feat: refactor syscall fork -> clone

kernel/src/main.rs

@@ -63,7 +63,7 @@ fn run_test() -> ! {
         "getppid",
         "chdir",
         "open",
-        // "clone",
+        "clone",
         "mount",
         "exit",
         "sleep",

kernel/src/syscall/mod.rs

@@ -14,7 +14,7 @@ const SYSCALL_GET_TIME: usize = 169;
 const SYSCALL_BRK: usize = 214;
 const SYSCALL_GETPID: usize = 172;
 const SYSCALL_GETPPID: usize = 173;
-const SYSCALL_FORK: usize = 220;
+const SYSCALL_CLONE: usize = 220;
 const SYSCALL_EXEC: usize = 221;
 const SYSCALL_WAITPID: usize = 260;
 const SYSCALL_GETCWD: usize = 17;
@@ -40,7 +40,7 @@ pub fn syscall(id: usize, args: [usize; 6]) -> isize {
         SYSCALL_BRK => sys_brk(args[0] as i32),
         SYSCALL_GETPID => sys_getpid(),
         SYSCALL_GETPPID => sys_getppid(),
-        SYSCALL_FORK => sys_fork(),
+        SYSCALL_CLONE => sys_clone(args[0], args[1]),
         SYSCALL_EXEC => sys_exec(args[0] as *const u8, args[1] as *const u8),
         SYSCALL_WAITPID => sys_waitpid(args[0] as isize, args[1] as *mut i32, args[2]),
         SYSCALL_GETCWD => sys_getcwd(args[0] as *mut u8, args[1]),

kernel/src/syscall/process.rs

@@ -62,12 +62,16 @@ pub fn sys_getppid() -> isize {
     parent_pid as isize
 }
 
-pub fn sys_fork() -> isize {
+pub fn sys_clone(flags: usize, sp: usize) -> isize {
+    const SIGCHLD: usize = 17;
+
     let current_task = task::get_processor().current();
     let new_task = current_task.fork();
     let new_pid = new_task.get_pid();
-    let trap_cx = new_task.get_trap_cx_mut();
-    trap_cx.set_a0(0);
+    if flags != SIGCHLD || sp != 0 {
+        new_task.get_trap_cx_mut().set_sp(sp as usize);
+    }
+    new_task.get_trap_cx_mut().set_a0(0);
     task::add_task(new_task);
 
     new_pid as isize