Hi Feifan Qian,

Trapping GPF to EL3 is permitted by the architecture, however I don't believe TF-A provides such option. In general for TF-A's reference software stacks, a GPF is trapped first at EL2 (hence SCR_EL3.GPF=0). E.g. In a system implementing RME, the RMM (@ R-EL2) traps a GPF occurring in an R-EL1/0 Realm (or R-EL2 itself). Similarly, in the secure world, the SPM (@ S-EL2) traps a GPF occurring in a S-EL1/0 secure partition (or S-EL2 itself).

Regards, Olivier.

________________________________ From: 钱非凡 qianfeifan@iie.ac.cn Sent: 01 July 2024 08:52 To: tf-a-owner@lists.trustedfirmware.org tf-a-owner@lists.trustedfirmware.org Subject: Questions about the Fault Handling of GPFs

Dear experts,

I have been learning the Fault Handling of the Granule Protection Fault in Arm CCA. Upon studying the Arm Document, I discovered that the GPF bit in the SCR_EL3 register controls whether the fault handling of GPFs occurs in EL3 or not. In addition, I noted that `include/arch/aarch64/arch.h` defines a macro `#define SCR_GPF_BIT (UL(1) << 48)`, yet I could not find any reference to this macro in the source code.

I want to know that whether ATF has implemented the fault handling of GPFs or if this is a feature to be expected in the future. If its not, how can I implement this. Any guidance or advice you could provide would be greatly appreciated.

Sincerely,

Feifan Qian