Bananymous/banan-os
1
1
Fork 1
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Kernel: Add fast write perm remove to page tables

Browse Source
This commit is contained in:
Bananymous
2026-04-03 01:54:22 +03:00
parent 7d8f7753d5
commit c09bca56f9
3 changed files with 103 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
kernel/arch/i686/PageTable.cpp
View File

@@ -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);

59
kernel/arch/x86_64/PageTable.cpp
View File

@@ -793,6 +793,65 @@ 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);
ASSERT(is_canonical(vaddr));
ASSERT(is_canonical(vaddr + size - 1));
const vaddr_t uc_vaddr_start = uncanonicalize(vaddr);
const vaddr_t uc_vaddr_end = uncanonicalize(vaddr + size - 1);
uint16_t pml4e = (uc_vaddr_start >> 39) & 0x1FF;
uint16_t pdpte = (uc_vaddr_start >> 30) & 0x1FF;
uint16_t pde = (uc_vaddr_start >> 21) & 0x1FF;
uint16_t pte = (uc_vaddr_start >> 12) & 0x1FF;
const uint16_t e_pml4e = (uc_vaddr_end >> 39) & 0x1FF;
const uint16_t e_pdpte = (uc_vaddr_end >> 30) & 0x1FF;
const uint16_t e_pde = (uc_vaddr_end >> 21) & 0x1FF;
const uint16_t e_pte = (uc_vaddr_end >> 12) & 0x1FF;
SpinLockGuard _(m_lock);
const uint64_t* pml4 = P2V(m_highest_paging_struct);
for (; pml4e <= e_pml4e; pml4e++)
{
if (!(pml4[pml4e] & Flags::ReadWrite))
continue;
const uint64_t* pdpt = P2V(pml4[pml4e] & s_page_addr_mask);
for (; pdpte < 512; pdpte++)
{
if (pml4e == e_pml4e && pdpte > e_pdpte)
break;
if (!(pdpt[pdpte] & Flags::ReadWrite))
continue;
const uint64_t* pd = P2V(pdpt[pdpte] & s_page_addr_mask);
for (; pde < 512; pde++)
{
if (pml4e == e_pml4e && 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 (pml4e == e_pml4e && pdpte == e_pdpte && pde == e_pde && pte > e_pte)
break;
pt[pte] &= ~static_cast<uint64_t>(Flags::ReadWrite);
}
pte = 0;
}
pde = 0;
}
pdpte = 0;
}
invalidate_range(vaddr, size / PAGE_SIZE, true);
}
uint64_t PageTable::get_page_data(vaddr_t vaddr) const
{
ASSERT(is_canonical(vaddr));

2
kernel/include/kernel/Memory/PageTable.h
View File

@@ -106,6 +106,8 @@ namespace Kernel
void map_page_at(paddr_t, vaddr_t, flags_t, MemoryType = MemoryType::Normal, bool invalidate = true);
void map_range_at(paddr_t, vaddr_t, size_t bytes, flags_t, MemoryType = MemoryType::Normal);
void remove_writable_from_range(vaddr_t, size_t);
paddr_t physical_address_of(vaddr_t) const;
flags_t get_page_flags(vaddr_t) const;