Re: Mach-O binary format support and Darwin syscall personality [Was: uts banner changes]

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2006-12-12 at 17:34 -0500, Kyle Moffett wrote:
> On Dec 12, 2006, at 13:20:19, Linus Torvalds wrote:
> > That said, powerpc simply doesn't historically do any system call  
> > translation, so you'll just have to implement the same kind of  
> > translation layer that sparc has done, for example.
> 
> Thanks a lot for all your help.  I've got two last questions:  From  
> the code in entry_32.s I can dig up "current" from ((struct  
> paca_struct *)r13)->__current to read a personality flag from it,  
> right?  Digging up offsets in assembly can't be very fun :-\   

That's what asm-offset.c is for :-) It generates all the offsets you
need. In general though, you probably want to copy your personality flag
to thread_info, along with other bits in there (like 32 vs. 64 bits).
Look how it's done on ppc64.

> Secondly, is there a preferred existing field into which I should  
> stick said flag or just stuff it somewhere?

Yes, thread_info->flags.

> Ok, I figured it was going to be ugly; maybe not quite _that_ ugly  
> but my hopes weren't high enough for you to dash to any real degree :-D.

Well... it can't be pretty :-)

Ben.