diff options
| -rw-r--r-- | arch/x86_64/include/arch/memory/paging/active_page_table.hpp | 23 | ||||
| -rw-r--r-- | arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp | 23 |
2 files changed, 14 insertions, 32 deletions
diff --git a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp index a60b3ad..8b12800 100644 --- a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp +++ b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp @@ -136,7 +136,6 @@ namespace teachos::arch::memory::paging "[Page Mapper] Attempted to unmap page, which has not been mapped previously"); auto current_handle = active_handle; - std::array<page_table_handle, 3U> handles{current_handle, current_handle, current_handle}; for (auto level = page_table_handle::LEVEL4; level != page_table_handle::LEVEL1; --level) { @@ -146,28 +145,10 @@ namespace teachos::arch::memory::paging // fail. This can only mean that we attempted to unmap a huge page, which is not supported in the first place. exception_handling::assert(next_handle.has_value(), "[Page Mapper] Unable to unmap huge pages"); current_handle = next_handle.value(); - // The level is used as the index, because it ensures the first level is the lowest one and then the remaining - // levels in ascending order. This is required, because we first have to clear the Level 1 page entry to check - // if the Level 1 page is now empty, to clear the Level 2 page entry, which will then also check if the Level 2 - // page is empty and clear the Level 3 page entry and so on. - handles.at(level - 1U) = current_handle; } - // Unmaps all entries starting from the Level 1 page table, and unmaps higher levels as well if that entry was the - // last one. We check if it was the last one using is empty on the page table handle, when we have removed the - // page to be unmapped. - for (auto & handle : handles) - { - unmap_page_table_entry(allocator, page, handle); - if (!handle.is_empty()) - { - break; - } - } - // Uses flush all instead of cpu::tlb_flush(page.start_address());, because when we unmap the active page and - // only flush one page, the rest of the page which is huge still exist in the cache and - // can therefore still be accessed. But because they are huge pages the new mapping can not be accessed correctly. - cpu::tlb_flush_all(); + unmap_page_table_entry(allocator, page, current_handle); + cpu::tlb_flush(page.start_address()); } private: 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 bcc3eba..f980451 100644 --- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp +++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp @@ -40,17 +40,17 @@ namespace teachos::arch::memory::paging */ auto remap_kernel() -> active_page_table & { - /*temporary_page temporary_page{virtual_page{0xCAFEBABE}, allocator};*/ + temporary_page temporary_page{virtual_page{0xCAFEBABE}, allocator}; auto & active_table = active_page_table::create_or_get(); - /*auto const frame = allocator.allocate_frame(); + auto const frame = allocator.allocate_frame(); exception_handling::assert(frame.has_value(), "[Kernel Mapper] Frame could not be allocated and therefore kernel not mapped"); - inactive_page_table new_table{frame.value(), active_table, temporary_page};*/ - remap_elf_kernel_sections(active_table); - /*auto const old_table = switch_active_page_table(new_table); + inactive_page_table new_table{frame.value(), active_table, temporary_page}; + remap_elf_kernel_sections(new_table, temporary_page, active_table); + auto const old_table = switch_active_page_table(new_table); auto const old_level_4_page = virtual_page::containing_address(old_table.page_table_level_4_frame.start_address()); - active_table.unmap_page(allocator, old_level_4_page);*/ + active_table.unmap_page(allocator, old_level_4_page); return active_table; } @@ -72,19 +72,20 @@ namespace teachos::arch::memory::paging * @param active_table Active level 4 page table that has its recursive mapping overwritten temporarily and then * restored once the process is finished. */ - auto remap_elf_kernel_sections(active_page_table & active_table) -> void + auto remap_elf_kernel_sections(inactive_page_table & inactive_table, temporary_page & temporary_page, + active_page_table & active_table) -> void { - /*auto const backup = + auto const backup = allocator::physical_frame::containing_address(cpu::read_control_register(cpu::control_register::CR3)); auto page_table_level4 = temporary_page.map_table_frame(backup, active_table); - active_table[511].set_entry(inactive_table.page_table_level_4_frame, entry::PRESENT | entry::WRITABLE);*/ + active_table[511].set_entry(inactive_table.page_table_level_4_frame, entry::PRESENT | entry::WRITABLE); cpu::tlb_flush_all(); map_elf_kernel_sections(active_table); - /*page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE);*/ + page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE); cpu::tlb_flush_all(); - /*temporary_page.unmap_page(active_table);*/ + temporary_page.unmap_page(active_table); } /** |