8a8be1b8c3
fix acquire() to cli() *before* incrementing nlock make T_SYSCALL a trap gate, not an interrupt gate sadly, various crashes if you hold down a keyboard key...
112 lines
2.5 KiB
C
112 lines
2.5 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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extern uint vectors[]; /* vectors.S, array of 256 entry point addresses */
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extern void trapenter(void);
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extern void trapenter1(void);
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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], 1, SEG_KCODE << 3, vectors[i], 0);
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}
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SETGATE(idt[T_SYSCALL], 1, SEG_KCODE << 3, vectors[48], 3);
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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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int v = tf->trapno;
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if(cpus[cpu()].nlock){
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cprintf("trap v %d eip %x cpu %d nlock %d\n",
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v, tf->eip, cpu(), cpus[cpu()].nlock);
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panic("interrupt while holding a lock");
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}
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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->eax;
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if((read_eflags() & FL_IF) == 0)
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panic("syscall but interrupts now disabled");
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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() < (uint)cp->kstack ||
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read_esp() >= (uint)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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// XXX probably ought to lgdt on trap return
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return;
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}
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//if(read_eflags() & FL_IF)
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//panic("interrupt but interrupts enabled");
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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(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->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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if(v == (IRQ_OFFSET + IRQ_KBD)){
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kbd_intr();
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return;
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}
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cprintf("trap %d\n", v);
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return;
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}
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