Generic SMCCC

[br]

Summary

Implement generic arm_smccc calls for arm and arm64

This is used by Intel Stratix 10 platform SMC drivers

Test Plan

Tested on Intel S10

[andrew]

sys/arm64/include/arm-smccc.h

1 ↗

(On Diff #61355)

Why is this file in sys/arm64/include? It doesn't seem to be arm64 specific.

[andrew]

sys/arm64/arm64/smccc-call.S

38 ↗

(On Diff #61355)

I think you mean struct arm_smccc_res *res.

42 ↗

(On Diff #61355)

You could allow for NULL to be passed as res by checking x4 is non-zero, e.g.

cbz x4, 1f
stp ...
stp ...
1f:
ret

Alternatively if x8 is preserved you could return the struct arm_smccc_res directly. The caller will allocate space for it and pass a pointer to the memory in x8 (assuming I'm remembering the ABI correctly).

50 ↗

(On Diff #61355)

And here.

[br]

address Andy's comments

[br]

sys/arm64/include/arm-smccc.h

1 ↗

(On Diff #61355)

Hmm I'm not sure where to put it then. Any idea ?

[andrew]

Can you update the psci code to use the arm_smccc_* functions? We should only have one copy the functions to make smccc calls and you can consider psci to be based on it.

sys/arm64/include/arm-smccc.h

1 ↗

(On Diff #61355)

I would leave the code where it was and add your changes to sys/dev/psci/smccc.h.

sys/arm64/arm64/smccc-call.S should also be moved to sys/dev/psci/smccc_arm64.S.

[br]

Reuse generic SMCCC for PSCI.

[br]

In D21439#469311, @andrew wrote:

Can you update the psci code to use the arm_smccc_* functions? We should only have one copy the functions to make smccc calls and you can consider psci to be based on it.

OK I updated. I did not test on arm since I dont have PSCI-enabled arm hardware