disable interrupts when holding kernel lock

f7cea12b · kaashoek · bd303ed0 · f7cea12b · f7cea12b · f7cea12b
--- a/defs.h
+++ b/defs.h
@@ -41,6 +41,7 @@ void lapic_init(int);
 void lapic_timerinit(void);
 void lapic_timerintr(void);
 void lapic_enableintr(void);
+void lapic_disableintr(void);
 // spinlock.c
 extern uint32_t kernel_lock;

--- a/mp.c
+++ b/mp.c
@@ -183,6 +183,12 @@ lapic_enableintr(void)
  lapic_write(LAPIC_TPR, 0);
 }
+void
+lapic_disableintr(void) 
+{
+  lapic_write(LAPIC_TPR, 0xFF);
+}
 int
 cpu(void)
 {

--- a/spinlock.c
+++ b/spinlock.c
@@ -14,6 +14,8 @@ acquire_spinlock(uint32_t* lock)
  if (*lock == cpu_id)
    return;
+  lapic_disableintr();
  while ( cmpxchg(LOCK_FREE, cpu_id, lock) != cpu_id ) { ; }
  // cprintf ("acquired: %d\n", cpu_id);
 }
@@ -26,6 +28,7 @@ release_spinlock(uint32_t* lock)
  if (*lock != cpu_id)
    panic("release_spinlock: releasing a lock that i don't own\n");
  *lock = LOCK_FREE;
+  lapic_enableintr();
 }
 void