design: function-exit probes

[Frank Ch. Eigler]

Hi -

On Mon, Feb 14, 2005 at 09:01:38AM -0800, Jim Keniston wrote:
> Here's my design for function-exit probes [...]

Looks really good.

One tricky issue will be the setting of the pt_regs at the return
handler.  Ideally, pt_regs should contain state that corresponds to
a hypothetical breakpoint in one of two points: (a) at the actual
return instruction in the callee; or (b) the instruction after the
call in the caller.  That way, accessing local variables in one or
the other scope would be possible.  

In the case of the trampoline breakpoint, at least the PC value
will point elsewhere.  If the SP/FP registers are as they would
be in one or the other scenario, that should be good enough.

- FChE
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