AMD Stops Advertising Linux RdRand Support for Bulldozer and Jaguar CPUs

Some time ago it became is knownthat computers with AMD Zen 2 processors will not run Destiny 2 and may not boot latest Linux distributions. The problem was related to the instruction to generate the random number RdRand. Even though the BIOS update decided problem for the latest "red" chips, the company decided not to take risks and more do not plan to advertise RdRand support for Family 15h (Bulldozer) and Family 16h (Jaguar) processors under Linux.

AMD Stops Advertising Linux RdRand Support for Bulldozer and Jaguar CPUs

The instruction will still work on eligible CPUs, but will fail for software that explicitly checks for support. The problem itself has existed for at least 5 years.

As noted, if necessary, RdRand can be forced to be activated using the rdrand_force kernel parameter. However, according to some reports, this could be a potential vulnerability, since sometimes the instruction could generate non-random numbers.

A change in the Linux kernel to work around the RdRand issue is available now as a patch. However, it is not yet clear whether it will be accepted into the general kernel code in the future. At least at the moment, there is no talk of a stable fix.

Recall that even before the release of the fix, some users were able to get around the problem of starting Linux by downgrading the systemd component or using a fixed version of the distribution. This appears to be another Linux issue besides freezes systems with a lack of RAM.



Source: 3dnews.ru

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