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fixing up paging issues

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slinky55
2026-06-15 18:09:04 -04:00
parent ac4b510221
commit 25da0f6a71
7 changed files with 101 additions and 85 deletions
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36
kernel/memory/mm.c
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@@ -13,8 +13,6 @@ static uint32_t max_address = 0;
static uint32_t total_available_memory = 0;
static uint8_t memory_bitmap[BITMAP_SIZE];
uint32_t* page_directory;
static void mark_free(uint32_t addr) {
uint32_t page_index = addr / PAGE_SIZE;
uint32_t byte_index = page_index / 8;
@@ -56,8 +54,10 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
continue;
}
uint32_t kernel_phys_start = (uint32_t)&__kernel_start - 0xC0000000;
uint32_t kernel_phys_end = (uint32_t)&__kernel_end - 0xC0000000;
for (uint32_t addr = usable_start; addr < usable_end; addr += 4096) {
if (addr <= (uint32_t)&__kernel_end && addr >= (uint32_t)&__kernel_start) {
if (addr <= (uint32_t)&kernel_phys_end && addr >= (uint32_t)&kernel_phys_start) {
continue;
}
@@ -78,7 +78,7 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
}
}
void init_mm(void* mmap_base, uint32_t mmap_limit) {
void init_pmm(void* mmap_base, uint32_t mmap_limit) {
for (int i = 0; i < BITMAP_SIZE; i++) {
memory_bitmap[i] = 0xFF;
}
@@ -92,7 +92,8 @@ uint32_t total_free_memory() {
return total_available_memory;
}
void* alloc_page() {
// this returns the virtual address of the physical page allocated
void* alloc_phys_page() {
for (uint32_t i = 0; i < BITMAP_SIZE; i++) {
uint8_t b = memory_bitmap[i];
if (b == 0xFF) {
@@ -103,7 +104,7 @@ void* alloc_page() {
if ((b & (1 << bit)) == 0) {
uint32_t page_addr = (i * 8 + bit) * PAGE_SIZE;
mark_used(page_addr);
return (void*)page_addr;
return (void*)(page_addr + 0xC0000000);
}
}
}
@@ -111,22 +112,19 @@ void* alloc_page() {
return 0;
}
void free_page(void* addr) {
void free_phys_page(void* addr) {
mark_free((uint32_t)addr);
}
void init_paging() {
page_directory = alloc_page();
extern uint32_t page_directory[1024];
extern void flush_tlb();
extern void disable_pae();
void init_page_tables() {
uint32_t* kernel_table = alloc_phys_page();
for (int i = 0; i < 1024; i++) {
page_directory[i] = 0x0;
kernel_table[i] = (i * PAGE_SIZE) | 0x3;
}
uint32_t* page_table = alloc_page();
page_directory[0] = (uint32_t)(page_table) | 0x3;
for (int i = 0; i < 1024; i++) {
page_table[i] = (i * PAGE_SIZE) | 0x3;
}
extern void load_page_directory(uint32_t* pd);
load_page_directory(page_directory);
uint32_t* phys_table = kernel_table - 0xC000000;
page_directory[768] = (uint32_t)(phys_table) | 0x3;
flush_tlb();
}