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  "path": "/syndications/kl-os-2025-12-30/",
  "publishedAt": "2025-12-30T00:00:00.000Z",
  "site": "https://scientiac.space",
  "tags": [
    "https://scientiac.space/syndications/kl-os-2025-12-30/POSSE",
    "Day 9"
  ],
  "textContent": "Day 9 was about memory management and virtual addressing.\n\nThe structure of the virtual address is defined by the RISC-V paging mechanism called `Sv32`. It uses a two level page table where the 32 bit virtual address is divided into a first-level page table index, a second level and a page offset. The tables are named `VPN[1]` and `VPN[0]` respectively.\n\nFirst the macros for the construction of the page table are defined. Then the function to map pages `map_page` is made which is utilized in process creation. For that we also add an element called `page_table` on the `struct` of process. And to make everything work we define the starting address of the kernel space `__kernel__base` in the linker script just after boot.\n\nTo utilize the above setup of page tables and switch them, we specify the first-level page table in `satp` (Supervisor Address Translation and Protection) register.\n\nI still need to understand more about this. I am not satisfied with the explanation from the resource.",
  "title": "KL-OS: Page Table",
  "updatedAt": "2026-04-22T08:40:47.378Z"
}