[Bug tapsets/10745] New: Give access to "hidden" tracepoints

["jistone at redhat dot com" <sourceware-bugzilla@sourceware.org>]

By "hidden" I mean tracepoints which are not exposed in a usable header.  This
might be because the header is not in include/trace/ or otherwise not packaged
in kernel-devel, or even when it is present it might be dependent on some
subsystem-internals.

The only way I know to really discover *all* tracepoints is through debugfs on a
live kernel.  That requirement doesn't really fit our general usage model.

I'm thinking instead to expose these as kernel.trace("foo").raw, analogous to
the kprobe.function("foo") which does no name checking.  If you specify an
incorrect name, you just won't get any hits, but no harm is done.

It's possible to register a handler without knowing the full callback signature.
 Instead of register_trace_foo(handler), we could imitate what that inline
really does with tracepoint_probe_register("foo", (void*)handler).

We couldn't know any argument names/types this way, but exposing $arg1, $arg2,
etc. as longs might be enough to be usable with @cast.  However, that assumes
though that passing a foo_handler(long, long, ...) with an incorrect number of
parameters wouldn't do any harm.

-- 
           Summary: Give access to "hidden" tracepoints
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tapsets
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: jistone at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10745

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