From cd12eea3c739bc08f0d1a4492073d2ff18f4c453 Mon Sep 17 00:00:00 2001
From: rsc <rsc>
Date: Fri, 8 Sep 2006 14:29:58 +0000
Subject: [PATCH] make trap fit on one page
---
trap.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/trap.c b/trap.c
index 0505c5f..d632ed6 100644
--- a/trap.c
+++ b/trap.c
@@ -9,10 +9,8 @@
// Interrupt descriptor table (shared by all CPUs).
struct gatedesc idt[256];
-
extern uint vectors[]; // in vectors.S: array of 256 entry pointers
-
void
tvinit(void)
{
@@ -46,8 +44,7 @@ trap(struct trapframe *tf)
}
// Increment nlock to make sure interrupts stay off
- // during interrupt handler. Must decrement before
- // returning.
+ // during interrupt handler. Decrement before returning.
cpus[cpu()].nlock++;
switch(v){
@@ -55,11 +52,9 @@ trap(struct trapframe *tf)
lapic_timerintr();
cpus[cpu()].nlock--;
if(cp){
- // Force process exit if it has been killed
- // and the interrupt came from user space.
- // (If the kernel was executing at time of interrupt,
- // don't kill the process. Let the process get back
- // out to its regular system call return.)
+ // Force process exit if it has been killed and is in user space.
+ // (If it is still executing in the kernel, let it keep running
+ // until it gets to the regular system call return.)
if((tf->cs&3) == 3 && cp->killed)
proc_exit();
@@ -85,14 +80,13 @@ trap(struct trapframe *tf)
default:
if(curproc[cpu()]) {
- // assume process caused unexpected trap,
- // for example by dividing by zero or dereferencing a bad pointer
+ // Assume process divided by zero or dereferenced null, etc.
cprintf("pid %d: unhandled trap %d on cpu %d eip %x -- kill proc\n",
curproc[cpu()]->pid, v, cpu(), tf->eip);
proc_exit();
}
- // otherwise it's our mistake
+ // Otherwise it's our mistake.
cprintf("unexpected trap %d from cpu %d eip %x\n", v, cpu(), tf->eip);
panic("trap");
}
--
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