/* Initializes the page allocator. */
void
palloc_init (void)
{
/* End of the kernel as recorded by the linker.
See kernel.lds.S. */
extern char _end;
/* Free memory. */
uint8_t *free_start = pg_round_up (&_end);
uint8_t *free_end = ptov (ram_pages * PGSIZE);
size_t free_pages = (free_end - free_start) / PGSIZE;
size_t user_pages = free_pages / 2;
size_t kernel_pages;
if (user_pages > user_page_limit)
user_pages = user_page_limit;
kernel_pages = free_pages - user_pages;
/* Give half of memory to kernel, half to user. */
init_pool (&kernel_pool, free_start, kernel_pages, "kernel pool");
init_pool (&user_pool, free_start + kernel_pages * PGSIZE,
user_pages, "user pool");
}
/*! Initializes the swap allocator. */
void swalloc_init(void)
{
uint32_t i;
swap_disk = block_get_role(BLOCK_SWAP);
swap_slots = block_size(swap_disk) / PAGE_SECTORS;
/* Initialize swap table */
uint32_t num_pages_used = sizeof(struct swap) * swap_slots;
num_pages_used = (uint32_t) pg_round_up((void *) num_pages_used) / PGSIZE;
/* Get pages for swap table */
swap_list = palloc_get_multiple(PAL_ASSERT | PAL_PAGING | PAL_ZERO, num_pages_used);
/* Initialize list */
list_init(open_swap_list);
/* Initialize swap entries */
for (i = 0; i < swap_slots; ++i)
{
swap_list[i].start_sector = i * PAGE_SECTORS;
swap_list[i].in_use = false;
list_push_back(open_swap_list, &(swap_list[i].open_elem));
}
}
static void
syscall_handler (struct intr_frame *f)
{
int32_t* esp = (int32_t*)f->esp;
/*
Any parameters passed to syscall will be above ESP, see illustration below.
Number of arguments each syscall expects is in argc[] array above.
syscall number is pointed to by ESP.
--------------------------------------
PHYS_BASE
.................
<param>
<param>
ESP ---> <syscall_number>
--------------------------------------
*/
// verify esp pointer is ok, first parameter: current thread
if(esp == NULL || verify_fix_length(esp, sizeof(esp)) == false){
sys_exit(-1);
}
// esp adress belongs to thread
if(pagedir_get_page(thread_current()->pagedir, esp) == NULL){
sys_exit(-1);
}
// ok syscall nr
int32_t syscall_nr = *esp;
if(syscall_nr < 0 || syscall_nr >= SYS_NUMBER_OF_CALLS){
sys_exit(-1);
}
// Make sure our data is not overwriting PHYS_BASE.
int expected_args = argc[syscall_nr];
unsigned long highest_addr = esp + (expected_args * sizeof(int));
if(highest_addr >= PHYS_BASE){
sys_exit(-1);
}
if(pagedir_get_page(thread_current()->pagedir, highest_addr) == NULL){
sys_exit(-1);
}
/*
int i = 1;
for(; i <= expected_args; i++){
if(verify_fix_length(&esp[i], sizeof(int) ) == false){
sys_exit(-1);
}
}
*/
DEBUG_SYSCALL("# SYSCALL received = %s\n", get_system_call_name(syscall_nr));
switch (syscall_nr)
{
case SYS_HALT:
power_off();
break;
case SYS_EXEC:
{
f->eax = SYS_EXEC_handler(esp);
}
break;
case SYS_WAIT:
{
int child_pid = *(esp + 1);
f->eax = process_wait (child_pid);
break;
}
case SYS_EXIT:
{
if(is_kernel_vaddr(pg_round_up((void*)esp[1]) )){
sys_exit(-1);
}
int exit_status = *(esp + 1);
process_exit(exit_status);
thread_exit();
break;
}
case SYS_PLIST:
process_print_list();
break;
case SYS_CREATE:
{
bool success = false;
char *name = (char*)*(esp + 1);
if(name == NULL){
sys_exit(-1);
}
unsigned initial_size = *(esp + 2);
if(verify_fix_length(esp[1], initial_size) == false){
sys_exit(-1);
}
if(verify_variable_length(esp[1]) == false){
sys_exit(-1);
}
success = filesys_create(name, initial_size);
if(success) {
DEBUG_SYSCALL("#SYS_CREATE - File with name: %s created. \n", name);
} else {
DEBUG_SYSCALL("#SYS_CREATE - filesys_create failed: file named \'%s\' already exists or internal memory allocation failed \n", name);
}
f->eax = success;
break;
}
case SYS_OPEN:
{
char *name = (char*)*(esp + 1);
if(name == NULL){
sys_exit(-1);
}
if(verify_variable_length(esp[1]) == false){
sys_exit(-1);
}
struct file *file;
file = filesys_open(name);
int retVal = -1;
if(file != NULL) {
DEBUG_SYSCALL("# SYS_OPEN - File with name: '%s' created. \n", name);
int fd = flist_add_file(file);
retVal = fd;
} else {
DEBUG_SYSCALL("# SYS_OPEN - filesys_open failed: no file named \'%s\' exists or internal memory allocation failed \n", name);
retVal = -1;
}
f->eax = retVal;
break;
}
case SYS_READ:
{
int retVal = SYS_READ_handler(esp);
f->eax = retVal;
break;
}
case SYS_CLOSE:
{
int retVal = SYS_CLOSE_handler(esp);
f->eax = retVal;
break;
}
case SYS_REMOVE:
{
int retVal = SYS_REMOVE_handler(esp);
f->eax = retVal;
break;
}
case SYS_WRITE:
{
int retVal = SYS_WRITE_handler(esp);
f->eax = retVal;
break;
}
case SYS_SEEK:
{
f->eax = SYS_SEEK_handler(esp);
break;
}
case SYS_TELL:
f->eax = SYS_TELL_handler(esp);
break;
case SYS_FILESIZE:
f->eax = SYS_FILESIZE_handler(esp);
break;
default:
{
DEBUG_SYSCALL ("Executed an unknown system call (nr: %i)!\n", syscall_nr);
DEBUG_SYSCALL ("Stack top + 0: %d\n", esp[0]);
DEBUG_SYSCALL ("Stack top + 1: %d\n", esp[1]);
thread_exit ();
}
}
}
