xv6/trap.c
rtm 46bbd72f3e no more recursive locks
wakeup1() assumes you hold proc_table_lock
sleep(chan, lock) provides atomic sleep-and-release to wait for condition
ugly code in swtch/scheduler to implement new sleep
fix lots of bugs in pipes, wait, and exit
fix bugs if timer interrupt goes off in schedule()
console locks per line, not per byte
2006-07-15 12:03:57 +00:00

105 lines
2.2 KiB
C

#include "types.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
#include "syscall.h"
struct Gatedesc idt[256];
struct Pseudodesc idt_pd = { 0, sizeof(idt) - 1, (unsigned) &idt };
extern unsigned vectors[]; /* vectors.S, array of 256 entry point addresses */
extern void trapenter();
extern void trapenter1();
void
tvinit()
{
int i;
for(i = 0; i < 256; i++){
SETGATE(idt[i], 1, SEG_KCODE << 3, vectors[i], 0);
}
SETGATE(idt[T_SYSCALL], T_SYSCALL, SEG_KCODE << 3, vectors[48], 3);
}
void
idtinit()
{
asm volatile("lidt %0" : : "g" (idt_pd.pd_lim));
}
void
trap(struct Trapframe *tf)
{
int v = tf->tf_trapno;
if(cpus[cpu()].clis){
cprintf("cpu %d v %d eip %x\n", cpu(), v, tf->tf_eip);
panic("interrupt while interrupts are off");
}
if(v == T_SYSCALL){
struct proc *cp = curproc[cpu()];
int num = cp->tf->tf_regs.reg_eax;
if(cp == 0)
panic("syscall with no proc");
if(cp->killed)
proc_exit();
cp->tf = tf;
syscall();
if(cp != curproc[cpu()])
panic("trap ret wrong curproc");
if(cp->state != RUNNING)
panic("trap ret but not RUNNING");
if(tf != cp->tf)
panic("trap ret wrong tf");
if(cp->locks){
cprintf("num=%d\n", num);
panic("syscall returning locks held");
}
if(cpus[cpu()].clis)
panic("syscall returning but clis != 0");
if((read_eflags() & FL_IF) == 0)
panic("syscall returning but FL_IF clear");
if(read_esp() < (unsigned)cp->kstack ||
read_esp() >= (unsigned)cp->kstack + KSTACKSIZE)
panic("trap ret esp wrong");
if(cp->killed)
proc_exit();
return;
}
if(v == (IRQ_OFFSET + IRQ_TIMER)){
struct proc *cp = curproc[cpu()];
lapic_timerintr();
if(cp && cp->locks)
panic("timer interrupt while holding a lock");
if(cp){
#if 1
if((read_eflags() & FL_IF) == 0)
panic("timer interrupt but interrupts now disabled");
#else
cpus[cpu()].clis += 1;
sti();
#endif
if(cp->killed)
proc_exit();
if(cp->state == RUNNING)
yield();
}
return;
}
if(v == (IRQ_OFFSET + IRQ_IDE)){
ide_intr();
return;
}
// XXX probably ought to lgdt on trap return
return;
}