eonix/include/kernel/mem/vm_area.hpp

#pragma once

#include <stdint.h>

#include <kernel/vfs.hpp>

namespace kernel::mem {

constexpr unsigned long MM_WRITE         = 0x00000000'00000001;
constexpr unsigned long MM_EXECUTE       = 0x00000000'00000002;
constexpr unsigned long MM_MAPPED        = 0x00000000'00000004;
constexpr unsigned long MM_ANONYMOUS     = 0x00000000'00000008;
constexpr unsigned long MM_INTERNAL_MASK = 0xffffffff'00000000;
constexpr unsigned long MM_BREAK         = 0x80000000'00000000;

struct vm_area {
    uintptr_t start;
    uintptr_t end;

    unsigned long flags;

    fs::inode* mapped_file;
    std::size_t file_offset;

    constexpr bool is_avail(uintptr_t ostart, uintptr_t oend) const noexcept
    {
        return (ostart >= end || oend <= start);
    }

    constexpr bool operator<(const vm_area& rhs) const noexcept
    { return end <= rhs.start; }
    constexpr bool operator<(uintptr_t rhs) const noexcept
    { return end <= rhs; }
    friend constexpr bool operator<(uintptr_t lhs, const vm_area& rhs) noexcept
    { return lhs < rhs.start; }

    constexpr vm_area(uintptr_t start, unsigned long flags, uintptr_t end,
            fs::inode* mapped_file = nullptr, std::size_t offset = 0)
        : start{start}, end{end}, flags{flags}, mapped_file{mapped_file}, file_offset{offset} { }

    constexpr vm_area(uintptr_t start, unsigned long flags,
            fs::inode* mapped_file = nullptr, std::size_t offset = 0)
        : start{start}, end{start}, flags{flags}, mapped_file{mapped_file}, file_offset{offset} { }
};

} // namespace kernel::mem