loader.h

#pragma once

#include <stdint.h>

#include "core/loader.h"
#include "core/vm.h"
#include "platform/mmu.h"

extern "C" uint8_t loader_begin_;
extern "C" uint8_t loader_end_;

namespace loader {

   using core::mem::PageList;
   using platform::mmu::PageDescriptor;

   /// @brief Data passed by the loader to the kernel
   extern LoaderData gLoaderData;
   /// @brief List of pages allocated for the kernel (incl. page tables)
   extern PageList KernelPages;
   /// @brief List of pages allocated for the loader (incl. page tables)
   extern PageList LoaderPages;

   /**
    * @brief Get the bootargs from the DTB (device tree blob).
    * 
    * @param dtb Pointer to the DTB address
    * @return const char* Boot arguments
    */
   const char *get_dtb_bootargs(void *dtb);

   /**
    * @brief Parse the boot arguments into `gLoaderData`
    */
   void parse_bootargs(char const* args);

   /**
    * @brief Bootstrap the PMM by setting up the PFNDB (Page Frame Number DB).
    *
    * @param initrd_end The physical end of the loader + initrd complex.
    */
   void bootstrap_pmm(uintptr_t initrd_end);

   /**
    * @brief Create initial mappings, sets up paging registers, including
    * writing to `TTBR0` and `TTBR1` the L0 structures.
    */
   void bootstrap_paging();

   /**
    * @brief Allocate a physical page
    *
    * @param out The allocated page's PFNDB struct will be appended here
    * @return uint64_t The physical address of the page
    */
   uint64_t alloc_page_phys(PageList& out);

   /**
    * @brief
    * Puts descriptor `pa` at the L3 table pointed by virtual address `va`.
    * The lower 12 bits of `va` will be ignored. Any newly allocated pages
    * will be appended to `out`.
    */
   void map(uint64_t va, PageDescriptor pa, PageList& out);

   /**
    * @brief
    * Map a range of contiguous physical addresses `pa` which is [start, end)
    * into the virtual range [start + `offset`, end + `offset`). The entire
    * range will have the flags given by `pd`. Any newly allocated pages will
    * be appended to `out`.
    */
   void map_range(Range pa, uint64_t offset, PageDescriptor pd, PageList& out);

   /**
    * @brief
    * Creates and allocates a virtual address chunk defined by `va` and populate
    * it with data copied from the physical address `copy_from`. The range will
    * have the flags given by `pd`, and ALL newly allocated pages will be
    * appended to the list given by `out`.
    */
   void map_create_range(Range va, Range copy_from, PageDescriptor pd, PageList& out);

}; // namespace loader