Uprobes: not quite there yet [LWN.net]

Uprobes: not quite there yet

Posted Feb 17, 2010 19:14 UTC (Wed) by oak (subscriber, #2786)
In reply to: Uprobes: not quite there yet by bronson
Parent article: Uprobes: not quite there yet

Even the SSOL approach one needs to "emulate" / "fix" those of the
instructions which use relative addressing, see Roland's old mail on the
subject:
http://sourceware.org/ml/systemtap/2007-q1/msg00571.html

And the instructions are of course architecture specific.

The good thing is that if one puts breakpoints just on function entry &
exit points, those usually use fairly small set of instructions. See e.g.
this user-space function tracing utility that uses SSOL with breakpoints:
http://repository.maemo.org/pool/fremantle/free/f/functra...

If breakpoints can be put anywhere, it's more of an issue. Good question
is how to test that emulation of all the required instructions for SSOL
works fine...

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