On Mon, 25 Feb 2019 11:40:18 -0500 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Mon, 25 Feb 2019 17:09:45 +0900 > Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > > > This should probably go with whatever effort makes nmi_uaccess_ok() > > > available on all architectures. That being said, how about just > > > making copy_from_user_nmi() work on all architectures, even if it just > > > fails unconditionally on some of them? > > > > I think even if we have copy_from_user_nmi(), we need something like > > nmi_uaccess_ok() because without it we can not correctly use > > __copy_from_user_inatomic()... > > But wouldn't that just be part of the implementation of > "copy_from_user_nmi()" as being in an NMI just assumes being inatomic? Yes for copy_from_user_nmi(). But there are some other fundamental functions, like __get_user(). And when we optimize the loop in strncpy/strnlen from user in atomic, I think one nmi_access_ok() at entry is enough. Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
