CTSRD-CHERI/cheribsd
Feb 2025 – Feb 2025
1 Month active
Languages Used
C
Technical Skills
ARM ArchitectureEmbedded SystemsSystem ProgrammingVirtualization
Mark Johnston
PROFILE
Mark Johnston
Mark Johnston focused on reliability and security improvements across the CTSRD-CHERI/cheribsd and CTSRD-CHERI/cheribuild repositories. He enhanced ARM64 virtualization stability by correcting trap frame ELR derivation during exception injection in Morello-enabled environments, applying deep knowledge of ARM architecture, system programming, and virtualization. This work improved guest exception handling and reduced the risk of mis-injected exceptions. In cheribuild, Mark addressed build system maintenance by removing obsolete DSA SSH key generation, aligning the tool with modern security standards and preventing build-time errors. His contributions, primarily in C and Python, demonstrated careful attention to system-level detail and long-term maintainability.
Overall Statistics
Feature vs Bugs
0%Features
Repository Contributions
2Total
Bugs
2
Commits
2
Features
0
Lines of code
24
Activity Months2
Work History
April 2025
1 Commits
Apr 1, 2025April 2025 monthly summary for CTSRD-CHERI/cheribuild: Removed DSA SSH key generation due to obsolescence, excluding 'dsa' from the key types during generation. This change prevents errors and aligns with modern SSH standards. Commit 2bfa20cd7d10ada9af6cdeb433feafcb668e003c (#414). Impact: reduces build-time SSH key generation failures, improves security posture, and simplifies maintenance. Demonstrated build tooling maintenance and security-conscious development with clear commit messages.
1 Commits
Apr 1, 2025April 2025 monthly summary for CTSRD-CHERI/cheribuild: Removed DSA SSH key generation due to obsolescence, excluding 'dsa' from the key types during generation. This change prevents errors and aligns with modern SSH standards. Commit 2bfa20cd7d10ada9af6cdeb433feafcb668e003c (#414). Impact: reduces build-time SSH key generation failures, improves security posture, and simplifies maintenance. Demonstrated build tooling maintenance and security-conscious development with clear commit messages.
April 2025
February 2025
1 Commits
Feb 1, 2025February 2025 CTSRD-CHERI/cheribsd monthly summary focused on stabilizing ARM64 virtualization by fixing trap frame ELR derivation during exception injection in Morello-enabled environments. No new features delivered this month; major bug fix delivered with downstream improvements to exception handling reliability and virtualization stability. Technologies demonstrated include ARM64 VMM expertise, trap frame management, Morello capability-based trapping configurations, and CPU execution mode awareness applied in patch delivery.
February 2025
1 Commits
Feb 1, 2025February 2025 CTSRD-CHERI/cheribsd monthly summary focused on stabilizing ARM64 virtualization by fixing trap frame ELR derivation during exception injection in Morello-enabled environments. No new features delivered this month; major bug fix delivered with downstream improvements to exception handling reliability and virtualization stability. Technologies demonstrated include ARM64 VMM expertise, trap frame management, Morello capability-based trapping configurations, and CPU execution mode awareness applied in patch delivery.
Activity
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Quality Metrics
Correctness95.0%
Maintainability90.0%
Architecture90.0%
Performance90.0%
AI Usage20.0%
Skills & Technologies
Programming Languages
CPython
Technical Skills
ARM ArchitectureBuild SystemsEmbedded SystemsSystem AdministrationSystem ProgrammingVirtualization
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline
CTSRD-CHERI/cheribuild
Apr 2025 – Apr 2025
1 Month active
Languages Used
Python
Technical Skills
Build SystemsSystem Administration