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Kernel: Booting with higher half kernel gets to Heap initialization

This commit is contained in:
Bananymous 2023-05-30 22:21:12 +03:00
parent 93e6455171
commit 57f7da6ce1
3 changed files with 98 additions and 65 deletions
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157
kernel/arch/x86_64/PageTable.cpp
View File

@ -4,12 +4,16 @@
#include <kernel/Memory/kmalloc.h>
#include <kernel/Memory/PageTable.h>
#define KERNEL_OFFSET 0xFFFFFFFF80000000
#define V2P(vaddr) (((vaddr_t)(vaddr)) - KERNEL_OFFSET)
#define P2V(paddr) (((paddr_t)(paddr)) + KERNEL_OFFSET)
#define CLEANUP_STRUCTURE(s) \
do { \
for (uint64_t i = 0; i < 512; i++) \
if ((s)[i] & Flags::Present) \
return; \
kfree(s); \
kfree((void*)P2V(s)); \
} while (false)
extern uint8_t g_kernel_start[];
@ -21,18 +25,25 @@ namespace Kernel
static PageTable* s_kernel = nullptr;
static PageTable* s_current = nullptr;
static inline bool is_canonical(uintptr_t addr)
static constexpr inline bool is_canonical(uintptr_t addr)
{
static constexpr uintptr_t mask = 0xFFFF800000000000;
constexpr uintptr_t mask = 0xFFFF800000000000;
addr &= mask;
return addr == mask || addr == 0;
}
static inline void uncanonicalize(uintptr_t& addr)
static constexpr inline uintptr_t uncanonicalize(uintptr_t addr)
{
static constexpr uintptr_t mask = 0xFFFF800000000000;
addr &= mask;
ASSERT(addr == mask || addr == 0);
if (addr & 0x0000800000000000)
return addr & ~0xFFFF000000000000;
return addr;
}
static constexpr inline uintptr_t canonicalize(uintptr_t addr)
{
if (addr & 0x0000800000000000)
return addr | 0xFFFF000000000000;
return addr;
}
void PageTable::initialize()
@ -66,12 +77,12 @@ namespace Kernel
void PageTable::initialize_kernel()
{
m_highest_paging_struct = allocate_page_aligned_page();
memset(m_highest_paging_struct, 0, PAGE_SIZE);
m_highest_paging_struct = V2P(allocate_page_aligned_page());
memset((void*)P2V(m_highest_paging_struct), 0, PAGE_SIZE);
// Identity map 4 KiB -> kernel end. We don't map the first page since nullptr derefs should
// page fault. Also there isn't anything useful in that memory.
identity_map_range((uintptr_t)g_kernel_start, (uintptr_t)(g_kernel_end - g_kernel_start), Flags::ReadWrite | Flags::Present);
map_range_at(0, KERNEL_OFFSET, (uintptr_t)g_kernel_end - KERNEL_OFFSET, Flags::ReadWrite | Flags::Present);
}
BAN::ErrorOr<PageTable*> PageTable::create_userspace()
@ -79,9 +90,11 @@ namespace Kernel
// Here we copy the s_kernel paging structs since they are
// global for every process
ASSERT_NOT_REACHED();
LockGuard _(s_kernel->m_lock);
uint64_t* global_pml4 = s_kernel->m_highest_paging_struct;
uint64_t* global_pml4 = (uint64_t*)P2V(s_kernel->m_highest_paging_struct);
uint64_t* pml4 = allocate_page_aligned_page();
for (uint32_t pml4e = 0; pml4e < 512; pml4e++)
@ -122,13 +135,15 @@ namespace Kernel
PageTable* result = new PageTable;
if (result == nullptr)
return BAN::Error::from_errno(ENOMEM);
result->m_highest_paging_struct = pml4;
result->m_highest_paging_struct = (paddr_t)pml4;
return result;
}
PageTable::~PageTable()
{
uint64_t* pml4 = m_highest_paging_struct;
ASSERT_NOT_REACHED();
uint64_t* pml4 = (uint64_t*)P2V(m_highest_paging_struct);
for (uint32_t pml4e = 0; pml4e < 512; pml4e++)
{
if (!(pml4[pml4e] & Flags::Present))
@ -180,29 +195,30 @@ namespace Kernel
identity_map_page(page * PAGE_SIZE, flags);
}
void PageTable::unmap_page(vaddr_t address)
void PageTable::unmap_page(vaddr_t vaddr)
{
LockGuard _(m_lock);
uncanonicalize(address);
ASSERT(is_canonical(vaddr));
vaddr = uncanonicalize(vaddr);
address &= PAGE_ADDR_MASK;
vaddr &= PAGE_ADDR_MASK;
if (is_page_free(address))
if (is_page_free(vaddr))
{
dwarnln("unmapping unmapped page {8H}", address);
dwarnln("unmapping unmapped page {8H}", vaddr);
return;
}
uint64_t pml4e = (address >> 39) & 0x1FF;
uint64_t pdpte = (address >> 30) & 0x1FF;
uint64_t pde = (address >> 21) & 0x1FF;
uint64_t pte = (address >> 12) & 0x1FF;
uint64_t pml4e = (vaddr >> 39) & 0x1FF;
uint64_t pdpte = (vaddr >> 30) & 0x1FF;
uint64_t pde = (vaddr >> 21) & 0x1FF;
uint64_t pte = (vaddr >> 12) & 0x1FF;
uint64_t* pml4 = m_highest_paging_struct;
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_ADDR_MASK);
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_ADDR_MASK);
uint64_t* pt = (uint64_t*)(pd[pde] & PAGE_ADDR_MASK);
uint64_t* pml4 = (uint64_t*)P2V(m_highest_paging_struct);
uint64_t* pdpt = (uint64_t*)P2V(pml4[pml4e] & PAGE_ADDR_MASK);
uint64_t* pd = (uint64_t*)P2V(pdpt[pdpte] & PAGE_ADDR_MASK);
uint64_t* pt = (uint64_t*)P2V(pd[pde] & PAGE_ADDR_MASK);
pt[pte] = 0;
CLEANUP_STRUCTURE(pt);
@ -213,12 +229,12 @@ namespace Kernel
pml4[pml4e] = 0;
}
void PageTable::unmap_range(vaddr_t address, size_t size)
void PageTable::unmap_range(vaddr_t vaddr, size_t size)
{
LockGuard _(m_lock);
vaddr_t s_page = address / PAGE_SIZE;
vaddr_t e_page = (address + size - 1) / PAGE_SIZE;
vaddr_t s_page = vaddr / PAGE_SIZE;
vaddr_t e_page = (vaddr + size - 1) / PAGE_SIZE;
for (vaddr_t page = s_page; page <= e_page; page++)
unmap_page(page * PAGE_SIZE);
}
@ -227,8 +243,8 @@ namespace Kernel
{
LockGuard _(m_lock);
ASSERT(is_canonical(paddr));
uncanonicalize(vaddr);
ASSERT(is_canonical(vaddr));
vaddr = uncanonicalize(vaddr);
ASSERT(paddr % PAGE_SIZE == 0);
ASSERT(vaddr % PAGE_SIZE == 0);;
@ -240,59 +256,74 @@ namespace Kernel
uint64_t pde = (vaddr >> 21) & 0x1FF;
uint64_t pte = (vaddr >> 12) & 0x1FF;
uint64_t* pml4 = m_highest_paging_struct;
uint64_t* pml4 = (uint64_t*)P2V(m_highest_paging_struct);
if ((pml4[pml4e] & flags) != flags)
{
if (!(pml4[pml4e] & Flags::Present))
pml4[pml4e] = (uint64_t)allocate_page_aligned_page();
pml4[pml4e] = V2P(allocate_page_aligned_page());
pml4[pml4e] = (pml4[pml4e] & PAGE_ADDR_MASK) | flags;
}
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_ADDR_MASK);
uint64_t* pdpt = (uint64_t*)P2V(pml4[pml4e] & PAGE_ADDR_MASK);
if ((pdpt[pdpte] & flags) != flags)
{
if (!(pdpt[pdpte] & Flags::Present))
pdpt[pdpte] = (uint64_t)allocate_page_aligned_page();
pdpt[pdpte] = V2P(allocate_page_aligned_page());
pdpt[pdpte] = (pdpt[pdpte] & PAGE_ADDR_MASK) | flags;
}
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_ADDR_MASK);
uint64_t* pd = (uint64_t*)P2V(pdpt[pdpte] & PAGE_ADDR_MASK);
if ((pd[pde] & flags) != flags)
{
if (!(pd[pde] & Flags::Present))
pd[pde] = (uint64_t)allocate_page_aligned_page();
pd[pde] = V2P(allocate_page_aligned_page());
pd[pde] = (pd[pde] & PAGE_ADDR_MASK) | flags;
}
uint64_t* pt = (uint64_t*)(pd[pde] & PAGE_ADDR_MASK);
uint64_t* pt = (uint64_t*)P2V(pd[pde] & PAGE_ADDR_MASK);
pt[pte] = paddr | flags;
}
uint64_t PageTable::get_page_data(vaddr_t address) const
void PageTable::map_range_at(paddr_t paddr, vaddr_t vaddr, size_t bytes, flags_t flags)
{
LockGuard _(m_lock);
uncanonicalize(address);
ASSERT(address % PAGE_SIZE == 0);
ASSERT(is_canonical(vaddr));
uint64_t pml4e = (address >> 39) & 0x1FF;
uint64_t pdpte = (address >> 30) & 0x1FF;
uint64_t pde = (address >> 21) & 0x1FF;
uint64_t pte = (address >> 12) & 0x1FF;
ASSERT(paddr % PAGE_SIZE == 0);
ASSERT(vaddr % PAGE_SIZE == 0);
uint64_t* pml4 = m_highest_paging_struct;
for (size_t offset = 0; offset < bytes; offset += PAGE_SIZE)
map_page_at(paddr + offset, vaddr + offset, flags);
}
uint64_t PageTable::get_page_data(vaddr_t vaddr) const
{
LockGuard _(m_lock);
ASSERT(is_canonical(vaddr));
vaddr = uncanonicalize(vaddr);
ASSERT(vaddr % PAGE_SIZE == 0);
uint64_t pml4e = (vaddr >> 39) & 0x1FF;
uint64_t pdpte = (vaddr >> 30) & 0x1FF;
uint64_t pde = (vaddr >> 21) & 0x1FF;
uint64_t pte = (vaddr >> 12) & 0x1FF;
uint64_t* pml4 = (uint64_t*)P2V(m_highest_paging_struct);
if (!(pml4[pml4e] & Flags::Present))
return 0;
uint64_t* pdpt = (uint64_t*)(pml4[pml4e] & PAGE_ADDR_MASK);
uint64_t* pdpt = (uint64_t*)P2V(pml4[pml4e] & PAGE_ADDR_MASK);
if (!(pdpt[pdpte] & Flags::Present))
return 0;
uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_ADDR_MASK);
uint64_t* pd = (uint64_t*)P2V(pdpt[pdpte] & PAGE_ADDR_MASK);
if (!(pd[pde] & Flags::Present))
return 0;
uint64_t* pt = (uint64_t*)(pd[pde] & PAGE_ADDR_MASK);
uint64_t* pt = (uint64_t*)P2V(pd[pde] & PAGE_ADDR_MASK);
if (!(pt[pte] & Flags::Present))
return 0;
@ -315,22 +346,22 @@ namespace Kernel
// Try to find free page that can be mapped without
// allocations (page table with unused entries)
vaddr_t* pml4 = m_highest_paging_struct;
uint64_t* pml4 = (uint64_t*)P2V(m_highest_paging_struct);
for (uint64_t pml4e = 0; pml4e < 512; pml4e++)
{
if (!(pml4[pml4e] & Flags::Present))
continue;
vaddr_t* pdpt = (vaddr_t*)(pml4[pml4e] & PAGE_ADDR_MASK);
uint64_t* pdpt = (uint64_t*)P2V(pml4[pml4e] & PAGE_ADDR_MASK);
for (uint64_t pdpte = 0; pdpte < 512; pdpte++)
{
if (!(pdpt[pdpte] & Flags::Present))
continue;
vaddr_t* pd = (vaddr_t*)(pdpt[pdpte] & PAGE_ADDR_MASK);
uint64_t* pd = (uint64_t*)P2V(pdpt[pdpte] & PAGE_ADDR_MASK);
for (uint64_t pde = 0; pde < 512; pde++)
{
if (!(pd[pde] & Flags::Present))
continue;
vaddr_t* pt = (vaddr_t*)(pd[pde] & PAGE_ADDR_MASK);
uint64_t* pt = (uint64_t*)P2V(pd[pde] & PAGE_ADDR_MASK);
for (uint64_t pte = !(pml4e + pdpte + pde); pte < 512; pte++)
{
if (!(pt[pte] & Flags::Present))
@ -340,7 +371,7 @@ namespace Kernel
vaddr |= pdpte << 30;
vaddr |= pde << 21;
vaddr |= pte << 12;
return vaddr;
return canonicalize(vaddr);
}
}
}
@ -348,12 +379,12 @@ namespace Kernel
}
// Find any free page page (except for page 0)
vaddr_t address = PAGE_SIZE;
while ((address >> 48) == 0)
vaddr_t vaddr = PAGE_SIZE;
while ((vaddr >> 48) == 0)
{
if (!(get_page_flags(address) & Flags::Present))
return address;
address += PAGE_SIZE;
if (!(get_page_flags(vaddr) & Flags::Present))
return vaddr;
vaddr += PAGE_SIZE;
}
ASSERT_NOT_REACHED();
@ -363,20 +394,20 @@ namespace Kernel
{
LockGuard _(m_lock);
for (vaddr_t address = PAGE_SIZE; !(address >> 48); address += PAGE_SIZE)
for (vaddr_t vaddr = PAGE_SIZE; !(vaddr >> 48); vaddr += PAGE_SIZE)
{
bool valid { true };
for (size_t page = 0; page < page_count; page++)
{
if (get_page_flags(address + page * PAGE_SIZE) & Flags::Present)
if (get_page_flags(vaddr + page * PAGE_SIZE) & Flags::Present)
{
address += page * PAGE_SIZE;
vaddr += page * PAGE_SIZE;
valid = false;
break;
}
}
if (valid)
return address;
return vaddr;
}
ASSERT_NOT_REACHED();

1
kernel/arch/x86_64/boot.S
View File

@ -199,6 +199,7 @@ long_mode:
jmp *%rcx
higher_half:
addq $KERNEL_OFFSET, g_multiboot_info
# call global constuctors
call _init

3
kernel/include/kernel/Memory/PageTable.h
View File

@ -33,6 +33,7 @@ namespace Kernel
void unmap_page(vaddr_t);
void unmap_range(vaddr_t, size_t bytes);
void map_range_at(paddr_t, vaddr_t, size_t, flags_t);
void map_page_at(paddr_t, vaddr_t, flags_t);
paddr_t physical_address_of(vaddr_t) const;
@ -56,7 +57,7 @@ namespace Kernel
void initialize_kernel();
private:
uint64_t* m_highest_paging_struct { nullptr };
paddr_t m_highest_paging_struct { 0 };
mutable RecursiveSpinLock m_lock;
};