Re: [PATCH 07/14] mce3: pass mce info to EDAC for decoding

Doug Thompson
2009-07-20T21:02:12Z

--- On Mon, 7/20/09, H. Peter Anvin <hpa@zytor.com> wrote:

> From: H. Peter Anvin <hpa@zytor.com>
> Subject: Re: [PATCH 07/14] mce3: pass mce info to EDAC for decoding
> To: "Andi Kleen" <andi@firstfloor.org>
> Cc: "Doug Thompson" <norsk5@yahoo.com>, "Borislav Petkov" <borislav.petkov@amd.com>, mingo@elte.hu, tglx@linutronix.de, aris@redhat.com, linux-kernel@vger.kernel.org, x86@kernel.org
> Date: Monday, July 20, 2009, 2:17 PM
> Andi Kleen wrote:
> >> The goal is to have a default handler within the
> kernel and a more specific handler in a module after it has
> loaded. Using the weak symbol as a mechanism to do that. I
> haven't used that, so I don't know if it works.
> >
> > weak symbols don't work over kernel modules.
> >
>
> For modules, you typically have to have a callback to
> update an internal
> function pointer.  If you think about it, it's pretty
> obvious -- a weak
> symbol changes the behavior at link time, but it's still a
> static call.
> If you want modules to change the behavior, you're talking
> about a
> *dynamic* change -- the call will point to different things
> at different
> points in time -- so you need another mechanism, i.e.
> function pointers.
>
>     -hpa

Thanks, that is exactly what I just posted in another reply.

now I understand weak symbols a bit better now as well

doug t