Kernel: Change Region allocation helpers

We now can create a cacheable Region, so when map() is called, if a
Region is cacheable then all the virtual memory space being allocated
to it will be marked as not cache disabled.

In addition to that, OS components can create a Region that will be
mapped to a specific physical address by using the appropriate helper
method.

6 files changed, 73 insertions, 51 deletions

diff --git a/Kernel/VM/MemoryManager.cpp b/Kernel/VM/MemoryManager.cpp
index 3cde372f64..c764a4c133 100644
--- a/Kernel/VM/MemoryManager.cpp
+++ b/Kernel/VM/MemoryManager.cpp
@@ -321,7 +321,7 @@ void MemoryManager::create_identity_mapping(PageDirectory& page_directory, Virtu
         pte.set_user_allowed(false);
         pte.set_present(true);
         pte.set_writable(true);
-        page_directory.flush(pte_address);
+        flush_tlb(pte_address);
     }
 }
 
@@ -394,7 +394,7 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
     return region->handle_fault(fault);
 }
 
-OwnPtr<Region> MemoryManager::allocate_kernel_region(size_t size, const StringView& name, u8 access, bool user_accessible, bool should_commit)
+OwnPtr<Region> MemoryManager::allocate_kernel_region(size_t size, const StringView& name, u8 access, bool user_accessible, bool should_commit, bool cacheable)
 {
     InterruptDisabler disabler;
     ASSERT(!(size % PAGE_SIZE));
@@ -402,28 +402,47 @@ OwnPtr<Region> MemoryManager::allocate_kernel_region(size_t size, const StringVi
     ASSERT(range.is_valid());
     OwnPtr<Region> region;
     if (user_accessible)
-        region = Region::create_user_accessible(range, name, access);
+        region = Region::create_user_accessible(range, name, access, cacheable);
     else
-        region = Region::create_kernel_only(range, name, access);
-    region->map(kernel_page_directory());
+        region = Region::create_kernel_only(range, name, access, cacheable);
+    region->set_page_directory(kernel_page_directory());
     // FIXME: It would be cool if these could zero-fill on demand instead.
     if (should_commit)
         region->commit();
     return region;
 }
 
-OwnPtr<Region> MemoryManager::allocate_user_accessible_kernel_region(size_t size, const StringView& name, u8 access)
+OwnPtr<Region> MemoryManager::allocate_kernel_region(PhysicalAddress paddr, size_t size, const StringView& name, u8 access, bool user_accessible, bool cacheable)
 {
-    return allocate_kernel_region(size, name, access, true);
+    InterruptDisabler disabler;
+    ASSERT(!(size % PAGE_SIZE));
+    auto range = kernel_page_directory().range_allocator().allocate_anywhere(size);
+    ASSERT(range.is_valid());
+    OwnPtr<Region> region;
+    if (user_accessible)
+        region = Region::create_user_accessible(range, AnonymousVMObject::create_for_physical_range(paddr, size), 0, name, access, cacheable);
+    else
+        region = Region::create_kernel_only(range, AnonymousVMObject::create_for_physical_range(paddr, size), 0, name, access, cacheable);
+    region->map(kernel_page_directory());
+    return region;
 }
 
-OwnPtr<Region> MemoryManager::allocate_kernel_region_with_vmobject(VMObject& vmobject, size_t size, const StringView& name, u8 access)
+OwnPtr<Region> MemoryManager::allocate_user_accessible_kernel_region(size_t size, const StringView& name, u8 access, bool cacheable)
+{
+    return allocate_kernel_region(size, name, access, true, true, cacheable);
+}
+
+OwnPtr<Region> MemoryManager::allocate_kernel_region_with_vmobject(VMObject& vmobject, size_t size, const StringView& name, u8 access, bool user_accessible, bool cacheable)
 {
     InterruptDisabler disabler;
     ASSERT(!(size % PAGE_SIZE));
     auto range = kernel_page_directory().range_allocator().allocate_anywhere(size);
     ASSERT(range.is_valid());
-    auto region = make<Region>(range, vmobject, 0, name, access);
+    OwnPtr<Region> region;
+    if (user_accessible)
+        region = Region::create_user_accessible(range, vmobject, 0, name, access, cacheable);
+    else
+        region = Region::create_kernel_only(range, vmobject, 0, name, access, cacheable);
     region->map(kernel_page_directory());
     return region;
 }
@@ -573,6 +592,9 @@ void MemoryManager::flush_entire_tlb()
 
 void MemoryManager::flush_tlb(VirtualAddress vaddr)
 {
+#ifdef MM_DEBUG
+    dbgprintf("MM: Flush page V%p\n", vaddr.get());
+#endif
     asm volatile("invlpg %0"
                  :
                  : "m"(*(char*)vaddr.get())
diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h
index 282bfd13ae..d3af2325af 100644
--- a/Kernel/VM/MemoryManager.h
+++ b/Kernel/VM/MemoryManager.h
@@ -62,9 +62,10 @@ public:
 
     void map_for_kernel(VirtualAddress, PhysicalAddress, bool cache_disabled = false);
 
-    OwnPtr<Region> allocate_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool should_commit = true);
-    OwnPtr<Region> allocate_kernel_region_with_vmobject(VMObject&, size_t, const StringView& name, u8 access);
-    OwnPtr<Region> allocate_user_accessible_kernel_region(size_t, const StringView& name, u8 access);
+    OwnPtr<Region> allocate_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool should_commit = true, bool cacheable = true);
+    OwnPtr<Region> allocate_kernel_region(PhysicalAddress, size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = false);
+    OwnPtr<Region> allocate_kernel_region_with_vmobject(VMObject&, size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = false);
+    OwnPtr<Region> allocate_user_accessible_kernel_region(size_t, const StringView& name, u8 access, bool cacheable = false);
 
     unsigned user_physical_pages() const { return m_user_physical_pages; }
     unsigned user_physical_pages_used() const { return m_user_physical_pages_used; }
diff --git a/Kernel/VM/PageDirectory.cpp b/Kernel/VM/PageDirectory.cpp
index 729cf4c9be..de230e8c35 100644
--- a/Kernel/VM/PageDirectory.cpp
+++ b/Kernel/VM/PageDirectory.cpp
@@ -74,15 +74,4 @@ PageDirectory::~PageDirectory()
 #endif
     InterruptDisabler disabler;
     cr3_map().remove(cr3());
-}
-
-void PageDirectory::flush(VirtualAddress vaddr)
-{
-#ifdef MM_DEBUG
-    dbgprintf("MM: Flush page V%p\n", vaddr.get());
-#endif
-    if (!current)
-        return;
-    if (this == &MM.kernel_page_directory() || &current->process().page_directory() == this)
-        MM.flush_tlb(vaddr);
-}
+}
\ No newline at end of file
diff --git a/Kernel/VM/PageDirectory.h b/Kernel/VM/PageDirectory.h
index 2d70eb0fe1..53b4d5d410 100644
--- a/Kernel/VM/PageDirectory.h
+++ b/Kernel/VM/PageDirectory.h
@@ -24,8 +24,6 @@ public:
     u32 cr3() const { return m_directory_table->paddr().get(); }
     PageDirectoryPointerTable& table() { return *reinterpret_cast<PageDirectoryPointerTable*>(cr3()); }
 
-    void flush(VirtualAddress);
-
     RangeAllocator& range_allocator() { return m_range_allocator; }
 
     Process* process() { return m_process; }
diff --git a/Kernel/VM/Region.cpp b/Kernel/VM/Region.cpp
index 244103a4f2..f189089cb2 100644
--- a/Kernel/VM/Region.cpp
+++ b/Kernel/VM/Region.cpp
@@ -9,30 +9,33 @@
 //#define MM_DEBUG
 //#define PAGE_FAULT_DEBUG
 
-Region::Region(const Range& range, const String& name, u8 access)
+Region::Region(const Range& range, const String& name, u8 access, bool cacheable)
     : m_range(range)
     , m_vmobject(AnonymousVMObject::create_with_size(size()))
     , m_name(name)
     , m_access(access)
+    , m_cacheable(cacheable)
 {
     MM.register_region(*this);
 }
 
-Region::Region(const Range& range, NonnullRefPtr<Inode> inode, const String& name, u8 access)
+Region::Region(const Range& range, NonnullRefPtr<Inode> inode, const String& name, u8 access, bool cacheable)
     : m_range(range)
     , m_vmobject(InodeVMObject::create_with_inode(*inode))
     , m_name(name)
     , m_access(access)
+    , m_cacheable(cacheable)
 {
     MM.register_region(*this);
 }
 
-Region::Region(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, u8 access)
+Region::Region(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, u8 access, bool cacheable)
     : m_range(range)
     , m_offset_in_vmobject(offset_in_vmobject)
     , m_vmobject(move(vmobject))
     , m_name(name)
     , m_access(access)
+    , m_cacheable(cacheable)
 {
     MM.register_region(*this);
 }
@@ -164,37 +167,37 @@ size_t Region::amount_shared() const
     return bytes;
 }
 
-NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, const StringView& name, u8 access)
+NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, const StringView& name, u8 access, bool cacheable)
 {
-    auto region = make<Region>(range, name, access);
+    auto region = make<Region>(range, name, access, cacheable);
     region->m_user_accessible = true;
     return region;
 }
 
-NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access)
+NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable)
 {
-    auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access);
+    auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access, cacheable);
     region->m_user_accessible = true;
     return region;
 }
 
-NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, NonnullRefPtr<Inode> inode, const StringView& name, u8 access)
+NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, NonnullRefPtr<Inode> inode, const StringView& name, u8 access, bool cacheable)
 {
-    auto region = make<Region>(range, move(inode), name, access);
+    auto region = make<Region>(range, move(inode), name, access, cacheable);
     region->m_user_accessible = true;
     return region;
 }
 
-NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, const StringView& name, u8 access)
+NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable)
 {
-    auto region = make<Region>(range, name, access);
+    auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access, cacheable);
     region->m_user_accessible = false;
     return region;
 }
 
-NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const StringView& name, u8 access)
+NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, const StringView& name, u8 access, bool cacheable)
 {
-    auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access);
+    auto region = make<Region>(range, name, access, cacheable);
     region->m_user_accessible = false;
     return region;
 }
@@ -228,6 +231,7 @@ void Region::map_individual_page_impl(size_t page_index)
         pte.set_physical_page_base(0);
         pte.set_present(false);
     } else {
+        pte.set_cache_disabled(!m_cacheable);
         pte.set_physical_page_base(physical_page->paddr().get());
         pte.set_present(is_readable());
         if (should_cow(page_index))
@@ -237,11 +241,11 @@ void Region::map_individual_page_impl(size_t page_index)
         if (g_cpu_supports_nx)
             pte.set_execute_disabled(!is_executable());
         pte.set_user_allowed(is_user_accessible());
-    }
-    m_page_directory->flush(page_vaddr);
 #ifdef MM_DEBUG
     dbg() << "MM: >> region map (PD=" << m_page_directory->cr3() << ", PTE=" << (void*)pte.raw() << "{" << &pte << "}) " << name() << " " << page_vaddr << " => " << physical_page->paddr() << " (@" << physical_page.ptr() << ")";
 #endif
+    }
+    MM.flush_tlb(page_vaddr);
 }
 
 void Region::remap_page(size_t page_index)
@@ -263,7 +267,7 @@ void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
         pte.set_present(false);
         pte.set_writable(false);
         pte.set_user_allowed(false);
-        m_page_directory->flush(vaddr);
+        MM.flush_tlb(vaddr);
 #ifdef MM_DEBUG
         auto& physical_page = vmobject().physical_pages()[first_page_index() + i];
         dbgprintf("MM: >> Unmapped V%p => P%p <<\n", vaddr.get(), physical_page ? physical_page->paddr().get() : 0);
@@ -274,11 +278,16 @@ void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
     m_page_directory = nullptr;
 }
 
-void Region::map(PageDirectory& page_directory)
+void Region::set_page_directory(PageDirectory& page_directory)
 {
     ASSERT(!m_page_directory || m_page_directory == &page_directory);
     InterruptDisabler disabler;
     m_page_directory = page_directory;
+}
+void Region::map(PageDirectory& page_directory)
+{
+    set_page_directory(page_directory);
+    InterruptDisabler disabler;
 #ifdef MM_DEBUG
     dbgprintf("MM: Region::map() will map VMO pages %u - %u (VMO page count: %u)\n", first_page_index(), last_page_index(), vmobject().page_count());
 #endif
diff --git a/Kernel/VM/Region.h b/Kernel/VM/Region.h
index 3af580af79..377344d348 100644
--- a/Kernel/VM/Region.h
+++ b/Kernel/VM/Region.h
@@ -26,11 +26,11 @@ public:
         Execute = 4,
     };
 
-    static NonnullOwnPtr<Region> create_user_accessible(const Range&, const StringView& name, u8 access);
-    static NonnullOwnPtr<Region> create_user_accessible(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const StringView& name, u8 access);
-    static NonnullOwnPtr<Region> create_user_accessible(const Range&, NonnullRefPtr<Inode>, const StringView& name, u8 access);
-    static NonnullOwnPtr<Region> create_kernel_only(const Range&, const StringView& name, u8 access);
-    static NonnullOwnPtr<Region> create_kernel_only(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const StringView& name, u8 access);
+    static NonnullOwnPtr<Region> create_user_accessible(const Range&, const StringView& name, u8 access, bool cacheable = true);
+    static NonnullOwnPtr<Region> create_user_accessible(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable = true);
+    static NonnullOwnPtr<Region> create_user_accessible(const Range&, NonnullRefPtr<Inode>, const StringView& name, u8 access, bool cacheable = true);
+    static NonnullOwnPtr<Region> create_kernel_only(const Range&, const StringView& name, u8 access, bool cacheable = true);
+    static NonnullOwnPtr<Region> create_kernel_only(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const StringView& name, u8 access, bool cacheable = true);
 
     ~Region();
 
@@ -40,6 +40,7 @@ public:
     bool is_readable() const { return m_access & Access::Read; }
     bool is_writable() const { return m_access & Access::Write; }
     bool is_executable() const { return m_access & Access::Execute; }
+    bool is_cacheable() const { return m_cacheable; }
     const String& name() const { return m_name; }
     unsigned access() const { return m_access; }
 
@@ -115,6 +116,7 @@ public:
     void set_writable(bool b) { set_access_bit(Access::Write, b); }
     void set_executable(bool b) { set_access_bit(Access::Execute, b); }
 
+    void set_page_directory(PageDirectory&);
     void map(PageDirectory&);
     enum class ShouldDeallocateVirtualMemoryRange {
         No,
@@ -130,9 +132,9 @@ public:
     Region* m_prev { nullptr };
 
     // NOTE: These are public so we can make<> them.
-    Region(const Range&, const String&, u8 access);
-    Region(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const String&, u8 access);
-    Region(const Range&, NonnullRefPtr<Inode>, const String&, u8 access);
+    Region(const Range&, const String&, u8 access, bool cacheable);
+    Region(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const String&, u8 access, bool cacheable);
+    Region(const Range&, NonnullRefPtr<Inode>, const String&, u8 access, bool cacheable);
 
 private:
     Bitmap& ensure_cow_map() const;
@@ -159,6 +161,7 @@ private:
     u8 m_access { 0 };
     bool m_shared { false };
     bool m_user_accessible { false };
+    bool m_cacheable { false };
     bool m_stack { false };
     bool m_mmap { false };
     mutable OwnPtr<Bitmap> m_cow_map;