RE: regarding transparent data ranges (in tracepoint support)

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

Could you be specific as to what kernel/file this is in?

I am using 2.4.18 and can't find it in kernel/ptrace.c .

                               Mark Newman

> -----Original Message-----
> From: Daniel Jacobowitz [mailto:drow@mvista.com]
> Sent: Wednesday, November 19, 2003 3:22 PM
> To: Newman, Mark (N-Superior Technical Resource Inc)
> Cc: ankit thukral; Jim Blandy; gdb@sources.redhat.com
> Subject: Re: regarding transparent data ranges (in tracepoint support)
> 
> 
> On Wed, Nov 19, 2003 at 02:50:29PM -0500, Newman, Mark 
> (N-Superior Technical Resource Inc) wrote:
> > Sorry about the tunnel vision.  When the SUT exits we loose 
> all of the
> > tracepoint data in target memory. Stopping that from 
> happening is the
> > next thing on my list after I finish making interrupt work. 
>  After the
> > program finishes it should not exit without an ok from the engineer.
> > 
> > So Ankit if that is what you are looking to do I agree completely.
> > However can't gdbserver do something more like the restart 
> that occurs
> > with a "w" or "x" status after the putpkt in the case statement in
> > server.c
> 
> For recent Linux kernels see PTRACE_EVENT_EXIT.
> 
> In general, however, there's no easy way to prevent it from exiting
> without that.
> 
> > 
> >                                            Mark
> > 
> > > -----Original Message-----
> > > From: Daniel Jacobowitz [mailto:drow@mvista.com]
> > > Sent: Wednesday, November 19, 2003 2:39 PM
> > > To: Newman, Mark (N-Superior Technical Resource Inc)
> > > Cc: ankit thukral; Jim Blandy; gdb@sources.redhat.com
> > > Subject: Re: regarding transparent data ranges (in 
> tracepoint support)
> > > 
> > > 
> > > On Wed, Nov 19, 2003 at 02:34:49PM -0500, Newman, Mark 
> > > (N-Superior Technical Resource Inc) wrote:
> > > > 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?
> > > 
> > > Ankit is talking about reading the transparant tracepoint 
> data after
> > > the program has exited - when its memory isn't there any more.
> > > 
> > > > 
> > > >                              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
> > > > > 
> > > > 
> > > 
> > > -- 
> > > Daniel Jacobowitz
> > > MontaVista Software                         Debian 
> GNU/Linux Developer
> > > 
> > 
> 
> -- 
> Daniel Jacobowitz
> MontaVista Software                         Debian GNU/Linux Developer
>