Re: Breakpoint on port write

[Bharata B Rao <bharata@in.ibm.com>]

On Tue, Oct 01, 2002 at 02:56:52PM +0200, Duncan Sands wrote:
> On Tuesday 01 October 2002 05:55, Bharata B Rao wrote:
> > On Mon, Sep 30, 2002 at 09:59:11AM +0200, Duncan Sands wrote:
> > > Hi all, I would like to monitor exactly when the kernel is writing
> > > to a certain I/O port.  The device is a PCI device with some I/O
> > > mapped registers.  They are written to/read from using outw, inw.
> > > Is there some debugging tool I can use to see all reads and writes?
> >
> > You could try putting io watchpoint on the port using dprobes.
> >
> > http://www.ibm.com/linux/ltc/projects/dprobes/
> 
> Thanks Bharata - I did that and it works fine.  Some things that would be nice:
> 
> (1) break only on io write / break only on io read

Unfortunately that's what the architecture(i386 in this case) provides.
Either read or write, not each one exclusively.
 
> (2) get the value written / read.

You mean some RPN instruction to do this ? Yes looks interesting.

> 
> It is possible to get on without these of course, but it would be convenient
> if they existed.
> 
> Thanks again for your help,
> 
> Duncan.
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