Nigel/BarinkOS
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FAT Filesystem implementation additions

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This commit is contained in:
Nigel Barink
2023-10-27 18:07:11 +02:00
parent 64c87a2a58
commit e82392e9d9
7 changed files with 101 additions and 74 deletions
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56
kernel/memory/VirtualMemoryManager.cpp
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@ -1,4 +1,6 @@
#include "VirtualMemoryManager.h"
#include "../../CoreLib/Memory.h"
#define ALIGN(addr, align) (((addr) & ~((align) - 1 )) + (align))
extern uint32_t boot_page_directory[1024] ; // points to the wrong location
@ -14,7 +16,7 @@ void flush_cr3(){
void AllocatePage(uint32_t vaddr)
{
uint32_t page_aligned_address = ALIGN(vaddr, 4096);
//uint32_t page_aligned_address = ALIGN(vaddr, 4096);
// allocate a page at virtual address
int PageDirectoryEntryIndex = vaddr >> 22;
@ -54,16 +56,16 @@ void AllocatePage(uint32_t vaddr)
void FreePage(uint32_t vaddr )
{
uint32_t page_aligned_address = ALIGN(vaddr, 4096);
// uint32_t page_aligned_address = ALIGN(vaddr, 4096);
// allocate a page at virtual address
int PageDirectoryEntryIndex = vaddr >> 22;
int PageTableEntryIndex = (vaddr >> 12) & 0x1FFF;
uint32_t* pageTable = (uint32_t*)(boot_page_directory[PageDirectoryEntryIndex] & 0xFFFFE000 + 0xC0000000);
uint32_t* pageTable = (uint32_t*)(boot_page_directory[PageDirectoryEntryIndex] & (0xFFFFE000 + 0xC0000000));
void* physicalAddressToFree = (void*)(pageTable[PageTableEntryIndex] & 0xFFFFE000 + 0xC0000000);
void* physicalAddressToFree = (void*)(pageTable[PageTableEntryIndex] & (0xFFFFE000 + 0xC0000000));
free_block(physicalAddressToFree);
pageTable[PageTableEntryIndex] = 0x0;
@ -80,9 +82,9 @@ void Immediate_Map ( uint32_t vaddr, uint32_t paddr)
int PageTableEntryIndex = (vaddr >> 12) & 0x1FFF;
printf("Map address at PDE 0x%x PTE 0x%x\n", PageDirectoryEntryIndex, PageTableEntryIndex);
if ((boot_page_directory - 0xC0000000)[PageDirectoryEntryIndex] & 0x1 )
{
printf("boot pagedirectoy address: 0x%x\n", &boot_page_directory);
printf("PDE : 0x%x\n", boot_page_directory[PageTableEntryIndex]);
if (boot_page_directory[PageDirectoryEntryIndex] & 0x1 ) {
printf("Directory entry is marked as present\n");
} else {
@ -90,37 +92,39 @@ void Immediate_Map ( uint32_t vaddr, uint32_t paddr)
// mark the page table as present and allocate a physical block for it
void* new_page_dir = allocate_block();
printf("New page directory address 0x%x\n", new_page_dir);
memset(new_page_dir, 0 , 1024 * sizeof (uint32_t));
printf("New page directory address 0x%x\n", &new_page_dir);
boot_page_directory[PageDirectoryEntryIndex] = (uint32_t)new_page_dir | 0x3;
}
printf("PDE found at : 0x%x\n", (uint32_t) &boot_page_directory[PageDirectoryEntryIndex]);
uint32_t* page_table = (uint32_t*)(boot_page_directory[PageDirectoryEntryIndex] & 0xFFFFE000) ;
//page_table = (uint32_t*) ((uint32_t)page_table - 0xC0000000); // remove kernel offset
printf("Page table address: 0x%x\n", (uint32_t)page_table);
uint32_t* page_table = (uint32_t*)(boot_page_directory[PageDirectoryEntryIndex] & 0xFFFFE000) ;
printf("Page table address: 0x%x\n", (uint32_t)page_table);
// check if the page table entry is marked as present
if ( page_table[PageTableEntryIndex] & 0x1 )
{
printf("page already present!\n");
printf("Entry found at addr: 0x%x\n", &(page_table[PageTableEntryIndex]));
} else{
printf("Mapping a physical page.\n");
// Map the entry to a physical page
page_table[PageTableEntryIndex] = (uint32_t)(paddr | 0x3);
}
// check if the page table entry is marked as present
if ( page_table[PageTableEntryIndex] & 0x1 )
{
printf("page already present!\n");
printf("Entry found at addr: 0x%x\n", &(page_table[PageTableEntryIndex]));
} else{
printf("Mapping a physical page.\n");
// Map the entry to a physical page
page_table[PageTableEntryIndex] = (uint32_t)(paddr | 0x3);
}
asm ("cli; invlpg (%0); sti" :: "r" (vaddr) : "memory" );
asm ("invlpg (%0)" :: "r" (vaddr) : "memory" );
}
// NOT IMPLEMENTED
void Immediate_Unmap(uint32_t vaddr)
{
// NOTE: I will implement lazy unmapping for now
uint32_t page_aligned_address = ALIGN(vaddr, 4096);
//uint32_t page_aligned_address = ALIGN(vaddr, 4096);
// allocate a page at virtual address
int PageDirectoryEntryIndex = vaddr >> 22;
int PageTableEntryIndex = (vaddr >> 12) & 0x1FFF;
//int PageDirectoryEntryIndex = vaddr >> 22;
//int PageTableEntryIndex = (vaddr >> 12) & 0x1FFF;
}