Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 7 Apr 2020 02:33:57 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Daniel Borkmann <daniel@iogearbox.net>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Masami Hiramatsu <mhiramat@kernel.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
        bgregg@netflix.com
Subject: Re: Question on "uaccess: Add strict non-pagefault kernel-space read
 function"
Message-ID: <20200407093357.GA24309@infradead.org>
References: <20200403133533.GA3424@infradead.org>
 <5ddc8c04-279d-9a14-eaa7-755467902ead@iogearbox.net>
 <20200404093105.GA445@infradead.org>
 <2adc77e1-e84d-f303-fd88-133ec950c33f@iogearbox.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <2adc77e1-e84d-f303-fd88-133ec950c33f@iogearbox.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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?