Re: Question on "uaccess: Add strict non-pagefault kernel-space read function"

From: Christoph Hellwig
Date: Tue Apr 07 2020 - 05:34:01 EST


On Tue, Apr 07, 2020 at 11:03:23AM +0200, Daniel Borkmann wrote:
>
> ... where archs with non-overlapping user and kernel address range would
> only end up having to implementing kernel_range_ok() check. Or, instead of
> a generic kernel_range_ok() this could perhaps be more probing-specific as
> in probe_kernel_range_ok() where this would then also cover the special
> cases we seem to have in parisc and um. Then, this would allow to get rid
> of all the __weak aliasing as well which may just be confusing. I could look
> into coming up with something along these lines. Thoughts?

FYI, this is what I cooked up a few days ago:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/maccess-fixups

Still misses the final work to switch probe_kernel_read to be the
strict version. Any good naming suggestion for the non-strict one?