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Kernel: Protect the PageDirectory from concurrent access

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Tom 2020-10-31 17:19:18 -06:00 • committed by Andreas Kling
parent 2b25a89ab5
commit 5b38132e3c
4 changed files with 14 additions and 3 deletions
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6
Kernel/VM/Region.cpp
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@ -229,6 +229,7 @@ Bitmap& Region::ensure_cow_map() const
bool Region::map_individual_page_impl(size_t page_index)
{
ASSERT(m_page_directory->get_lock().own_lock());
auto page_vaddr = vaddr_from_page_index(page_index);
auto* pte = MM.ensure_pte(*m_page_directory, page_vaddr);
if (!pte) {
@ -260,8 +261,9 @@ bool Region::map_individual_page_impl(size_t page_index)
bool Region::remap_page(size_t page_index, bool with_flush)
{
ASSERT(m_page_directory);
ScopedSpinLock lock(s_mm_lock);
ASSERT(m_page_directory);
ScopedSpinLock page_lock(m_page_directory->get_lock());
ASSERT(physical_page(page_index));
bool success = map_individual_page_impl(page_index);
if (with_flush)
@ -273,6 +275,7 @@ void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
{
ScopedSpinLock lock(s_mm_lock);
ASSERT(m_page_directory);
ScopedSpinLock page_lock(m_page_directory->get_lock());
size_t count = page_count();
for (size_t i = 0; i < count; ++i) {
auto vaddr = vaddr_from_page_index(i);
@ -302,6 +305,7 @@ void Region::set_page_directory(PageDirectory& page_directory)
bool Region::map(PageDirectory& page_directory)
{
ScopedSpinLock lock(s_mm_lock);
ScopedSpinLock page_lock(page_directory.get_lock());
set_page_directory(page_directory);
#ifdef MM_DEBUG
dbg() << "MM: Region::map() will map VMO pages " << first_page_index() << " - " << last_page_index() << " (VMO page count: " << vmobject().page_count() << ")";