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#include "types.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
#include "syscall.h"
// 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)
{
int i;
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], 3);
}
void
idtinit(void)
{
lidt(idt, sizeof idt);
}
void
trap(struct trapframe *tf)
{
int v = tf->trapno;
struct proc *cp = curproc[cpu()];
if(v == T_SYSCALL){
if(cp->killed)
proc_exit();
cp->tf = tf;
syscall();
if(cp->killed)
proc_exit();
return;
}
// Increment nlock to make sure interrupts stay off
// during interrupt handler. Must decrement before
// returning.
cpus[cpu()].nlock++;
switch(v){
case IRQ_OFFSET + IRQ_TIMER:
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.)
if((tf->cs&3) == 3 && cp->killed)
proc_exit();
// Force process to give up CPU and let others run.
if(cp->state == RUNNING)
yield();
}
return;
case IRQ_OFFSET + IRQ_IDE:
ide_intr();
lapic_eoi();
break;
case IRQ_OFFSET + IRQ_KBD:
kbd_intr();
lapic_eoi();
break;
case IRQ_OFFSET + IRQ_SPURIOUS:
cprintf("spurious interrupt from cpu %d eip %x\n", cpu(), tf->eip);
break;
default:
if(curproc[cpu()]) {
// assume process caused unexpected trap,
// for example by dividing by zero or dereferencing a bad pointer
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
cprintf("unexpected trap %d from cpu %d eip %x\n", v, cpu(), tf->eip);
panic("trap");
}
cpus[cpu()].nlock--;
}
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