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Kernel: Use intrusive RegionTree solution for kernel regions as well

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This patch ports MemoryManager to RegionTree as well. The biggest
difference between this and the userspace code is that kernel regions
are owned by extant OwnPtr<Region> objects spread around the kernel,
while userspace regions are owned by the AddressSpace itself.

For kernelspace, there are a couple of situations where we need to make
large VM reservations that never get backed by regular VMObjects
(for example the kernel image reservation, or the big kmalloc range.)
Since we can't make a VM reservation without a Region object anymore,
this patch adds a way to create unbacked Region objects that can be
used for this exact purpose. They have no internal VMObject.)
This commit is contained in:
Andreas Kling 2022-04-03 13:28:16 +02:00
parent ffe2e77eba
commit e8f543c390
12 changed files with 72 additions and 50 deletions
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11
Kernel/Memory/PageDirectory.cpp
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@ -22,16 +22,7 @@ namespace Kernel::Memory {
UNMAP_AFTER_INIT NonnullRefPtr<PageDirectory> PageDirectory::must_create_kernel_page_directory()
{
auto directory = adopt_ref_if_nonnull(new (nothrow) PageDirectory).release_nonnull();
auto kernel_range_start = kernel_mapping_base + 2 * MiB; // The first 2 MiB are used for mapping the pre-kernel
MUST(directory->m_range_allocator.initialize_with_range(VirtualAddress(kernel_range_start), KERNEL_PD_END - kernel_range_start));
// Carve out the whole page directory covering the kernel image to make MemoryManager::initialize_physical_pages() happy
FlatPtr start_of_range = ((FlatPtr)start_of_kernel_image & ~(FlatPtr)0x1fffff);
FlatPtr end_of_range = ((FlatPtr)end_of_kernel_image & ~(FlatPtr)0x1fffff) + 0x200000;
MUST(directory->m_range_allocator.try_allocate_specific(VirtualAddress(start_of_range), end_of_range - start_of_range));
return directory;
return adopt_ref_if_nonnull(new (nothrow) PageDirectory).release_nonnull();
}
ErrorOr<NonnullRefPtr<PageDirectory>> PageDirectory::try_create_for_userspace()