impl sys_set_tid_address. ignore invalid 'clear_child_tid' on exit

kernel/src/arch/x86_64/paging.rs

@@ -47,23 +47,21 @@ impl PageTable for ActivePageTable {
     fn map(&mut self, addr: usize, target: usize) -> &mut Entry {
         let flags = EF::PRESENT | EF::WRITABLE | EF::NO_EXECUTE;
         unsafe {
-            if let Ok(flush) = self.0.map_to(
+            self.0
+                .map_to(
                     Page::of_addr(addr),
                     Frame::of_addr(target),
                     flags,
                     &mut FrameAllocatorForX86,
-            ) {
-                flush.flush();
-            }
+                )
+                .unwrap()
+                .flush();
         }
         unsafe { &mut *(get_entry_ptr(addr, 1)) }
     }
 
     fn unmap(&mut self, addr: usize) {
-        // unmap and flush if it is mapped
-        if let Ok((_, flush)) = self.0.unmap(Page::of_addr(addr)) {
-            flush.flush();
-        }
+        self.0.unmap(Page::of_addr(addr)).unwrap().1.flush();
     }
 
     fn get_entry(&mut self, addr: usize) -> Option<&mut Entry> {
@@ -238,6 +236,9 @@ impl InactivePageTable for InactivePageTable0 {
 
     fn edit<T>(&mut self, f: impl FnOnce(&mut Self::Active) -> T) -> T {
         let target = Cr3::read().0.start_address().as_u64() as usize;
+        if self.p4_frame == Cr3::read().0 {
+            return f(&mut active_table());
+        }
         active_table().with_temporary_map(target, |active_table, p4_table: &mut x86PageTable| {
             let backup = p4_table[0o777].clone();
 

kernel/src/syscall/mem.rs

@@ -88,14 +88,6 @@ pub fn sys_mprotect(addr: usize, len: usize, prot: usize) -> SysResult {
     if memory_area.is_none() {
         return Err(SysError::ENOMEM);
     }
-    proc.vm.edit(|pt| {
-        for page in Page::range_of(addr, addr + len) {
-            let entry = pt
-                .get_entry(page.start_address())
-                .expect("failed to get entry");
-            attr.apply(entry);
-        }
-    });
     Ok(0)
 }
 

kernel/src/syscall/mod.rs

@@ -187,7 +187,7 @@ pub fn syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> isize {
         SYS_EXIT => sys_exit(args[0] as usize),
         SYS_EXIT_GROUP => sys_exit_group(args[0]),
         SYS_WAIT4 => sys_wait4(args[0] as isize, args[1] as *mut i32), // TODO: wait4
-        SYS_SET_TID_ADDRESS => unimplemented("set_tid_address", Ok(thread::current().id())),
+        SYS_SET_TID_ADDRESS => sys_set_tid_address(args[0] as *mut u32),
         SYS_FUTEX => sys_futex(
             args[0],
             args[1] as u32,

kernel/src/syscall/proc.rs

@@ -281,14 +281,17 @@ pub fn sys_exit(exit_code: usize) -> ! {
     // ref: http://man7.org/linux/man-pages/man2/set_tid_address.2.html
     // FIXME: do it in all possible ways a thread can exit
     //        it has memory access so we can't move it to Thread::drop?
-    let clear_child_tid = current_thread().clear_child_tid;
-    if clear_child_tid != 0 {
-        unsafe {
-            (clear_child_tid as *mut u32).write(0);
-        }
-        let queue = process().get_futex(clear_child_tid);
+    let mut proc = process();
+    let clear_child_tid = current_thread().clear_child_tid as *mut u32;
+    if !clear_child_tid.is_null() {
+        info!("exit: futex {:#?} wake 1", clear_child_tid);
+        if let Ok(clear_child_tid_ref) = unsafe { proc.vm.check_write_ptr(clear_child_tid) } {
+            *clear_child_tid_ref = 0;
+            let queue = proc.get_futex(clear_child_tid as usize);
             queue.notify_one();
         }
+    }
+    drop(proc);
 
     processor().manager().exit(tid, exit_code as usize);
     processor().yield_now();
@@ -334,6 +337,12 @@ pub fn sys_set_priority(priority: usize) -> SysResult {
     Ok(0)
 }
 
+pub fn sys_set_tid_address(tidptr: *mut u32) -> SysResult {
+    info!("set_tid_address: {:?}", tidptr);
+    current_thread().clear_child_tid = tidptr as usize;
+    Ok(thread::current().id())
+}
+
 bitflags! {
     pub struct CloneFlags: usize {
         const CSIGNAL = 0x000000ff;