tell SETGATE to leave interrupts on for T_SYSCALL

panic if unknown fault with CPL=0 (i.e. in kernel)

tell SETGATE to leave interrupts on for T_SYSCALL
3eda2714 · rtm · d7a90d3b · 3eda2714
--- a/trap.c
+++ b/trap.c
@@ -20,7 +20,7 @@ tvinit(void)

  for(i = 0; i < 256; i++)
    SETGATE(idt[i], 0, SEG_KCODE<<3, vectors[i], 0);
-  SETGATE(idt[T_SYSCALL], 0, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER);
+  SETGATE(idt[T_SYSCALL], 1, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER);
  
  initlock(&tickslock, "time");
 }
@@ -72,7 +72,7 @@ trap(struct trapframe *tf)
    break;
    
  default:
-    if(cp == 0){
+    if(cp == 0 || (tf->cs & 3) == 0){
      // Otherwise it's our mistake.
      cprintf("unexpected trap %d from cpu %d eip %x\n",
              tf->trapno, cpu(), tf->eip);