diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp | 4 | ||||
| -rw-r--r-- | arch/x86_64/include/arch/memory/paging/page_entry.hpp | 20 | ||||
| -rw-r--r-- | arch/x86_64/src/memory/paging/page_entry.cpp | 22 |
3 files changed, 43 insertions, 3 deletions
diff --git a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp index f30ca24..54ec682 100644 --- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp +++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp @@ -116,11 +116,11 @@ namespace teachos::arch::memory::paging allocator::physical_frame_iterator const begin{start_frame}; allocator::physical_frame_iterator const end{end_frame}; frame_container frames{begin, end}; + entry entry{section.flags}; for (auto const & frame : frames) { - // TODO: Use actual elf section flags, convert from one to the other flag type. - active_table.identity_map(allocator, frame, entry::WRITABLE); + active_table.identity_map(allocator, frame, entry.get_flags()); } } } diff --git a/arch/x86_64/include/arch/memory/paging/page_entry.hpp b/arch/x86_64/include/arch/memory/paging/page_entry.hpp index 5959801..ab9659d 100644 --- a/arch/x86_64/include/arch/memory/paging/page_entry.hpp +++ b/arch/x86_64/include/arch/memory/paging/page_entry.hpp @@ -2,6 +2,7 @@ #define TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_ENTRY_HPP #include "arch/memory/allocator/physical_frame.hpp" +#include "arch/memory/multiboot/elf_symbols_section.hpp" #include <bitset> #include <optional> @@ -48,6 +49,18 @@ namespace teachos::arch::memory::paging explicit entry(uint64_t flags); /** + * @brief Converts the given elf section flags into the corresponding correct entry flags. + * + * @note Enables us to set the correct flags on a entry depending on which elf section it is contained in. For + * example entries of .text sections should be executable and read only or entries of .data sections should be + * writable but not executable. + * + * @param elf_flags Elf section flags we want to convert into entry flags. + * @return Entry that has the corresponding bit flags set. + */ + explicit entry(multiboot::elf_section_flags elf_flags); + + /** * @brief Whether the current page is unused, meaning the underlying std::bitset is 0. * * @return Current page is in memory. @@ -86,6 +99,13 @@ namespace teachos::arch::memory::paging */ auto contains_flags(std::bitset<64U> other) const -> bool; + /** + * @brief Extracts only the flags from the underlying entry and ignores all bits that contain the physical address. + * + * @return Extracted entry flags, without the physical address. + */ + auto get_flags() -> std::bitset<64U>; + private: std::bitset<64U> flags; ///< Underlying bitset used to read the flags from. Bits 9 - 11 and 52 - 62 can be ///< freely used for additional flags by the operating system. diff --git a/arch/x86_64/src/memory/paging/page_entry.cpp b/arch/x86_64/src/memory/paging/page_entry.cpp index 23c700f..5c4bc67 100644 --- a/arch/x86_64/src/memory/paging/page_entry.cpp +++ b/arch/x86_64/src/memory/paging/page_entry.cpp @@ -7,7 +7,8 @@ namespace teachos::arch::memory::paging namespace { std::size_t constexpr PHYSICAL_ADDRESS_MASK = 0x000fffff'fffff000; - } + std::size_t constexpr ENTRY_FLAGS_MASK = 0xfff00000'00000fff; + } // namespace entry::entry(uint64_t flags) : flags(flags) @@ -15,6 +16,23 @@ namespace teachos::arch::memory::paging // Nothing to do. } + entry::entry(multiboot::elf_section_flags elf_flags) + { + if (elf_flags.contains_flags(multiboot::elf_section_flags::OCCUPIES_MEMORY)) + { + flags = flags.to_ulong() | entry::PRESENT; + } + if (elf_flags.contains_flags(multiboot::elf_section_flags::WRITABLE)) + { + flags = flags.to_ulong() | entry::WRITABLE; + } + if (!elf_flags.contains_flags(multiboot::elf_section_flags::EXECUTABLE_CODE)) + { + // TODO: Ensure to set the NXE bit, if we don't using this entry flag causes crashes + // flags = flags.to_ulong() | entry::EXECUTING_CODE_FORBIDDEN; + } + } + auto entry::is_unused() const -> bool { return flags == 0U; } auto entry::set_unused() -> void { flags = 0U; } @@ -37,4 +55,6 @@ namespace teachos::arch::memory::paging "[Paging Entry] Start address is not aligned with page"); flags = frame.start_address() | additional_flags.to_ulong(); } + + auto entry::get_flags() -> std::bitset<64U> { return flags.to_ulong() & ENTRY_FLAGS_MASK; } } // namespace teachos::arch::memory::paging |