Re: [PATCH] C undefined behavior fix

From: Paul Mackerras (paulus@samba.org)
Date: Wed Jan 02 2002 - 18:11:53 EST


Tom Rini writes:

> Okay, here's a summary of all of the options we have:
> 1) Change this particular strcpy to a memcpy
> 2) Add -ffreestanding to the CFLAGS of arch/ppc/kernel/prom.o (If this
> optimization comes back on with this flag later on, it would be a
> compiler bug, yes?)
> 3) Modify the RELOC() marco in such a way that GCC won't attempt to
> optimize anything which touches it [1]. (Franz, again by Jakub)
> 4) Introduce a function to do the calculations [2]. (Corey Minyard)
> 5) 'Properly' set things up so that we don't need the RELOC() macros
> (-mrelocatable or so?), and forget this mess altogether.

I would add:

6) change strcpy to string_copy so gcc doesn't think it knows what the
   function does
7) code RELOC etc. in assembly, which would let us get rid of the
        offset = reloc_offset();
   at the beginning of each function which uses RELOC.

Maybe 7 is the way to go, at least it will shut the bush-lawyers up.

Paul.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Mon Jan 07 2002 - 21:00:19 EST