system/serenity
system/serenity
1
0
Fork 0
mirror of https://github.com/SerenityOS/serenity synced 2024-10-08 00:50:32 +00:00
Code Issues Packages Projects Releases Wiki Activity

Kernel: Automatically populate page tables with lazy kernel regions.

Browse source 
If we get an NP page fault in a process, and the fault address is in the
kernel address range (anywhere above 0xc0000000), we probably just need
to copy the page table info over from the kernel page directory.

The kernel doesn't allocate address space until it's needed, and when it
does allocate some, it only puts the info in the kernel page directory,
and any *new* page directories created from that point on. Existing page
directories need to be updated, and that's what this patch fixes.
This commit is contained in:
Andreas Kling 2019-06-26 22:27:41 +02:00
parent 183205d51c
commit 8f3f5ac8ce
1 changed files with 8 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
Kernel/VM/MemoryManager.cpp
View file

@ -405,6 +405,14 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
dbgprintf("MM: handle_page_fault(%w) at L%x\n", fault.code(), fault.vaddr().get());
#endif
ASSERT(fault.vaddr() != m_quickmap_addr);
if (fault.is_not_present() && fault.vaddr().get() >= 0xc0000000) {
dword page_directory_index = (fault.vaddr().get() >> 22) & 0x3ff;
if (kernel_page_directory().entries()[page_directory_index].is_present()) {
current->process().page_directory().entries()[page_directory_index].copy_from({}, kernel_page_directory().entries()[page_directory_index]);
dbgprintf("NP(kernel): copying new kernel mapping for L%x into process\n", fault.vaddr().get());
return PageFaultResponse::Continue;
}
}
auto* region = region_from_vaddr(current->process(), fault.vaddr());
if (!region) {
kprintf("NP(error) fault at invalid address L%x\n", fault.vaddr().get());