lab-04: mmap, munmap

os/src/syscall/process.rs

@@ -1,6 +1,8 @@
 //! Process management syscalls
 
-use crate::task::{change_program_brk, exit_current_and_run_next, suspend_current_and_run_next};
+use crate::config::PAGE_SIZE;
+use crate::mm::{MapPermission, VPNRange, VirtAddr};
+use crate::task::{change_program_brk, create_new_map_area, exit_current_and_run_next, get_current_task_page_table_entry, suspend_current_and_run_next, unmap_virtual_page};
 use crate::timer::get_time_ms;
 
 /// task exits and submit an exit code
@@ -29,3 +31,47 @@ pub fn sys_sbrk(size: i32) -> isize {
         -1
     }
 }
+
+/// map files or devices into memory
+pub fn sys_mmap(start: usize, len: usize, prot: usize) -> isize {
+    if start % PAGE_SIZE != 0 || prot & !0x7 != 0 || prot & 0x7 == 0 {
+        return -1;
+    }
+    let vpn_start = VirtAddr::from(start).floor();
+    let vpn_end = VirtAddr::from(start + len).ceil();
+    let vpn_range = VPNRange::new(vpn_start, vpn_end);
+    for vpn in vpn_range {
+        if let Some(pte) = get_current_task_page_table_entry(vpn) {
+            if pte.is_valid() {
+                return -1;
+            }
+        }
+    }
+    create_new_map_area(
+        vpn_start.into(),
+        vpn_end.into(),
+        MapPermission::from_bits_truncate((prot << 1) as u8) | MapPermission::U
+    );
+    0
+}
+
+/// unmap files or devices into memory
+pub fn sys_munmap(start: usize, len: usize) -> isize {
+    if start % PAGE_SIZE != 0 {
+        return -1;
+    }
+    let vpn_start = VirtAddr::from(start).floor();
+    let vpn_end = VirtAddr::from(start + len).ceil();
+    let vpn_range = VPNRange::new(vpn_start, vpn_end);
+    for vpn in vpn_range {
+        if let Some(pte) = get_current_task_page_table_entry(vpn) {
+            if !pte.is_valid() {
+                return -1;
+            }
+            unmap_virtual_page(vpn)
+        } else {
+            return -1;
+        }
+    }
+    0
+}