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Kernel: Unmap Prekernel pages after they are no longer needed

The Prekernel's memory is only accessed until MemoryManager has been
initialized. Keeping them around afterwards is both unnecessary and bad,
as it prevents the userland from using the 0x100000-0x155000 virtual
address range.

Co-authored-by: Idan Horowitz <idan.horowitz@gmail.com>
This commit is contained in:
Daniel Bertalan 2021-12-19 01:15:12 +01:00 committed by Brian Gianforcaro
parent 2f1b4b8a81
commit 4fc28bfe02
4 changed files with 31 additions and 8 deletions

View file

@ -49,19 +49,19 @@ inline FlatPtr virtual_to_low_physical(FlatPtr virtual_)
enum class UsedMemoryRangeType {
LowMemory = 0,
Prekernel,
Kernel,
BootModule,
PhysicalPages,
__Count
};
static constexpr StringView UserMemoryRangeTypeNames[] {
"Low memory",
"Prekernel",
"Kernel",
"Boot module",
"Physical Pages"
};
static_assert(array_size(UserMemoryRangeTypeNames) == to_underlying(UsedMemoryRangeType::__Count));
struct UsedMemoryRange {
UsedMemoryRangeType type {};
@ -159,6 +159,7 @@ public:
void set_page_writable_direct(VirtualAddress, bool);
void protect_readonly_after_init_memory();
void unmap_prekernel();
void unmap_text_after_init();
void protect_ksyms_after_init();
@ -276,7 +277,15 @@ private:
PageTableEntry* pte(PageDirectory&, VirtualAddress);
PageTableEntry* ensure_pte(PageDirectory&, VirtualAddress);
void release_pte(PageDirectory&, VirtualAddress, bool);
enum class IsLastPTERelease {
Yes,
No
};
enum class UnsafeIgnoreMissingPageTable {
Yes,
No
};
void release_pte(PageDirectory&, VirtualAddress, IsLastPTERelease, UnsafeIgnoreMissingPageTable = UnsafeIgnoreMissingPageTable::No);
RefPtr<PageDirectory> m_kernel_page_directory;