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https://github.com/RGBCube/serenity
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Kernel: Introduce basic pre-kernel environment
This implements a simple bootloader that is capable of loading ELF64 kernel images. It does this by using QEMU/GRUB to load the kernel image from disk and pass it to our bootloader as a Multiboot module. The bootloader then parses the ELF image and sets it up appropriately. The kernel's entry point is a C++ function with architecture-native code. Co-authored-by: Liav A <liavalb@gmail.com>
This commit is contained in:
Gunnar Beutner
Andreas Kling
parent
357ddd393e
commit
7e94b090fe
30 changed files with 1207 additions and 181 deletions
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@ -22,6 +22,8 @@
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#include <Kernel/VM/PhysicalRegion.h>
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#include <Kernel/VM/SharedInodeVMObject.h>
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extern u8* start_of_bootloader_image;
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extern u8* end_of_bootloader_image;
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extern u8* start_of_kernel_image;
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extern u8* end_of_kernel_image;
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extern FlatPtr start_of_kernel_text;
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@ -34,6 +36,9 @@ extern FlatPtr end_of_unmap_after_init;
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extern FlatPtr start_of_kernel_ksyms;
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extern FlatPtr end_of_kernel_ksyms;
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extern "C" void* boot_pd_kernel;
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extern "C" void* boot_pd_kernel_pt1023;
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extern multiboot_module_entry_t multiboot_copy_boot_modules_array[16];
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extern size_t multiboot_copy_boot_modules_count;
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@ -196,6 +201,7 @@ UNMAP_AFTER_INIT void MemoryManager::parse_memory_map()
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// Register used memory regions that we know of.
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m_used_memory_ranges.ensure_capacity(4);
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m_used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::LowMemory, PhysicalAddress(0x00000000), PhysicalAddress(1 * MiB) });
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m_used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::Bootloader, PhysicalAddress(virtual_to_low_physical(FlatPtr(start_of_bootloader_image))), PhysicalAddress(page_round_up(virtual_to_low_physical(FlatPtr(end_of_bootloader_image)))) });
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m_used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::Kernel, PhysicalAddress(virtual_to_low_physical(FlatPtr(&start_of_kernel_image))), PhysicalAddress(page_round_up(virtual_to_low_physical(FlatPtr(&end_of_kernel_image)))) });
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if (multiboot_info_ptr->flags & 0x4) {
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@ -334,8 +340,6 @@ UNMAP_AFTER_INIT void MemoryManager::parse_memory_map()
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}
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}
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extern "C" PageDirectoryEntry boot_pd3[1024];
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UNMAP_AFTER_INIT void MemoryManager::initialize_physical_pages()
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{
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// We assume that the physical page range is contiguous and doesn't contain huge gaps!
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@ -436,10 +440,10 @@ UNMAP_AFTER_INIT void MemoryManager::initialize_physical_pages()
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unquickmap_page();
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// Hook the page table into the kernel page directory
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PhysicalAddress boot_pd3_paddr(virtual_to_low_physical((FlatPtr)boot_pd3));
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PhysicalAddress boot_pd_kernel_paddr(virtual_to_low_physical((FlatPtr)boot_pd_kernel));
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u32 page_directory_index = (virtual_page_base_for_this_pt >> 21) & 0x1ff;
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auto* pd = reinterpret_cast<PageDirectoryEntry*>(quickmap_page(boot_pd3_paddr));
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auto* pd = reinterpret_cast<PageDirectoryEntry*>(quickmap_page(boot_pd_kernel_paddr));
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PageDirectoryEntry& pde = pd[page_directory_index];
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VERIFY(!pde.is_present()); // Nothing should be using this PD yet
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@ -909,7 +913,7 @@ RefPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
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return {};
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}
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fast_u32_fill((u32*)page->paddr().offset(KERNEL_BASE).as_ptr(), 0, PAGE_SIZE / sizeof(u32));
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fast_u32_fill((u32*)page->paddr().offset(kernel_base).as_ptr(), 0, PAGE_SIZE / sizeof(u32));
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++m_system_memory_info.super_physical_pages_used;
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return page;
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}
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@ -939,13 +943,11 @@ void MemoryManager::flush_tlb(PageDirectory const* page_directory, VirtualAddres
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Processor::flush_tlb(page_directory, vaddr, page_count);
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}
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extern "C" PageTableEntry boot_pd3_pt1023[1024];
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PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t pdpt_index)
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{
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VERIFY(s_mm_lock.own_lock());
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auto& mm_data = get_data();
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auto& pte = boot_pd3_pt1023[(KERNEL_QUICKMAP_PD - KERNEL_PT1024_BASE) / PAGE_SIZE];
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auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[(KERNEL_QUICKMAP_PD - KERNEL_PT1024_BASE) / PAGE_SIZE];
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auto pd_paddr = directory.m_directory_pages[pdpt_index]->paddr();
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if (pte.physical_page_base() != pd_paddr.get()) {
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pte.set_physical_page_base(pd_paddr.get());
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@ -971,7 +973,7 @@ PageTableEntry* MemoryManager::quickmap_pt(PhysicalAddress pt_paddr)
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{
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VERIFY(s_mm_lock.own_lock());
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auto& mm_data = get_data();
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auto& pte = boot_pd3_pt1023[(KERNEL_QUICKMAP_PT - KERNEL_PT1024_BASE) / PAGE_SIZE];
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auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[(KERNEL_QUICKMAP_PT - KERNEL_PT1024_BASE) / PAGE_SIZE];
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if (pte.physical_page_base() != pt_paddr.get()) {
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pte.set_physical_page_base(pt_paddr.get());
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pte.set_present(true);
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@ -1002,7 +1004,7 @@ u8* MemoryManager::quickmap_page(PhysicalAddress const& physical_address)
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VirtualAddress vaddr(KERNEL_QUICKMAP_PER_CPU_BASE + Processor::id() * PAGE_SIZE);
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u32 pte_idx = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
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auto& pte = boot_pd3_pt1023[pte_idx];
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auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[pte_idx];
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if (pte.physical_page_base() != physical_address.get()) {
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pte.set_physical_page_base(physical_address.get());
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pte.set_present(true);
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@ -1021,7 +1023,7 @@ void MemoryManager::unquickmap_page()
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VERIFY(mm_data.m_quickmap_in_use.is_locked());
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VirtualAddress vaddr(KERNEL_QUICKMAP_PER_CPU_BASE + Processor::id() * PAGE_SIZE);
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u32 pte_idx = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
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auto& pte = boot_pd3_pt1023[pte_idx];
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auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[pte_idx];
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pte.clear();
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flush_tlb_local(vaddr);
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mm_data.m_quickmap_in_use.unlock(mm_data.m_quickmap_prev_flags);
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@ -43,16 +43,17 @@ constexpr FlatPtr page_round_down(FlatPtr x)
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inline FlatPtr low_physical_to_virtual(FlatPtr physical)
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{
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return physical + KERNEL_BASE;
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return physical + kernel_base;
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}
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inline FlatPtr virtual_to_low_physical(FlatPtr virtual_)
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{
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return virtual_ - KERNEL_BASE;
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return virtual_ - kernel_base;
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}
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enum class UsedMemoryRangeType {
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LowMemory = 0,
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Bootloader,
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Kernel,
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BootModule,
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PhysicalPages,
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@ -60,6 +61,7 @@ enum class UsedMemoryRangeType {
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static constexpr StringView UserMemoryRangeTypeNames[] {
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"Low memory",
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"Bootloader",
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"Kernel",
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"Boot module",
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"Physical Pages"
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@ -6,12 +6,15 @@
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#include <AK/Memory.h>
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#include <AK/Singleton.h>
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#include <Kernel/Prekernel/Prekernel.h>
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#include <Kernel/Process.h>
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#include <Kernel/Random.h>
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#include <Kernel/Sections.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PageDirectory.h>
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extern u8* end_of_kernel_image;
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namespace Kernel {
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static AK::Singleton<HashMap<FlatPtr, PageDirectory*>> s_cr3_map;
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@ -28,16 +31,19 @@ RefPtr<PageDirectory> PageDirectory::find_by_cr3(FlatPtr cr3)
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return cr3_map().get(cr3).value_or({});
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}
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extern "C" FlatPtr kernel_base;
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#if ARCH(X86_64)
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extern "C" PageDirectoryEntry boot_pml4t[1024];
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extern "C" void* boot_pml4t;
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#endif
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extern "C" PageDirectoryEntry* boot_pdpt[4];
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extern "C" PageDirectoryEntry boot_pd0[1024];
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extern "C" PageDirectoryEntry boot_pd3[1024];
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extern "C" void* boot_pdpt;
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extern "C" void* boot_pd0;
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extern "C" void* boot_pd_kernel;
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UNMAP_AFTER_INIT PageDirectory::PageDirectory()
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{
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m_range_allocator.initialize_with_range(VirtualAddress(KERNEL_BASE + KERNEL_PD_OFFSET), KERNEL_PD_END - (KERNEL_BASE + KERNEL_PD_OFFSET));
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// make sure this starts in a new page directory to make MemoryManager::initialize_physical_pages() happy
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FlatPtr start_of_range = ((FlatPtr)&end_of_kernel_image & ~(FlatPtr)0x1fffff) + 0x200000;
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m_range_allocator.initialize_with_range(VirtualAddress(start_of_range), KERNEL_PD_END - start_of_range);
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m_identity_range_allocator.initialize_with_range(VirtualAddress(FlatPtr(0x00000000)), 0x00200000);
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}
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@ -51,13 +57,13 @@ UNMAP_AFTER_INIT void PageDirectory::allocate_kernel_directory()
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#endif
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PhysicalAddress boot_pdpt_paddr(virtual_to_low_physical((FlatPtr)boot_pdpt));
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PhysicalAddress boot_pd0_paddr(virtual_to_low_physical((FlatPtr)boot_pd0));
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PhysicalAddress boot_pd3_paddr(virtual_to_low_physical((FlatPtr)boot_pd3));
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PhysicalAddress boot_pd_kernel_paddr(virtual_to_low_physical((FlatPtr)boot_pd_kernel));
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dmesgln("MM: boot_pdpt @ {}", boot_pdpt_paddr);
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dmesgln("MM: boot_pd0 @ {}", boot_pd0_paddr);
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dmesgln("MM: boot_pd3 @ {}", boot_pd3_paddr);
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dmesgln("MM: boot_pd_kernel @ {}", boot_pd_kernel_paddr);
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m_directory_table = PhysicalPage::create(boot_pdpt_paddr, MayReturnToFreeList::No);
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m_directory_pages[0] = PhysicalPage::create(boot_pd0_paddr, MayReturnToFreeList::No);
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m_directory_pages[3] = PhysicalPage::create(boot_pd3_paddr, MayReturnToFreeList::No);
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m_directory_pages[(kernel_base >> 30) & 0x1ff] = PhysicalPage::create(boot_pd_kernel_paddr, MayReturnToFreeList::No);
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}
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PageDirectory::PageDirectory(const RangeAllocator* parent_range_allocator)
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@ -83,15 +89,13 @@ PageDirectory::PageDirectory(const RangeAllocator* parent_range_allocator)
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m_directory_table = MM.allocate_user_physical_page();
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if (!m_directory_table)
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return;
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auto kernel_pd_index = (KERNEL_BASE >> 30) & 0xffu;
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for (size_t i = 0; i < 4; i++) {
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if (i == kernel_pd_index)
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continue;
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auto kernel_pd_index = (kernel_base >> 30) & 0x1ffu;
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for (size_t i = 0; i < kernel_pd_index; i++) {
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m_directory_pages[i] = MM.allocate_user_physical_page();
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if (!m_directory_pages[i])
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return;
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}
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// Share the top 1 GiB of kernel-only mappings (>=3GiB or >=KERNEL_BASE)
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// Share the top 1 GiB of kernel-only mappings (>=kernel_base)
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m_directory_pages[kernel_pd_index] = MM.kernel_page_directory().m_directory_pages[kernel_pd_index];
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#if ARCH(X86_64)
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@ -86,7 +86,7 @@ public:
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void set_mmap(bool mmap) { m_mmap = mmap; }
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bool is_user() const { return !is_kernel(); }
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bool is_kernel() const { return vaddr().get() < 0x00800000 || vaddr().get() >= KERNEL_BASE; }
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bool is_kernel() const { return vaddr().get() < 0x00800000 || vaddr().get() >= kernel_base; }
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PageFaultResponse handle_fault(const PageFault&, ScopedSpinLock<RecursiveSpinLock>&);
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