MemoryManager.cpp 28 KB

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  1. #include "CMOS.h"
  2. #include "Process.h"
  3. #include "StdLib.h"
  4. #include <AK/Assertions.h>
  5. #include <AK/kstdio.h>
  6. #include <Kernel/Arch/i386/CPU.h>
  7. #include <Kernel/FileSystem/Inode.h>
  8. #include <Kernel/Multiboot.h>
  9. #include <Kernel/VM/MemoryManager.h>
  10. //#define MM_DEBUG
  11. //#define PAGE_FAULT_DEBUG
  12. static MemoryManager* s_the;
  13. MemoryManager& MM
  14. {
  15. return *s_the;
  16. }
  17. MemoryManager::MemoryManager()
  18. {
  19. m_kernel_page_directory = PageDirectory::create_at_fixed_address(PhysicalAddress(0x4000));
  20. m_page_table_zero = (PageTableEntry*)0x6000;
  21. m_page_table_one = (PageTableEntry*)0x7000;
  22. initialize_paging();
  23. kprintf("MM initialized.\n");
  24. }
  25. MemoryManager::~MemoryManager()
  26. {
  27. }
  28. void MemoryManager::populate_page_directory(PageDirectory& page_directory)
  29. {
  30. page_directory.m_directory_page = allocate_supervisor_physical_page();
  31. page_directory.entries()[0].copy_from({}, kernel_page_directory().entries()[0]);
  32. page_directory.entries()[1].copy_from({}, kernel_page_directory().entries()[1]);
  33. // Defer to the kernel page tables for 0xC0000000-0xFFFFFFFF
  34. for (int i = 768; i < 1024; ++i)
  35. page_directory.entries()[i].copy_from({}, kernel_page_directory().entries()[i]);
  36. }
  37. void MemoryManager::initialize_paging()
  38. {
  39. memset(m_page_table_zero, 0, PAGE_SIZE);
  40. memset(m_page_table_one, 0, PAGE_SIZE);
  41. #ifdef MM_DEBUG
  42. dbgprintf("MM: Kernel page directory @ %p\n", kernel_page_directory().cr3());
  43. #endif
  44. #ifdef MM_DEBUG
  45. dbgprintf("MM: Protect against null dereferences\n");
  46. #endif
  47. // Make null dereferences crash.
  48. map_protected(VirtualAddress(0), PAGE_SIZE);
  49. #ifdef MM_DEBUG
  50. dbgprintf("MM: Identity map bottom 5MB\n");
  51. #endif
  52. // The bottom 5 MB (except for the null page) are identity mapped & supervisor only.
  53. // Every process shares these mappings.
  54. create_identity_mapping(kernel_page_directory(), VirtualAddress(PAGE_SIZE), (5 * MB) - PAGE_SIZE);
  55. // Basic memory map:
  56. // 0 -> 512 kB Kernel code. Root page directory & PDE 0.
  57. // (last page before 1MB) Used by quickmap_page().
  58. // 1 MB -> 3 MB kmalloc_eternal() space.
  59. // 3 MB -> 4 MB kmalloc() space.
  60. // 4 MB -> 5 MB Supervisor physical pages (available for allocation!)
  61. // 5 MB -> 0xc0000000 Userspace physical pages (available for allocation!)
  62. // 0xc0000000-0xffffffff Kernel-only virtual address space
  63. #ifdef MM_DEBUG
  64. dbgprintf("MM: Quickmap will use %p\n", m_quickmap_addr.get());
  65. #endif
  66. m_quickmap_addr = VirtualAddress((1 * MB) - PAGE_SIZE);
  67. RefPtr<PhysicalRegion> region;
  68. bool region_is_super = false;
  69. for (auto* mmap = (multiboot_memory_map_t*)multiboot_info_ptr->mmap_addr; (unsigned long)mmap < multiboot_info_ptr->mmap_addr + multiboot_info_ptr->mmap_length; mmap = (multiboot_memory_map_t*)((unsigned long)mmap + mmap->size + sizeof(mmap->size))) {
  70. kprintf("MM: Multiboot mmap: base_addr = 0x%x%08x, length = 0x%x%08x, type = 0x%x\n",
  71. (u32)(mmap->addr >> 32),
  72. (u32)(mmap->addr & 0xffffffff),
  73. (u32)(mmap->len >> 32),
  74. (u32)(mmap->len & 0xffffffff),
  75. (u32)mmap->type);
  76. if (mmap->type != MULTIBOOT_MEMORY_AVAILABLE)
  77. continue;
  78. // FIXME: Maybe make use of stuff below the 1MB mark?
  79. if (mmap->addr < (1 * MB))
  80. continue;
  81. #ifdef MM_DEBUG
  82. kprintf("MM: considering memory at %p - %p\n",
  83. (u32)mmap->addr, (u32)(mmap->addr + mmap->len));
  84. #endif
  85. for (size_t page_base = mmap->addr; page_base < (mmap->addr + mmap->len); page_base += PAGE_SIZE) {
  86. auto addr = PhysicalAddress(page_base);
  87. if (page_base < 4 * MB) {
  88. // nothing
  89. } else if (page_base >= 4 * MB && page_base < 5 * MB) {
  90. if (region.is_null() || !region_is_super || region->upper().offset(PAGE_SIZE) != addr) {
  91. m_super_physical_regions.append(PhysicalRegion::create(addr, addr));
  92. region = m_super_physical_regions.last();
  93. region_is_super = true;
  94. } else {
  95. region->expand(region->lower(), addr);
  96. }
  97. } else {
  98. if (region.is_null() || region_is_super || region->upper().offset(PAGE_SIZE) != addr) {
  99. m_user_physical_regions.append(PhysicalRegion::create(addr, addr));
  100. region = &m_user_physical_regions.last();
  101. region_is_super = false;
  102. } else {
  103. region->expand(region->lower(), addr);
  104. }
  105. }
  106. }
  107. }
  108. for (auto& region : m_super_physical_regions)
  109. m_super_physical_pages += region.finalize_capacity();
  110. for (auto& region : m_user_physical_regions)
  111. m_user_physical_pages += region.finalize_capacity();
  112. #ifdef MM_DEBUG
  113. dbgprintf("MM: Installing page directory\n");
  114. #endif
  115. asm volatile("movl %%eax, %%cr3" ::"a"(kernel_page_directory().cr3()));
  116. asm volatile(
  117. "movl %%cr0, %%eax\n"
  118. "orl $0x80000001, %%eax\n"
  119. "movl %%eax, %%cr0\n" ::
  120. : "%eax", "memory");
  121. #ifdef MM_DEBUG
  122. dbgprintf("MM: Paging initialized.\n");
  123. #endif
  124. }
  125. RefPtr<PhysicalPage> MemoryManager::allocate_page_table(PageDirectory& page_directory, unsigned index)
  126. {
  127. ASSERT(!page_directory.m_physical_pages.contains(index));
  128. auto physical_page = allocate_supervisor_physical_page();
  129. if (!physical_page)
  130. return nullptr;
  131. page_directory.m_physical_pages.set(index, physical_page);
  132. return physical_page;
  133. }
  134. void MemoryManager::remove_identity_mapping(PageDirectory& page_directory, VirtualAddress vaddr, size_t size)
  135. {
  136. InterruptDisabler disabler;
  137. // FIXME: ASSERT(vaddr is 4KB aligned);
  138. for (u32 offset = 0; offset < size; offset += PAGE_SIZE) {
  139. auto pte_address = vaddr.offset(offset);
  140. auto& pte = ensure_pte(page_directory, pte_address);
  141. pte.set_physical_page_base(0);
  142. pte.set_user_allowed(false);
  143. pte.set_present(true);
  144. pte.set_writable(true);
  145. flush_tlb(pte_address);
  146. }
  147. }
  148. PageTableEntry& MemoryManager::ensure_pte(PageDirectory& page_directory, VirtualAddress vaddr)
  149. {
  150. ASSERT_INTERRUPTS_DISABLED();
  151. u32 page_directory_index = (vaddr.get() >> 22) & 0x3ff;
  152. u32 page_table_index = (vaddr.get() >> 12) & 0x3ff;
  153. PageDirectoryEntry& pde = page_directory.entries()[page_directory_index];
  154. if (!pde.is_present()) {
  155. #ifdef MM_DEBUG
  156. dbgprintf("MM: PDE %u not present (requested for L%x), allocating\n", page_directory_index, vaddr.get());
  157. #endif
  158. if (page_directory_index == 0) {
  159. ASSERT(&page_directory == m_kernel_page_directory);
  160. pde.set_page_table_base((u32)m_page_table_zero);
  161. pde.set_user_allowed(false);
  162. pde.set_present(true);
  163. pde.set_writable(true);
  164. } else if (page_directory_index == 1) {
  165. ASSERT(&page_directory == m_kernel_page_directory);
  166. pde.set_page_table_base((u32)m_page_table_one);
  167. pde.set_user_allowed(false);
  168. pde.set_present(true);
  169. pde.set_writable(true);
  170. } else {
  171. //ASSERT(&page_directory != m_kernel_page_directory.ptr());
  172. auto page_table = allocate_page_table(page_directory, page_directory_index);
  173. #ifdef MM_DEBUG
  174. dbgprintf("MM: PD K%x (%s) at P%x allocated page table #%u (for L%x) at P%x\n",
  175. &page_directory,
  176. &page_directory == m_kernel_page_directory ? "Kernel" : "User",
  177. page_directory.cr3(),
  178. page_directory_index,
  179. vaddr.get(),
  180. page_table->paddr().get());
  181. #endif
  182. pde.set_page_table_base(page_table->paddr().get());
  183. pde.set_user_allowed(true);
  184. pde.set_present(true);
  185. pde.set_writable(true);
  186. page_directory.m_physical_pages.set(page_directory_index, move(page_table));
  187. }
  188. }
  189. return pde.page_table_base()[page_table_index];
  190. }
  191. void MemoryManager::map_protected(VirtualAddress vaddr, size_t length)
  192. {
  193. InterruptDisabler disabler;
  194. ASSERT(vaddr.is_page_aligned());
  195. for (u32 offset = 0; offset < length; offset += PAGE_SIZE) {
  196. auto pte_address = vaddr.offset(offset);
  197. auto& pte = ensure_pte(kernel_page_directory(), pte_address);
  198. pte.set_physical_page_base(pte_address.get());
  199. pte.set_user_allowed(false);
  200. pte.set_present(false);
  201. pte.set_writable(false);
  202. flush_tlb(pte_address);
  203. }
  204. }
  205. void MemoryManager::create_identity_mapping(PageDirectory& page_directory, VirtualAddress vaddr, size_t size)
  206. {
  207. InterruptDisabler disabler;
  208. ASSERT((vaddr.get() & ~PAGE_MASK) == 0);
  209. for (u32 offset = 0; offset < size; offset += PAGE_SIZE) {
  210. auto pte_address = vaddr.offset(offset);
  211. auto& pte = ensure_pte(page_directory, pte_address);
  212. pte.set_physical_page_base(pte_address.get());
  213. pte.set_user_allowed(false);
  214. pte.set_present(true);
  215. pte.set_writable(true);
  216. page_directory.flush(pte_address);
  217. }
  218. }
  219. void MemoryManager::initialize()
  220. {
  221. s_the = new MemoryManager;
  222. }
  223. Region* MemoryManager::region_from_vaddr(Process& process, VirtualAddress vaddr)
  224. {
  225. ASSERT_INTERRUPTS_DISABLED();
  226. if (vaddr.get() >= 0xc0000000) {
  227. for (auto& region : MM.m_kernel_regions) {
  228. if (region->contains(vaddr))
  229. return region;
  230. }
  231. }
  232. // FIXME: Use a binary search tree (maybe red/black?) or some other more appropriate data structure!
  233. for (auto& region : process.m_regions) {
  234. if (region.contains(vaddr))
  235. return &region;
  236. }
  237. dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), vaddr.get(), process.page_directory().cr3());
  238. return nullptr;
  239. }
  240. const Region* MemoryManager::region_from_vaddr(const Process& process, VirtualAddress vaddr)
  241. {
  242. if (vaddr.get() >= 0xc0000000) {
  243. for (auto& region : MM.m_kernel_regions) {
  244. if (region->contains(vaddr))
  245. return region;
  246. }
  247. }
  248. // FIXME: Use a binary search tree (maybe red/black?) or some other more appropriate data structure!
  249. for (auto& region : process.m_regions) {
  250. if (region.contains(vaddr))
  251. return &region;
  252. }
  253. dbgprintf("%s(%u) Couldn't find region for L%x (CR3=%x)\n", process.name().characters(), process.pid(), vaddr.get(), process.page_directory().cr3());
  254. return nullptr;
  255. }
  256. bool MemoryManager::zero_page(Region& region, unsigned page_index_in_region)
  257. {
  258. ASSERT_INTERRUPTS_DISABLED();
  259. auto& vmo = region.vmo();
  260. auto& vmo_page = vmo.physical_pages()[region.first_page_index() + page_index_in_region];
  261. sti();
  262. LOCKER(vmo.m_paging_lock);
  263. cli();
  264. if (!vmo_page.is_null()) {
  265. #ifdef PAGE_FAULT_DEBUG
  266. dbgprintf("MM: zero_page() but page already present. Fine with me!\n");
  267. #endif
  268. remap_region_page(region, page_index_in_region);
  269. return true;
  270. }
  271. auto physical_page = allocate_user_physical_page(ShouldZeroFill::Yes);
  272. #ifdef PAGE_FAULT_DEBUG
  273. dbgprintf(" >> ZERO P%x\n", physical_page->paddr().get());
  274. #endif
  275. region.set_should_cow(page_index_in_region, false);
  276. vmo.physical_pages()[page_index_in_region] = move(physical_page);
  277. remap_region_page(region, page_index_in_region);
  278. return true;
  279. }
  280. bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
  281. {
  282. ASSERT_INTERRUPTS_DISABLED();
  283. auto& vmo = region.vmo();
  284. if (vmo.physical_pages()[page_index_in_region]->ref_count() == 1) {
  285. #ifdef PAGE_FAULT_DEBUG
  286. dbgprintf(" >> It's a COW page but nobody is sharing it anymore. Remap r/w\n");
  287. #endif
  288. region.set_should_cow(page_index_in_region, false);
  289. remap_region_page(region, page_index_in_region);
  290. return true;
  291. }
  292. #ifdef PAGE_FAULT_DEBUG
  293. dbgprintf(" >> It's a COW page and it's time to COW!\n");
  294. #endif
  295. auto physical_page_to_copy = move(vmo.physical_pages()[page_index_in_region]);
  296. auto physical_page = allocate_user_physical_page(ShouldZeroFill::No);
  297. u8* dest_ptr = quickmap_page(*physical_page);
  298. const u8* src_ptr = region.vaddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
  299. #ifdef PAGE_FAULT_DEBUG
  300. dbgprintf(" >> COW P%x <- P%x\n", physical_page->paddr().get(), physical_page_to_copy->paddr().get());
  301. #endif
  302. memcpy(dest_ptr, src_ptr, PAGE_SIZE);
  303. vmo.physical_pages()[page_index_in_region] = move(physical_page);
  304. unquickmap_page();
  305. region.set_should_cow(page_index_in_region, false);
  306. remap_region_page(region, page_index_in_region);
  307. return true;
  308. }
  309. bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_region)
  310. {
  311. ASSERT(region.page_directory());
  312. auto& vmo = region.vmo();
  313. ASSERT(!vmo.is_anonymous());
  314. ASSERT(vmo.inode());
  315. auto& vmo_page = vmo.physical_pages()[region.first_page_index() + page_index_in_region];
  316. InterruptFlagSaver saver;
  317. sti();
  318. LOCKER(vmo.m_paging_lock);
  319. cli();
  320. if (!vmo_page.is_null()) {
  321. dbgprintf("MM: page_in_from_inode() but page already present. Fine with me!\n");
  322. remap_region_page(region, page_index_in_region);
  323. return true;
  324. }
  325. #ifdef MM_DEBUG
  326. dbgprintf("MM: page_in_from_inode ready to read from inode\n");
  327. #endif
  328. sti();
  329. u8 page_buffer[PAGE_SIZE];
  330. auto& inode = *vmo.inode();
  331. auto nread = inode.read_bytes(vmo.inode_offset() + ((region.first_page_index() + page_index_in_region) * PAGE_SIZE), PAGE_SIZE, page_buffer, nullptr);
  332. if (nread < 0) {
  333. kprintf("MM: page_in_from_inode had error (%d) while reading!\n", nread);
  334. return false;
  335. }
  336. if (nread < PAGE_SIZE) {
  337. // If we read less than a page, zero out the rest to avoid leaking uninitialized data.
  338. memset(page_buffer + nread, 0, PAGE_SIZE - nread);
  339. }
  340. cli();
  341. vmo_page = allocate_user_physical_page(ShouldZeroFill::No);
  342. if (vmo_page.is_null()) {
  343. kprintf("MM: page_in_from_inode was unable to allocate a physical page\n");
  344. return false;
  345. }
  346. remap_region_page(region, page_index_in_region);
  347. u8* dest_ptr = region.vaddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
  348. memcpy(dest_ptr, page_buffer, PAGE_SIZE);
  349. return true;
  350. }
  351. PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
  352. {
  353. ASSERT_INTERRUPTS_DISABLED();
  354. ASSERT(current);
  355. #ifdef PAGE_FAULT_DEBUG
  356. dbgprintf("MM: handle_page_fault(%w) at L%x\n", fault.code(), fault.vaddr().get());
  357. #endif
  358. ASSERT(fault.vaddr() != m_quickmap_addr);
  359. if (fault.type() == PageFault::Type::PageNotPresent && fault.vaddr().get() >= 0xc0000000) {
  360. u32 page_directory_index = (fault.vaddr().get() >> 22) & 0x3ff;
  361. auto& kernel_pde = kernel_page_directory().entries()[page_directory_index];
  362. if (kernel_pde.is_present()) {
  363. dbgprintf("NP(kernel): copying new kernel mapping for L%x into current page directory\n", fault.vaddr().get());
  364. auto* current_page_directory = reinterpret_cast<PageDirectoryEntry*>(cpu_cr3());
  365. current_page_directory[page_directory_index].copy_from({}, kernel_pde);
  366. flush_tlb(fault.vaddr().page_base());
  367. return PageFaultResponse::Continue;
  368. }
  369. }
  370. auto* region = region_from_vaddr(current->process(), fault.vaddr());
  371. if (!region) {
  372. kprintf("NP(error) fault at invalid address L%x\n", fault.vaddr().get());
  373. return PageFaultResponse::ShouldCrash;
  374. }
  375. auto page_index_in_region = region->page_index_from_address(fault.vaddr());
  376. if (fault.type() == PageFault::Type::PageNotPresent) {
  377. if (region->vmo().inode()) {
  378. #ifdef PAGE_FAULT_DEBUG
  379. dbgprintf("NP(inode) fault in Region{%p}[%u]\n", region, page_index_in_region);
  380. #endif
  381. page_in_from_inode(*region, page_index_in_region);
  382. return PageFaultResponse::Continue;
  383. }
  384. #ifdef PAGE_FAULT_DEBUG
  385. dbgprintf("NP(zero) fault in Region{%p}[%u]\n", region, page_index_in_region);
  386. #endif
  387. zero_page(*region, page_index_in_region);
  388. return PageFaultResponse::Continue;
  389. }
  390. ASSERT(fault.type() == PageFault::Type::ProtectionViolation);
  391. if (region->should_cow(page_index_in_region)) {
  392. #ifdef PAGE_FAULT_DEBUG
  393. dbgprintf("PV(cow) fault in Region{%p}[%u]\n", region, page_index_in_region);
  394. #endif
  395. bool success = copy_on_write(*region, page_index_in_region);
  396. ASSERT(success);
  397. return PageFaultResponse::Continue;
  398. }
  399. kprintf("PV(error) fault in Region{%p}[%u] at L%x\n", region, page_index_in_region, fault.vaddr().get());
  400. return PageFaultResponse::ShouldCrash;
  401. }
  402. RefPtr<Region> MemoryManager::allocate_kernel_region(size_t size, const StringView& name, bool user_accessible)
  403. {
  404. InterruptDisabler disabler;
  405. ASSERT(!(size % PAGE_SIZE));
  406. auto range = kernel_page_directory().range_allocator().allocate_anywhere(size);
  407. ASSERT(range.is_valid());
  408. RefPtr<Region> region;
  409. if (user_accessible)
  410. region = Region::create_user_accessible(range, name, PROT_READ | PROT_WRITE | PROT_EXEC, false);
  411. else
  412. region = Region::create_kernel_only(range, name, PROT_READ | PROT_WRITE | PROT_EXEC, false);
  413. MM.map_region_at_address(*m_kernel_page_directory, *region, range.base());
  414. // FIXME: It would be cool if these could zero-fill on demand instead.
  415. region->commit();
  416. return region;
  417. }
  418. RefPtr<Region> MemoryManager::allocate_user_accessible_kernel_region(size_t size, const StringView& name)
  419. {
  420. return allocate_kernel_region(size, name, true);
  421. }
  422. void MemoryManager::deallocate_user_physical_page(PhysicalPage&& page)
  423. {
  424. for (auto& region : m_user_physical_regions) {
  425. if (!region.contains(page)) {
  426. kprintf(
  427. "MM: deallocate_user_physical_page: %p not in %p -> %p\n",
  428. page.paddr(), region.lower().get(), region.upper().get());
  429. continue;
  430. }
  431. region.return_page(move(page));
  432. --m_user_physical_pages_used;
  433. return;
  434. }
  435. kprintf("MM: deallocate_user_physical_page couldn't figure out region for user page @ %p\n", page.paddr());
  436. ASSERT_NOT_REACHED();
  437. }
  438. RefPtr<PhysicalPage> MemoryManager::allocate_user_physical_page(ShouldZeroFill should_zero_fill)
  439. {
  440. InterruptDisabler disabler;
  441. RefPtr<PhysicalPage> page;
  442. for (auto& region : m_user_physical_regions) {
  443. page = region.take_free_page(false);
  444. if (page.is_null())
  445. continue;
  446. }
  447. if (!page) {
  448. if (m_user_physical_regions.is_empty()) {
  449. kprintf("MM: no user physical regions available (?)\n");
  450. }
  451. kprintf("MM: no user physical pages available\n");
  452. ASSERT_NOT_REACHED();
  453. return {};
  454. }
  455. #ifdef MM_DEBUG
  456. dbgprintf("MM: allocate_user_physical_page vending P%p\n", page->paddr().get());
  457. #endif
  458. if (should_zero_fill == ShouldZeroFill::Yes) {
  459. auto* ptr = (u32*)quickmap_page(*page);
  460. fast_u32_fill(ptr, 0, PAGE_SIZE / sizeof(u32));
  461. unquickmap_page();
  462. }
  463. ++m_user_physical_pages_used;
  464. return page;
  465. }
  466. void MemoryManager::deallocate_supervisor_physical_page(PhysicalPage&& page)
  467. {
  468. for (auto& region : m_super_physical_regions) {
  469. if (!region.contains(page)) {
  470. kprintf(
  471. "MM: deallocate_supervisor_physical_page: %p not in %p -> %p\n",
  472. page.paddr(), region.lower().get(), region.upper().get());
  473. continue;
  474. }
  475. region.return_page(move(page));
  476. --m_super_physical_pages_used;
  477. return;
  478. }
  479. kprintf("MM: deallocate_supervisor_physical_page couldn't figure out region for super page @ %p\n", page.paddr());
  480. ASSERT_NOT_REACHED();
  481. }
  482. RefPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
  483. {
  484. InterruptDisabler disabler;
  485. RefPtr<PhysicalPage> page;
  486. for (auto& region : m_super_physical_regions) {
  487. page = region.take_free_page(true);
  488. if (page.is_null())
  489. continue;
  490. }
  491. if (!page) {
  492. if (m_super_physical_regions.is_empty()) {
  493. kprintf("MM: no super physical regions available (?)\n");
  494. }
  495. kprintf("MM: no super physical pages available\n");
  496. ASSERT_NOT_REACHED();
  497. return {};
  498. }
  499. #ifdef MM_DEBUG
  500. dbgprintf("MM: allocate_supervisor_physical_page vending P%p\n", page->paddr().get());
  501. #endif
  502. fast_u32_fill((u32*)page->paddr().as_ptr(), 0, PAGE_SIZE / sizeof(u32));
  503. ++m_super_physical_pages_used;
  504. return page;
  505. }
  506. void MemoryManager::enter_process_paging_scope(Process& process)
  507. {
  508. ASSERT(current);
  509. InterruptDisabler disabler;
  510. current->tss().cr3 = process.page_directory().cr3();
  511. asm volatile("movl %%eax, %%cr3" ::"a"(process.page_directory().cr3())
  512. : "memory");
  513. }
  514. void MemoryManager::flush_entire_tlb()
  515. {
  516. asm volatile(
  517. "mov %%cr3, %%eax\n"
  518. "mov %%eax, %%cr3\n" ::
  519. : "%eax", "memory");
  520. }
  521. void MemoryManager::flush_tlb(VirtualAddress vaddr)
  522. {
  523. asm volatile("invlpg %0"
  524. :
  525. : "m"(*(char*)vaddr.get())
  526. : "memory");
  527. }
  528. void MemoryManager::map_for_kernel(VirtualAddress vaddr, PhysicalAddress paddr)
  529. {
  530. auto& pte = ensure_pte(kernel_page_directory(), vaddr);
  531. pte.set_physical_page_base(paddr.get());
  532. pte.set_present(true);
  533. pte.set_writable(true);
  534. pte.set_user_allowed(false);
  535. flush_tlb(vaddr);
  536. }
  537. u8* MemoryManager::quickmap_page(PhysicalPage& physical_page)
  538. {
  539. ASSERT_INTERRUPTS_DISABLED();
  540. ASSERT(!m_quickmap_in_use);
  541. m_quickmap_in_use = true;
  542. auto page_vaddr = m_quickmap_addr;
  543. auto& pte = ensure_pte(kernel_page_directory(), page_vaddr);
  544. pte.set_physical_page_base(physical_page.paddr().get());
  545. pte.set_present(true);
  546. pte.set_writable(true);
  547. pte.set_user_allowed(false);
  548. flush_tlb(page_vaddr);
  549. ASSERT((u32)pte.physical_page_base() == physical_page.paddr().get());
  550. #ifdef MM_DEBUG
  551. dbgprintf("MM: >> quickmap_page L%x => P%x @ PTE=%p\n", page_vaddr, physical_page.paddr().get(), pte.ptr());
  552. #endif
  553. return page_vaddr.as_ptr();
  554. }
  555. void MemoryManager::unquickmap_page()
  556. {
  557. ASSERT_INTERRUPTS_DISABLED();
  558. ASSERT(m_quickmap_in_use);
  559. auto page_vaddr = m_quickmap_addr;
  560. auto& pte = ensure_pte(kernel_page_directory(), page_vaddr);
  561. #ifdef MM_DEBUG
  562. auto old_physical_address = pte.physical_page_base();
  563. #endif
  564. pte.set_physical_page_base(0);
  565. pte.set_present(false);
  566. pte.set_writable(false);
  567. flush_tlb(page_vaddr);
  568. #ifdef MM_DEBUG
  569. dbgprintf("MM: >> unquickmap_page L%x =/> P%x\n", page_vaddr, old_physical_address);
  570. #endif
  571. m_quickmap_in_use = false;
  572. }
  573. void MemoryManager::remap_region_page(Region& region, unsigned page_index_in_region)
  574. {
  575. ASSERT(region.page_directory());
  576. InterruptDisabler disabler;
  577. auto page_vaddr = region.vaddr().offset(page_index_in_region * PAGE_SIZE);
  578. auto& pte = ensure_pte(*region.page_directory(), page_vaddr);
  579. auto& physical_page = region.vmo().physical_pages()[page_index_in_region];
  580. ASSERT(physical_page);
  581. pte.set_physical_page_base(physical_page->paddr().get());
  582. pte.set_present(true); // FIXME: Maybe we should use the is_readable flag here?
  583. if (region.should_cow(page_index_in_region))
  584. pte.set_writable(false);
  585. else
  586. pte.set_writable(region.is_writable());
  587. pte.set_cache_disabled(!region.vmo().m_allow_cpu_caching);
  588. pte.set_write_through(!region.vmo().m_allow_cpu_caching);
  589. pte.set_user_allowed(region.is_user_accessible());
  590. region.page_directory()->flush(page_vaddr);
  591. #ifdef MM_DEBUG
  592. 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_vaddr.get(), physical_page->paddr().get(), physical_page.ptr());
  593. #endif
  594. }
  595. void MemoryManager::remap_region(PageDirectory& page_directory, Region& region)
  596. {
  597. InterruptDisabler disabler;
  598. ASSERT(region.page_directory() == &page_directory);
  599. map_region_at_address(page_directory, region, region.vaddr());
  600. }
  601. void MemoryManager::map_region_at_address(PageDirectory& page_directory, Region& region, VirtualAddress vaddr)
  602. {
  603. InterruptDisabler disabler;
  604. region.set_page_directory(page_directory);
  605. auto& vmo = region.vmo();
  606. #ifdef MM_DEBUG
  607. 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());
  608. #endif
  609. for (size_t i = 0; i < region.page_count(); ++i) {
  610. auto page_vaddr = vaddr.offset(i * PAGE_SIZE);
  611. auto& pte = ensure_pte(page_directory, page_vaddr);
  612. auto& physical_page = vmo.physical_pages()[region.first_page_index() + i];
  613. if (physical_page) {
  614. pte.set_physical_page_base(physical_page->paddr().get());
  615. pte.set_present(true); // FIXME: Maybe we should use the is_readable flag here?
  616. // FIXME: It seems wrong that the *region* cow map is essentially using *VMO* relative indices.
  617. if (region.should_cow(region.first_page_index() + i))
  618. pte.set_writable(false);
  619. else
  620. pte.set_writable(region.is_writable());
  621. pte.set_cache_disabled(!region.vmo().m_allow_cpu_caching);
  622. pte.set_write_through(!region.vmo().m_allow_cpu_caching);
  623. } else {
  624. pte.set_physical_page_base(0);
  625. pte.set_present(false);
  626. pte.set_writable(region.is_writable());
  627. }
  628. pte.set_user_allowed(region.is_user_accessible());
  629. page_directory.flush(page_vaddr);
  630. #ifdef MM_DEBUG
  631. dbgprintf("MM: >> map_region_at_address (PD=%x) '%s' L%x => P%x (@%p)\n", &page_directory, region.name().characters(), page_vaddr, physical_page ? physical_page->paddr().get() : 0, physical_page.ptr());
  632. #endif
  633. }
  634. }
  635. bool MemoryManager::unmap_region(Region& region)
  636. {
  637. ASSERT(region.page_directory());
  638. InterruptDisabler disabler;
  639. for (size_t i = 0; i < region.page_count(); ++i) {
  640. auto vaddr = region.vaddr().offset(i * PAGE_SIZE);
  641. auto& pte = ensure_pte(*region.page_directory(), vaddr);
  642. pte.set_physical_page_base(0);
  643. pte.set_present(false);
  644. pte.set_writable(false);
  645. pte.set_user_allowed(false);
  646. region.page_directory()->flush(vaddr);
  647. #ifdef MM_DEBUG
  648. auto& physical_page = region.vmo().physical_pages()[region.first_page_index() + i];
  649. dbgprintf("MM: >> Unmapped L%x => P%x <<\n", vaddr, physical_page ? physical_page->paddr().get() : 0);
  650. #endif
  651. }
  652. region.release_page_directory();
  653. return true;
  654. }
  655. bool MemoryManager::map_region(Process& process, Region& region)
  656. {
  657. map_region_at_address(process.page_directory(), region, region.vaddr());
  658. return true;
  659. }
  660. bool MemoryManager::validate_user_read(const Process& process, VirtualAddress vaddr) const
  661. {
  662. auto* region = region_from_vaddr(process, vaddr);
  663. return region && region->is_readable();
  664. }
  665. bool MemoryManager::validate_user_write(const Process& process, VirtualAddress vaddr) const
  666. {
  667. auto* region = region_from_vaddr(process, vaddr);
  668. return region && region->is_writable();
  669. }
  670. void MemoryManager::register_vmo(VMObject& vmo)
  671. {
  672. InterruptDisabler disabler;
  673. m_vmos.set(&vmo);
  674. }
  675. void MemoryManager::unregister_vmo(VMObject& vmo)
  676. {
  677. InterruptDisabler disabler;
  678. m_vmos.remove(&vmo);
  679. }
  680. void MemoryManager::register_region(Region& region)
  681. {
  682. InterruptDisabler disabler;
  683. if (region.vaddr().get() >= 0xc0000000)
  684. m_kernel_regions.set(&region);
  685. else
  686. m_user_regions.set(&region);
  687. }
  688. void MemoryManager::unregister_region(Region& region)
  689. {
  690. InterruptDisabler disabler;
  691. if (region.vaddr().get() >= 0xc0000000)
  692. m_kernel_regions.remove(&region);
  693. else
  694. m_user_regions.remove(&region);
  695. }
  696. ProcessPagingScope::ProcessPagingScope(Process& process)
  697. {
  698. ASSERT(current);
  699. MM.enter_process_paging_scope(process);
  700. }
  701. ProcessPagingScope::~ProcessPagingScope()
  702. {
  703. MM.enter_process_paging_scope(current->process());
  704. }