Re: [PATCH 2/6] kexec jump: check code size in control page

From: Pavel Machek
Date: Thu Aug 07 2008 - 16:32:02 EST


Hi!

> > PAGE_SIZE/2. This patch adds runtime checking for this.
> >
> > Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
...

> > {
> > if (nx_enabled)
> > set_pages_x(image->control_code_page, 1);
> > +
> > + BUG_ON((unsigned long)kexec_control_page_code_end - \
> > + (unsigned long)relocate_kernel >= PAGE_SIZE/2);
> > +
>

> Run time check is better than nothing but I think in this case it would
> be better if we can catch it at compile time.
>
> One of the methods will be to write a small program of your own and
> put in script/ and at build time check for the size and flag error. May
> be there are other better ways to do this.

BUILD_BUG_ON()?

--
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