On Wed, 2011-03-16 at 17:03 +0100, Alexander Graf wrote:
>
> > +int spapr_tce_dma_zero(VIOsPAPRDevice *dev, uint64_t taddr,
> uint32_t size)
> > +{
> > + uint8_t *zeroes;
> > +
> > +#ifdef DEBUG_TCE
> > + fprintf(stderr, "spapr_tce_dma_zero taddr=0x%llx size=0x%x\n",
> > + (unsigned long long)taddr, size);
> > +#endif
> > +
> > + /* FIXME: do this better... */
> > + zeroes = alloca(size);
> > + memset(zeroes, 0, size);
>
> You sure that zeroes is still alive during the call? If I were a
> compiler, I'd probably optimize the return away so that it'd end up
> being a simple branch to spapr_tce_dma_write - coincidentally
> invalidating the stack that zeroes is on.
Ugh ? How would this ever be legal for a compiler to do that ?
Ben.
