2006-06-13 15:50:40 +00:00
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#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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2006-06-15 16:02:20 +00:00
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#include "traps.h"
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2006-07-12 01:48:35 +00:00
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#include "syscall.h"
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2006-06-13 15:50:40 +00:00
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2006-07-17 01:58:13 +00:00
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struct gatedesc idt[256];
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2006-07-17 01:52:13 +00:00
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extern uint vectors[]; /* vectors.S, array of 256 entry point addresses */
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2006-06-13 15:50:40 +00:00
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2006-07-17 01:25:22 +00:00
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extern void trapenter(void);
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extern void trapenter1(void);
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2006-06-13 15:50:40 +00:00
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void
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2006-07-17 01:25:22 +00:00
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tvinit(void)
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2006-06-13 15:50:40 +00:00
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{
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int i;
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for(i = 0; i < 256; i++){
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2006-06-15 16:02:20 +00:00
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SETGATE(idt[i], 1, SEG_KCODE << 3, vectors[i], 0);
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2006-06-13 15:50:40 +00:00
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}
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2006-08-10 02:07:10 +00:00
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SETGATE(idt[T_SYSCALL], 1, SEG_KCODE << 3, vectors[48], 3);
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2006-06-26 20:31:52 +00:00
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}
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void
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2006-07-17 01:25:22 +00:00
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idtinit(void)
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2006-06-26 20:31:52 +00:00
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{
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2006-07-16 16:55:52 +00:00
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lidt(idt, sizeof idt);
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2006-06-13 15:50:40 +00:00
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}
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void
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2006-07-17 01:58:13 +00:00
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trap(struct trapframe *tf)
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2006-06-13 15:50:40 +00:00
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{
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2006-07-16 15:41:47 +00:00
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int v = tf->trapno;
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2006-08-08 19:58:06 +00:00
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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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2006-06-22 20:47:23 +00:00
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2006-08-15 22:18:20 +00:00
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if(curproc[cpu()] == 0){
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if(&tf < cpus[cpu()].mpstack || &tf > cpus[cpu()].mpstack + MPSTACK){
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2006-08-10 22:08:14 +00:00
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cprintf("&tf %x mpstack %x\n", &tf, cpus[cpu()].mpstack);
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panic("trap cpu stack");
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}
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} else if(curproc[cpu()]){
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if(&tf < curproc[cpu()]->kstack){
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panic("trap kstack");
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}
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}
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2006-06-15 16:02:20 +00:00
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if(v == T_SYSCALL){
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2006-07-01 21:26:01 +00:00
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struct proc *cp = curproc[cpu()];
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2006-07-17 01:36:39 +00:00
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int num = cp->tf->eax;
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2006-08-10 02:07:10 +00:00
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if((read_eflags() & FL_IF) == 0)
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panic("syscall but interrupts now disabled");
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Changes to allow use of native x86 ELF compilers, which on my
Linux 2.4 box using gcc 3.4.6 don't seem to follow the same
conventions as the i386-jos-elf-gcc compilers.
Can run make 'TOOLPREFIX=' or edit the Makefile.
curproc[cpu()] can now be NULL, indicating that no proc is running.
This seemed safer to me than having curproc[0] and curproc[1]
both pointing at proc[0] potentially.
The old implementation of swtch depended on the stack frame layout
used inside swtch being okay to return from on the other stack
(exactly the V6 you are not expected to understand this).
It also could be called in two contexts: at boot time, to schedule
the very first process, and later, on behalf of a process, to sleep
or schedule some other process.
I split this into two functions: scheduler and swtch.
The scheduler is now a separate never-returning function, invoked
by each cpu once set up. The scheduler looks like:
scheduler() {
setjmp(cpu.context);
pick proc to schedule
blah blah blah
longjmp(proc.context)
}
The new swtch is intended to be called only when curproc[cpu()] is not NULL,
that is, only on behalf of a user proc. It does:
swtch() {
if(setjmp(proc.context) == 0)
longjmp(cpu.context)
}
to save the current proc context and then jump over to the scheduler,
running on the cpu stack.
Similarly the system call stubs are now in assembly in usys.S to avoid
needing to know the details of stack frame layout used by the compiler.
Also various changes in the debugging prints.
2006-07-11 01:07:40 +00:00
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if(cp == 0)
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panic("syscall with no proc");
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2006-07-11 17:39:45 +00:00
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if(cp->killed)
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proc_exit();
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2006-07-01 21:26:01 +00:00
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cp->tf = tf;
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2006-06-15 16:02:20 +00:00
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syscall();
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2006-07-01 21:26:01 +00:00
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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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2006-07-16 01:15:28 +00:00
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if(cpus[cpu()].nlock){
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2006-07-15 12:03:57 +00:00
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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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2006-07-17 01:52:13 +00:00
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if(read_esp() < (uint)cp->kstack ||
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read_esp() >= (uint)cp->kstack + KSTACKSIZE)
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2006-07-01 21:26:01 +00:00
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panic("trap ret esp wrong");
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2006-07-11 17:39:45 +00:00
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if(cp->killed)
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proc_exit();
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2006-08-08 19:58:06 +00:00
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// XXX probably ought to lgdt on trap return
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2006-06-15 16:02:20 +00:00
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return;
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}
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2006-08-10 02:07:10 +00:00
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//if(read_eflags() & FL_IF)
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//panic("interrupt but interrupts enabled");
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2006-06-28 16:35:03 +00:00
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if(v == (IRQ_OFFSET + IRQ_TIMER)){
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2006-07-11 17:39:45 +00:00
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struct proc *cp = curproc[cpu()];
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2006-06-28 16:35:03 +00:00
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lapic_timerintr();
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2006-07-11 17:39:45 +00:00
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if(cp){
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2006-07-16 02:09:45 +00:00
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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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2006-07-16 15:41:47 +00:00
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if((tf->cs&3) == 3 && cp->killed)
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2006-07-11 17:39:45 +00:00
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proc_exit();
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2006-07-16 02:09:45 +00:00
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// Force process to give up CPU and let others run.
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2006-07-15 12:03:57 +00:00
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if(cp->state == RUNNING)
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yield();
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2006-07-11 17:39:45 +00:00
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}
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2006-06-15 16:02:20 +00:00
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return;
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}
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2006-07-12 15:35:33 +00:00
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2006-07-06 21:47:22 +00:00
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if(v == (IRQ_OFFSET + IRQ_IDE)){
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ide_intr();
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2006-08-10 22:08:14 +00:00
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if(cpus[cpu()].nlock)
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panic("ide_intr returned while holding a lock");
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cli(); // prevent a waiting interrupt from overflowing stack
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lapic_eoi();
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2006-07-06 21:47:22 +00:00
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return;
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}
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2006-06-15 16:02:20 +00:00
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2006-08-10 02:07:10 +00:00
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if(v == (IRQ_OFFSET + IRQ_KBD)){
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kbd_intr();
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2006-08-10 22:08:14 +00:00
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if(cpus[cpu()].nlock){
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panic("kbd_intr returned while holding a lock");
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}
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cli(); // prevent a waiting interrupt from overflowing stack
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lapic_eoi();
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2006-08-10 02:07:10 +00:00
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return;
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}
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2006-08-15 22:18:20 +00:00
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cprintf("trap %d from cpu %d eip %x\n", v, cpu(), tf->eip);
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2006-08-25 00:43:17 +00:00
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if(curproc[cpu()]) {
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2006-08-16 01:56:00 +00:00
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cprintf("pid %d\n", curproc[cpu()]->pid);
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2006-08-25 00:43:17 +00:00
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proc_exit();
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}
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2006-08-19 23:41:34 +00:00
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// panic("trap");
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2006-08-10 02:07:10 +00:00
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2006-06-28 16:35:03 +00:00
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return;
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2006-06-13 15:50:40 +00:00
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}
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