Justin C. Miller
4ccaa2dfea
Remove ELF and initrd loading from the kernel. The bootloader now loads the initial programs, as it does with the kernel. Other files that were in the initrd are now on the ESP, and non-program files are just passed as modules.
53 lines
1.6 KiB
C++
53 lines
1.6 KiB
C++
#pragma once
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/// \file paging.h
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/// Page table structure and related definitions
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#include <stdint.h>
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#include <uefi/boot_services.h>
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#include "kernel_args.h"
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namespace boot {
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namespace paging {
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/// Struct to allow easy accessing of a memory page being used as a page table.
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struct page_table
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{
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uint64_t entries[512];
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inline page_table * get(int i, uint16_t *flags = nullptr) const {
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uint64_t entry = entries[i];
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if ((entry & 1) == 0) return nullptr;
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if (flags) *flags = entry & 0xfff;
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return reinterpret_cast<page_table *>(entry & ~0xfffull);
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}
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inline void set(int i, void *p, uint16_t flags) {
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entries[i] = reinterpret_cast<uint64_t>(p) | (flags & 0xfff);
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}
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};
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/// Allocate memory to be used for initial page tables. Initial offset-mapped
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/// page tables are pre-filled. All pages are saved as a module in kernel args
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/// and kernel args' `page_table_cache` and `num_free_tables` are updated with
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/// the leftover space.
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void allocate_tables(
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kernel::args::header *args,
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uefi::boot_services *bs);
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/// Copy existing page table entries to a new page table. Does not do a deep
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/// copy - the new PML4 is updated to point to the existing next-level page
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/// tables in the current PML4.
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void add_current_mappings(page_table *new_pml4);
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/// Map a physical address to a virtual address in the given page tables.
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/// \arg args The kernel args header, used for the page table cache and pml4
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/// \arg phys The phyiscal address to map in
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/// \arg virt The virtual address to map in
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/// \arg size The size in bytes of the mapping
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void map_pages(
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kernel::args::header *args,
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uintptr_t phys, uintptr_t virt,
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size_t bytes);
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} // namespace paging
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} // namespace boot
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