Re: [patch 07/13] Initialize per cpu lowcores on cpu hotplug.

From: Heiko Carstens
Date: Tue Feb 19 2008 - 10:42:03 EST


On Tue, Feb 19, 2008 at 04:38:56PM +0100, Heiko Carstens wrote:
> On Tue, Feb 19, 2008 at 04:13:55PM +0100, Bastian Blank wrote:
> > On Tue, Feb 19, 2008 at 03:40:54PM +0100, Martin Schwidefsky wrote:
> > > + /*
> > > + * Only need to copy the first 512 bytes from address 0. But since
> > > + * the compiler emits a warning if src == NULL for memcpy use copy_page
> > > + * instead. Copies more than needed but this code is not performance
> > > + * critical.
> > > + */
> > > + copy_page(lowcore, &S390_lowcore);
> >
> > Boah, workaround alert. Why do you not fix the compiler?
>
> We need to copy from address 0 (that's where the lowcore resides). But gcc
> insists to complain if memcpy is used with src == NULL.. Now what?

Erm sorry, misread your question. Usually it's a bug to use memcpy with
src == NULL. In this case it's ok. So I think it's perfectly ok if gcc
emits a warning.
If you know of a better way to get around this please let me know.
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