Re: GDBDSX support for new linux boot loading sequence?

Re: GDBDSX support for new linux boot loading sequence?

[Mukesh Rathor]

On Tue, 18 Jun 2013 21:38:42 +0000
"Zulauf, John" <john.zulauf@intel.com> wrote:

> I recently tried to use gdbsx to debug a linux kernel running as an
> HVM.  Even with the correct vmlinux, gdb was unable to correctly map
> the symbol information to the correct memory locations.  Upon some
> investigation it appears that the new Linux loader sequence is
> loading the compressed vmlinux as a file, decompressing and then
> relocating it before executing it.
> 
> Are there known methods to getting gdbsx to work in the context of
> this new loading scheme?
> 
> Any pointers would be of great use.

CCing xen-devel.

Hmm... no, have not run into that, so never thought about it. I don't
mind looking into it, but it will take some time. Meanwhile, if you
find something, do let me know.

BTW, please cc xen-devel in future.

thanks
Mukesh

Re: GDBDSX support for new linux boot loading sequence?

[Ian Campbell]

On Thu, 2013-06-20 at 14:42 -0700, Mukesh Rathor wrote:
> On Tue, 18 Jun 2013 21:38:42 +0000
> "Zulauf, John" <john.zulauf@intel.com> wrote:
> 
> > I recently tried to use gdbsx to debug a linux kernel running as an
> > HVM.  Even with the correct vmlinux, gdb was unable to correctly map
> > the symbol information to the correct memory locations.  Upon some
> > investigation it appears that the new Linux loader sequence is
> > loading the compressed vmlinux as a file, decompressing and then
> > relocating it before executing it.
> >

What is this "new Linux loader"? Are you talking about a new bootloader
or a new revision of the bzImage format or something else?

I have no idea about the gdbsx side of things here, but if there is a
new bootloader protocol doing the rounds it would be useful to know
about...

> > Are there known methods to getting gdbsx to work in the context of
> > this new loading scheme?
> > 
> > Any pointers would be of great use.
> 
> CCing xen-devel.
> 
> Hmm... no, have not run into that, so never thought about it. I don't
> mind looking into it, but it will take some time. Meanwhile, if you
> find something, do let me know.
> 
> BTW, please cc xen-devel in future.
> 
> thanks
> Mukesh
> 
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