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Add a bootstrap physical memory manager.

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This will allow the real physical memory manager to use allocations.
This commit is contained in:
Drew Galbraith 2023-05-18 11:00:05 -07:00
parent 747c2a4e17
commit 2d719d0443
5 changed files with 105 additions and 6 deletions
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34
zion/memory/paging_util.cpp
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@ -2,6 +2,7 @@
#include "boot/boot_info.h"
#include "debug/debug.h"
#include "memory/physical_memory.h"
#define PRESENT_BIT 0x1
#define READ_WRITE_BIT 0x2
@ -39,6 +40,31 @@ uint64_t ShiftForEntryIndexing(uint64_t addr, uint64_t offset) {
addr <<= 3;
return addr;
}
void MapPage(uint64_t virt, uint64_t phys) {
if (PageLoaded(virt)) {
panic("Allocating Over Existing Page: %m", virt);
}
if (!PageDirectoryPointerLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*Pml4Entry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
ZeroOutPage(PageDirectoryPointerEntry(virt));
}
if (!PageDirectoryLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*PageDirectoryPointerEntry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
ZeroOutPage(PageDirectoryEntry(virt));
}
if (!PageTableLoaded(virt)) {
uint64_t page = phys_mem::AllocatePage();
*PageDirectoryEntry(virt) = page | PRESENT_BIT | READ_WRITE_BIT;
ZeroOutPage(PageTableEntry(virt));
}
*PageTableEntry(virt) = PageAlign(phys) | PRESENT_BIT | READ_WRITE_BIT;
ZeroOutPage(reinterpret_cast<uint64_t*>(virt));
}
} // namespace
void InitPaging() {
@ -55,10 +81,10 @@ void InitializePml4(uint64_t pml4_physical_addr) {
pml4_virtual[0x1FE] = recursive_entry;
}
void AllocatePageDirectoryPointer(uint64_t addr);
void AllocatePageDirectory(uint64_t addr);
void AllocatePageTable(uint64_t addr);
void AllocatePage(uint64_t addr) { panic("Page Allocation Not Implemented."); }
void AllocatePage(uint64_t addr) {
uint64_t physical_page = phys_mem::AllocatePage();
MapPage(addr, physical_page);
}
void EnsureResident(uint64_t addr, uint64_t size) {
uint64_t max = addr + size;