This release introduces a new unified build environment that supports both the original std and the newly added no-std, along with a new crate to simplify the process of building trusted applications. It also includes real-world examples and updates to support the latest OP-TEE release (4.5.0).

The following are the key updates:

Breaking Changes in the Build Environment

In this release candidate, we have reorganized the code structure and build environment to support both no-std and std build options, simplifying the overall build process.

Additionally, the TA build scripts have been streamlined by introducing the new optee-utee-build crate.

Since the process is quite complex, the following breakdown provides more details:

Starting with an intermediate branch no-std, which simplifies the build environment from scratch:

• On no-std branch: Cleaned up the build environment for no-std and simplified the build process. The works processed on PR114-PR122, e.g.: PR #115
• Based on no-std, added std support: PR #141
• Renamed no-std to main and set it as the default branch: Issue #143
• Further improvements on main after setting it as default:
  Introduced optee-utee-build crate for simplified TA builds. PR #156

Integration with OP-TEE

• Updated CI Docker image for the new OP-TEE build environment: PR #157
• Pinned the setup to OP-TEE 4.5.0: Commit 3aa0c94

New Features

• Made panic_handler optional in optee-utee: PR #147
• Added support for configuring the capacity of shared buffers in LoadablePlugin: PR #154
• Added no-std networking support in optee-utee: PR #164

New Examples

• Added error-handling example: PR #127
• Introduced project/ directory for real-world examples, including a Web3 ETH wallet example: PR #150
• Added no-std support for tcp_client-rs and udp_socket-rs. PR #164

Bug Fixes

• Fixed a double-free bug in optee-utee: PR #127
• Improved argument validation error messages: PR #134

Documentation Updates

• README updates:
  • no-std improvements: PR #128
  • Re-added std support in the new build environment: PR #144
• New migration guide:
  • Migrating to the new build environment (Post-Oct 2024)
• Guide for writing Rust TAs using optee-utee-build:
  • Writing Rust TAs