32-bit Thumb-2 breakpoints

[Russell King - ARM Linux]

On Wed, Feb 03, 2010 at 10:35:01AM -0500, Daniel Jacobowitz wrote:
> On Wed, Feb 03, 2010 at 03:30:25PM +0000, Russell King - ARM Linux wrote:
> > On Wed, Feb 03, 2010 at 10:19:31AM -0500, Daniel Jacobowitz wrote:
> > > On a related note, it would be Very Helpful(TM) if someone would
> > > implement read-only access to the helper page via ptrace!  Not as
> > > helpful as a visible vDSO with symbol names would be, but it would
> > > still make things a lot easier.
> > 
> > Apart from the TLS value which can be obtained by PTRACE_GET_THREAD_AREA,
> > the contents of the page is constant across all processes on all CPUs.
> 
> Yes, I'm aware of that - but having it unreadable means special cases
> all through GDB, gdbserver, and anything else that wants to read
> memory.

Well, we could siphon off the PEEK calls, and special case them at
the arch layer - it'll basically be the same hack as what you're
suggesting, only in the kernel instead.

So really the question is whether we want a hack for this in the
kernel or in userspace.