• Stephan Mueller's avatar
    crypto: jitterentropy - use ktime_get_ns as fallback · b578456c
    Stephan Mueller authored
    As part of the Y2038 development, __getnstimeofday is not supposed to be
    used any more. It is now replaced with ktime_get_ns. The Jitter RNG uses
    the time stamp to measure the execution time of a given code path and
    tries to detect variations in the execution time. Therefore, the only
    requirement the Jitter RNG has, is a sufficient high resolution to
    detect these variations.
    
    The change was tested on x86 to show an identical behavior as RDTSC. The
    used test code simply measures the execution time of the heart of the
    RNG:
    
            jent_get_nstime(&time);
            jent_memaccess(ec, min);
            jent_fold_time(NULL, time, &folded, min);
            jent_get_nstime(&time2);
            return ((time2 - time));
    Signed-off-by: 's avatarStephan Mueller <smueller@chronox.de>
    Acked-by: 's avatarArnd Bergmann <arnd@arndb.de>
    Signed-off-by: 's avatarHerbert Xu <herbert@gondor.apana.org.au>
    b578456c