[Feature] Systemtap probes supoort on ppc64LE

[bugproxy]

== Comment: #0 ==
Systemtap isn't able to get any hit on most of the kernel and user space functions on ppc64 LE. PPC64 ELF ABI v2 has a Global entry point and a local entry point for the functions. We need the Local entry point in order to probe these functions. However, the DIE for these functions in debuginfo return the function.entrypc which is same as the global entry point. The local entry point is not encoded in the debuginfo of the ELFs. The offset to local entry point is however encoded in the st_other field of these symbols in the symbol table.
We need to use this field to adjust the sym.st_value to actually point to the local entry point instead of the global entry point.

The patches are already merged with upstream systemtap. Here are the links to the patches :
https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commit;h=d16f315faaffbff7a495f26859ce6c200d7667fa : Generic bugfix for dwarfless probing into multiple static functions with same names

https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commit;h=66ac435c7cb7b907642ebfd4daf4d84cdca242a3 : Testcase for the above fix

https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commit;h=b4c6a4b1cd00fd1681d76de6850a88aa516c4fef : Prioritize symbol lookup for ABIv2 (for ppc64LE)

[Ubuntu Foundations Team Bug Bot (crichton)]

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[Steve Langasek (vorlon)]

Ubuntu 15.10 includes systemtap 2.8, which includes these commits. Marking as resolved.

[Breno Leitão (breno-leitao)]

Thank you. Closing it at our side also.