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Kernel: Use the whole kernel PD range when randomizing the KASLR offset

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Now that we reclaim the memory range that is created by KASLR before
the start of the kernel image, there's no need to be conservative with
the KASLR offset.
This commit is contained in:
Idan Horowitz 2022-03-22 19:10:17 +02:00 • committed by Idan Horowitz
parent e0c7727934
commit f0166efe8c
6 changed files with 5 additions and 8 deletions
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3
Kernel/Memory/PageDirectory.cpp
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@ -36,7 +36,8 @@ UNMAP_AFTER_INIT NonnullRefPtr<PageDirectory> PageDirectory::must_create_kernel_
{
auto directory = adopt_ref_if_nonnull(new (nothrow) PageDirectory).release_nonnull();
MUST(directory->m_range_allocator.initialize_with_range(VirtualAddress(default_kernel_load_base), KERNEL_PD_END - default_kernel_load_base));
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;