Kernel: Move page remapping into Region::remap_page(index)

Let Region deal with this, instead of everyone calling MemoryManager.

Kernel/VM/MemoryManager.cpp

@@ -302,7 +302,7 @@ bool MemoryManager::zero_page(Region& region, unsigned page_index_in_region)
 #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);
+        region.remap_page(page_index_in_region);
         return true;
     }
 
@@ -314,7 +314,7 @@ bool MemoryManager::zero_page(Region& region, unsigned page_index_in_region)
     dbgprintf("      >> ZERO P%p\n", physical_page->paddr().get());
 #endif
     vmo.physical_pages()[page_index_in_region] = move(physical_page);
-    remap_region_page(region, page_index_in_region);
+    region.remap_page(page_index_in_region);
     return true;
 }
 
@@ -327,7 +327,7 @@ bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
         dbgprintf("    >> It's a COW page but nobody is sharing it anymore. Remap r/w\n");
 #endif
         region.set_should_cow(page_index_in_region, false);
-        remap_region_page(region, page_index_in_region);
+        region.remap_page(page_index_in_region);
         return true;
     }
 
@@ -348,7 +348,7 @@ bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
     vmo.physical_pages()[page_index_in_region] = move(physical_page);
     unquickmap_page();
     region.set_should_cow(page_index_in_region, false);
-    remap_region_page(region, page_index_in_region);
+    region.remap_page(page_index_in_region);
     return true;
 }
 
@@ -372,7 +372,7 @@ bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_re
 #ifdef PAGE_FAULT_DEBUG
         dbgprintf("MM: page_in_from_inode() but page already present. Fine with me!\n");
 #endif
-        remap_region_page(region, page_index_in_region);
+        region.remap_page( page_index_in_region);
         return true;
     }
 
@@ -400,7 +400,7 @@ bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_re
         kprintf("MM: page_in_from_inode was unable to allocate a physical page\n");
         return false;
     }
-    remap_region_page(region, page_index_in_region);
+    region.remap_page(page_index_in_region);
     u8* dest_ptr = region.vaddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
     memcpy(dest_ptr, page_buffer, PAGE_SIZE);
     return true;
@@ -672,27 +672,6 @@ void MemoryManager::unquickmap_page()
     m_quickmap_in_use = false;
 }
 
-void MemoryManager::remap_region_page(Region& region, unsigned page_index_in_region)
-{
-    ASSERT(region.page_directory());
-    InterruptDisabler disabler;
-    auto page_vaddr = region.vaddr().offset(page_index_in_region * PAGE_SIZE);
-    auto& pte = ensure_pte(*region.page_directory(), page_vaddr);
-    auto& physical_page = region.vmobject().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.should_cow(page_index_in_region))
-        pte.set_writable(false);
-    else
-        pte.set_writable(region.is_writable());
-    pte.set_user_allowed(region.is_user_accessible());
-    region.page_directory()->flush(page_vaddr);
-#ifdef MM_DEBUG
-    dbg() << "MM: >> remap_region_page (PD=" << region.page_directory()->cr3() << ", PTE=" << (void*)pte.raw() << "{" << &pte << "}) " << region.name() << " " << page_vaddr << " => " << physical_page->paddr() << " (@" << physical_page.ptr() << ")";
-#endif
-}
-
 void MemoryManager::remap_region(PageDirectory& page_directory, Region& region)
 {
     InterruptDisabler disabler;

Kernel/VM/MemoryManager.h

@@ -98,8 +98,6 @@ private:
     void register_region(Region&);
     void unregister_region(Region&);
 
-    void remap_region_page(Region&, unsigned page_index_in_region);
-
     void initialize_paging();
     void flush_entire_tlb();
     void flush_tlb(VirtualAddress);

Kernel/VM/Region.cpp

@@ -96,7 +96,7 @@ int Region::commit()
             return -ENOMEM;
         }
         vmobject().physical_pages()[i] = move(physical_page);
-        MM.remap_region_page(*this, i);
+        remap_page(i - first_page_index());
     }
     return 0;
 }
@@ -169,3 +169,25 @@ Bitmap& Region::ensure_cow_map() const
         m_cow_map = make<Bitmap>(page_count(), true);
     return *m_cow_map;
 }
+
+void Region::remap_page(size_t index)
+{
+    ASSERT(page_directory());
+    InterruptDisabler disabler;
+    auto page_vaddr = vaddr().offset(index * PAGE_SIZE);
+    auto& pte = MM.ensure_pte(*page_directory(), page_vaddr);
+    auto& physical_page = vmobject().physical_pages()[first_page_index() + index];
+    ASSERT(physical_page);
+    pte.set_physical_page_base(physical_page->paddr().get());
+    pte.set_present(true);
+    if (should_cow(index))
+        pte.set_writable(false);
+    else
+        pte.set_writable(is_writable());
+    pte.set_user_allowed(is_user_accessible());
+    page_directory()->flush(page_vaddr);
+#ifdef MM_DEBUG
+    dbg() << "MM: >> region.remap_page (PD=" << page_directory()->cr3() << ", PTE=" << (void*)pte.raw() << "{" << &pte << "}) " << name() << " " << page_vaddr << " => " << physical_page->paddr() << " (@" << physical_page.ptr() << ")";
+#endif
+
+}

Kernel/VM/Region.h

@@ -114,6 +114,8 @@ public:
             m_access &= ~Access::Write;
     }
 
+    void remap_page(size_t index);
+
     // For InlineLinkedListNode
     Region* m_next { nullptr };
     Region* m_prev { nullptr };