fix race in holding() check in acquire()

give cpu1 a TSS and gdt for when it enters scheduler()
and a pseudo proc[] entry for each cpu
cpu0 waits for each other cpu to start up
read() for files

1 files changed, 9 insertions, 7 deletions

diff --git a/trap.c b/trap.c
index ccbc754..7031223 100644
--- a/trap.c
+++ b/trap.c
@@ -34,6 +34,14 @@ void
 trap(struct trapframe *tf)
 {
   int v = tf->trapno;
+  
+  if(cpus[cpu()].nlock){
+    cprintf("trap v %d eip %x cpu %d nlock %d\n",
+            v, tf->eip, cpu(), cpus[cpu()].nlock);
+    panic("interrupt while holding a lock");
+  }
+  if((read_eflags() & FL_IF) == 0)
+    panic("interrupt but interrupts now disabled");
 
   if(v == T_SYSCALL){
     struct proc *cp = curproc[cpu()];
@@ -61,16 +69,13 @@ trap(struct trapframe *tf)
       panic("trap ret esp wrong");
     if(cp->killed)
       proc_exit();
+    // XXX probably ought to lgdt on trap return
     return;
   }
 
   if(v == (IRQ_OFFSET + IRQ_TIMER)){
     struct proc *cp = curproc[cpu()];
     lapic_timerintr();
-    if(cpus[cpu()].nlock)
-      panic("timer interrupt while holding a lock");
-    if((read_eflags() & FL_IF) == 0)
-      panic("timer interrupt but interrupts now disabled");
     if(cp){
       // Force process exit if it has been killed
       // and the interrupt came from user space.
@@ -92,8 +97,5 @@ trap(struct trapframe *tf)
     return;
   }
 
-
-  // XXX probably ought to lgdt on trap return
-
   return;
 }