Implement U mode and PMP/SMEPMP support - Githubissues

chipsalliance / caliptra-sw

Caliptra software (ROM, FMC, runtime firmware), and libraries/tools needed to build and test

Apache License 2.0

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Implement U mode and PMP/SMEPMP support #1542

Closed Elizafox closed 1 month ago

Elizafox commented 1 month ago

Hello,

This PR implements U mode and PMP/SMEPMP support in Caliptra.

This work has been performed on behalf of Microsoft.

What is implemented:

U mode
pmp_i_cfg`and pmpaddri registers 0-15
MPP and MPRV bits in mstatus
Separate exceptions for mcall/mret in U mode

What has changed:

CSR reads/writes are rewritten to work using functions in a table
mcall environment exceptions are split into machine and user mode

What is not implemented:

S mode
medeleg registers
Usermode interrupts