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Kernel: MMU now takes flags when allocating pages

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Bananymous
2023-03-01 20:15:58 +02:00
parent 7d84f290a1
commit 9756de02ef
5 changed files with 70 additions and 54 deletions
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69
kernel/arch/x86_64/MMU.cpp
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@@ -2,15 +2,12 @@
#include <kernel/kmalloc.h>
#include <kernel/MMU.h>
#define PRESENT (1 << 0)
#define READ_WRITE (1 << 1)
#define PAGE_SIZE 0x1000
#define PAGE_MASK ~(PAGE_SIZE - 1)
#define CLEANUP_STRUCTURE(s) \
for (uint64_t i = 0; i < 512; i++) \
if (s[i] & PRESENT) \
if (s[i] & Flags::Present) \
goto cleanup_done; \
kfree(s)
@@ -42,17 +39,17 @@ MMU::MMU()
m_highest_paging_struct = allocate_page_aligned_page();
uint64_t* pdpt = allocate_page_aligned_page();
m_highest_paging_struct[0] = (uint64_t)pdpt | READ_WRITE | PRESENT;
m_highest_paging_struct[0] = (uint64_t)pdpt | Flags::ReadWrite | Flags::Present;
uint64_t* pd = allocate_page_aligned_page();
pdpt[0] = (uint64_t)pd | READ_WRITE | PRESENT;
pdpt[0] = (uint64_t)pd | Flags::ReadWrite | Flags::Present;
for (uint32_t i = 0; i < 2; i++)
{
uint64_t* pt = allocate_page_aligned_page();
for (uint64_t j = 0; j < 512; j++)
pt[j] = (i << 21) | (j << 12) | READ_WRITE | PRESENT;
pd[i] = (uint64_t)pt | READ_WRITE | PRESENT;
pt[j] = (i << 21) | (j << 12) | Flags::ReadWrite | Flags::Present;
pd[i] = (uint64_t)pt | Flags::ReadWrite | Flags::Present;
}
// Unmap 0 -> 4 KiB
@@ -68,17 +65,17 @@ MMU::~MMU()
uint64_t* pml4 = m_highest_paging_struct;
for (uint32_t pml4e = 0; pml4e < 512; pml4e++)
{
if (!(pml4[pml4e] & PRESENT))
if (!(pml4[pml4e] & Flags::Present))
continue;
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_MASK);
for (uint32_t pdpte = 0; pdpte < 512; pdpte++)
{
if (!(pdpt[pdpte] & PRESENT))
if (!(pdpt[pdpte] & Flags::Present))
continue;
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_MASK);
for (uint32_t pde = 0; pde < 512; pde++)
{
if (!(pd[pde] & PRESENT))
if (!(pd[pde] & Flags::Present))
continue;
kfree((void*)(pd[pde] & PAGE_MASK));
}
@@ -89,10 +86,13 @@ MMU::~MMU()
kfree(pml4);
}
void MMU::allocate_page(uintptr_t address)
void MMU::allocate_page(uintptr_t address, uint8_t flags)
{
ASSERT((address >> 48) == 0);
ASSERT(flags & Flags::Present);
bool should_invalidate = false;
address &= PAGE_MASK;
uint64_t pml4e = (address >> 39) & 0x1FF;
@@ -101,40 +101,49 @@ void MMU::allocate_page(uintptr_t address)
uint64_t pte = (address >> 12) & 0x1FF;
uint64_t* pml4 = m_highest_paging_struct;
if (!(pml4[pml4e] & PRESENT))
if ((pml4[pml4e] & flags) != flags)
{
uint64_t* pdpt = allocate_page_aligned_page();
pml4[pml4e] = (uint64_t)pdpt | READ_WRITE | PRESENT;
if (!(pml4[pml4e] & Flags::Present))
pml4[pml4e] = (uint64_t)allocate_page_aligned_page();
pml4[pml4e] = (pml4[pml4e] & PAGE_MASK) | flags;
should_invalidate = true;
}
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_MASK);
if (!(pdpt[pdpte] & PRESENT))
if ((pdpt[pdpte] & flags) != flags)
{
uint64_t* pd = allocate_page_aligned_page();
pdpt[pdpte] = (uint64_t)pd | READ_WRITE | PRESENT;
if (!(pdpt[pdpte] & Flags::Present))
pdpt[pdpte] = (uint64_t)allocate_page_aligned_page();
pdpt[pdpte] = (pdpt[pdpte] & PAGE_MASK) | flags;
should_invalidate = true;
}
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_MASK);
if (!(pd[pde] & PRESENT))
if ((pd[pde] & flags) != flags)
{
uint64_t* pt = allocate_page_aligned_page();
pd[pde] = (uint64_t)pt | READ_WRITE | PRESENT;
if (!(pd[pde] & Flags::Present))
pd[pde] = (uint64_t)allocate_page_aligned_page();
pd[pde] = (pd[pde] & PAGE_MASK) | flags;
should_invalidate = true;
}
uint64_t* pt = (uint64_t*)(pd[pde] & PAGE_MASK);
if (!(pt[pte] & PRESENT))
if ((pt[pte] & flags) != flags)
{
pt[pte] = address | READ_WRITE | PRESENT;
asm volatile("invlpg (%0)" :: "r"(address) : "memory");
pt[pte] = address | flags;
should_invalidate = true;
}
if (should_invalidate)
asm volatile("invlpg (%0)" :: "r"(address) : "memory");
}
void MMU::allocate_range(uintptr_t address, ptrdiff_t size)
void MMU::allocate_range(uintptr_t address, ptrdiff_t size, uint8_t flags)
{
uintptr_t s_page = address & PAGE_MASK;
uintptr_t e_page = (address + size - 1) & PAGE_MASK;
for (uintptr_t page = s_page; page <= e_page; page += PAGE_SIZE)
allocate_page(page);
allocate_page(page, flags);
}
void MMU::unallocate_page(uintptr_t address)
@@ -149,19 +158,19 @@ void MMU::unallocate_page(uintptr_t address)
uint64_t pte = (address >> 12) & 0x1FF;
uint64_t* pml4 = m_highest_paging_struct;
if (!(pml4[pml4e] & PRESENT))
if (!(pml4[pml4e] & Flags::Present))
return;
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_MASK);
if (!(pdpt[pdpte] & PRESENT))
if (!(pdpt[pdpte] & Flags::Present))
return;
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_MASK);
if (!(pd[pde] & PRESENT))
if (!(pd[pde] & Flags::Present))
return;
uint64_t* pt = (uint64_t*)(pd[pde] & PAGE_MASK);
if (!(pt[pte] & PRESENT))
if (!(pt[pte] & Flags::Present))
return;
pt[pte] = 0;