os gettime syscall consistent with user mod

os/src/syscall/mod.rs

@@ -14,7 +14,7 @@ pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
         SYSCALL_WRITE => sys_write(args[0], args[1] as *const u8, args[2]),
         SYSCALL_EXIT => sys_exit(args[0] as i32),
         SYSCALL_YIELD => sys_yield(),
-        SYSCALL_GET_TIME => sys_get_time(),
+        SYSCALL_GET_TIME => sys_get_time(args[0] as *mut TimeVal, args[1]),
         _ => panic!("Unsupported syscall_id: {}", syscall_id),
     }
 }

os/src/syscall/process.rs

@@ -2,7 +2,14 @@ use crate::task::{
     suspend_current_and_run_next,
     exit_current_and_run_next,
 };
-use crate::timer::get_time_ms;
+use crate::timer::get_time_us;
+
+#[repr(C)]
+#[derive(Debug)]
+pub struct TimeVal {
+    pub sec: usize,
+    pub usec: usize,
+}
 
 pub fn sys_exit(exit_code: i32) -> ! {
     println!("[kernel] Application exited with code {}", exit_code);
@@ -15,6 +22,17 @@ pub fn sys_yield() -> isize {
     0
 }
 
-pub fn sys_get_time() -> isize {
-    get_time_ms() as isize
+// pub fn sys_get_time() -> isize {
+//     get_time_ms() as isize
+// }
+
+pub fn sys_get_time(ts: *mut TimeVal, _tz: usize) -> isize {
+    let us = get_time_us();
+    unsafe {
+        *ts = TimeVal {
+            sec: us / 1_000_000,
+            usec: us % 1_000_000,
+        };
+    }
+    0
 }

os/src/timer.rs

@@ -1,16 +1,16 @@
-use riscv::register::time;
-use crate::sbi::set_timer;
 use crate::config::CLOCK_FREQ;
+use crate::sbi::set_timer;
+use riscv::register::time;
 
 const TICKS_PER_SEC: usize = 100;
-const MSEC_PER_SEC: usize = 1000;
+const MICRO_PER_SEC: usize = 1_000_000;
 
 pub fn get_time() -> usize {
     time::read()
 }
 
-pub fn get_time_ms() -> usize {
-    time::read() / (CLOCK_FREQ / MSEC_PER_SEC)
+pub fn get_time_us() -> usize {
+    time::read() / (CLOCK_FREQ / MICRO_PER_SEC)
 }
 
 pub fn set_next_trigger() {