1 #include "types.h" 2 #include "defs.h" 3 #include "param.h" 4 #include "mmu.h" 5 #include "proc.h" 6 #include "x86.h" 7 #include "traps.h" 8 #include "spinlock.h" 9 10 // Interrupt descriptor table (shared by all CPUs). 11 struct gatedesc idt[256]; 12 extern uint vectors[]; // in vectors.S: array of 256 entry pointers 13 struct spinlock tickslock; 14 int ticks; 15 16 void 17 tvinit(void) 18 { 19 int i; 20 21 for(i = 0; i < 256; i++) 22 SETGATE(idt[i], 0, SEG_KCODE<<3, vectors[i], 0); 23 SETGATE(idt[T_SYSCALL], 1, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER); 24 25 initlock(&tickslock, "time"); 26 } 27 28 void 29 idtinit(void) 30 { 31 lidt(idt, sizeof(idt)); 32 } 33 34 //PAGEBREAK: 41 35 void 36 trap(struct trapframe *tf) 37 { 38 if(tf->trapno == T_SYSCALL){ 39 if(proc->killed) 40 exit(); 41 proc->tf = tf; 42 syscall(); 43 if(proc->killed) 44 exit(); 45 return; 46 } 47 48 switch(tf->trapno){ 49 case T_IRQ0 + IRQ_TIMER: 50 if(cpu->id == 0){ 51 acquire(&tickslock); 52 ticks++; 53 wakeup(&ticks); 54 release(&tickslock); 55 } 56 lapiceoi(); 57 break; 58 case T_IRQ0 + IRQ_IDE: 59 ideintr(); 60 lapiceoi(); 61 break; 62 case T_IRQ0 + IRQ_KBD: 63 kbdintr(); 64 lapiceoi(); 65 break; 66 case T_IRQ0 + IRQ_COM1: 67 uartintr(); 68 lapiceoi(); 69 break; 70 case T_IRQ0 + 7: 71 case T_IRQ0 + IRQ_SPURIOUS: 72 cprintf("cpu%d: spurious interrupt at %x:%x\n", 73 cpu->id, tf->cs, tf->eip); 74 lapiceoi(); 75 break; 76 77 default: 78 if(proc == 0 || (tf->cs&3) == 0){ 79 // In kernel, it must be our mistake. 80 cprintf("unexpected trap %d from cpu %d eip %x\n", 81 tf->trapno, cpu->id, tf->eip); 82 panic("trap"); 83 } 84 // In user space, assume process misbehaved. 85 cprintf("pid %d %s: trap %d err %d on cpu %d eip %x -- kill proc\n", 86 proc->pid, proc->name, tf->trapno, tf->err, cpu->id, tf->eip); 87 proc->killed = 1; 88 } 89 90 // Force process exit if it has been killed and is in user space. 91 // (If it is still executing in the kernel, let it keep running 92 // until it gets to the regular system call return.) 93 if(proc && proc->killed && (tf->cs&3) == DPL_USER) 94 exit(); 95 96 // Force process to give up CPU on clock tick. 97 // If interrupts were on while locks held, would need to check nlock. 98 if(proc && proc->state == RUNNING && tf->trapno == T_IRQ0+IRQ_TIMER) 99 yield(); 100 101 // Check if the process has been killed since we yielded 102 if(proc && proc->killed && (tf->cs&3) == DPL_USER) 103 exit(); 104 } 105