8.8. Architectural Checkpoints

Chipyard supports generating architectural checkpoints using Spike. These checkpoints contain a snapshot of the architectural state of a RISC-V SoC at some point in the execution of a program. The checkpoints include the contents of cacheable memory, core architectural registers, and core CSRs. RTL simulations of SoCs can resume execution from checkpoints after restoring the architectural state.


Currently, only checkpoints of single-core systems are supported

8.8.1. Generating Checkpoints

scripts/generate-ckpt.sh is a script that runs spike with the right commands to generate an architectural checkpoint scripts/generate-ckpt.sh -h lists options for checkpoint generation.

Example: run the hello.riscv binary for 1000 instructions before generating a checkpoint. This should produce a directory named hello.riscv.0x80000000.1000.loadarch

scripts/generate-ckpt.sh -b tests/hello.riscv -i 1000

8.8.2. Loading Checkpoints in RTL Simulation

Checkpoints can be loaded in RTL simulations with the LOADARCH flag. The target config MUST use dmi-based bringup (as opposed to the default TSI-based bringup), and support fast LOADMEM. The target config should also match the architectural configuration of however spike was configured when generating the checkpoint.

cd sims/vcs
make CONFIG=dmiRocketConfig run-binary LOADARCH=../../hello.riscv.0x80000000.1000.loadarch