Change time offset to RwLock

src/arch/aarch64/device/generic_timer.rs

@@ -128,7 +128,7 @@ impl InterruptHandler for GenericTimer {
     fn irq_handler(&mut self, irq: u32, token: &mut CleanLockToken) {
         self.clear_irq();
         {
-            *time::OFFSET.lock(token.token()) += self.clk_freq as u128;
+            *time::OFFSET.write(token.token()) += self.clk_freq as u128;
         }
 
         timeout::trigger(token);

src/arch/x86_shared/interrupt/irq.rs

@@ -169,7 +169,7 @@ interrupt_stack!(pit_stack, |_stack| {
 
     let mut token = unsafe { CleanLockToken::new() };
     {
-        *time::OFFSET.lock(token.token()) += pit::RATE;
+        *time::OFFSET.write(token.token()) += pit::RATE;
     }
 
     unsafe { eoi(0) };

src/arch/x86_shared/time.rs

@@ -12,7 +12,8 @@ pub fn monotonic_absolute(token: &mut CleanLockToken) -> u128 {
         return ns;
     }
 
-    *crate::time::OFFSET.lock(token.token()) + hpet_or_pit()
+    let offset = { *crate::time::OFFSET.read(token.token()) };
+    offset + hpet_or_pit()
 }
 fn hpet_or_pit() -> u128 {
     #[cfg(feature = "acpi")]

src/time.rs

@@ -1,5 +1,5 @@
 use crate::{
-    sync::{CleanLockToken, Mutex, L1},
+    sync::{CleanLockToken, Mutex, RwLock, L1},
     syscall::error::{Error, Result, EINVAL},
 };
 
@@ -9,7 +9,7 @@ pub const NANOS_PER_SEC: u128 = 1_000_000_000;
 /// Kernel start time, measured in nanoseconds since Unix epoch
 pub static START: Mutex<L1, u128> = Mutex::new(0);
 /// Kernel up time, measured in nanoseconds since `START_TIME`
-pub static OFFSET: Mutex<L1, u128> = Mutex::new(0);
+pub static OFFSET: RwLock<L1, u128> = RwLock::new(0);
 
 pub fn monotonic(token: &mut CleanLockToken) -> u128 {
     crate::arch::time::monotonic_absolute(token)