• Herbert Xu's avatar
    crypto: padlock - Avoid resetting cword on successive operations · 420a4b20
    Herbert Xu authored
    Resetting the control word is quite expensive.  Fortunately this
    isn't an issue for the common operations such as CBC and ECB as
    the whole operation is done through a single call.  However, modes
    such as LRW and XTS have to call padlock over and over again for
    one operation which really hurts if each call resets the control
    word.
    
    This patch uses an idea by Sebastian Siewior to store the last
    control word used on a CPU and only reset the control word if
    that changes.
    
    Note that any task switch automatically resets the control word
    so we only need to be accurate with regard to the stored control
    word when no task switches occur.
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    420a4b20
padlock-aes.c 12.4 KB