diff options
Diffstat (limited to 'arch/x86_64/src/memory/kernel_mapper.cpp')
| -rw-r--r-- | arch/x86_64/src/memory/kernel_mapper.cpp | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/x86_64/src/memory/kernel_mapper.cpp b/arch/x86_64/src/memory/kernel_mapper.cpp new file mode 100644 index 0000000..b1d12a4 --- /dev/null +++ b/arch/x86_64/src/memory/kernel_mapper.cpp @@ -0,0 +1,107 @@ +#include "x86_64/memory/kernel_mapper.hpp" + +#include "kapi/cio.hpp" +#include "kapi/memory.hpp" +#include "kapi/system.hpp" + +#include "x86_64/boot/ld.hpp" +#include "x86_64/memory/page_table.hpp" +#include "x86_64/memory/paging_root.hpp" + +#include <elf/format.hpp> +#include <elf/section_header.hpp> + +#include <algorithm> +#include <ranges> + +namespace teachos::memory::x86_64 +{ + + inline namespace + { + using namespace std::string_view_literals; + + constexpr auto static ignored_section_prefixes = std::array{ + ".boot_"sv, + }; + + constexpr auto static user_accessible_prefixes = std::array{ + ".user"sv, + ".stl"sv, + }; + + } // namespace + + kernel_mapper::kernel_mapper(frame_allocator & allocator, multiboot2::information_view const * mbi) + : m_allocator{&allocator} + , m_mbi(std::move(mbi)) + , m_kernel_load_base{std::bit_cast<std::uintptr_t>(&boot::x86_64::TEACHOS_VMA)} + {} + + auto kernel_mapper::remap_kernel() -> void + { + auto elf_information = m_mbi->maybe_elf_symbols<elf::format::elf64>(); + if (!elf_information) + { + system::panic("[x86_64:MEM] ELF section information is not available."); + } + + auto sections = *elf_information; + auto allocated_sections = + std::views::all(sections) | std::views::filter(&elf::section_header<elf::format::elf64>::allocated) | + std::views::filter([&](auto const & section) -> auto { + auto name = sections.name(section); + return !std::ranges::any_of(ignored_section_prefixes, + [&](auto const & prefix) -> auto { return name.starts_with(prefix); }); + }); + + if (allocated_sections.empty()) + { + system::panic("[x86_64:MEM] No allocated ELF sections were found."); + } + + std::ranges::for_each(allocated_sections, + [&](auto const & section) -> auto { map_section(section, sections.name(section)); }); + } + + auto kernel_mapper::map_section(section_header_type const & section, std::string_view name) -> void + { + cio::print("[x86_64:MEM] mapping "); + cio::println(name); + + auto number_of_pages = (section.size + (PLATFORM_PAGE_SIZE - 1)) / PLATFORM_PAGE_SIZE; + + auto linear_start_address = linear_address{section.virtual_load_address}; + auto physical_start_address = physical_address{section.virtual_load_address & ~m_kernel_load_base}; + + auto first_page = page::containing(linear_start_address); + auto first_frame = frame::containing(physical_start_address); + + auto page_flags = page_table::entry::flags::empty; + + if (section.writable()) + { + page_flags |= page_table::entry::flags::writable; + } + + if (!section.executable()) + { + page_flags |= page_table::entry::flags::no_execute; + } + + auto is_prefix_of_name = [=](auto prefix) -> bool { + return name.starts_with(prefix); + }; + + if (std::ranges::any_of(user_accessible_prefixes, is_prefix_of_name)) + { + page_flags |= page_table::entry::flags::user_accessible; + } + + for (auto i = 0uz; i < number_of_pages; ++i) + { + paging_root::get().map(page{first_page.number() + i}, frame{first_frame.number() + i}, page_flags, *m_allocator); + } + } + +} // namespace teachos::memory::x86_64
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