On 11/6/19 10:30 PM, Ard Biesheuvel wrote:
> On Wed, 6 Nov 2019 at 15:20, Richard Henderson
> <richard.henderson@xxxxxxxxxx> wrote:
>> +static inline bool has_random(void)
>> +{
>> + /*
>> + * We "have" RNG if either
>> + * (1) every cpu in the system has RNG, or
>> + * (2) in a non-preemptable context, current cpu has RNG.
>> + * Case 1 is the expected case when RNG is deployed, but
>> + * case 2 is present as a backup in case some big/little
>> + * system only has RNG on big cpus, we can still add entropy
>> + * from the interrupt handler of the big cpus.
>
> I don't understand the reference to the interrupt handler here.
To add_interrupt_randomness(), invoked by handle_irq_event_percpu().
Better if I reword the above to include the function name?
> It is
> worth mentioning though that this arrangement permits
> rand_initialize() to use the instructions regardless of whether they
> are implemented only by the boot CPU or by all of them.
Yes, I'll include that.
r~
