[U-Boot] [PATCH RFC] armv7: fixloop: don't fixup if location is NULL

[Andreas Bießmann]

Dear Albert ARIBAUD,

Am 08.01.2011 um 13:18 schrieb Albert ARIBAUD:

> Le 08/01/2011 11:49, Albert ARIBAUD a écrit :
> 
>>> In my investigations for 'NULL fixup' (-> see
>>> http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/89864/focus=89906)
>>> pointed out that only symbols in 'absolute fixup' loop could be 'NULL'
>>> if there is a not aliased/empty weakly linked symbol.
> 
> BTW: is such a situation normal? IIUC, it means there is a weakly linked symbol without *any* defintion, *and* it is referenced in the code.

Yes you may have a weakly linked symbol which was declared but nowhere implemented. See http://patchwork.ozlabs.org/patch/73647, this fixed such a situation for arm920t/at91 style SoC.

BTW: Without the mentioned patch there was another issue with linking (-> see http://patchwork.ozlabs.org/patch/73563). The linker introduced a .plt section which could not be placed and lead to a segfault of linker.

> Granted, maybe it is checked before it is referenced, but we may want to check for and report at build time if possible. Would that be useful?

AFAIR there was a statement to remove those 'undefined weakly linked symbols' from code. So it would be useful to have a tool to detect those symbols at build time.

regards

Andreas Bießmann