Support for userspace drivers #4

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opened 2025-12-03 09:54:24 -06:00 by pfarley · 0 comments

pfarley commented

2025-12-03 09:54:24 -06:00

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Requirements:

Syscall to read/write ports (x86)
- Potentially syscall to request access to specific ports, so a faulty driver that attempts to access a port it hasn't requested, it can be terminated
Memory mapping syscall
Registering and handling interrupts from userspace
- Potentially by having a thread for each interrupt source, and blocking until the kernel messages it that an interrupt has been received
- Threads waiting on an interrupt could also potentially be re-prioritized on interrupt reception, and the scheduler called
- Registering a callback with the kernel would be more efficient, but would sacrifice some of the security/stability concerns of moving drivers to userspace
  - Inefficient drivers whose interrupts fire often can bog down the system
  - If drivers are run in kernel mode, they have greater access to the system

Requirements: * Syscall to read/write ports (x86) * Potentially syscall to request access to specific ports, so a faulty driver that attempts to access a port it hasn't requested, it can be terminated * Memory mapping syscall * Registering and handling interrupts from userspace * Potentially by having a thread for each interrupt source, and blocking until the kernel messages it that an interrupt has been received * Threads waiting on an interrupt could also potentially be re-prioritized on interrupt reception, and the scheduler called * Registering a callback with the kernel would be more efficient, but would sacrifice some of the security/stability concerns of moving drivers to userspace * Inefficient drivers whose interrupts fire often can bog down the system * If drivers are run in kernel mode, they have greater access to the system