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-rw-r--r--Kernel/VM/.gitignore2
-rw-r--r--Kernel/VM/MemoryManager.cpp642
-rw-r--r--Kernel/VM/MemoryManager.h227
-rw-r--r--Kernel/VM/PageDirectory.cpp32
-rw-r--r--Kernel/VM/PageDirectory.h26
-rw-r--r--Kernel/VM/PhysicalPage.cpp42
-rw-r--r--Kernel/VM/PhysicalPage.h46
-rw-r--r--Kernel/VM/Region.cpp142
-rw-r--r--Kernel/VM/Region.h97
-rw-r--r--Kernel/VM/VMObject.cpp167
-rw-r--r--Kernel/VM/VMObject.h57
11 files changed, 1480 insertions, 0 deletions
diff --git a/Kernel/VM/.gitignore b/Kernel/VM/.gitignore
new file mode 100644
index 0000000000..6142305dc1
--- /dev/null
+++ b/Kernel/VM/.gitignore
@@ -0,0 +1,2 @@
+*.o
+*.d
diff --git a/Kernel/VM/MemoryManager.cpp b/Kernel/VM/MemoryManager.cpp
new file mode 100644
index 0000000000..06e9ef65ef
--- /dev/null
+++ b/Kernel/VM/MemoryManager.cpp
@@ -0,0 +1,642 @@
+#include <Kernel/VM/MemoryManager.h>
+#include <AK/Assertions.h>
+#include <AK/kstdio.h>
+#include "i386.h"
+#include "StdLib.h"
+#include "Process.h"
+#include "CMOS.h"
+
+//#define MM_DEBUG
+//#define PAGE_FAULT_DEBUG
+
+static MemoryManager* s_the;
+unsigned MemoryManager::s_user_physical_pages_in_existence;
+unsigned MemoryManager::s_super_physical_pages_in_existence;
+
+MemoryManager& MM
+{
+ return *s_the;
+}
+
+MemoryManager::MemoryManager()
+{
+ // FIXME: This is not the best way to do memory map detection.
+ // Rewrite to use BIOS int 15,e820 once we have VM86 support.
+ word base_memory = (CMOS::read(0x16) << 8) | CMOS::read(0x15);
+ word ext_memory = (CMOS::read(0x18) << 8) | CMOS::read(0x17);
+
+ kprintf("%u kB base memory\n", base_memory);
+ kprintf("%u kB extended memory\n", ext_memory);
+
+ m_ram_size = ext_memory * 1024;
+
+ m_kernel_page_directory = PageDirectory::create_at_fixed_address(PhysicalAddress(0x4000));
+ m_page_table_zero = (dword*)0x6000;
+
+ initialize_paging();
+
+ kprintf("MM initialized.\n");
+}
+
+MemoryManager::~MemoryManager()
+{
+}
+
+void MemoryManager::populate_page_directory(PageDirectory& page_directory)
+{
+ page_directory.m_directory_page = allocate_supervisor_physical_page();
+ page_directory.entries()[0] = kernel_page_directory().entries()[0];
+ // Defer to the kernel page tables for 0xC0000000-0xFFFFFFFF
+ for (int i = 768; i < 1024; ++i)
+ page_directory.entries()[i] = kernel_page_directory().entries()[i];
+}
+
+void MemoryManager::initialize_paging()
+{
+ static_assert(sizeof(MemoryManager::PageDirectoryEntry) == 4);
+ static_assert(sizeof(MemoryManager::PageTableEntry) == 4);
+ memset(m_page_table_zero, 0, PAGE_SIZE);
+
+#ifdef MM_DEBUG
+ dbgprintf("MM: Kernel page directory @ %p\n", kernel_page_directory().cr3());
+#endif
+
+#ifdef MM_DEBUG
+ dbgprintf("MM: Protect against null dereferences\n");
+#endif
+ // Make null dereferences crash.
+ map_protected(LinearAddress(0), PAGE_SIZE);
+
+#ifdef MM_DEBUG
+ dbgprintf("MM: Identity map bottom 4MB\n");
+#endif
+ // The bottom 4 MB (except for the null page) are identity mapped & supervisor only.
+ // Every process shares these mappings.
+ create_identity_mapping(kernel_page_directory(), LinearAddress(PAGE_SIZE), (4 * MB) - PAGE_SIZE);
+
+ // Basic memory map:
+ // 0 -> 512 kB Kernel code. Root page directory & PDE 0.
+ // (last page before 1MB) Used by quickmap_page().
+ // 1 MB -> 2 MB kmalloc_eternal() space.
+ // 2 MB -> 3 MB kmalloc() space.
+ // 3 MB -> 4 MB Supervisor physical pages (available for allocation!)
+ // 4 MB -> (max) MB Userspace physical pages (available for allocation!)
+ for (size_t i = (2 * MB); i < (4 * MB); i += PAGE_SIZE)
+ m_free_supervisor_physical_pages.append(PhysicalPage::create_eternal(PhysicalAddress(i), true));
+
+ dbgprintf("MM: 4MB-%uMB available for allocation\n", m_ram_size / 1048576);
+ for (size_t i = (4 * MB); i < m_ram_size; i += PAGE_SIZE)
+ m_free_physical_pages.append(PhysicalPage::create_eternal(PhysicalAddress(i), false));
+ m_quickmap_addr = LinearAddress((1 * MB) - PAGE_SIZE);
+#ifdef MM_DEBUG
+ dbgprintf("MM: Quickmap will use P%x\n", m_quickmap_addr.get());
+ dbgprintf("MM: Installing page directory\n");
+#endif
+
+ asm volatile("movl %%eax, %%cr3"::"a"(kernel_page_directory().cr3()));
+ asm volatile(
+ "movl %%cr0, %%eax\n"
+ "orl $0x80000001, %%eax\n"
+ "movl %%eax, %%cr0\n"
+ :::"%eax", "memory");
+
+#ifdef MM_DEBUG
+ dbgprintf("MM: Paging initialized.\n");
+#endif
+}
+
+RetainPtr<PhysicalPage> MemoryManager::allocate_page_table(PageDirectory& page_directory, unsigned index)
+{
+ ASSERT(!page_directory.m_physical_pages.contains(index));
+ auto physical_page = allocate_supervisor_physical_page();
+ if (!physical_page)
+ return nullptr;
+ page_directory.m_physical_pages.set(index, physical_page.copy_ref());
+ return physical_page;
+}
+
+void MemoryManager::remove_identity_mapping(PageDirectory& page_directory, LinearAddress laddr, size_t size)
+{
+ InterruptDisabler disabler;
+ // FIXME: ASSERT(laddr is 4KB aligned);
+ for (dword offset = 0; offset < size; offset += PAGE_SIZE) {
+ auto pte_address = laddr.offset(offset);
+ auto pte = ensure_pte(page_directory, pte_address);
+ pte.set_physical_page_base(0);
+ pte.set_user_allowed(false);
+ pte.set_present(true);
+ pte.set_writable(true);
+ flush_tlb(pte_address);
+ }
+}
+
+auto MemoryManager::ensure_pte(PageDirectory& page_directory, LinearAddress laddr) -> PageTableEntry
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ dword page_directory_index = (laddr.get() >> 22) & 0x3ff;
+ dword page_table_index = (laddr.get() >> 12) & 0x3ff;
+
+ PageDirectoryEntry pde = PageDirectoryEntry(&page_directory.entries()[page_directory_index]);
+ if (!pde.is_present()) {
+#ifdef MM_DEBUG
+ dbgprintf("MM: PDE %u not present (requested for L%x), allocating\n", page_directory_index, laddr.get());
+#endif
+ if (page_directory_index == 0) {
+ ASSERT(&page_directory == m_kernel_page_directory.ptr());
+ pde.set_page_table_base((dword)m_page_table_zero);
+ pde.set_user_allowed(false);
+ pde.set_present(true);
+ pde.set_writable(true);
+ } else {
+ //ASSERT(&page_directory != m_kernel_page_directory.ptr());
+ auto page_table = allocate_page_table(page_directory, page_directory_index);
+#ifdef MM_DEBUG
+ dbgprintf("MM: PD K%x (%s) at P%x allocated page table #%u (for L%x) at P%x\n",
+ &page_directory,
+ &page_directory == m_kernel_page_directory.ptr() ? "Kernel" : "User",
+ page_directory.cr3(),
+ page_directory_index,
+ laddr.get(),
+ page_table->paddr().get());
+#endif
+
+ pde.set_page_table_base(page_table->paddr().get());
+ pde.set_user_allowed(true);
+ pde.set_present(true);
+ pde.set_writable(true);
+ page_directory.m_physical_pages.set(page_directory_index, move(page_table));
+ }
+ }
+ return PageTableEntry(&pde.page_table_base()[page_table_index]);
+}
+
+void MemoryManager::map_protected(LinearAddress laddr, size_t length)
+{
+ InterruptDisabler disabler;
+ // FIXME: ASSERT(linearAddress is 4KB aligned);
+ for (dword offset = 0; offset < length; offset += PAGE_SIZE) {
+ auto pte_address = laddr.offset(offset);
+ auto pte = ensure_pte(kernel_page_directory(), pte_address);
+ pte.set_physical_page_base(pte_address.get());
+ pte.set_user_allowed(false);
+ pte.set_present(false);
+ pte.set_writable(false);
+ flush_tlb(pte_address);
+ }
+}
+
+void MemoryManager::create_identity_mapping(PageDirectory& page_directory, LinearAddress laddr, size_t size)
+{
+ InterruptDisabler disabler;
+ ASSERT((laddr.get() & ~PAGE_MASK) == 0);
+ for (dword offset = 0; offset < size; offset += PAGE_SIZE) {
+ auto pte_address = laddr.offset(offset);
+ auto pte = ensure_pte(page_directory, pte_address);
+ pte.set_physical_page_base(pte_address.get());
+ pte.set_user_allowed(false);
+ pte.set_present(true);
+ pte.set_writable(true);
+ page_directory.flush(pte_address);
+ }
+}
+
+void MemoryManager::initialize()
+{
+ s_the = new MemoryManager;
+}
+
+Region* MemoryManager::region_from_laddr(Process& process, LinearAddress laddr)
+{
+ ASSERT_INTERRUPTS_DISABLED();
+
+ // FIXME: Use a binary search tree (maybe red/black?) or some other more appropriate data structure!
+ for (auto& region : process.m_regions) {
+ if (region->contains(laddr))
+ return region.ptr();
+ }
+ dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), laddr.get(), process.page_directory().cr3());
+ return nullptr;
+}
+
+const Region* MemoryManager::region_from_laddr(const Process& process, LinearAddress laddr)
+{
+ // FIXME: Use a binary search tree (maybe red/black?) or some other more appropriate data structure!
+ for (auto& region : process.m_regions) {
+ if (region->contains(laddr))
+ return region.ptr();
+ }
+ dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), laddr.get(), process.page_directory().cr3());
+ return nullptr;
+}
+
+bool MemoryManager::zero_page(Region& region, unsigned page_index_in_region)
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ auto& vmo = region.vmo();
+ auto& vmo_page = vmo.physical_pages()[region.first_page_index() + page_index_in_region];
+ sti();
+ LOCKER(vmo.m_paging_lock);
+ cli();
+ if (!vmo_page.is_null()) {
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf("MM: zero_page() but page already present. Fine with me!\n");
+#endif
+ remap_region_page(region, page_index_in_region, true);
+ return true;
+ }
+ auto physical_page = allocate_physical_page(ShouldZeroFill::Yes);
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf(" >> ZERO P%x\n", physical_page->paddr().get());
+#endif
+ region.m_cow_map.set(page_index_in_region, false);
+ vmo.physical_pages()[page_index_in_region] = move(physical_page);
+ remap_region_page(region, page_index_in_region, true);
+ return true;
+}
+
+bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ auto& vmo = region.vmo();
+ if (vmo.physical_pages()[page_index_in_region]->retain_count() == 1) {
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf(" >> It's a COW page but nobody is sharing it anymore. Remap r/w\n");
+#endif
+ region.m_cow_map.set(page_index_in_region, false);
+ remap_region_page(region, page_index_in_region, true);
+ return true;
+ }
+
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf(" >> It's a COW page and it's time to COW!\n");
+#endif
+ auto physical_page_to_copy = move(vmo.physical_pages()[page_index_in_region]);
+ auto physical_page = allocate_physical_page(ShouldZeroFill::No);
+ byte* dest_ptr = quickmap_page(*physical_page);
+ const byte* src_ptr = region.laddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf(" >> COW P%x <- P%x\n", physical_page->paddr().get(), physical_page_to_copy->paddr().get());
+#endif
+ memcpy(dest_ptr, src_ptr, PAGE_SIZE);
+ vmo.physical_pages()[page_index_in_region] = move(physical_page);
+ unquickmap_page();
+ region.m_cow_map.set(page_index_in_region, false);
+ remap_region_page(region, page_index_in_region, true);
+ return true;
+}
+
+
+bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_region)
+{
+ ASSERT(region.page_directory());
+ auto& vmo = region.vmo();
+ ASSERT(!vmo.is_anonymous());
+ ASSERT(vmo.inode());
+
+ auto& vmo_page = vmo.physical_pages()[region.first_page_index() + page_index_in_region];
+
+ InterruptFlagSaver saver;
+
+ sti();
+ LOCKER(vmo.m_paging_lock);
+ cli();
+
+ if (!vmo_page.is_null()) {
+ dbgprintf("MM: page_in_from_inode() but page already present. Fine with me!\n");
+ remap_region_page(region, page_index_in_region, true);
+ return true;
+ }
+
+#ifdef MM_DEBUG
+ dbgprintf("MM: page_in_from_inode ready to read from inode\n");
+#endif
+ sti();
+ byte page_buffer[PAGE_SIZE];
+ auto& inode = *vmo.inode();
+ auto nread = inode.read_bytes(vmo.inode_offset() + ((region.first_page_index() + page_index_in_region) * PAGE_SIZE), PAGE_SIZE, page_buffer, nullptr);
+ if (nread < 0) {
+ kprintf("MM: page_in_from_inode had error (%d) while reading!\n", nread);
+ return false;
+ }
+ if (nread < PAGE_SIZE) {
+ // If we read less than a page, zero out the rest to avoid leaking uninitialized data.
+ memset(page_buffer + nread, 0, PAGE_SIZE - nread);
+ }
+ cli();
+ vmo_page = allocate_physical_page(ShouldZeroFill::No);
+ if (vmo_page.is_null()) {
+ kprintf("MM: page_in_from_inode was unable to allocate a physical page\n");
+ return false;
+ }
+ remap_region_page(region, page_index_in_region, true);
+ byte* dest_ptr = region.laddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
+ memcpy(dest_ptr, page_buffer, PAGE_SIZE);
+ return true;
+}
+
+PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ ASSERT(current);
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf("MM: handle_page_fault(%w) at L%x\n", fault.code(), fault.laddr().get());
+#endif
+ ASSERT(fault.laddr() != m_quickmap_addr);
+ auto* region = region_from_laddr(current->process(), fault.laddr());
+ if (!region) {
+ kprintf("NP(error) fault at invalid address L%x\n", fault.laddr().get());
+ return PageFaultResponse::ShouldCrash;
+ }
+ auto page_index_in_region = region->page_index_from_address(fault.laddr());
+ if (fault.is_not_present()) {
+ if (region->vmo().inode()) {
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf("NP(inode) fault in Region{%p}[%u]\n", region, page_index_in_region);
+#endif
+ page_in_from_inode(*region, page_index_in_region);
+ return PageFaultResponse::Continue;
+ } else {
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf("NP(zero) fault in Region{%p}[%u]\n", region, page_index_in_region);
+#endif
+ zero_page(*region, page_index_in_region);
+ return PageFaultResponse::Continue;
+ }
+ } else if (fault.is_protection_violation()) {
+ if (region->m_cow_map.get(page_index_in_region)) {
+#ifdef PAGE_FAULT_DEBUG
+ dbgprintf("PV(cow) fault in Region{%p}[%u]\n", region, page_index_in_region);
+#endif
+ bool success = copy_on_write(*region, page_index_in_region);
+ ASSERT(success);
+ return PageFaultResponse::Continue;
+ }
+ kprintf("PV(error) fault in Region{%p}[%u] at L%x\n", region, page_index_in_region, fault.laddr().get());
+ } else {
+ ASSERT_NOT_REACHED();
+ }
+
+ return PageFaultResponse::ShouldCrash;
+}
+
+RetainPtr<PhysicalPage> MemoryManager::allocate_physical_page(ShouldZeroFill should_zero_fill)
+{
+ InterruptDisabler disabler;
+ if (1 > m_free_physical_pages.size()) {
+ kprintf("FUCK! No physical pages available.\n");
+ ASSERT_NOT_REACHED();
+ return { };
+ }
+#ifdef MM_DEBUG
+ dbgprintf("MM: allocate_physical_page vending P%x (%u remaining)\n", m_free_physical_pages.last()->paddr().get(), m_free_physical_pages.size());
+#endif
+ auto physical_page = m_free_physical_pages.take_last();
+ if (should_zero_fill == ShouldZeroFill::Yes) {
+ auto* ptr = (dword*)quickmap_page(*physical_page);
+ fast_dword_fill(ptr, 0, PAGE_SIZE / sizeof(dword));
+ unquickmap_page();
+ }
+ return physical_page;
+}
+
+RetainPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
+{
+ InterruptDisabler disabler;
+ if (1 > m_free_supervisor_physical_pages.size()) {
+ kprintf("FUCK! No physical pages available.\n");
+ ASSERT_NOT_REACHED();
+ return { };
+ }
+#ifdef MM_DEBUG
+ dbgprintf("MM: allocate_supervisor_physical_page vending P%x (%u remaining)\n", m_free_supervisor_physical_pages.last()->paddr().get(), m_free_supervisor_physical_pages.size());
+#endif
+ auto physical_page = m_free_supervisor_physical_pages.take_last();
+ fast_dword_fill((dword*)physical_page->paddr().as_ptr(), 0, PAGE_SIZE / sizeof(dword));
+ return physical_page;
+}
+
+void MemoryManager::enter_process_paging_scope(Process& process)
+{
+ ASSERT(current);
+ InterruptDisabler disabler;
+ current->tss().cr3 = process.page_directory().cr3();
+ asm volatile("movl %%eax, %%cr3"::"a"(process.page_directory().cr3()):"memory");
+}
+
+void MemoryManager::enter_kernel_paging_scope()
+{
+ InterruptDisabler disabler;
+ asm volatile("movl %%eax, %%cr3"::"a"(kernel_page_directory().cr3()):"memory");
+}
+
+void MemoryManager::flush_entire_tlb()
+{
+ asm volatile(
+ "mov %%cr3, %%eax\n"
+ "mov %%eax, %%cr3\n"
+ ::: "%eax", "memory"
+ );
+}
+
+void MemoryManager::flush_tlb(LinearAddress laddr)
+{
+ asm volatile("invlpg %0": :"m" (*(char*)laddr.get()) : "memory");
+}
+
+void MemoryManager::map_for_kernel(LinearAddress laddr, PhysicalAddress paddr)
+{
+ auto pte = ensure_pte(kernel_page_directory(), laddr);
+ pte.set_physical_page_base(paddr.get());
+ pte.set_present(true);
+ pte.set_writable(true);
+ pte.set_user_allowed(false);
+ flush_tlb(laddr);
+}
+
+byte* MemoryManager::quickmap_page(PhysicalPage& physical_page)
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ ASSERT(!m_quickmap_in_use);
+ m_quickmap_in_use = true;
+ auto page_laddr = m_quickmap_addr;
+ auto pte = ensure_pte(kernel_page_directory(), page_laddr);
+ pte.set_physical_page_base(physical_page.paddr().get());
+ pte.set_present(true);
+ pte.set_writable(true);
+ pte.set_user_allowed(false);
+ flush_tlb(page_laddr);
+ ASSERT((dword)pte.physical_page_base() == physical_page.paddr().get());
+#ifdef MM_DEBUG
+ dbgprintf("MM: >> quickmap_page L%x => P%x @ PTE=%p\n", page_laddr, physical_page.paddr().get(), pte.ptr());
+#endif
+ return page_laddr.as_ptr();
+}
+
+void MemoryManager::unquickmap_page()
+{
+ ASSERT_INTERRUPTS_DISABLED();
+ ASSERT(m_quickmap_in_use);
+ auto page_laddr = m_quickmap_addr;
+ auto pte = ensure_pte(kernel_page_directory(), page_laddr);
+#ifdef MM_DEBUG
+ auto old_physical_address = pte.physical_page_base();
+#endif
+ pte.set_physical_page_base(0);
+ pte.set_present(false);
+ pte.set_writable(false);
+ flush_tlb(page_laddr);
+#ifdef MM_DEBUG
+ dbgprintf("MM: >> unquickmap_page L%x =/> P%x\n", page_laddr, old_physical_address);
+#endif
+ m_quickmap_in_use = false;
+}
+
+void MemoryManager::remap_region_page(Region& region, unsigned page_index_in_region, bool user_allowed)
+{
+ ASSERT(region.page_directory());
+ InterruptDisabler disabler;
+ auto page_laddr = region.laddr().offset(page_index_in_region * PAGE_SIZE);
+ auto pte = ensure_pte(*region.page_directory(), page_laddr);
+ auto& physical_page = region.vmo().physical_pages()[page_index_in_region];
+ ASSERT(physical_page);
+ pte.set_physical_page_base(physical_page->paddr().get());
+ pte.set_present(true); // FIXME: Maybe we should use the is_readable flag here?
+ if (region.m_cow_map.get(page_index_in_region))
+ pte.set_writable(false);
+ else
+ pte.set_writable(region.is_writable());
+ pte.set_cache_disabled(!region.vmo().m_allow_cpu_caching);
+ pte.set_write_through(!region.vmo().m_allow_cpu_caching);
+ pte.set_user_allowed(user_allowed);
+ region.page_directory()->flush(page_laddr);
+#ifdef MM_DEBUG
+ dbgprintf("MM: >> remap_region_page (PD=%x, PTE=P%x) '%s' L%x => P%x (@%p)\n", region.page_directory()->cr3(), pte.ptr(), region.name().characters(), page_laddr.get(), physical_page->paddr().get(), physical_page.ptr());
+#endif
+}
+
+void MemoryManager::remap_region(PageDirectory& page_directory, Region& region)
+{
+ InterruptDisabler disabler;
+ ASSERT(region.page_directory() == &page_directory);
+ map_region_at_address(page_directory, region, region.laddr(), true);
+}
+
+void MemoryManager::map_region_at_address(PageDirectory& page_directory, Region& region, LinearAddress laddr, bool user_allowed)
+{
+ InterruptDisabler disabler;
+ region.set_page_directory(page_directory);
+ auto& vmo = region.vmo();
+#ifdef MM_DEBUG
+ dbgprintf("MM: map_region_at_address will map VMO pages %u - %u (VMO page count: %u)\n", region.first_page_index(), region.last_page_index(), vmo.page_count());
+#endif
+ for (size_t i = 0; i < region.page_count(); ++i) {
+ auto page_laddr = laddr.offset(i * PAGE_SIZE);
+ auto pte = ensure_pte(page_directory, page_laddr);
+ auto& physical_page = vmo.physical_pages()[region.first_page_index() + i];
+ if (physical_page) {
+ pte.set_physical_page_base(physical_page->paddr().get());
+ pte.set_present(true); // FIXME: Maybe we should use the is_readable flag here?
+ // FIXME: It seems wrong that the *region* cow map is essentially using *VMO* relative indices.
+ if (region.m_cow_map.get(region.first_page_index() + i))
+ pte.set_writable(false);
+ else
+ pte.set_writable(region.is_writable());
+ pte.set_cache_disabled(!region.vmo().m_allow_cpu_caching);
+ pte.set_write_through(!region.vmo().m_allow_cpu_caching);
+ } else {
+ pte.set_physical_page_base(0);
+ pte.set_present(false);
+ pte.set_writable(region.is_writable());
+ }
+ pte.set_user_allowed(user_allowed);
+ page_directory.flush(page_laddr);
+#ifdef MM_DEBUG
+ dbgprintf("MM: >> map_region_at_address (PD=%x) '%s' L%x => P%x (@%p)\n", &page_directory, region.name().characters(), page_laddr, physical_page ? physical_page->paddr().get() : 0, physical_page.ptr());
+#endif
+ }
+}
+
+bool MemoryManager::unmap_region(Region& region)
+{
+ ASSERT(region.page_directory());
+ InterruptDisabler disabler;
+ for (size_t i = 0; i < region.page_count(); ++i) {
+ auto laddr = region.laddr().offset(i * PAGE_SIZE);
+ auto pte = ensure_pte(*region.page_directory(), laddr);
+ pte.set_physical_page_base(0);
+ pte.set_present(false);
+ pte.set_writable(false);
+ pte.set_user_allowed(false);
+ region.page_directory()->flush(laddr);
+#ifdef MM_DEBUG
+ auto& physical_page = region.vmo().physical_pages()[region.first_page_index() + i];
+ dbgprintf("MM: >> Unmapped L%x => P%x <<\n", laddr, physical_page ? physical_page->paddr().get() : 0);
+#endif
+ }
+ region.release_page_directory();
+ return true;
+}
+
+bool MemoryManager::map_region(Process& process, Region& region)
+{
+ map_region_at_address(process.page_directory(), region, region.laddr(), true);
+ return true;
+}
+
+bool MemoryManager::validate_user_read(const Process& process, LinearAddress laddr) const
+{
+ auto* region = region_from_laddr(process, laddr);
+ return region && region->is_readable();
+}
+
+bool MemoryManager::validate_user_write(const Process& process, LinearAddress laddr) const
+{
+ auto* region = region_from_laddr(process, laddr);
+ return region && region->is_writable();
+}
+
+void MemoryManager::register_vmo(VMObject& vmo)
+{
+ InterruptDisabler disabler;
+ m_vmos.set(&vmo);
+}
+
+void MemoryManager::unregister_vmo(VMObject& vmo)
+{
+ InterruptDisabler disabler;
+ m_vmos.remove(&vmo);
+}
+
+void MemoryManager::register_region(Region& region)
+{
+ InterruptDisabler disabler;
+ m_regions.set(&region);
+}
+
+void MemoryManager::unregister_region(Region& region)
+{
+ InterruptDisabler disabler;
+ m_regions.remove(&region);
+}
+
+ProcessPagingScope::ProcessPagingScope(Process& process)
+{
+ ASSERT(current);
+ MM.enter_process_paging_scope(process);
+}
+
+ProcessPagingScope::~ProcessPagingScope()
+{
+ MM.enter_process_paging_scope(current->process());
+}
+
+KernelPagingScope::KernelPagingScope()
+{
+ ASSERT(current);
+ MM.enter_kernel_paging_scope();
+}
+
+KernelPagingScope::~KernelPagingScope()
+{
+ MM.enter_process_paging_scope(current->process());
+}
diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h
new file mode 100644
index 0000000000..b33ae2605f
--- /dev/null
+++ b/Kernel/VM/MemoryManager.h
@@ -0,0 +1,227 @@
+#pragma once
+
+#include "types.h"
+#include "i386.h"
+#include <AK/Bitmap.h>
+#include <AK/ByteBuffer.h>
+#include <AK/Retainable.h>
+#include <AK/RetainPtr.h>
+#include <AK/Vector.h>
+#include <AK/HashTable.h>
+#include <AK/AKString.h>
+#include <AK/Badge.h>
+#include <AK/Weakable.h>
+#include <Kernel/VM/PhysicalPage.h>
+#include <Kernel/VM/Region.h>
+#include <Kernel/VM/VMObject.h>
+#include <Kernel/FileSystem/InodeIdentifier.h>
+
+#define PAGE_ROUND_UP(x) ((((dword)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
+
+class SynthFSInode;
+
+enum class PageFaultResponse {
+ ShouldCrash,
+ Continue,
+};
+
+#define MM MemoryManager::the()
+
+class MemoryManager {
+ AK_MAKE_ETERNAL
+ friend class PageDirectory;
+ friend class PhysicalPage;
+ friend class Region;
+ friend class VMObject;
+ friend ByteBuffer procfs$mm(InodeIdentifier);
+ friend ByteBuffer procfs$memstat(InodeIdentifier);
+public:
+ [[gnu::pure]] static MemoryManager& the();
+
+ static void initialize();
+
+ PageFaultResponse handle_page_fault(const PageFault&);
+
+ bool map_region(Process&, Region&);
+ bool unmap_region(Region&);
+
+ void populate_page_directory(PageDirectory&);
+
+ void enter_process_paging_scope(Process&);
+ void enter_kernel_paging_scope();
+
+ bool validate_user_read(const Process&, LinearAddress) const;
+ bool validate_user_write(const Process&, LinearAddress) const;
+
+ enum class ShouldZeroFill { No, Yes };
+
+ RetainPtr<PhysicalPage> allocate_physical_page(ShouldZeroFill);
+ RetainPtr<PhysicalPage> allocate_supervisor_physical_page();
+
+ void remap_region(PageDirectory&, Region&);
+
+ size_t ram_size() const { return m_ram_size; }
+
+ int user_physical_pages_in_existence() const { return s_user_physical_pages_in_existence; }
+ int super_physical_pages_in_existence() const { return s_super_physical_pages_in_existence; }
+
+ void map_for_kernel(LinearAddress, PhysicalAddress);
+
+private:
+ MemoryManager();
+ ~MemoryManager();
+
+ void register_vmo(VMObject&);
+ void unregister_vmo(VMObject&);
+ void register_region(Region&);
+ void unregister_region(Region&);
+
+ void map_region_at_address(PageDirectory&, Region&, LinearAddress, bool user_accessible);
+ void remap_region_page(Region&, unsigned page_index_in_region, bool user_allowed);
+
+ void initialize_paging();
+ void flush_entire_tlb();
+ void flush_tlb(LinearAddress);
+
+ RetainPtr<PhysicalPage> allocate_page_table(PageDirectory&, unsigned index);
+
+ void map_protected(LinearAddress, size_t length);
+
+ void create_identity_mapping(PageDirectory&, LinearAddress, size_t length);
+ void remove_identity_mapping(PageDirectory&, LinearAddress, size_t);
+
+ static Region* region_from_laddr(Process&, LinearAddress);
+ static const Region* region_from_laddr(const Process&, LinearAddress);
+
+ bool copy_on_write(Region&, unsigned page_index_in_region);
+ bool page_in_from_inode(Region&, unsigned page_index_in_region);
+ bool zero_page(Region& region, unsigned page_index_in_region);
+
+ byte* quickmap_page(PhysicalPage&);
+ void unquickmap_page();
+
+ PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
+
+ struct PageDirectoryEntry {
+ explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
+
+ dword* page_table_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
+ void set_page_table_base(dword value)
+ {
+ *m_pde &= 0xfff;
+ *m_pde |= value & 0xfffff000;
+ }
+
+ dword raw() const { return *m_pde; }
+ dword* ptr() { return m_pde; }
+
+ enum Flags {
+ Present = 1 << 0,
+ ReadWrite = 1 << 1,
+ UserSupervisor = 1 << 2,
+ WriteThrough = 1 << 3,
+ CacheDisabled = 1 << 4,
+ };
+
+ bool is_present() const { return raw() & Present; }
+ void set_present(bool b) { set_bit(Present, b); }
+
+ bool is_user_allowed() const { return raw() & UserSupervisor; }
+ void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
+
+ bool is_writable() const { return raw() & ReadWrite; }
+ void set_writable(bool b) { set_bit(ReadWrite, b); }
+
+ bool is_write_through() const { return raw() & WriteThrough; }
+ void set_write_through(bool b) { set_bit(WriteThrough, b); }
+
+ bool is_cache_disabled() const { return raw() & CacheDisabled; }
+ void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
+
+ void set_bit(byte bit, bool value)
+ {
+ if (value)
+ *m_pde |= bit;
+ else
+ *m_pde &= ~bit;
+ }
+
+ dword* m_pde;
+ };
+
+ struct PageTableEntry {
+ explicit PageTableEntry(dword* pte) : m_pte(pte) { }
+
+ dword* physical_page_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
+ void set_physical_page_base(dword value)
+ {
+ *m_pte &= 0xfffu;
+ *m_pte |= value & 0xfffff000u;
+ }
+
+ dword raw() const { return *m_pte; }
+ dword* ptr() { return m_pte; }
+
+ enum Flags {
+ Present = 1 << 0,
+ ReadWrite = 1 << 1,
+ UserSupervisor = 1 << 2,
+ WriteThrough = 1 << 3,
+ CacheDisabled = 1 << 4,
+ };
+
+ bool is_present() const { return raw() & Present; }
+ void set_present(bool b) { set_bit(Present, b); }
+
+ bool is_user_allowed() const { return raw() & UserSupervisor; }
+ void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
+
+ bool is_writable() const { return raw() & ReadWrite; }
+ void set_writable(bool b) { set_bit(ReadWrite, b); }
+
+ bool is_write_through() const { return raw() & WriteThrough; }
+ void set_write_through(bool b) { set_bit(WriteThrough, b); }
+
+ bool is_cache_disabled() const { return raw() & CacheDisabled; }
+ void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
+
+ void set_bit(byte bit, bool value)
+ {
+ if (value)
+ *m_pte |= bit;
+ else
+ *m_pte &= ~bit;
+ }
+
+ dword* m_pte;
+ };
+
+ static unsigned s_user_physical_pages_in_existence;
+ static unsigned s_super_physical_pages_in_existence;
+
+ PageTableEntry ensure_pte(PageDirectory&, LinearAddress);
+
+ RetainPtr<PageDirectory> m_kernel_page_directory;
+ dword* m_page_table_zero;
+
+ LinearAddress m_quickmap_addr;
+
+ Vector<Retained<PhysicalPage>> m_free_physical_pages;
+ Vector<Retained<PhysicalPage>> m_free_supervisor_physical_pages;
+
+ HashTable<VMObject*> m_vmos;
+ HashTable<Region*> m_regions;
+
+ size_t m_ram_size { 0 };
+ bool m_quickmap_in_use { false };
+};
+
+struct ProcessPagingScope {
+ ProcessPagingScope(Process&);
+ ~ProcessPagingScope();
+};
+
+struct KernelPagingScope {
+ KernelPagingScope();
+ ~KernelPagingScope();
+};
diff --git a/Kernel/VM/PageDirectory.cpp b/Kernel/VM/PageDirectory.cpp
new file mode 100644
index 0000000000..d5c10c189a
--- /dev/null
+++ b/Kernel/VM/PageDirectory.cpp
@@ -0,0 +1,32 @@
+#include <Kernel/VM/PageDirectory.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <Kernel/Process.h>
+#include <Kernel/Thread.h>
+
+PageDirectory::PageDirectory(PhysicalAddress paddr)
+{
+ m_directory_page = PhysicalPage::create_eternal(paddr, true);
+}
+
+PageDirectory::PageDirectory()
+{
+ MM.populate_page_directory(*this);
+}
+
+PageDirectory::~PageDirectory()
+{
+#ifdef MM_DEBUG
+ dbgprintf("MM: ~PageDirectory K%x\n", this);
+#endif
+}
+
+void PageDirectory::flush(LinearAddress laddr)
+{
+#ifdef MM_DEBUG
+ dbgprintf("MM: Flush page L%x\n", laddr.get());
+#endif
+ if (!current)
+ return;
+ if (&current->process().page_directory() == this)
+ MM.flush_tlb(laddr);
+}
diff --git a/Kernel/VM/PageDirectory.h b/Kernel/VM/PageDirectory.h
new file mode 100644
index 0000000000..ba655178b2
--- /dev/null
+++ b/Kernel/VM/PageDirectory.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <Kernel/VM/PhysicalPage.h>
+#include <AK/HashMap.h>
+#include <AK/Retainable.h>
+#include <AK/RetainPtr.h>
+
+class PageDirectory : public Retainable<PageDirectory> {
+ friend class MemoryManager;
+public:
+ static Retained<PageDirectory> create() { return adopt(*new PageDirectory); }
+ static Retained<PageDirectory> create_at_fixed_address(PhysicalAddress paddr) { return adopt(*new PageDirectory(paddr)); }
+ ~PageDirectory();
+
+ dword cr3() const { return m_directory_page->paddr().get(); }
+ dword* entries() { return reinterpret_cast<dword*>(cr3()); }
+
+ void flush(LinearAddress);
+
+private:
+ PageDirectory();
+ explicit PageDirectory(PhysicalAddress);
+
+ RetainPtr<PhysicalPage> m_directory_page;
+ HashMap<unsigned, RetainPtr<PhysicalPage>> m_physical_pages;
+};
diff --git a/Kernel/VM/PhysicalPage.cpp b/Kernel/VM/PhysicalPage.cpp
new file mode 100644
index 0000000000..459fde5c60
--- /dev/null
+++ b/Kernel/VM/PhysicalPage.cpp
@@ -0,0 +1,42 @@
+#include <Kernel/VM/PhysicalPage.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <Kernel/kmalloc.h>
+
+Retained<PhysicalPage> PhysicalPage::create_eternal(PhysicalAddress paddr, bool supervisor)
+{
+ void* slot = kmalloc_eternal(sizeof(PhysicalPage));
+ new (slot) PhysicalPage(paddr, supervisor);
+ return adopt(*(PhysicalPage*)slot);
+}
+
+Retained<PhysicalPage> PhysicalPage::create(PhysicalAddress paddr, bool supervisor)
+{
+ void* slot = kmalloc(sizeof(PhysicalPage));
+ new (slot) PhysicalPage(paddr, supervisor, false);
+ return adopt(*(PhysicalPage*)slot);
+}
+
+PhysicalPage::PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist)
+ : m_may_return_to_freelist(may_return_to_freelist)
+ , m_supervisor(supervisor)
+ , m_paddr(paddr)
+{
+ if (supervisor)
+ ++MemoryManager::s_super_physical_pages_in_existence;
+ else
+ ++MemoryManager::s_user_physical_pages_in_existence;
+}
+
+void PhysicalPage::return_to_freelist()
+{
+ ASSERT((paddr().get() & ~PAGE_MASK) == 0);
+ InterruptDisabler disabler;
+ m_retain_count = 1;
+ if (m_supervisor)
+ MM.m_free_supervisor_physical_pages.append(adopt(*this));
+ else
+ MM.m_free_physical_pages.append(adopt(*this));
+#ifdef MM_DEBUG
+ dbgprintf("MM: P%x released to freelist\n", m_paddr.get());
+#endif
+}
diff --git a/Kernel/VM/PhysicalPage.h b/Kernel/VM/PhysicalPage.h
new file mode 100644
index 0000000000..f3b15378dc
--- /dev/null
+++ b/Kernel/VM/PhysicalPage.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <Kernel/Assertions.h>
+#include <Kernel/types.h>
+#include <AK/Retained.h>
+
+class PhysicalPage {
+ friend class MemoryManager;
+ friend class PageDirectory;
+ friend class VMObject;
+public:
+ PhysicalAddress paddr() const { return m_paddr; }
+
+ void retain()
+ {
+ ASSERT(m_retain_count);
+ ++m_retain_count;
+ }
+
+ void release()
+ {
+ ASSERT(m_retain_count);
+ if (!--m_retain_count) {
+ if (m_may_return_to_freelist)
+ return_to_freelist();
+ else
+ delete this;
+ }
+ }
+
+ static Retained<PhysicalPage> create_eternal(PhysicalAddress, bool supervisor);
+ static Retained<PhysicalPage> create(PhysicalAddress, bool supervisor);
+
+ word retain_count() const { return m_retain_count; }
+
+private:
+ PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
+ ~PhysicalPage() { }
+
+ void return_to_freelist();
+
+ word m_retain_count { 1 };
+ bool m_may_return_to_freelist { true };
+ bool m_supervisor { false };
+ PhysicalAddress m_paddr;
+};
diff --git a/Kernel/VM/Region.cpp b/Kernel/VM/Region.cpp
new file mode 100644
index 0000000000..1f01b0b33d
--- /dev/null
+++ b/Kernel/VM/Region.cpp
@@ -0,0 +1,142 @@
+#include <Kernel/VM/Region.h>
+#include <Kernel/VM/VMObject.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <Kernel/Process.h>
+#include <Kernel/Thread.h>
+
+Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
+ : m_laddr(a)
+ , m_size(s)
+ , m_vmo(VMObject::create_anonymous(s))
+ , m_name(move(n))
+ , m_readable(r)
+ , m_writable(w)
+ , m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
+{
+ m_vmo->set_name(m_name);
+ MM.register_region(*this);
+}
+
+Region::Region(LinearAddress a, size_t s, RetainPtr<Inode>&& inode, String&& n, bool r, bool w)
+ : m_laddr(a)
+ , m_size(s)
+ , m_vmo(VMObject::create_file_backed(move(inode)))
+ , m_name(move(n))
+ , m_readable(r)
+ , m_writable(w)
+ , m_cow_map(Bitmap::create(m_vmo->page_count()))
+{
+ MM.register_region(*this);
+}
+
+Region::Region(LinearAddress a, size_t s, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
+ : m_laddr(a)
+ , m_size(s)
+ , m_offset_in_vmo(offset_in_vmo)
+ , m_vmo(move(vmo))
+ , m_name(move(n))
+ , m_readable(r)
+ , m_writable(w)
+ , m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
+{
+ MM.register_region(*this);
+}
+
+Region::~Region()
+{
+ if (m_page_directory) {
+ MM.unmap_region(*this);
+ ASSERT(!m_page_directory);
+ }
+ MM.unregister_region(*this);
+}
+
+bool Region::page_in()
+{
+ ASSERT(m_page_directory);
+ ASSERT(!vmo().is_anonymous());
+ ASSERT(vmo().inode());
+#ifdef MM_DEBUG
+ dbgprintf("MM: page_in %u pages\n", page_count());
+#endif
+ for (size_t i = 0; i < page_count(); ++i) {
+ auto& vmo_page = vmo().physical_pages()[first_page_index() + i];
+ if (vmo_page.is_null()) {
+ bool success = MM.page_in_from_inode(*this, i);
+ if (!success)
+ return false;
+ }
+ MM.remap_region_page(*this, i, true);
+ }
+ return true;
+}
+
+Retained<Region> Region::clone()
+{
+ ASSERT(current);
+ if (m_shared || (m_readable && !m_writable)) {
+#ifdef MM_DEBUG
+ dbgprintf("%s<%u> Region::clone(): sharing %s (L%x)\n",
+ current->process().name().characters(),
+ current->pid(),
+ m_name.characters(),
+ laddr().get());
+#endif
+ // Create a new region backed by the same VMObject.
+ return adopt(*new Region(laddr(), size(), m_vmo.copy_ref(), m_offset_in_vmo, String(m_name), m_readable, m_writable));
+ }
+
+#ifdef MM_DEBUG
+ dbgprintf("%s<%u> Region::clone(): cowing %s (L%x)\n",
+ current->process().name().characters(),
+ current->pid(),
+ m_name.characters(),
+ laddr().get());
+#endif
+ // Set up a COW region. The parent (this) region becomes COW as well!
+ for (size_t i = 0; i < page_count(); ++i)
+ m_cow_map.set(i, true);
+ MM.remap_region(current->process().page_directory(), *this);
+ return adopt(*new Region(laddr(), size(), m_vmo->clone(), m_offset_in_vmo, String(m_name), m_readable, m_writable, true));
+}
+
+int Region::commit()
+{
+ InterruptDisabler disabler;
+#ifdef MM_DEBUG
+ dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at L%x\n", vmo().page_count(), this, &vmo(), laddr().get());
+#endif
+ for (size_t i = first_page_index(); i <= last_page_index(); ++i) {
+ if (!vmo().physical_pages()[i].is_null())
+ continue;
+ auto physical_page = MM.allocate_physical_page(MemoryManager::ShouldZeroFill::Yes);
+ if (!physical_page) {
+ kprintf("MM: commit was unable to allocate a physical page\n");
+ return -ENOMEM;
+ }
+ vmo().physical_pages()[i] = move(physical_page);
+ MM.remap_region_page(*this, i, true);
+ }
+ return 0;
+}
+
+size_t Region::amount_resident() const
+{
+ size_t bytes = 0;
+ for (size_t i = 0; i < page_count(); ++i) {
+ if (m_vmo->physical_pages()[first_page_index() + i])
+ bytes += PAGE_SIZE;
+ }
+ return bytes;
+}
+
+size_t Region::amount_shared() const
+{
+ size_t bytes = 0;
+ for (size_t i = 0; i < page_count(); ++i) {
+ auto& physical_page = m_vmo->physical_pages()[first_page_index() + i];
+ if (physical_page && physical_page->retain_count() > 1)
+ bytes += PAGE_SIZE;
+ }
+ return bytes;
+}
diff --git a/Kernel/VM/Region.h b/Kernel/VM/Region.h
new file mode 100644
index 0000000000..1ddc9b50ef
--- /dev/null
+++ b/Kernel/VM/Region.h
@@ -0,0 +1,97 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <AK/Bitmap.h>
+#include <Kernel/VM/PageDirectory.h>
+
+class Inode;
+class VMObject;
+
+class Region : public Retainable<Region> {
+ friend class MemoryManager;
+public:
+ Region(LinearAddress, size_t, String&&, bool r, bool w, bool cow = false);
+ Region(LinearAddress, size_t, Retained<VMObject>&&, size_t offset_in_vmo, String&&, bool r, bool w, bool cow = false);
+ Region(LinearAddress, size_t, RetainPtr<Inode>&&, String&&, bool r, bool w);
+ ~Region();
+
+ LinearAddress laddr() const { return m_laddr; }
+ size_t size() const { return m_size; }
+ bool is_readable() const { return m_readable; }
+ bool is_writable() const { return m_writable; }
+ String name() const { return m_name; }
+
+ void set_name(String&& name) { m_name = move(name); }
+
+ const VMObject& vmo() const { return *m_vmo; }
+ VMObject& vmo() { return *m_vmo; }
+
+ bool is_shared() const { return m_shared; }
+ void set_shared(bool shared) { m_shared = shared; }
+
+ bool is_bitmap() const { return m_is_bitmap; }
+ void set_is_bitmap(bool b) { m_is_bitmap = b; }
+
+ Retained<Region> clone();
+ bool contains(LinearAddress laddr) const
+ {
+ return laddr >= m_laddr && laddr < m_laddr.offset(size());
+ }
+
+ unsigned page_index_from_address(LinearAddress laddr) const
+ {
+ return (laddr - m_laddr).get() / PAGE_SIZE;
+ }
+
+ size_t first_page_index() const
+ {
+ return m_offset_in_vmo / PAGE_SIZE;
+ }
+
+ size_t last_page_index() const
+ {
+ return (first_page_index() + page_count()) - 1;
+ }
+
+ size_t page_count() const
+ {
+ return m_size / PAGE_SIZE;
+ }
+
+ bool page_in();
+ int commit();
+
+ size_t amount_resident() const;
+ size_t amount_shared() const;
+
+ PageDirectory* page_directory() { return m_page_directory.ptr(); }
+
+ void set_page_directory(PageDirectory& page_directory)
+ {
+ ASSERT(!m_page_directory || m_page_directory.ptr() == &page_directory);
+ m_page_directory = page_directory;
+ }
+
+ void release_page_directory()
+ {
+ ASSERT(m_page_directory);
+ m_page_directory.clear();
+ }
+
+ const Bitmap& cow_map() const { return m_cow_map; }
+
+ void set_writable(bool b) { m_writable = b; }
+
+private:
+ RetainPtr<PageDirectory> m_page_directory;
+ LinearAddress m_laddr;
+ size_t m_size { 0 };
+ size_t m_offset_in_vmo { 0 };
+ Retained<VMObject> m_vmo;
+ String m_name;
+ bool m_readable { true };
+ bool m_writable { true };
+ bool m_shared { false };
+ bool m_is_bitmap { false };
+ Bitmap m_cow_map;
+};
diff --git a/Kernel/VM/VMObject.cpp b/Kernel/VM/VMObject.cpp
new file mode 100644
index 0000000000..a31edaac7d
--- /dev/null
+++ b/Kernel/VM/VMObject.cpp
@@ -0,0 +1,167 @@
+#include <Kernel/VM/VMObject.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <FileSystem/FileSystem.h>
+
+Retained<VMObject> VMObject::create_file_backed(RetainPtr<Inode>&& inode)
+{
+ InterruptDisabler disabler;
+ if (inode->vmo())
+ return *inode->vmo();
+ auto vmo = adopt(*new VMObject(move(inode)));
+ vmo->inode()->set_vmo(*vmo);
+ return vmo;
+}
+
+Retained<VMObject> VMObject::create_anonymous(size_t size)
+{
+ size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
+ return adopt(*new VMObject(size));
+}
+
+Retained<VMObject> VMObject::create_for_physical_range(PhysicalAddress paddr, size_t size)
+{
+ size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
+ auto vmo = adopt(*new VMObject(paddr, size));
+ vmo->m_allow_cpu_caching = false;
+ return vmo;
+}
+
+Retained<VMObject> VMObject::clone()
+{
+ return adopt(*new VMObject(*this));
+}
+
+VMObject::VMObject(VMObject& other)
+ : m_name(other.m_name)
+ , m_anonymous(other.m_anonymous)
+ , m_inode_offset(other.m_inode_offset)
+ , m_size(other.m_size)
+ , m_inode(other.m_inode)
+ , m_physical_pages(other.m_physical_pages)
+{
+ MM.register_vmo(*this);
+}
+
+VMObject::VMObject(size_t size)
+ : m_anonymous(true)
+ , m_size(size)
+{
+ MM.register_vmo(*this);
+ m_physical_pages.resize(page_count());
+}
+
+VMObject::VMObject(PhysicalAddress paddr, size_t size)
+ : m_anonymous(true)
+ , m_size(size)
+{
+ MM.register_vmo(*this);
+ for (size_t i = 0; i < size; i += PAGE_SIZE) {
+ m_physical_pages.append(PhysicalPage::create(paddr.offset(i), false));
+ }
+ ASSERT(m_physical_pages.size() == page_count());
+}
+
+
+VMObject::VMObject(RetainPtr<Inode>&& inode)
+ : m_inode(move(inode))
+{
+ ASSERT(m_inode);
+ m_size = ceil_div(m_inode->size(), PAGE_SIZE) * PAGE_SIZE;
+ m_physical_pages.resize(page_count());
+ MM.register_vmo(*this);
+}
+
+VMObject::~VMObject()
+{
+ if (m_inode)
+ ASSERT(m_inode->vmo() == this);
+ MM.unregister_vmo(*this);
+}
+
+template<typename Callback>
+void VMObject::for_each_region(Callback callback)
+{
+ // FIXME: Figure out a better data structure so we don't have to walk every single region every time an inode changes.
+ // Perhaps VMObject could have a Vector<Region*> with all of his mappers?
+ for (auto* region : MM.m_regions) {
+ if (&region->vmo() == this)
+ callback(*region);
+ }
+}
+
+void VMObject::inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size)
+{
+ (void)old_size;
+ InterruptDisabler disabler;
+
+ size_t old_page_count = page_count();
+ m_size = new_size;
+
+ if (page_count() > old_page_count) {
+ // Add null pages and let the fault handler page these in when that day comes.
+ for (size_t i = old_page_count; i < page_count(); ++i)
+ m_physical_pages.append(nullptr);
+ } else {
+ // Prune the no-longer valid pages. I'm not sure this is actually correct behavior.
+ for (size_t i = page_count(); i < old_page_count; ++i)
+ m_physical_pages.take_last();
+ }
+
+ // FIXME: Consolidate with inode_contents_changed() so we only do a single walk.
+ for_each_region([] (Region& region) {
+ ASSERT(region.page_directory());
+ MM.remap_region(*region.page_directory(), region);
+ });
+}
+
+void VMObject::inode_contents_changed(Badge<Inode>, off_t offset, ssize_t size, const byte* data)
+{
+ (void)size;
+ (void)data;
+ InterruptDisabler disabler;
+ ASSERT(offset >= 0);
+
+ // FIXME: Only invalidate the parts that actually changed.
+ for (auto& physical_page : m_physical_pages)
+ physical_page = nullptr;
+
+#if 0
+ size_t current_offset = offset;
+ size_t remaining_bytes = size;
+ const byte* data_ptr = data;
+
+ auto to_page_index = [] (size_t offset) -> size_t {
+ return offset / PAGE_SIZE;
+ };
+
+ if (current_offset & PAGE_MASK) {
+ size_t page_index = to_page_index(current_offset);
+ size_t bytes_to_copy = min(size, PAGE_SIZE - (current_offset & PAGE_MASK));
+ if (m_physical_pages[page_index]) {
+ auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
+ memcpy(ptr, data_ptr, bytes_to_copy);
+ MM.unquickmap_page();
+ }
+ current_offset += bytes_to_copy;
+ data += bytes_to_copy;
+ remaining_bytes -= bytes_to_copy;
+ }
+
+ for (size_t page_index = to_page_index(current_offset); page_index < m_physical_pages.size(); ++page_index) {
+ size_t bytes_to_copy = PAGE_SIZE - (current_offset & PAGE_MASK);
+ if (m_physical_pages[page_index]) {
+ auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
+ memcpy(ptr, data_ptr, bytes_to_copy);
+ MM.unquickmap_page();
+ }
+ current_offset += bytes_to_copy;
+ data += bytes_to_copy;
+ }
+#endif
+
+ // FIXME: Consolidate with inode_size_changed() so we only do a single walk.
+ for_each_region([] (Region& region) {
+ ASSERT(region.page_directory());
+ MM.remap_region(*region.page_directory(), region);
+ });
+}
diff --git a/Kernel/VM/VMObject.h b/Kernel/VM/VMObject.h
new file mode 100644
index 0000000000..f376fa25a4
--- /dev/null
+++ b/Kernel/VM/VMObject.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <AK/Badge.h>
+#include <AK/Retainable.h>
+#include <AK/Weakable.h>
+#include <AK/RetainPtr.h>
+#include <AK/Vector.h>
+#include <AK/AKString.h>
+#include <Kernel/Lock.h>
+
+class Inode;
+class PhysicalPage;
+
+class VMObject : public Retainable<VMObject>, public Weakable<VMObject> {
+ friend class MemoryManager;
+public:
+ static Retained<VMObject> create_file_backed(RetainPtr<Inode>&&);
+ static Retained<VMObject> create_anonymous(size_t);
+ static Retained<VMObject> create_for_physical_range(PhysicalAddress, size_t);
+ Retained<VMObject> clone();
+
+ ~VMObject();
+ bool is_anonymous() const { return m_anonymous; }
+
+ Inode* inode() { return m_inode.ptr(); }
+ const Inode* inode() const { return m_inode.ptr(); }
+ size_t inode_offset() const { return m_inode_offset; }
+
+ String name() const { return m_name; }
+ void set_name(const String& name) { m_name = name; }
+
+ size_t page_count() const { return m_size / PAGE_SIZE; }
+ const Vector<RetainPtr<PhysicalPage>>& physical_pages() const { return m_physical_pages; }
+ Vector<RetainPtr<PhysicalPage>>& physical_pages() { return m_physical_pages; }
+
+ void inode_contents_changed(Badge<Inode>, off_t, ssize_t, const byte*);
+ void inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size);
+
+ size_t size() const { return m_size; }
+
+private:
+ VMObject(RetainPtr<Inode>&&);
+ explicit VMObject(VMObject&);
+ explicit VMObject(size_t);
+ VMObject(PhysicalAddress, size_t);
+
+ template<typename Callback> void for_each_region(Callback);
+
+ String m_name;
+ bool m_anonymous { false };
+ off_t m_inode_offset { 0 };
+ size_t m_size { 0 };
+ bool m_allow_cpu_caching { true };
+ RetainPtr<Inode> m_inode;
+ Vector<RetainPtr<PhysicalPage>> m_physical_pages;
+ Lock m_paging_lock;
+};
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