Re: What does __user do?

[Thomas Petazzoni <thomas.petazzoni@xxxxxxxx>]

Le Fri, 07 Dec 2007 10:28:53 +0100,
Peter Poulsen <peter@xxxxxxxxx> a écrit :

> I have noticed __user in some code, when a pointer points to
> userspace code. What does that do exaclty?

AFAIK, they are used by sparse[1] to verify that the kernel code doesn't
access directly to pointers pointing to userspace part of the address
space, but rather use the copy_from_user(), copy_to_user() functions or
one of their variants.

Thomas

[1] http://www.kernel.org/pub/software/devel/sparse/
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