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Create a MemoryObject class and use it to load programs.

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This commit is contained in:
Drew Galbraith 2023-06-06 21:44:10 -07:00
parent 1fda0f3fae
commit b06c76e477
9 changed files with 209 additions and 49 deletions
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82
zion/memory/paging_util.cpp
View file

@ -89,45 +89,6 @@ uint64_t PagePhysIfResident(uint64_t cr3, uint64_t virt) {
return *pt_entry & ~0xFFF;
}
uint64_t MapPage(uint64_t cr3, uint64_t virt) {
uint64_t access_bits = PRESENT_BIT | READ_WRITE_BIT;
uint64_t higher_half = 0xffff8000'00000000;
if ((virt & higher_half) != higher_half) {
access_bits |= USER_MODE_BIT;
}
uint64_t* pml4_entry = Pml4Entry(cr3, virt);
if (!(*pml4_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*pml4_entry = page | access_bits;
ZeroOutPage(PageDirectoryPointerEntry(*pml4_entry, virt));
}
uint64_t* pdp_entry = PageDirectoryPointerEntry(*pml4_entry, virt);
if (!(*pdp_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*pdp_entry = page | access_bits;
ZeroOutPage(PageDirectoryEntry(*pdp_entry, virt));
}
uint64_t* pd_entry = PageDirectoryEntry(*pdp_entry, virt);
if (!(*pd_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*(pd_entry) = page | access_bits;
ZeroOutPage(PageTableEntry(*pd_entry, virt));
}
uint64_t* pt_entry = PageTableEntry(*pd_entry, virt);
if (!(*pt_entry & PRESENT_BIT)) {
uint64_t phys = phys_mem::AllocatePage();
*pt_entry = PageAlign(phys) | access_bits;
ZeroOutPage(reinterpret_cast<uint64_t*>(boot::GetHigherHalfDirectMap() +
PageAlign(phys)));
return phys;
} else {
panic("Page already allocated.");
return 0;
}
}
uint64_t Pml4Index(uint64_t addr) { return (addr >> PML_OFFSET) & 0x1FF; }
uint64_t CurrCr3() {
@ -170,6 +131,42 @@ void InitializePml4(uint64_t pml4_physical_addr) {
pml4_virtual[Pml4Index(hhdm)] = *Pml4Entry(curr_cr3, hhdm);
}
void MapPage(uint64_t cr3, uint64_t vaddr, uint64_t paddr) {
vaddr = PageAlign(vaddr);
paddr = PageAlign(paddr);
uint64_t access_bits = PRESENT_BIT | READ_WRITE_BIT;
uint64_t higher_half = 0xffff8000'00000000;
if ((vaddr & higher_half) != higher_half) {
access_bits |= USER_MODE_BIT;
}
uint64_t* pml4_entry = Pml4Entry(cr3, vaddr);
if (!(*pml4_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*pml4_entry = page | access_bits;
ZeroOutPage(PageDirectoryPointerEntry(*pml4_entry, vaddr));
}
uint64_t* pdp_entry = PageDirectoryPointerEntry(*pml4_entry, vaddr);
if (!(*pdp_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*pdp_entry = page | access_bits;
ZeroOutPage(PageDirectoryEntry(*pdp_entry, vaddr));
}
uint64_t* pd_entry = PageDirectoryEntry(*pdp_entry, vaddr);
if (!(*pd_entry & PRESENT_BIT)) {
uint64_t page = phys_mem::AllocatePage();
*(pd_entry) = page | access_bits;
ZeroOutPage(PageTableEntry(*pd_entry, vaddr));
}
uint64_t* pt_entry = PageTableEntry(*pd_entry, vaddr);
if (!(*pt_entry & PRESENT_BIT)) {
*pt_entry = paddr | access_bits;
} else {
panic("Page already allocated.");
}
}
uint64_t AllocatePageIfNecessary(uint64_t addr, uint64_t cr3) {
if (cr3 == 0) {
cr3 = CurrCr3();
@ -178,7 +175,12 @@ uint64_t AllocatePageIfNecessary(uint64_t addr, uint64_t cr3) {
if (phys) {
return phys;
}
return MapPage(cr3, addr);
phys = phys_mem::AllocatePage();
// FIXME: Maybe move this to the physical memory allocator.
ZeroOutPage(
reinterpret_cast<uint64_t*>(boot::GetHigherHalfDirectMap() + phys));
MapPage(cr3, addr, phys);
return phys;
}
void EnsureResident(uint64_t addr, uint64_t size) {

2
zion/memory/paging_util.h
View file

@ -6,6 +6,8 @@
void InitializePml4(uint64_t pml4_physical_addr);
void MapPage(uint64_t cr3, uint64_t vaddr, uint64_t paddr);
uint64_t AllocatePageIfNecessary(uint64_t addr, uint64_t cr3 = 0);
void EnsureResident(uint64_t addr, uint64_t size);