thanks for your previous answers.
I've done a bit of homework, and it seems to me that the situation of Red
Hat's backport is as follows (please correct me if I'm wrong or if I've
- Red Hat's most recent 2.4.xx kernel is in Red Hat Enterprise Linux 3, with
sources in kernel-2.4.21-4.EL.src.rpm;
- the matching sources for oprofile are in oprofile-0.5.4-12.src.rpm, and
are based on a rather old release of oprofile (around June 2003, I guess);
- the only architectures supported by Red Hat's backport are amd64, ia64,
s390, x86, ppc64, e.g. support for x86 processors is in
If my understanding is correct, there is a lot of work to do:
- first I'll need to apply the oprofile-related patches in
kernel-2.4.21-4.EL.src.rpm to my version of the kernel. Since I'm starting
from a 2.4.21 kernel that's already been heavily patched (to add support
first generically for ARM, then specifically for XScale, and then even more
specifically for the Intel Bulverde evaluation board that we're developing
on), I will have to go through the patches by hand to check that source
files and lines match, and to see whether there are any conflicts between
the various modifications;
- then I'll need to study the 2.6 kernel code which was written to make
oprofile support ARM and XScale, and by comparing it e.g. with x86-specific
oprofile code and with what's in linux-2.4.20-x86-oprofile.patch, I'll have
to rewrite the code to make it work with the custom functions and data
structures that Red Hat used in the backporting;
- once I've gotten everything to work, if I want to upgrade to oprofile-0.8,
I'll need to redo myself every change that was made between the 0.5.4 and
the 0.8 releases, paying attention not to break compatibility between what
goes on in the modified kernel and what goes on in user space.
I can see a long road stretching before me. Do you think there could be any
shortcuts? Have I gotten something wrong?
----- Original Message -----
From: "John Levon" <levon@...>
To: "Luca Rossato" <l.rossato@...>
Sent: Thursday, July 08, 2004 7:42 PM
Subject: Re: Backporting oprofile to 2.4 kernels (XScale arch)
> On Thu, Jul 08, 2004 at 07:07:53PM +0200, Luca Rossato wrote:
> > > You can start from Red Hat's backport.
> > I didn't know that Red Hat's backport worked on ARM architectures
> Which is why I said "start from".
> > check right now because I don't have a RH system at hand). Do you think
> > their work extended to ARM- and XScale-specific stuff?
> Of course it will, it's a backport of the 2.6 kernel's oprofile.
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