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SubjectRe: [PATCH 09/17] firmware: qcom_scm-64: Improve SMC convention detection
On 2019-11-07 11:18, Bjorn Andersson wrote:
>> + (qcom_smc_convention == SMC_CONVENTION_ARM_64) ?
>> + ARM_SMCCC_SMC_64 :
>> + ARM_SMCCC_SMC_32,
>
> Here SMC_CONVENTION_UNKNOWN would mean ARM_SMCCC_SMC_32...

Idea is that __qcom_scm_call_smccc would only be called if
qcom_smc_convention
is SMC_CONVENTION_ARM_64 or _32. It should not be possible to get into
__qcom_scm_call_smccc with the current convention being
SMC_CONVENTION_UNKNOWN.

>
>> desc->owner,
>> SMCCC_FUNCNUM(desc->svc, desc->cmd));
>> smc.a[1] = desc->arginfo;
>> @@ -117,7 +125,7 @@ static int ___qcom_scm_call_smccc(struct device
>> *dev,
>> if (!args_virt)
>> return -ENOMEM;
>>
>> - if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
>> + if (qcom_smc_convention == SMC_CONVENTION_ARM_32) {
>
> ...but here it would mean ARM_SMCCC_SMC_64.

I will clean up to be consistent what the "else" case is.


>> @@ -583,19 +591,17 @@ int __qcom_scm_qsmmu500_wait_safe_toggle(struct
>> device *dev, bool en)
>>
>> void __qcom_scm_init(void)
>> {
>> - u64 cmd;
>> - struct arm_smccc_res res;
>> - u32 function = SMCCC_FUNCNUM(QCOM_SCM_SVC_INFO,
>> QCOM_SCM_INFO_IS_CALL_AVAIL);
>> -
>> - /* First try a SMC64 call */
>> - cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64,
>> - ARM_SMCCC_OWNER_SIP, function);
>> -
>> - arm_smccc_smc(cmd, QCOM_SCM_ARGS(1), cmd &
>> (~BIT(ARM_SMCCC_TYPE_SHIFT)),
>> - 0, 0, 0, 0, 0, &res);
>> -
>> - if (!res.a0 && res.a1)
>> - qcom_smccc_convention = ARM_SMCCC_SMC_64;
>> - else
>> - qcom_smccc_convention = ARM_SMCCC_SMC_32;
>> + qcom_smc_convention = SMC_CONVENTION_ARM_64;
>> + if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
>> + QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
>> + goto out;
>> +
>> + qcom_smc_convention = SMC_CONVENTION_ARM_32;
>> + if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
>> + QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
>> + goto out;
>> +
>> + qcom_smc_convention = SMC_CONVENTION_UNKNOWN;
>
> If above two tests can be considered reliable I would suggest that you
> fail hard here instead.

Is the suggestion here to BUG out?

Thanks,

Elliot


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