oxidecomputer / oxidecomputer/humility
ARMCore::has_tz() returns true for Cortex-M33 w/o TZ-M
Nobody has claimed this yet.
- Dominant language
- Rust
- Stars
- 584
- Forks
- 63
- Avg merge
- 3h
- Merged PRs (30d)
- 2
Description
TrustZone-M is an optional feature both architecturally and in core designs. ARMCore::has_tz() currently assumes that all Cortex-M33 implementations include TrustZone-M which is definitely not true (see NXP LPC55S28, NXP LPC55S69 core 1). This currently manifests as #315 causing humility probe to claim there are two MPUs in an LPC55S28 when there is really only one.
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating ARMCore::has_tz() and the code used by humility probe to determine MPU count. Compare the TrustZone-M assumption with the Cortex-M33 cases described for LPC55S28 and LPC55S69 core 1, and review issue #315 for the observed failure. Done means has_tz() no longer reports TrustZone-M where it is absent and humility probe reports the correct MPU count.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- devtools, embedded-iot
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100