Re: [PATCH] x86: NX protection for kernel data

From: Sam Ravnborg
Date: Mon Jul 20 2009 - 03:10:22 EST


> >
> > But here _edata does not cover until page boundary.
> > And alignmnet is located outside the output section
> > definition.
> > It would be better/more consistent to follow the style you use for .text here.
>
> You are correct. _edata should be the last thing in .data, and
> alignment should be done before it. However, this brings up a
> question: was there any specific reason to leave .data.init_task
> beyond the _edata? Should we move _edata into the the last of the
> .data.* sections to have poper view of kernel layout?

.data.init_task is loaded into another segment so this is less trivial.
Jan Beulich has posted a patch some time ago to address this,
but it failed when forwardported to the unified layout.

Btw. -tip (the x86 tree) has a patch included that unify the definition
of _edata for 32 and 64 bit.
So the best thing you can do is to base your patch on top of
the -tip tree.

Sam
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