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Kernel: On kernel NP fault, always copy into *active* page directory

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If we were using a ProcessPagingScope to temporarily go into another
process's page tables, things would fall apart when hitting a kernel
NP fault, since we'd clone the kernel page directory entry into the
*currently active process's* page directory rather than cloning it
into the *currently active* page directory.
This commit is contained in:
Andreas Kling 2019-08-06 07:28:35 +02:00
parent 2d7a993db3
commit da6c8fe3f8
1 changed files with 5 additions and 3 deletions
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8
Kernel/VM/MemoryManager.cpp
View file

@ -407,9 +407,11 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
ASSERT(fault.vaddr() != m_quickmap_addr);
if (fault.is_not_present() && fault.vaddr().get() >= 0xc0000000) {
u32 page_directory_index = (fault.vaddr().get() >> 22) & 0x3ff;
if (kernel_page_directory().entries()[page_directory_index].is_present()) {
dbgprintf("NP(kernel): copying new kernel mapping for L%x into process\n", fault.vaddr().get());
current->process().page_directory().entries()[page_directory_index].copy_from({}, kernel_page_directory().entries()[page_directory_index]);
auto& kernel_pde = kernel_page_directory().entries()[page_directory_index];
if (kernel_pde.is_present()) {
dbgprintf("NP(kernel): copying new kernel mapping for L%x into current page directory\n", fault.vaddr().get());
auto* current_page_directory = reinterpret_cast<PageDirectoryEntry*>(cpu_cr3());
current_page_directory[page_directory_index].copy_from({}, kernel_pde);
flush_tlb(fault.vaddr().page_base());
return PageFaultResponse::Continue;
}