RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 06:37:43 +00:00
Code Issues Activity Actions

Kernel: Protect the PageDirectory from concurrent access

Browse source
This commit is contained in:
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
Download patch file Download diff file Expand all files Collapse all files

6
Kernel/VM/MemoryManager.cpp
View file

@ -87,6 +87,7 @@ MemoryManager::~MemoryManager()
void MemoryManager::protect_kernel_image()
{
ScopedSpinLock page_lock(kernel_page_directory().get_lock());
// Disable writing to the kernel text and rodata segments.
for (size_t i = (FlatPtr)&start_of_kernel_text; i < (FlatPtr)&start_of_kernel_data; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
@ -193,10 +194,11 @@ void MemoryManager::parse_memory_map()
ASSERT(m_user_physical_pages > 0);
}
PageTableEntry* MemoryManager::pte(const PageDirectory& page_directory, VirtualAddress vaddr)
PageTableEntry* MemoryManager::pte(PageDirectory& page_directory, VirtualAddress vaddr)
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(s_mm_lock.own_lock());
ASSERT(page_directory.get_lock().own_lock());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x3;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;
@ -213,6 +215,7 @@ PageTableEntry* MemoryManager::ensure_pte(PageDirectory& page_directory, Virtual
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(s_mm_lock.own_lock());
ASSERT(page_directory.get_lock().own_lock());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x3;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;
@ -259,6 +262,7 @@ void MemoryManager::release_pte(PageDirectory& page_directory, VirtualAddress va
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(s_mm_lock.own_lock());
ASSERT(page_directory.get_lock().own_lock());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x3;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;