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[Bug runtime/10013] Support ENABLED sdt probe macro


------- Additional Comments From mjw at redhat dot com  2009-04-05 19:17 -------
Maybe we can teach uprobes to replace with a specific move/assignment
instruction instead of a trap instruction. Then you could define ENABLE_PROBE()
with something like:

#define ENABLED_PROBE() ({char e = 0; asm ("mov $0x0, %0" :"=r"(e):"0"(e)); e;})

(of course with the magic macro label .probe section stuff to know the actual
address of the mov instruction)

Then instead of with a normal STAP_PROBE replacing a "nop" with "int3", you
would replace the "mov $0x0, %somereg" with "mov $0x1, %somereg".

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=10013

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