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Introduction

Info

Please read the general instructions first.

The assignment is due 17:59 on 22 Apr 2024. Late submissions will lose 1 mark per hour.

If you discover any errors or need any clarification or have any question, please create an issue here.

Part A (35 marks)

Note

Please accept the assignment on GitHub Classroom first. The invitation link is available on Canvas.

Task 1: Character Device Driver

Question 1 (6 marks)

Please explain, in detail, how the container_of macro works in the onebyte_open function, and how it's used to retrieve the onebyte_data structure.

Additionally, explain why the onebyte_data structure is stored as the private data of the file instead of being stored as a global variable?

Question 2 (2 marks)

Provide the exact mknod command you used to create the device file.

Task 2: PCI Device

Question 3 (4 marks)

Why can't we read from the file resource0?

Hint:

  • According to the documentation, rw access is allowed for IORESOURCE_IO regions only in files named resource0..N.
  • You should refer to the information from the configuration space.

Question 4 (5 marks)

Please finish the implementation under the directory task2-mmap/ in the repository.

Task 3: Interrupt handler

Question 5 (18 marks)

Please finish the implementation under the directory task3-factorial/ in the repository.

Submission Guidelines

Please accept the assignment on GitHub Classroom first. The invitation link is available on Canvas. Then, proceed to complete the tasks in the repository and push your changes accordingly. I'll pull your work from the repository after the deadline.

Please note the following instructions:

  1. The deadline posted on GitHub is the hard deadline — you'll lose write access to the repository after that time. However, late penalties will apply starting from the due date on Canvas.

  2. I will evaluate two versions of your code for grading: (1) the last commit before the due date on Canvas and (2) the last commit pushed to the repository with late penalties applied. The higher grade of the two versions will be your final grade for this part.

  3. Ensure that your code can be successfully built and that modules can be loaded into the kernel. Failure to build or load will result in a mark of 0.

  4. Coding style matters.

    • Inside the repository, there's a file named .clang-format which sets rules for how your code should look.
    • You can use a tool called clang-format to automatically format your code according to these rules.
    • Feel free to adjust the .clang-format file to your liking, but whatever changes you make, your final submission needs to follow those rules that you set.
    • I'll run a check on your code using clang-format --dry-run --Werror. This includes both C source code files and header files. If clang-format has any complaints with your code, you'll lose 1 mark per file.
    • It's recommended to use clang-format version 18, but you can also use version 14, which comes with Ubuntu 22.04.

  5. Only push essential files to the repository.

    • Do not include binaries, object files, or any other generated files from your source code.
    • Make sure to properly utilize the .gitignore file to exclude inappropriate files from being pushed to the repository.
    • If your repository is messy or contains any unnecessary files, there will be a one-time penalty of 2 marks.

The repository contains the following files or directories:

Filename Description
/qn1.md Your response to Question 1 in Markdown format.
/qn2.md Your response to Question 2 in Markdown format.
/qn3.md Your response to Question 3 in Markdown format.
/task2-mmap/* Your code operating the PCI device using mmap.
/task3-factorial/* Your device driver implementing the factorial calculation.

Please, besides, fill in your GitHub username in the Assignment 4 (Part A) on Canvas.

Part B (15 marks)

Please complete the quiz Assignment 4 (Part B) on Canvas.