Re: [PATCH v2 1/2] ppc64le: Store correct function entry address in symbol_table

[Ravi Bangoria <ravi dot bangoria at linux dot vnet dot ibm dot com>]

On Tuesday 23 August 2016 04:34 PM, Naveen N. Rao wrote:
> On 2016/08/23 05:44AM, Ravi Bangoria wrote:
>> PPC64 ELF ABI v2 has a Global Entry Point and a Local Entry Point for
>> the functions. Debuginfo of ELF contains GEP which is same as entrypc
>> while symbol table contains GEP and offset, from which we can calculate
>> LEP. LEP is used to call function within single CU, when TOC pointer
>> update is not required. Placing a probe on LEP catches call from both
>> the GEP and the LEP but, by default, systemtap probes on GEP.
>>
>> For ppc64le, Systemtap stores LEP in symbol table and prioritize symbol
>> table over debuginfo. But, storing LEP in symbol table has couple of
>> regression effect. As LEP is only required at a time of adding a probe,
>> don't store it in symbol table.
>>
>> No need to prioritize symbol table as well because debuginfo and symbol
>> table both will contain Global Entry Point.
>>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
>> ---
>> Changes in v2:
>>   - Little bit change in patch description, no logical changes.
> You should also mention that this reverts whatever commit that this 
> does...

Hmm. Thanks, will send next version with this change.

-Ravi

>
> - Naveen
>