• Nick Piggin's avatar
    x86: fence oostores on 64-bit · df1bdc06
    Nick Piggin authored
    movnt* instructions are not strongly ordered with respect to other stores,
    so if we are to assume stores are strongly ordered in the rest of the 64
    bit code, we must fence these off (see similar examples in 32 bit code).
    
    [ The AMD memory ordering document seems to say that nontemporal stores can
      also pass earlier regular stores, so maybe we need sfences _before_
      movnt* everywhere too? ]
    Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    df1bdc06
copy_user_nocache_64.S 4.08 KB