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Kernel: Add fast write perm remove to page tables

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Bananymous
2026-04-03 01:54:22 +03:00
parent 7d8f7753d5
commit c09bca56f9
3 changed files with 103 additions and 0 deletions
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42
kernel/arch/i686/PageTable.cpp
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@@ -470,6 +470,48 @@ namespace Kernel
invalidate_range(vaddr, page_count, true);
}
void PageTable::remove_writable_from_range(vaddr_t vaddr, size_t size)
{
ASSERT(vaddr);
ASSERT(vaddr % PAGE_SIZE == 0);
uint32_t pdpte = (vaddr >> 30) & 0x1FF;
uint32_t pde = (vaddr >> 21) & 0x1FF;
uint32_t pte = (vaddr >> 12) & 0x1FF;
const uint32_t e_pdpte = ((vaddr + size - 1) >> 30) & 0x1FF;
const uint32_t e_pde = ((vaddr + size - 1) >> 21) & 0x1FF;
const uint32_t e_pte = ((vaddr + size - 1) >> 12) & 0x1FF;
SpinLockGuard _(m_lock);
const uint64_t* pdpt = P2V(m_highest_paging_struct);
for (; pdpte <= e_pdpte; pdpte++)
{
if (!(pdpt[pdpte] & Flags::Present))
continue;
const uint64_t* pd = P2V(pdpt[pdpte] & s_page_addr_mask);
for (; pde < 512; pde++)
{
if (pdpte == e_pdpte && pde > e_pde)
break;
if (!(pd[pde] & Flags::ReadWrite))
continue;
uint64_t* pt = P2V(pd[pde] & s_page_addr_mask);
for (; pte < 512; pte++)
{
if (pdpte == e_pdpte && pde == e_pde && pte > e_pte)
break;
pt[pte] &= ~static_cast<uint64_t>(Flags::ReadWrite);
}
pte = 0;
}
pde = 0;
}
invalidate_range(vaddr, size / PAGE_SIZE, true);
}
uint64_t PageTable::get_page_data(vaddr_t vaddr) const
{
ASSERT(vaddr % PAGE_SIZE == 0);