Re: [PATCH v2 4/5] arm64: Add support for SMCCC TRNG entropy source
From: Mark Brown
Date: Thu Nov 05 2020 - 08:41:55 EST
On Thu, Nov 05, 2020 at 12:56:55PM +0000, Andre Przywara wrote:
> static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
> {
> + struct arm_smccc_res res;
> unsigned long val;
> - bool ok = arch_get_random_seed_long(&val);
>
> - *v = val;
> - return ok;
> + if (cpus_have_const_cap(ARM64_HAS_RNG)) {
> + if (arch_get_random_seed_long(&val)) {
> + *v = val;
> + return true;
> + }
> + return false;
> + }
It isn't obvious to me why we don't fall through to trying the SMCCC
TRNG here if for some reason the v8.5-RNG didn't give us something.
Definitely an obscure possibility but still...
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