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#include "types.h"
#include "defs.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
#include "traps.h"
#include "spinlock.h"
// Interrupt descriptor table (shared by all CPUs).
struct gatedesc idt[256];
extern uint vectors[]; // in vectors.S: array of 256 entry pointers
struct spinlock tickslock;
uint ticks;
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], 1, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER);
initlock(&tickslock, "time");
}
void
idtinit(void)
{
lidt(idt, sizeof(idt));
}
void
trap(struct trapframe *tf)
{
if(tf->trapno == T_SYSCALL){
if(proc->killed)
exit();
proc->tf = tf;
syscall();
if(proc->killed)
exit();
return;
}
switch(tf->trapno){
case T_IRQ0 + IRQ_TIMER:
if(cpu->id == 0){
acquire(&tickslock);
ticks++;
wakeup(&ticks);
release(&tickslock);
}
lapiceoi();
break;
case T_IRQ0 + IRQ_IDE:
ideintr();
lapiceoi();
break;
case T_IRQ0 + IRQ_IDE+1:
// Bochs generates spurious IDE1 interrupts.
break;
case T_IRQ0 + IRQ_KBD:
kbdintr();
lapiceoi();
break;
case T_IRQ0 + IRQ_COM1:
uartintr();
lapiceoi();
break;
case T_IRQ0 + 7:
case T_IRQ0 + IRQ_SPURIOUS:
cprintf("cpu%d: spurious interrupt at %x:%x\n",
cpu->id, tf->cs, tf->eip);
lapiceoi();
break;
default:
if(proc == 0 || (tf->cs&3) == 0){
// In kernel, it must be our mistake.
cprintf("unexpected trap %d from cpu %d eip %x (cr2=0x%x)\n",
tf->trapno, cpu->id, tf->eip, rcr2());
panic("trap");
}
// In user space, assume process misbehaved.
cprintf("pid %d %s: trap %d err %d on cpu %d "
"eip 0x%x addr 0x%x--kill proc\n",
proc->pid, proc->name, tf->trapno, tf->err, cpu->id, tf->eip,
rcr2());
proc->killed = 1;
}
// 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(proc && proc->killed && (tf->cs&3) == DPL_USER)
exit();
// Force process to give up CPU on clock tick.
// If interrupts were on while locks held, would need to check nlock.
if(proc && proc->state == RUNNING && tf->trapno == T_IRQ0+IRQ_TIMER)
yield();
// Check if the process has been killed since we yielded
if(proc && proc->killed && (tf->cs&3) == DPL_USER)
exit();
}
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