The SBI HFENCE VVMA calls use current VMID (in HGATP CSR) of calling HART for flushing TLB enteries. This fact is not clearly evident in current documentatation of HFENCE VVMA calls hence this patch

This patch adds SBI v0.2 compliant system reset extension. It defines the sbi_system_reset function which does different things based on reset_type parameter: 1. shutdown - Power-off the entire

Thanks Anup and Atish, Just wondering the way to submit the changes for adding firmware code base SBI extension space to riscv-sbi-doc. I already had a PR on Github, we can discuss this in the

Kindly send the proposal to the mailing list. We have enough topics now that we can schedule a meeting to finalize things. -- Regards, Atish

For riscv-sbi-doc, we have not finalized mailing list based review OR Github PR based review so most of usl are sending riscv-sbi-doc changes as patches to mailing list and Github PR.

We would like to have firmware code base SBI based on OpenSBI implementation ID, because edk2 is not one of the implementations of SBI. I saw the patches of overriding SBI implementation ID was also

As-per my understanding, U-Boot and Coreboot don’t need this SBI firmware code base extension. Other SBI extensions are sufficient for these bootloaders. In my opinion, use of SBI firmware code

Anup wrote: But EDK2 can and will register extensions with OpenSBI, meaning that even identical OpenSBI versions might behave differently with regards to such extension. So far I think you are right

and that is fine if other firmware code base use the same0xA000000 + opensbi_imp_id however the extension is incompatible each other, because the firmware code base SBI is very firmware code base

Jonathan, With EDK2 + OpenSBI running in background, the S-mode software will see SBI implementation ID of OpenSBI because EDK2 uses unmodified OpenSBI as library. This means from S-mode

Anup, are you saying that EDK2's extension would be the only use of ext_id = 0xA000000 + opensbi_imp_id or that any firmware that uses OpenSBI is free to make a (potentially incompatible) extension

Hi Anup, Thanks for the clarification. I have updated PR according to this. edk2 is removed from SBI implementation ID. Thanks Anup and Jonathan. Abner From: Anup Patel

Hi Abner, Yes, your understanding is correct. The 0xA000000 + opensbi_imp_id is the SBI Firmware code base extension meant to be used by OpenSBI. Now EDK2 uses unmodified OpenSBI as

From: Jonathan Behrens [mailto:behrensj@...] Sent: Monday, April 13, 2020 10:49 AM To: Chang, Abner (HPS SW/FW Technologist) <abner.chang@...> Cc: Anup Patel <Anup.Patel@...>; Atish Patra

That is fine, just realize that if you are using OpenSBI's implementation ID then you need to get approval from them before defining the extension. Jonathan

Basically OpenSBI is a git submodule of edk2 and we don’t make any modification on it, we just build OpenSBI on edk2 build environment. Yes, edk2 will have its own control of extensions for those

Is the code for the extension you want to add going to live in the OpenSBI repository or in the EDK2 repository? If I understand correctly, it would live in the EDK2 repository, meaning that your

Hi Abner, We have two options here: EDK2 can use 0xA000000 + <opensbi_imp_id> as SBI Extension OpenSBI provides a way to EDK2 for overriding SBI implementation ID (preferably using some API)

This is the PR according to the discussion we had in mail thread. However you may see some confusions from this