On Thu, Jul 02, 2020 at 02:55:19PM -0700, Linus Torvalds wrote: > And while XSTATE_OP() is still disgusting, it's > > (a) slightly less disgusting than it used to be > > (b) now easily fixable if we do the "exceptions clear AC" thing. > > so it's an improvement all around. > > If it works, that is. As mentioned: IT HAS NO TESTING.
What about load_unaligned_zeropad()? Normally the caller doesn't want to know about the exception on crossing into an unmapped page. Blanket "clear #AC of fixup, don't go through user_access_end() in case of exception" would complicate the code that calls that sucker.
