Re: [PATCH v7 1/3] x86: Add classes to exception tables

From: Borislav Petkov
Date: Wed Jan 06 2016 - 13:00:00 EST


On Wed, Jan 06, 2016 at 09:54:19AM -0800, Andy Lutomirski wrote:
> I assume that this zero is to save the couple of bytes for the
> relocation entry on relocatable kernels?

I didn't want to touch all _ASM_EXTABLE() macro invocations by adding a
third param @handler which is redundant as we know which it is.

> > + new_ip = ex_fixup_addr(e);
> > + handler = ex_fixup_handler(e);
> > +
> > + if (!handler)
> > + handler = ex_handler_default;
>
> the !handler condition here will never trigger because the offset was
> already applied.

Actually, if I do "0 - .", that would overflow the int because current
location is virtual address and that's 64-bit. Or would gas simply
truncate it? Lemme check...

Anyway, what we should do instead is simply

.long 0

to denote that the @handler is implicit.

Right?

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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