100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
#include "types.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 "defs.h"
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#include "x86.h"
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#include "traps.h"
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#include "syscall.h"
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struct Gatedesc idt[256];
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struct Pseudodesc idt_pd = { 0, sizeof(idt) - 1, (unsigned) &idt };
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extern unsigned vectors[]; /* vectors.S, array of 256 entry point addresses */
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extern void trapenter();
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extern void trapenter1();
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void
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tvinit()
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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], 1, SEG_KCODE << 3, vectors[i], 0);
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}
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SETGATE(idt[T_SYSCALL], T_SYSCALL, SEG_KCODE << 3, vectors[48], 3);
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}
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void
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idtinit()
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{
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asm volatile("lidt %0" : : "g" (idt_pd.pd_lim));
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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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int v = tf->tf_trapno;
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if(v == T_SYSCALL){
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struct proc *cp = curproc[cpu()];
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int num = cp->tf->tf_regs.reg_eax;
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if(cp == 0)
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panic("syscall with no proc");
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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 != curproc[cpu()])
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panic("trap ret wrong curproc");
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if(cp->state != RUNNING)
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panic("trap ret but not RUNNING");
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if(tf != cp->tf)
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panic("trap ret wrong tf");
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if(cpus[cpu()].nlock){
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cprintf("num=%d\n", num);
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panic("syscall returning locks held");
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}
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if((read_eflags() & FL_IF) == 0)
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panic("syscall returning but FL_IF clear");
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if(read_esp() < (unsigned)cp->kstack ||
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read_esp() >= (unsigned)cp->kstack + KSTACKSIZE)
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panic("trap ret esp wrong");
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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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if(v == (IRQ_OFFSET + IRQ_TIMER)){
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struct proc *cp = curproc[cpu()];
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lapic_timerintr();
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if(cpus[cpu()].nlock)
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panic("timer interrupt while holding a lock");
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if((read_eflags() & FL_IF) == 0)
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panic("timer interrupt but interrupts now disabled");
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if(cp){
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// Force process exit if it has been killed
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// and the interrupt came from user space.
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// (If the kernel was executing at time of interrupt,
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// don't kill the process. Let the process get back
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// out to its regular system call return.)
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if((tf->tf_cs&3) == 3 && 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(cp->state == RUNNING)
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yield();
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}
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return;
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}
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if(v == (IRQ_OFFSET + IRQ_IDE)){
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ide_intr();
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return;
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}
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// XXX probably ought to lgdt on trap return
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return;
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}
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