pagetable lab initialized

kernel/trap.c

@@ -68,8 +68,8 @@ usertrap(void)
   } else if((which_dev = devintr()) != 0){
     // ok
   } else {
-    printf("usertrap(): unexpected scause %p pid=%d\n", r_scause(), p->pid);
-    printf("            sepc=%p stval=%p\n", r_sepc(), r_stval());
+    printf("usertrap(): unexpected scause 0x%lx pid=%d\n", r_scause(), p->pid);
+    printf("            sepc=0x%lx stval=0x%lx\n", r_sepc(), r_stval());
     setkilled(p);
   }
 
@@ -145,13 +145,13 @@ kerneltrap()
     panic("kerneltrap: interrupts enabled");
 
   if((which_dev = devintr()) == 0){
-    printf("scause %p\n", scause);
-    printf("sepc=%p stval=%p\n", r_sepc(), r_stval());
+    // interrupt or trap from an unknown source
+    printf("scause=0x%lx sepc=0x%lx stval=0x%lx\n", scause, r_sepc(), r_stval());
     panic("kerneltrap");
   }
 
   // give up the CPU if this is a timer interrupt.
-  if(which_dev == 2 && myproc() != 0 && myproc()->state == RUNNING)
+  if(which_dev == 2 && myproc() != 0)
     yield();
 
   // the yield() may have caused some traps to occur,
@@ -163,10 +163,17 @@ kerneltrap()
 void
 clockintr()
 {
-  acquire(&tickslock);
-  ticks++;
-  wakeup(&ticks);
-  release(&tickslock);
+  if(cpuid() == 0){
+    acquire(&tickslock);
+    ticks++;
+    wakeup(&ticks);
+    release(&tickslock);
+  }
+
+  // ask for the next timer interrupt. this also clears
+  // the interrupt request. 1000000 is about a tenth
+  // of a second.
+  w_stimecmp(r_time() + 1000000);
 }
 
 // check if it's an external interrupt or software interrupt,
@@ -179,8 +186,7 @@ devintr()
 {
   uint64 scause = r_scause();
 
-  if((scause & 0x8000000000000000L) &&
-     (scause & 0xff) == 9){
+  if(scause == 0x8000000000000009L){
     // this is a supervisor external interrupt, via PLIC.
 
     // irq indicates which device interrupted.
@@ -201,18 +207,9 @@ devintr()
       plic_complete(irq);
 
     return 1;
-  } else if(scause == 0x8000000000000001L){
-    // software interrupt from a machine-mode timer interrupt,
-    // forwarded by timervec in kernelvec.S.
-
-    if(cpuid() == 0){
-      clockintr();
-    }
-    
-    // acknowledge the software interrupt by clearing
-    // the SSIP bit in sip.
-    w_sip(r_sip() & ~2);
-
+  } else if(scause == 0x8000000000000005L){
+    // timer interrupt.
+    clockintr();
     return 2;
   } else {
     return 0;