diff --git a/pintos/include/userprog/process.h b/pintos/include/userprog/process.h
index ece3420..3167ebd 100644
--- a/pintos/include/userprog/process.h
+++ b/pintos/include/userprog/process.h
@@ -9,6 +9,7 @@ int process_exec (void *f_name);
 int process_wait (tid_t);
 void process_exit (void);
 void process_activate (struct thread *next);
+bool lazy_load_segment(struct page *page, void *aux);
 
 #endif /* userprog/process.h */
 
diff --git a/pintos/include/vm/file.h b/pintos/include/vm/file.h
index cf1b8b4..56e4b17 100644
--- a/pintos/include/vm/file.h
+++ b/pintos/include/vm/file.h
@@ -3,10 +3,12 @@
 #include "filesys/file.h"
 #include "vm/vm.h"
 
+
 struct page;
 enum vm_type;
 
 struct file_page {
+	void *aux;
 };
 
 void vm_file_init (void);
diff --git a/pintos/include/vm/vm.h b/pintos/include/vm/vm.h
index 3d0da9e..0d1e14f 100644
--- a/pintos/include/vm/vm.h
+++ b/pintos/include/vm/vm.h
@@ -51,6 +51,7 @@ struct page {
 	/* Your implementation */
 	struct hash_elem hash_elem; 
 	bool writable;
+	unsigned page_length;
          
 	/* Per-type data are binded into the union.
 	 * Each function automatically detects the current union */
diff --git a/pintos/userprog/exception.c b/pintos/userprog/exception.c
index bc3760f..e5b9ef2 100644
--- a/pintos/userprog/exception.c
+++ b/pintos/userprog/exception.c
@@ -7,6 +7,7 @@
 #include "threads/vaddr.h"
 #include "intrinsic.h"
 
+
 /* Number of page faults processed. */
 static long long page_fault_cnt;
 
@@ -153,6 +154,15 @@ page_fault (struct intr_frame *f) {
 		return;
 	}
 
+	/* my_entry가 NULL이 아닌지 확인하는 안전장치가 있으면 좋습니다. */
+
+    if (thread_current()->my_entry != NULL) {
+        thread_current()->my_entry->exit_status = -1;
+    }
+    
+    thread_exit();
+
+
 	/* Count page faults. */
 	page_fault_cnt++;
 
diff --git a/pintos/userprog/process.c b/pintos/userprog/process.c
index 7af0d1a..3dc3e30 100644
--- a/pintos/userprog/process.c
+++ b/pintos/userprog/process.c
@@ -600,7 +600,10 @@ bool lazy_load_segment(struct page *page, void *aux) {
     if (success)
         memset(kva + info->page_read_bytes, 0, info->page_zero_bytes);
 
-    free (info);
+
+    if (VM_TYPE(page->uninit.type) != VM_FILE)
+        free(info); 
+     
     return true;
 }
 
diff --git a/pintos/userprog/syscall.c b/pintos/userprog/syscall.c
index dacc945..8204059 100644
--- a/pintos/userprog/syscall.c
+++ b/pintos/userprog/syscall.c
@@ -50,6 +50,8 @@ static void syscall_seek(int fd, unsigned position);
 static unsigned syscall_tell(int fd);
 static void syscall_close(int fd);
 static int syscall_dup2(int oldfd, int newfd);
+static void *syscall_mmap(void *addr, size_t length, int writable, int fd, off_t offset);
+static void sys_munmap (void *addr);
 
 void syscall_init(void) {
     write_msr(MSR_STAR, ((uint64_t)SEL_UCSEG - 0x10) << 48 | ((uint64_t)SEL_KCSEG) << 32);
@@ -65,7 +67,7 @@ void syscall_init(void) {
 /* The main system call interface */
 void syscall_handler(struct intr_frame* f) {
     thread_current()->tf = *f;
-    uint64_t arg1 = f->R.rdi, arg2 = f->R.rsi, arg3 = f->R.rdx;
+    uint64_t arg1 = f->R.rdi, arg2 = f->R.rsi, arg3 = f->R.rdx, arg4 = f->R.r10, arg5 = f->R.r8;
     switch (f->R.rax) {
         case SYS_HALT:
             syscall_halt();
@@ -112,6 +114,12 @@ void syscall_handler(struct intr_frame* f) {
         case SYS_DUP2:
             f->R.rax = syscall_dup2(arg1, arg2);
             break;
+        case SYS_MMAP:
+            f->R.rax = syscall_mmap(arg1, arg2, arg3, arg4, arg5);
+            break;
+        case SYS_MUNMAP:
+            sys_munmap(arg1);
+            break;
     }
 }
 
@@ -260,3 +268,27 @@ static int syscall_dup2(int oldfd, int newfd) {
     lock_release(&file_lock);
     return result;
 }
+
+static void *syscall_mmap(void *addr, size_t length, int writable, int fd, off_t offset) {
+    struct file *file;
+
+    if (fd == 0 || fd == 1) {
+        return NULL;
+    }
+
+    file = get_fd_entry(thread_current(), fd);
+    if (file == NULL) {
+        return NULL;
+    }
+
+    if (addr == 0 || length == 0 || addr == NULL || pg_ofs(addr) || pg_ofs(offset)) {
+		return NULL;
+	}
+
+    return do_mmap(addr, length, writable, file, offset);
+}
+
+static void sys_munmap (void *addr) {
+
+    do_munmap(addr);
+}
diff --git a/pintos/vm/file.c b/pintos/vm/file.c
index 5f7eba9..4c4772e 100644
--- a/pintos/vm/file.c
+++ b/pintos/vm/file.c
@@ -1,6 +1,11 @@
 /* file.c: Implementation of memory backed file object (mmaped object). */
 
 #include "vm/vm.h"
+#include "threads/vaddr.h"
+#include "userprog/process.h"
+#include "threads/malloc.h"
+#include "threads/mmu.h"
+
 
 static bool file_backed_swap_in (struct page *page, void *kva);
 static bool file_backed_swap_out (struct page *page);
@@ -19,13 +24,16 @@ void
 vm_file_init (void) {
 }
 
-/* Initialize the file backed page */
-bool
-file_backed_initializer (struct page *page, enum vm_type type, void *kva) {
-	/* Set up the handler */
+bool file_backed_initializer (struct page *page, enum vm_type type, void *kva) {
 	page->operations = &file_ops;
+	lazy_load_info *aux;
+
+	aux = page->uninit.aux;
 
 	struct file_page *file_page = &page->file;
+	file_page->aux = aux;
+
+	return true;
 }
 
 /* Swap in the page by read contents from the file. */
@@ -40,19 +48,98 @@ file_backed_swap_out (struct page *page) {
 	struct file_page *file_page UNUSED = &page->file;
 }
 
-/* Destory the file backed page. PAGE will be freed by the caller. */
-static void
-file_backed_destroy (struct page *page) {
-	struct file_page *file_page UNUSED = &page->file;
+
+static void file_backed_destroy (struct page *page) {
+	struct file_page *file_page = &page->file;
+	lazy_load_info *aux = file_page->aux;
+
+	if (pml4_is_dirty(thread_current()->pml4, page->va)) {
+		file_write_at(aux->file, page->frame->kva, aux->page_read_bytes, aux->ofs);
+		pml4_set_dirty(thread_current()->pml4, page->va, 0);
+	}
+
+	if (aux->file) {
+		file_close(aux->file);
+	}
+
+	free(aux);
 }
 
-/* Do the mmap */
-void *
-do_mmap (void *addr, size_t length, int writable,
-		struct file *file, off_t offset) {
+void *do_mmap (void *addr, size_t length, int writable, struct file *file, off_t offset) {
+	void *cur = addr;
+	unsigned count = 0;
+	struct page *head_page = NULL;
+
+	while (cur - addr < length) {
+
+		if (is_kernel_vaddr(cur) || spt_find_page(&thread_current()->spt, cur) != NULL) {
+			return NULL;
+		}
+
+		cur += PGSIZE;
+		count++;
+	}
+
+	cur = addr;
+	while (length > 0) {
+		struct lazy_load_info* aux = malloc(sizeof *aux);
+		size_t page_read_bytes = length < PGSIZE ? length : PGSIZE;
+        size_t page_zero_bytes = PGSIZE - page_read_bytes;
+
+        if (aux == NULL) 
+            return NULL;
+
+        aux->file = file_reopen(file);  
+
+        if (aux->file == NULL) {
+            free(aux);
+            return NULL;
+        }
+
+        aux->ofs = offset;
+		aux->page_read_bytes = page_read_bytes;
+		aux->page_zero_bytes = page_zero_bytes;
+
+		if (!vm_alloc_page_with_initializer(VM_FILE, cur, writable, lazy_load_segment, aux)) {
+			file_close(aux->file);
+			free(aux);
+			return NULL;
+		}
+
+		if (cur == addr) {
+			head_page = spt_find_page(&thread_current()->spt, addr);
+			head_page->page_length = count;
+		}
+
+		cur += PGSIZE;
+		offset += page_read_bytes;
+		length -= page_read_bytes;
+	}
+
+	return addr;
 }
 
-/* Do the munmap */
-void
-do_munmap (void *addr) {
+void do_munmap (void *addr) {
+	
+	struct page *head_page;
+	void *current;
+	unsigned count;
+	struct supplemental_page_table *spt;
+
+	spt = &thread_current()->spt;
+	head_page = spt_find_page(spt, addr);
+	if (head_page == NULL) {
+		return;
+	} 
+
+	count = head_page->page_length;
+	current = addr;
+
+	for (int i = 0; i < count; i++) {
+		struct page *page = spt_find_page(spt, current);
+		if (page != NULL) {
+			spt_remove_page(spt, page);
+		}
+		current += PGSIZE;
+	}
 }