RE: regarding transparent data ranges (in tracepoint support)

["Newman, Mark (N-Superior Technical Resource Inc)" <mark.newman@lmco.com>]

Guys - again please excuse my ignorance but

I was assuming that transparent memory would either be

In ROM
In a write protected page
In an unprotected page (for those systems without memory protection)
Possibly swapped out to the disk (for those system with a disk)

However definitely readable by "read_inferior_memory".

Why would the data not be loaded into some form of memory?  
What kind of data are we talking about?

                             Mark Newman

> -----Original Message-----
> From: gdb-owner@sources.redhat.com
> [mailto:gdb-owner@sources.redhat.com]On Behalf Of Daniel Jacobowitz
> Sent: Wednesday, November 19, 2003 1:56 PM
> To: ankit thukral
> Cc: Jim Blandy; gdb@sources.redhat.com
> Subject: Re: regarding transparent data ranges (in tracepoint support)
> 
> 
> On Wed, Nov 19, 2003 at 08:25:37AM -0800, ankit thukral wrote:
> > 
> > --- Jim Blandy <jimb@redhat.com> wrote:
> > > 
> > > ankit thukral <ankit_plug@yahoo.com> writes:
> > > 
> > > > hi all,
> > > >      i read about the transparent data ranges and
> > > > learned that data in these ranges are not supposed
> > > to
> > > > be collected by the remote stub since they belong
> > > to
> > > > read-only segment of the debuggee.my problem is :
> > > a
> > > > TSTART would start the debuggee and it may so
> > > happen
> > > > that the debuggee finishes executing.at this
> > > point,if
> > > > the GDB requests for some data in the transparent
> > > data
> > > > range,then how can the remote stub provide it with
> > > one
> > > > since the debuggee has exited ?
> > > 
> > > If the target is a gdbserver, then it would need to
> > > read the bytes
> > > from the executable file.  This is easy to do with
> > > BFD, but if I
> > > remember right, gdbserver doesn't use BFD at the
> > > moment; not sure how
> > > to get around that.
> > > 
> > > If the target is an embedded system, then presumably
> > > the transparent
> > > data ranges correspond to ROM regions, so the data
> > > is still there.
> > 
> > 
> > 
> >   how about setting a (internal) breakpoint in the
> > debuggee which would prevent it from exiting even
> > though it has finished executing main(),and then
> > entertain GDB requests for the transparent (or
> > read-only) memory regions by reading from the memory
> > of the debuggee???
> 
> That would work (but be wasteful).  At least on Linux, you could read
> /proc/pid/maps to find what ranges correspond to where in what file,
> and save that information.
> 
> -- 
> Daniel Jacobowitz
> MontaVista Software                         Debian GNU/Linux Developer
>