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Kernel: Add mechanism to identity map the lowest 2MB

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Tom 2020-06-01 22:55:09 -06:00 • committed by Andreas Kling
parent 19190267a6
commit 841364b609
7 changed files with 40 additions and 12 deletions
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18
Kernel/VM/MemoryManager.cpp
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@ -211,8 +211,6 @@ void MemoryManager::initialize()
Region* MemoryManager::kernel_region_from_vaddr(VirtualAddress vaddr)
{
if (vaddr.get() < 0xc0000000)
return nullptr;
for (auto& region : MM.m_kernel_regions) {
if (region.contains(vaddr))
return &region;
@ -318,6 +316,18 @@ OwnPtr<Region> MemoryManager::allocate_kernel_region(PhysicalAddress paddr, size
return allocate_kernel_region_with_vmobject(range, *vmobject, name, access, user_accessible, cacheable);
}
OwnPtr<Region> MemoryManager::allocate_kernel_region_identity(PhysicalAddress paddr, size_t size, const StringView& name, u8 access, bool user_accessible, bool cacheable)
{
ASSERT(!(size % PAGE_SIZE));
auto range = kernel_page_directory().identity_range_allocator().allocate_specific(VirtualAddress(paddr.get()), size);
if (!range.is_valid())
return nullptr;
auto vmobject = AnonymousVMObject::create_for_physical_range(paddr, size);
if (!vmobject)
return nullptr;
return allocate_kernel_region_with_vmobject(range, *vmobject, name, access, user_accessible, cacheable);
}
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);
@ -665,7 +675,7 @@ void MemoryManager::unregister_vmobject(VMObject& vmobject)
void MemoryManager::register_region(Region& region)
{
InterruptDisabler disabler;
if (region.vaddr().get() >= 0xc0000000)
if (region.is_kernel())
m_kernel_regions.append(&region);
else
m_user_regions.append(&region);
@ -674,7 +684,7 @@ void MemoryManager::register_region(Region& region)
void MemoryManager::unregister_region(Region& region)
{
InterruptDisabler disabler;
if (region.vaddr().get() >= 0xc0000000)
if (region.is_kernel())
m_kernel_regions.remove(&region);
else
m_user_regions.remove(&region);