105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
#include "types.h"
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#include "defs.h"
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#include "param.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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int ticks;
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void
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tvinit(void)
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{
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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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SETGATE(idt[T_SYSCALL], 0, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER);
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initlock(&tickslock, "time");
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}
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void
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idtinit(void)
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{
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lidt(idt, sizeof(idt));
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}
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void
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trap(struct trapframe *tf)
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{
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if(tf->trapno == T_SYSCALL){
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if(cp->killed)
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proc_exit();
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cp->tf = tf;
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syscall();
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if(cp->killed)
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proc_exit();
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return;
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}
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// Increment nlock to make sure interrupts stay off
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// during interrupt handler. Decrement before returning.
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cpus[cpu()].nlock++;
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// PAGEBREAK: 10
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switch(tf->trapno){
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case IRQ_OFFSET + IRQ_TIMER:
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if(cpu() == 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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lapic_eoi();
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break;
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case IRQ_OFFSET + IRQ_IDE:
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ide_intr();
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lapic_eoi();
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break;
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case IRQ_OFFSET + IRQ_KBD:
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kbd_intr();
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lapic_eoi();
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break;
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case IRQ_OFFSET + IRQ_SPURIOUS:
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cprintf("spurious interrupt from cpu %d eip %x\n", cpu(), tf->eip);
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lapic_eoi();
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break;
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default:
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if(cp) {
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// Assume process divided by zero or dereferenced null, etc.
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cprintf("pid %d %s: trap %d err %d on cpu %d eip %x -- kill proc\n",
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cp->pid, cp->name, tf->trapno, tf->err, cpu(), tf->eip);
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proc_exit();
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}
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// Otherwise it's our mistake.
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cprintf("unexpected trap %d from cpu %d eip %x\n",
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tf->trapno, cpu(), tf->eip);
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panic("trap");
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}
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cpus[cpu()].nlock--;
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if(tf->trapno == IRQ_OFFSET + IRQ_TIMER && cp != 0){
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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((tf->cs&3) == DPL_USER && cp->killed)
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proc_exit();
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// Force process to give up CPU and let others run.
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// If locks were held with interrupts on, would need to check nlock.
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if(cp->state == RUNNING)
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yield();
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}
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}
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