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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 22 Feb 2019 13:59:10 -0800
Message-ID: <CAHk-=wh9uWJaih5i6qBPer5rzcs=A+yb_ejU093b1esAhoFveQ@mail.gmail.com>
Subject: Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access
 kernel memory that can fault
To:     David Miller <davem@davemloft.net>
Cc:     Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        stable <stable@vger.kernel.org>,
        Changbin Du <changbin.du@gmail.com>,
        Jann Horn <jannh@google.com>,
        Kees Cook <keescook@chromium.org>,
        Andrew Lutomirski <luto@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Netdev <netdev@vger.kernel.org>, bpf@vger.kernel.org
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On Fri, Feb 22, 2019 at 1:38 PM David Miller <davem@davemloft.net> wrote:
>
> Don't be surprised if we see more separation like this in the future too.

Yes, with the whole meltdown fiasco, there's actually more pressure to
add more support for separation of kernel/user address spaces. As Andy
pointed out, it's been discussed as a future wish-list for x86-64 too.

But yeah, right now the *common* architectures all distinguish kernel
and user space by pointers (ie x86-64, arm64 and powerpc).

                 Linus