added origin program

kernel/memory/mm.c

@@ -1,4 +1,4 @@
-#include "lib/print.h"
+#include "memory/mm.h"
 #include "multiboot.h"
 
 #include <stddef.h>
@@ -19,10 +19,6 @@ extern void disable_pae();
 
 #define TEMP_MAPPING_VADDR 0xE0000000
 
-#define PAGE_PRESENT  0x1
-#define PAGE_WRITABLE 0x2
-#define PAGE_USER     0x4
-
 static uint32_t max_address = 0;
 static uint32_t total_available_memory = 0;
 static uint8_t memory_bitmap[BITMAP_SIZE];
@@ -92,7 +88,7 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
     }
 }
 
-static void* p_alloc_frame() {
+void* p_alloc_frame() {
     for (uint32_t i = 0; i < BITMAP_SIZE; i++) {
         uint8_t b = memory_bitmap[i];
         if (b == 0xFF) {
@@ -116,7 +112,7 @@ static void p_free_frame(void* addr) {
 }
 
 // MODIFIES THE ACTIVE PAGE TABLE AT THE PHYSICAL ADDRESS LOADED INTO CR3 VIA RECURSIVE MAPPING
-static void map_page(uint32_t vaddr, uint32_t paddr, uint32_t flags) {
+void map_page(uint32_t vaddr, uint32_t paddr, uint32_t flags) {
     uint32_t pde_entry = vaddr >> 22;
     uint32_t pte_entry = (vaddr >> 12) & 0x3FF;
     uint32_t* pd = (uint32_t*)PAGE_DIRECTORY;
@@ -124,7 +120,7 @@ static void map_page(uint32_t vaddr, uint32_t paddr, uint32_t flags) {
 
     if ((pd[pde_entry] & PAGE_PRESENT) == 0) {
         uint32_t new_table = (uint32_t)p_alloc_frame();
-        pd[pde_entry] = new_table | PAGE_PRESENT | PAGE_WRITABLE;
+        pd[pde_entry] = new_table | flags;
         flush_tlb();
         for (int i = 0; i < 1024; i++) {
             tablev[i] = 0;
@@ -146,11 +142,16 @@ void init_pmm(void* mmap_base, uint32_t mmap_limit) {
 }
 
 void init_page_tables() {
-    uint32_t* kernel_table = p_alloc_frame();
-    for (int i = 0; i < 1024; i++) {
-        kernel_table[i] = (i * PAGE_SIZE) | 0x3;
+    uint32_t kernel_size = (uint32_t)&__kernel_end - (uint32_t)&__kernel_start;
+    uint32_t num_pages = kernel_size / PAGE_SIZE + 1;
+    uint32_t num_page_tables = (num_pages + 1023) / 1024;
+    for (uint32_t table = 0; table < num_page_tables; table++) {
+        uint32_t* kernel_table = p_alloc_frame();
+        for (int i = 0; i < 1024; i++) {
+            kernel_table[i] = (i * PAGE_SIZE) | 0x3;
+        }
+        page_directory[768 + table] = (uint32_t)(kernel_table) | 0x3;
     }
-    page_directory[768] = (uint32_t)(kernel_table) | 0x3;
     page_directory[0] = 0;
     disable_pae();
     flush_tlb();
@@ -171,17 +172,19 @@ void* create_user_pd() {
     uint32_t* user_pd = (uint32_t*)TEMP_MAPPING_VADDR;
     uint32_t* kernel_pd = (uint32_t*)PAGE_DIRECTORY;
 
-    for(int i = 0; i < 1024; i++) {
+    for(int i = 0; i < 768; i++) {
         user_pd[i] = 0;
     }
 
-    user_pd[768] = kernel_pd[768];
+    for(int i = 768; i < 1023; i++) {
+        user_pd[i] = kernel_pd[i];
+    }
+    
     user_pd[1023] = (uint32_t)pd_address | PAGE_PRESENT | PAGE_WRITABLE;
 
     uint32_t pde = TEMP_MAPPING_VADDR >> 22;
     uint32_t pte = (TEMP_MAPPING_VADDR >> 12) & 0x3FF; 
     uint32_t* kernel_pt = (uint32_t*)(PAGE_TABLES + (pde * PAGE_SIZE));
     kernel_pt[pte] = 0;
-    flush_tlb();
     return (void*)pd_address;
 }

kernel/memory/mm.h

@@ -3,16 +3,23 @@
 
 #include <stdint.h>
 
+#define PAGE_PRESENT  0x1
+#define PAGE_WRITABLE 0x2
+#define PAGE_USER     0x4
+
 typedef struct __attribute__((packed)) {
     uint32_t addr;
 } mem_page_t;
 
 void init_pmm(void* mmap_base, uint32_t mmap_limit);
 void init_page_tables();
-void* init_kheap();
+
+void* p_alloc_frame();
 
 uint32_t total_free_memory();
 
 void* create_user_pd();
 
+void map_page(uint32_t vaddr, uint32_t paddr, uint32_t flags);
+
 #endif 

kernel/memory/mm_stubs.S

@@ -11,4 +11,15 @@ disable_pae:
     and $0xFFFFFFEF, %edx
     mov %edx, %cr4
     ret
-    
+    
+.global load_pd
+load_pd:
+    push %ebp 
+    mov %esp, %ebp 
+    mov 8(%ebp), %eax
+    mov %eax, %cr3
+    lea flush, %ecx
+    jmp *%ecx
+flush:
+    leave
+    ret