Re: [Y2038] [PATCH v2] crypto: Jitter RNG - use ktime_get_ns as fallback

On Wednesday, June 22, 2016 7:26:06 PM CEST Stephan Mueller wrote:

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: Stephan Mueller smueller@chronox.de

Acked-by: Arnd Bergmann arnd@arndb.de