Kernel: Allow contiguous allocations in physical memory

For that, we have a new type of VMObject, called
ContiguousVMObject, that is responsible for allocating contiguous
physical pages.

Kernel/Makefile

@@ -103,6 +103,7 @@ OBJS = \
     TTY/VirtualConsole.o \
     Thread.o \
     VM/AnonymousVMObject.o \
+    VM/ContiguousVMObject.o \
     VM/InodeVMObject.o \
     VM/MemoryManager.o \
     VM/PageDirectory.o \

Kernel/VM/ContiguousVMObject.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/VM/ContiguousVMObject.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <Kernel/VM/PhysicalPage.h>
+
+namespace Kernel {
+
+//#define CONTIGUOUS_VMOBJECT_DEBUG
+
+NonnullRefPtr<ContiguousVMObject> ContiguousVMObject::create_with_size(size_t size)
+{
+    return adopt(*new ContiguousVMObject(size));
+}
+
+ContiguousVMObject::ContiguousVMObject(size_t size)
+    : VMObject(size)
+{
+    auto contiguous_physical_pages = MM.allocate_contiguous_supervisor_physical_pages(size);
+    for (size_t i = 0; i < page_count(); i++) {
+        physical_pages()[i] = contiguous_physical_pages[i];
+#ifdef CONTIGUOUS_VMOBJECT_DEBUG
+        dbg() << "Contiguous page[" << i << "]: " << physical_pages()[i]->paddr();
+#endif
+    }
+}
+
+ContiguousVMObject::ContiguousVMObject(const ContiguousVMObject& other)
+    : VMObject(other)
+{
+}
+
+ContiguousVMObject::~ContiguousVMObject()
+{
+}
+
+NonnullRefPtr<VMObject> ContiguousVMObject::clone()
+{
+    ASSERT_NOT_REACHED();
+}
+
+}

Kernel/VM/ContiguousVMObject.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <Kernel/VM/VMObject.h>
+#include <LibBareMetal/Memory/PhysicalAddress.h>
+
+namespace Kernel {
+
+class ContiguousVMObject final : public VMObject {
+public:
+    virtual ~ContiguousVMObject() override;
+
+    static NonnullRefPtr<ContiguousVMObject> create_with_size(size_t);
+
+private:
+    explicit ContiguousVMObject(size_t);
+    explicit ContiguousVMObject(const ContiguousVMObject&);
+
+    virtual const char* class_name() const override { return "ContiguousVMObject"; }
+    virtual NonnullRefPtr<VMObject> clone() override;
+
+    ContiguousVMObject& operator=(const ContiguousVMObject&) = delete;
+    ContiguousVMObject& operator=(ContiguousVMObject&&) = delete;
+    ContiguousVMObject(ContiguousVMObject&&) = delete;
+
+    virtual bool is_contiguous() const override { return true; }
+};
+}

Kernel/VM/MemoryManager.cpp

@@ -32,6 +32,7 @@
 #include <Kernel/FileSystem/Inode.h>
 #include <Kernel/Multiboot.h>
 #include <Kernel/VM/AnonymousVMObject.h>
+#include <Kernel/VM/ContiguousVMObject.h>
 #include <Kernel/VM/MemoryManager.h>
 #include <Kernel/VM/PageDirectory.h>
 #include <Kernel/VM/PhysicalRegion.h>
@@ -302,6 +303,19 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
     return region->handle_fault(fault);
 }
 
+OwnPtr<Region> MemoryManager::allocate_contiguous_kernel_region(size_t size, const StringView& name, u8 access, bool user_accessible, bool cacheable)
+{
+    ASSERT(!(size % PAGE_SIZE));
+    auto range = kernel_page_directory().range_allocator().allocate_anywhere(size);
+    if (!range.is_valid())
+        return nullptr;
+    auto vmobject = ContiguousVMObject::create_with_size(size);
+    auto region = allocate_kernel_region_with_vmobject(range, vmobject, name, access, user_accessible, cacheable);
+    if (!region)
+        return nullptr;
+    return region;
+}
+
 OwnPtr<Region> MemoryManager::allocate_kernel_region(size_t size, const StringView& name, u8 access, bool user_accessible, bool should_commit, bool cacheable)
 {
     ASSERT(!(size % PAGE_SIZE));
@@ -447,6 +461,36 @@ void MemoryManager::deallocate_supervisor_physical_page(PhysicalPage&& page)
     ASSERT_NOT_REACHED();
 }
 
+Vector<RefPtr<PhysicalPage>> MemoryManager::allocate_contiguous_supervisor_physical_pages(size_t size)
+{
+    ASSERT(!(size % PAGE_SIZE));
+    InterruptDisabler disabler;
+    size_t count = ceil_div(size, PAGE_SIZE);
+    Vector<RefPtr<PhysicalPage>> physical_pages;
+    physical_pages.ensure_capacity(count);
+
+    for (auto& region : m_super_physical_regions) {
+        physical_pages = region.take_contiguous_free_pages((count), true);
+        if (physical_pages.is_empty())
+            continue;
+    }
+
+    if (physical_pages.is_empty()) {
+        if (m_super_physical_regions.is_empty()) {
+            klog() << "MM: no super physical regions available (?)";
+        }
+
+        klog() << "MM: no super physical pages available";
+        ASSERT_NOT_REACHED();
+        return {};
+    }
+
+    auto cleanup_region = MM.allocate_kernel_region(physical_pages[0]->paddr(), PAGE_SIZE * count, "MemoryManager Allocation Sanitization", Region::Access::Read | Region::Access::Write);
+    fast_u32_fill((u32*)cleanup_region->vaddr().as_ptr(), 0, (PAGE_SIZE * count) / sizeof(u32));
+    m_super_physical_pages_used += count;
+    return physical_pages;
+}
+
 RefPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
 {
     InterruptDisabler disabler;

Kernel/VM/MemoryManager.h

@@ -100,9 +100,11 @@ public:
 
     RefPtr<PhysicalPage> allocate_user_physical_page(ShouldZeroFill = ShouldZeroFill::Yes);
     RefPtr<PhysicalPage> allocate_supervisor_physical_page();
+    Vector<RefPtr<PhysicalPage>> allocate_contiguous_supervisor_physical_pages(size_t size);
     void deallocate_user_physical_page(PhysicalPage&&);
     void deallocate_supervisor_physical_page(PhysicalPage&&);
 
+    OwnPtr<Region> allocate_contiguous_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
     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 = true);
     OwnPtr<Region> allocate_kernel_region_with_vmobject(VMObject&, size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);

Kernel/VM/PhysicalRegion.cpp

@@ -27,6 +27,7 @@
 #include <AK/Bitmap.h>
 #include <AK/NonnullRefPtr.h>
 #include <AK/RefPtr.h>
+#include <AK/Vector.h>
 #include <Kernel/Assertions.h>
 #include <Kernel/VM/PhysicalPage.h>
 #include <Kernel/VM/PhysicalRegion.h>
@@ -63,36 +64,59 @@ unsigned PhysicalRegion::finalize_capacity()
     return size();
 }
 
-RefPtr<PhysicalPage> PhysicalRegion::take_free_page(bool supervisor)
+Vector<RefPtr<PhysicalPage>> PhysicalRegion::take_contiguous_free_pages(size_t count, bool supervisor)
 {
     ASSERT(m_pages);
+    ASSERT(m_used != m_pages);
 
-    if (m_used == m_pages)
-        return nullptr;
+    Vector<RefPtr<PhysicalPage>> physical_pages;
+    physical_pages.ensure_capacity(count);
 
-    // search from the last page we allocated
-    for (unsigned page = m_last; page < m_pages; page++) {
-        if (!m_bitmap.get(page)) {
-            m_bitmap.set(page, true);
-            m_used++;
-            m_last = page + 1;
-            return PhysicalPage::create(m_lower.offset(page * PAGE_SIZE), supervisor);
-        }
+    auto first_contiguous_page = find_contiguous_free_pages(count);
+
+    for (size_t index = 0; index < count; index++) {
+        physical_pages.append(PhysicalPage::create(m_lower.offset(PAGE_SIZE * (index + first_contiguous_page)), supervisor));
     }
+    return physical_pages;
+}
 
-    // wrap back around to the start in case we missed something
-    for (unsigned page = 0; page < m_last; page++) {
-        if (!m_bitmap.get(page)) {
-            m_bitmap.set(page, true);
-            m_used++;
-            m_last = page + 1;
-            return PhysicalPage::create(m_lower.offset(page * PAGE_SIZE), supervisor);
+unsigned PhysicalRegion::find_contiguous_free_pages(size_t count)
+{
+    ASSERT(count != 0);
+    // search from the last page we allocated
+    auto range = find_and_allocate_contiguous_range(count);
+    ASSERT(range.has_value());
+    return range.value();
+}
+
+Optional<unsigned> PhysicalRegion::find_and_allocate_contiguous_range(size_t count)
+{
+    ASSERT(count != 0);
+    size_t found_pages_count = 0;
+    auto first_index = m_bitmap.find_longest_range_of_unset_bits(count, found_pages_count);
+    if (!first_index.has_value())
+        return {};
+
+    auto page = first_index.value();
+    if (count == found_pages_count) {
+        for (unsigned page_index = page; page_index < (page + count); page_index++) {
+            m_bitmap.set(page_index, true);
         }
+        m_used += count;
+        m_last = page + count;
+        return page;
     }
+    return {};
+}
 
-    ASSERT_NOT_REACHED();
+RefPtr<PhysicalPage> PhysicalRegion::take_free_page(bool supervisor)
+{
+    ASSERT(m_pages);
+
+    if (m_used == m_pages)
+        return nullptr;
 
-    return nullptr;
+    return PhysicalPage::create(m_lower.offset(find_contiguous_free_pages(1) * PAGE_SIZE), supervisor);
 }
 
 void PhysicalRegion::return_page_at(PhysicalAddress addr)

Kernel/VM/PhysicalRegion.h

@@ -28,6 +28,7 @@
 
 #include <AK/Bitmap.h>
 #include <AK/NonnullRefPtr.h>
+#include <AK/Optional.h>
 #include <AK/RefCounted.h>
 #include <Kernel/VM/PhysicalPage.h>
 
@@ -51,10 +52,14 @@ public:
     bool contains(PhysicalPage& page) const { return page.paddr() >= m_lower && page.paddr() <= m_upper; }
 
     RefPtr<PhysicalPage> take_free_page(bool supervisor);
+    Vector<RefPtr<PhysicalPage>> take_contiguous_free_pages(size_t count, bool supervisor);
     void return_page_at(PhysicalAddress addr);
     void return_page(PhysicalPage&& page) { return_page_at(page.paddr()); }
 
 private:
+    unsigned find_contiguous_free_pages(size_t count);
+    Optional<unsigned> find_and_allocate_contiguous_range(size_t count);
+
     PhysicalRegion(PhysicalAddress lower, PhysicalAddress upper);
 
     PhysicalAddress m_lower;

Kernel/VM/VMObject.h

@@ -54,6 +54,7 @@ public:
     virtual bool is_inode() const { return false; }
     virtual bool is_shared_inode() const { return false; }
     virtual bool is_private_inode() const { return false; }
+    virtual bool is_contiguous() const { return false; }
 
     size_t page_count() const { return m_physical_pages.size(); }
     const FixedArray<RefPtr<PhysicalPage>>& physical_pages() const { return m_physical_pages; }