[OpenBIOS] Q: How to "squeeze" C functions in between two symbols?
Andreas Färber
andreas.faerber at web.de
Sat Oct 16 19:18:32 CEST 2010
Am 16.10.2010 um 13:43 schrieb Andreas Färber:
> Am 14.10.2010 um 18:45 schrieb Mark Cave-Ayland:
>
>> Andreas Färber wrote:
>>
>>> I got OpenBIOS to load my RTAS blob and AIX to enter my RTAS C
>>> function and emit something to escc uart from there. It looks like
>>> AIX is trying to emit "\nAIX " via display-character RTAS calls.
>>> My code's not very stable though, the same code snippet didn't
>>> work inside a [{static,inline}] serial_putchar() function but did
>>> directly in my main function called from assembly. Still poking at
>>> ldscript and assembler to find the cause or a workaround. Right
>>> now it does print okay but hangs on returning from the RTAS call.
>>> Will post an RFC once I've cleaned it up a little, maybe it's
>>> something obvious...
>>> Andreas
>>
>> I don't know if it helps with PPC, but on SPARC64 there is an issue
>> whereby if you are compiling with -O0 (which is typical during
>> development), you need to allow extra stack space when switching
>> contexts. Does compiling with -Os solve the issue at all?
>
> Seems like it was compiling with -Os by default.
Update: I've been successful with the combination of -lgcc link and
rtas-tokens.c compilation with -O2 -fpie (-O2 solved the _savegpr_31
issue).
The _GLOBAL_OFFSET_TABLE_ issue remains though, I've been extending
the rtas-ldscript without success so far.
Andreas
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