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#include <Kernel/FileSystem/Inode.h>
#include <Kernel/Process.h>
#include <Kernel/Thread.h>
#include <Kernel/VM/AnonymousVMObject.h>
#include <Kernel/VM/InodeVMObject.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/Region.h>
Region::Region(const Range& range, const String& name, u8 access)
: m_range(range)
, m_vmobject(AnonymousVMObject::create_with_size(size()))
, m_name(name)
, m_access(access)
{
MM.register_region(*this);
}
Region::Region(const Range& range, RefPtr<Inode>&& inode, const String& name, u8 access)
: m_range(range)
, m_vmobject(InodeVMObject::create_with_inode(*inode))
, m_name(name)
, m_access(access)
{
MM.register_region(*this);
}
Region::Region(const Range& range, NonnullRefPtr<VMObject> vmo, size_t offset_in_vmo, const String& name, u8 access)
: m_range(range)
, m_offset_in_vmo(offset_in_vmo)
, m_vmobject(move(vmo))
, m_name(name)
, m_access(access)
{
MM.register_region(*this);
}
Region::~Region()
{
// Make sure we disable interrupts so we don't get interrupted between unmapping and unregistering.
// Unmapping the region will give the VM back to the RangeAllocator, so an interrupt handler would
// find the address<->region mappings in an invalid state there.
InterruptDisabler disabler;
if (m_page_directory) {
MM.unmap_region(*this);
ASSERT(!m_page_directory);
}
MM.unregister_region(*this);
}
NonnullOwnPtr<Region> Region::clone()
{
ASSERT(current);
// NOTE: Kernel-only regions should never be cloned.
ASSERT(is_user_accessible());
if (m_shared || (is_readable() && !is_writable())) {
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): sharing %s (V%p)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
vaddr().get());
#endif
// Create a new region backed by the same VMObject.
return Region::create_user_accessible(m_range, m_vmobject, m_offset_in_vmo, m_name, m_access);
}
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): cowing %s (V%p)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
vaddr().get());
#endif
// Set up a COW region. The parent (this) region becomes COW as well!
ensure_cow_map().fill(true);
MM.remap_region(current->process().page_directory(), *this);
auto clone_region = Region::create_user_accessible(m_range, m_vmobject->clone(), m_offset_in_vmo, m_name, m_access);
clone_region->ensure_cow_map();
return clone_region;
}
int Region::commit()
{
InterruptDisabler disabler;
#ifdef MM_DEBUG
dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at V%p\n", vmobject().page_count(), this, &vmobject(), vaddr().get());
#endif
for (size_t i = first_page_index(); i <= last_page_index(); ++i) {
if (!vmobject().physical_pages()[i].is_null())
continue;
auto physical_page = MM.allocate_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
if (!physical_page) {
kprintf("MM: commit was unable to allocate a physical page\n");
return -ENOMEM;
}
vmobject().physical_pages()[i] = move(physical_page);
MM.remap_region_page(*this, i);
}
return 0;
}
size_t Region::amount_resident() const
{
size_t bytes = 0;
for (size_t i = 0; i < page_count(); ++i) {
if (m_vmobject->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_vmobject->physical_pages()[first_page_index() + i];
if (physical_page && physical_page->ref_count() > 1)
bytes += PAGE_SIZE;
}
return bytes;
}
NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, const StringView& name, u8 access)
{
auto region = make<Region>(range, name, access);
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)
{
auto region = make<Region>(range, move(vmobject), offset_in_vmobject, name, access);
region->m_user_accessible = true;
return region;
}
NonnullOwnPtr<Region> Region::create_user_accessible(const Range& range, NonnullRefPtr<Inode> inode, const StringView& name, u8 access)
{
auto region = make<Region>(range, move(inode), name, access);
region->m_user_accessible = true;
return region;
}
NonnullOwnPtr<Region> Region::create_kernel_only(const Range& range, const StringView& name, u8 access)
{
auto region = make<Region>(range, name, access);
region->m_user_accessible = false;
return region;
}
bool Region::should_cow(size_t page_index) const
{
if (m_shared)
return false;
return m_cow_map && m_cow_map->get(page_index);
}
void Region::set_should_cow(size_t page_index, bool cow)
{
ASSERT(!m_shared);
ensure_cow_map().set(page_index, cow);
}
Bitmap& Region::ensure_cow_map() const
{
if (!m_cow_map)
m_cow_map = make<Bitmap>(page_count(), true);
return *m_cow_map;
}
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