As described in the document SMC Calling Convention (ARM DEN 0028 1.5 F), section 7 "Arm Architecture Calls", the SMC call SMCCC_ARCH_FEATURES is not expected to support the function ID ARM_SMCCC_TRNG_VERSION. Trusted Firmware-A follows up the specification in its implementation.
This commit removes the invocation to avoid the failure - which is a wrong calling in U-boot. The later code invokes ARM_SMCCC_TRNG_VERSION for retrieving the TRNG version, except it can read back the version number, it also can be used to detect whether the TRNG is supported or not.
Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/rng/smccc_trng.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/rng/smccc_trng.c b/drivers/rng/smccc_trng.c index f59b80666b..1da1affd8e 100644 --- a/drivers/rng/smccc_trng.c +++ b/drivers/rng/smccc_trng.c @@ -135,10 +135,6 @@ static bool smccc_trng_is_supported(void (*invoke_fn)(unsigned long a0, unsigned { struct arm_smccc_res res;
- (*invoke_fn)(ARM_SMCCC_ARCH_FEATURES, ARM_SMCCC_TRNG_VERSION, 0, 0, 0, 0, 0, 0, &res); - if (res.a0 == ARM_SMCCC_RET_NOT_SUPPORTED) - return false; - (*invoke_fn)(ARM_SMCCC_TRNG_VERSION, 0, 0, 0, 0, 0, 0, 0, &res); if (res.a0 & BIT(31)) return false;