrong question. I mean, where
> > does this specific value comes from when linking the root server. I am
> > not specifying it anywhere.  I fured out that I can change it by
> > setting _LINKADDRESS in machine if I want to link usercode to a
> > different address.
> 
> Hi Tomas
> 
> The programs are laid out in memory by the build system.  Hence
> this address is picked by the build system.  However, I don't
> think this answers what are you are really after.  Do you have
> a specific problem that you are trying to solve?
> 
> 
> > 
> > 		T.
> > 
> 
> 	-gl
> 
> > > Of course, depending on your setup, it is possible to change this  
> > > address and still have a working system (for example, simply telling the 
> > > bootloader to start at a different address).
> > >
> > > Which platform are you working on, and what linker is being used?
> > >
> > > Nelson.
> > >
> > > On 18/08/2008, at 11:30 AM, Tomas Hruby wrote:
> > >
> > >> when linking, elfadorn gets called with -Ttext=100000 option. Where
> > >> does it come from? How can I change it (or not to use it)?
> > >
> > > --
> > > (nt)
> > >
> > > Nelson Tam
> > >
> > >
> > 
> > _______________________________________________
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> > https://lists.okl4.org/mailman/listinfo/developer
> > 
> 
> -- 
> 
> 
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