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