bootstrap_mmu.cpp

PML phys_map_pt __attribute__((aligned(PAGE_SIZE)));

void paging_init(void)
{
    /* Get the current PML and store it */
    boot_pt = (PML *) arm64_get_kernel_page_table();
    /* Bootstrap the first 1GB */
    uintptr_t virt = PHYS_BASE;

    unsigned int indices[arm64_max_paging_levels];

    addr_to_indices(virt, indices);

    // Create two mappings of 512GB(1TB)
    auto page_table_flags = ARM64_MMU_INNER_SHAREABLE | ARM64_MMU_TABLE | ARM64_MMU_VALID |
                            ARM64_MMU_AF | MMU_PTR_ATTR_NORMAL_MEMORY;
    unsigned long page_table = ((unsigned long) &phys_map_pt) - KERNEL_VIRTUAL_BASE;
    boot_pt->entries[indices[arm64_paging_levels - 1]] = page_table | page_table_flags;

    for (unsigned int i = 0; i < 512; i++)
    {
        phys_map_pt.entries[i] = (i << HUGE1GB_SHIFT) | ARM64_MMU_INNER_SHAREABLE |
                                 ARM64_MMU_BLOCK | ARM64_MMU_VALID | ARM64_MMU_AF |
                                 MMU_PTR_ATTR_NORMAL_MEMORY;
    }
}