From b9d445bf92725d79269becf978059e040519c00a Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Wed, 10 Dec 2025 16:51:44 +0100 Subject: x86_64/memory: implement simple kernel remapper --- arch/x86_64/src/memory/kernel_mapper.cpp | 107 +++++++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 arch/x86_64/src/memory/kernel_mapper.cpp (limited to 'arch/x86_64/src/memory/kernel_mapper.cpp') 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 +#include + +#include +#include + +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(&boot::x86_64::TEACHOS_VMA)} + {} + + auto kernel_mapper::remap_kernel() -> void + { + auto elf_information = m_mbi->maybe_elf_symbols(); + 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::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 \ No newline at end of file -- cgit v1.2.3 From eafbf588760c289b7f54a4771b39af0ccfe8cf59 Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Wed, 10 Dec 2025 21:55:42 +0100 Subject: kapi: extract page_mapper interface --- arch/x86_64/src/memory/kernel_mapper.cpp | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch/x86_64/src/memory/kernel_mapper.cpp') diff --git a/arch/x86_64/src/memory/kernel_mapper.cpp b/arch/x86_64/src/memory/kernel_mapper.cpp index b1d12a4..f46b5b5 100644 --- a/arch/x86_64/src/memory/kernel_mapper.cpp +++ b/arch/x86_64/src/memory/kernel_mapper.cpp @@ -32,9 +32,8 @@ namespace teachos::memory::x86_64 } // namespace - kernel_mapper::kernel_mapper(frame_allocator & allocator, multiboot2::information_view const * mbi) - : m_allocator{&allocator} - , m_mbi(std::move(mbi)) + kernel_mapper::kernel_mapper(multiboot2::information_view const * mbi) + : m_mbi{std::move(mbi)} , m_kernel_load_base{std::bit_cast(&boot::x86_64::TEACHOS_VMA)} {} @@ -100,7 +99,7 @@ namespace teachos::memory::x86_64 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); + paging_root::get().map(page{first_page.number() + i}, frame{first_frame.number() + i}, page_flags); } } -- cgit v1.2.3 From 50c9c9a1d963e66f7658ab31e9ecd65bf227cfff Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Fri, 12 Dec 2025 14:07:28 +0100 Subject: x86_64/memory: clean up dependencies --- arch/x86_64/src/memory/kernel_mapper.cpp | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'arch/x86_64/src/memory/kernel_mapper.cpp') diff --git a/arch/x86_64/src/memory/kernel_mapper.cpp b/arch/x86_64/src/memory/kernel_mapper.cpp index f46b5b5..a28cf00 100644 --- a/arch/x86_64/src/memory/kernel_mapper.cpp +++ b/arch/x86_64/src/memory/kernel_mapper.cpp @@ -5,8 +5,6 @@ #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 #include @@ -17,7 +15,7 @@ namespace teachos::memory::x86_64 { - inline namespace + namespace { using namespace std::string_view_literals; @@ -37,7 +35,7 @@ namespace teachos::memory::x86_64 , m_kernel_load_base{std::bit_cast(&boot::x86_64::TEACHOS_VMA)} {} - auto kernel_mapper::remap_kernel() -> void + auto kernel_mapper::remap_kernel(page_mapper & mapper) -> void { auto elf_information = m_mbi->maybe_elf_symbols(); if (!elf_information) @@ -60,10 +58,11 @@ namespace teachos::memory::x86_64 } std::ranges::for_each(allocated_sections, - [&](auto const & section) -> auto { map_section(section, sections.name(section)); }); + [&](auto const & section) -> auto { map_section(section, sections.name(section), mapper); }); } - auto kernel_mapper::map_section(section_header_type const & section, std::string_view name) -> void + auto kernel_mapper::map_section(section_header_type const & section, std::string_view name, page_mapper & mapper) + -> void { cio::print("[x86_64:MEM] mapping "); cio::println(name); @@ -76,30 +75,30 @@ namespace teachos::memory::x86_64 auto first_page = page::containing(linear_start_address); auto first_frame = frame::containing(physical_start_address); - auto page_flags = page_table::entry::flags::empty; + auto page_flags = page_mapper::flags::empty; if (section.writable()) { - page_flags |= page_table::entry::flags::writable; + page_flags |= page_mapper::flags::writable; } - if (!section.executable()) + if (section.executable()) { - page_flags |= page_table::entry::flags::no_execute; + page_flags |= page_mapper::flags::executable; } 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)) + if (!std::ranges::any_of(user_accessible_prefixes, is_prefix_of_name)) { - page_flags |= page_table::entry::flags::user_accessible; + page_flags |= page_mapper::flags::supervisor_only; } 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); + mapper.map(first_page + i, first_frame + i, page_flags); } } -- cgit v1.2.3 From 1945dd16716392e70e74efacd19e779f121bd1da Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Mon, 15 Dec 2025 16:46:51 +0100 Subject: chore: fix missing includes --- arch/x86_64/src/memory/kernel_mapper.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86_64/src/memory/kernel_mapper.cpp') diff --git a/arch/x86_64/src/memory/kernel_mapper.cpp b/arch/x86_64/src/memory/kernel_mapper.cpp index a28cf00..4781d64 100644 --- a/arch/x86_64/src/memory/kernel_mapper.cpp +++ b/arch/x86_64/src/memory/kernel_mapper.cpp @@ -8,9 +8,15 @@ #include #include +#include #include +#include +#include +#include #include +#include +#include namespace teachos::memory::x86_64 { -- cgit v1.2.3