2006-06-12 17:22:12 +02:00
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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 18:02:20 +02:00
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#include "traps.h"
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#include "syscall.h"
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2006-06-22 22:47:23 +02:00
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#include "elf.h"
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#include "param.h"
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2006-07-12 13:15:38 +02:00
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#include "spinlock.h"
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2006-06-12 17:22:12 +02:00
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2006-06-14 00:08:20 +02:00
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extern char edata[], end[];
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2006-09-07 16:10:52 +02:00
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extern uchar _binary__init_start[], _binary__init_size[];
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2006-06-12 17:22:12 +02:00
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2006-08-29 21:06:37 +02:00
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void process0();
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2006-08-16 03:56:00 +02:00
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2006-09-08 16:36:44 +02:00
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// Bootstrap processor starts running C code here.
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2006-07-16 18:03:51 +02:00
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// This is called main0 not main so that it can have
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// a void return type. Gcc can't handle functions named
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// main that don't return int. Really.
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void
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main0(void)
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2006-06-12 17:22:12 +02:00
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{
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2006-07-16 17:50:13 +02:00
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int i;
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2007-08-08 11:10:16 +02:00
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static int bcpu; // cannot be on stack
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2006-06-12 17:22:12 +02:00
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struct proc *p;
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2006-06-22 03:28:57 +02:00
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2006-06-14 00:08:20 +02:00
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// clear BSS
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memset(edata, 0, end - edata);
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2006-08-29 21:06:37 +02:00
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// Prevent release() from enabling interrupts.
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for(i=0; i<NCPU; i++)
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cpus[i].nlock = 1;
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2006-07-16 17:50:13 +02:00
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2006-07-12 19:00:54 +02:00
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mp_init(); // collect info about this machine
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2006-09-08 16:48:07 +02:00
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bcpu = mp_bcpu();
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// switch to bootstrap processor's stack
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2007-08-08 11:10:16 +02:00
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asm volatile("movl %0, %%esp" : : "r" (cpus[bcpu].mpstack + MPSTACK - 32));
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asm volatile("movl %0, %%ebp" : : "r" (cpus[bcpu].mpstack + MPSTACK));
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2006-07-12 19:00:54 +02:00
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2006-09-08 16:48:07 +02:00
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lapic_init(bcpu);
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2006-07-12 19:00:54 +02:00
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2006-08-29 21:06:37 +02:00
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cprintf("\ncpu%d: starting xv6\n\n", cpu());
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2006-06-12 17:22:12 +02:00
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2006-08-29 21:06:37 +02:00
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pinit(); // process table
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binit(); // buffer cache
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pic_init();
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2006-08-04 20:12:31 +02:00
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ioapic_init();
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2006-06-13 17:50:06 +02:00
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kinit(); // physical memory allocator
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2006-06-26 22:31:52 +02:00
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tvinit(); // trap vectors
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2006-08-29 21:06:37 +02:00
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idtinit(); // this CPU's interrupt descriptor table
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2006-09-06 20:43:45 +02:00
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fileinit();
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2006-08-29 21:06:37 +02:00
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iinit(); // i-node table
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2006-08-08 21:58:06 +02:00
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2006-08-16 03:56:00 +02:00
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// initialize process 0
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2006-06-12 17:22:12 +02:00
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p = &proc[0];
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2006-08-16 03:56:00 +02:00
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p->state = RUNNABLE;
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2006-08-15 17:54:53 +02:00
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p->kstack = kalloc(KSTACKSIZE);
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2006-08-16 03:56:00 +02:00
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2006-08-29 21:06:37 +02:00
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// cause proc[0] to start in kernel at process0
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p->jmpbuf.eip = (uint) process0;
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2006-08-16 03:56:00 +02:00
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p->jmpbuf.esp = (uint) (p->kstack + KSTACKSIZE - 4);
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2006-08-16 00:18:20 +02:00
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// make sure there's a TSS
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setupsegs(0);
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2006-06-12 17:22:12 +02:00
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2006-08-10 04:07:10 +02:00
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// initialize I/O devices, let them enable interrupts
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2006-08-09 18:04:04 +02:00
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console_init();
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2006-09-06 19:27:19 +02:00
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ide_init();
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2006-08-08 21:58:06 +02:00
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2006-08-29 21:06:37 +02:00
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// start other CPUs
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2006-07-12 13:15:38 +02:00
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mp_startthem();
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2006-07-12 03:48:35 +02:00
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2006-09-07 03:37:58 +02:00
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// turn on timer
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2006-09-08 17:14:43 +02:00
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if(ismp)
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lapic_timerinit();
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else
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pit8253_timerinit();
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2006-09-07 03:37:58 +02:00
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// enable interrupts on the local APIC
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2006-06-28 18:35:03 +02:00
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lapic_enableintr();
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2006-07-12 03:48:35 +02:00
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2006-09-07 04:15:28 +02:00
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// enable interrupts on this processor.
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2006-07-16 17:50:13 +02:00
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cpus[cpu()].nlock--;
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2006-07-11 19:39:45 +02:00
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sti();
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2006-06-16 22:29:25 +02:00
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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 03:07:40 +02:00
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scheduler();
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2006-06-12 17:22:12 +02:00
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}
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2006-06-22 22:47:23 +02:00
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2006-07-16 17:50:13 +02:00
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// Additional processors start here.
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2006-07-16 18:03:51 +02:00
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void
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2006-07-16 17:50:13 +02:00
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mpmain(void)
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{
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2006-08-08 21:58:06 +02:00
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cprintf("cpu%d: starting\n", cpu());
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2006-07-16 17:50:13 +02:00
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idtinit(); // CPU's idt
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2006-07-29 11:35:02 +02:00
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if(cpu() == 0)
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panic("mpmain on cpu 0");
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2006-07-16 17:50:13 +02:00
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lapic_init(cpu());
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lapic_timerinit();
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lapic_enableintr();
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2006-08-16 00:18:20 +02:00
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// make sure there's a TSS
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setupsegs(0);
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2006-08-08 21:58:06 +02:00
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2006-09-06 19:04:06 +02:00
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cpuid(0, 0, 0, 0, 0); // memory barrier
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2006-08-08 21:58:06 +02:00
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cpus[cpu()].booted = 1;
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2006-07-16 17:50:13 +02:00
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// Enable interrupts on this processor.
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cpus[cpu()].nlock--;
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sti();
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scheduler();
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}
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2006-08-16 03:56:00 +02:00
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// proc[0] starts here, called by scheduler() in the ordinary way.
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void
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2006-08-29 21:06:37 +02:00
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process0()
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2006-08-16 03:56:00 +02:00
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{
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struct proc *p0 = &proc[0];
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struct proc *p1;
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extern struct spinlock proc_table_lock;
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struct trapframe tf;
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release(&proc_table_lock);
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p0->cwd = iget(rootdev, 1);
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iunlock(p0->cwd);
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2006-09-08 17:14:43 +02:00
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// dummy user memory to make copyproc() happy.
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// must be big enough to hold the init binary.
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2006-09-08 17:09:48 +02:00
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p0->sz = PAGE;
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2006-08-29 21:06:37 +02:00
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p0->mem = kalloc(p0->sz);
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2006-08-16 03:56:00 +02:00
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// fake a trap frame as if a user process had made a system
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// call, so that copyproc will have a place for the new
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// process to return to.
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p0->tf = &tf;
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memset(p0->tf, 0, sizeof(struct trapframe));
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2007-08-08 11:02:42 +02:00
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p0->tf->es = p0->tf->ds = p0->tf->ss = (SEG_UDATA << 3) | DPL_USER;
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p0->tf->cs = (SEG_UCODE << 3) | DPL_USER;
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2006-08-16 03:56:00 +02:00
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p0->tf->eflags = FL_IF;
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p0->tf->esp = p0->sz;
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2006-08-29 21:06:37 +02:00
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p1 = copyproc(p0);
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2006-09-06 19:27:19 +02:00
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2006-09-07 16:10:52 +02:00
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load_icode(p1, _binary__init_start, (uint) _binary__init_size);
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2006-08-16 03:56:00 +02:00
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p1->state = RUNNABLE;
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2007-08-08 10:57:55 +02:00
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safestrcpy(p1->name, "init", sizeof p1->name);
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2006-08-16 03:56:00 +02:00
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proc_wait();
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panic("init exited");
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}
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2006-06-22 22:47:23 +02:00
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void
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2006-07-20 11:07:53 +02:00
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load_icode(struct proc *p, uchar *binary, uint size)
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2006-06-22 22:47:23 +02:00
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{
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2006-06-28 18:35:03 +02:00
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int i;
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2006-07-17 03:58:13 +02:00
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struct elfhdr *elf;
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struct proghdr *ph;
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2006-06-22 22:47:23 +02:00
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2006-07-17 03:58:13 +02:00
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elf = (struct elfhdr*) binary;
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2006-09-06 19:27:19 +02:00
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if(elf->magic != ELF_MAGIC)
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2006-06-28 18:35:03 +02:00
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panic("load_icode: not an ELF binary");
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2006-06-22 22:47:23 +02:00
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2006-07-16 17:41:47 +02:00
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p->tf->eip = elf->entry;
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2006-06-22 22:47:23 +02:00
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2006-06-28 18:35:03 +02:00
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// Map and load segments as directed.
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2006-07-17 03:58:13 +02:00
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ph = (struct proghdr*) (binary + elf->phoff);
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2006-09-06 19:27:19 +02:00
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for(i = 0; i < elf->phnum; i++, ph++) {
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if(ph->type != ELF_PROG_LOAD)
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2006-06-28 18:35:03 +02:00
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continue;
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2006-09-06 19:27:19 +02:00
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if(ph->va + ph->memsz < ph->va)
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2006-09-07 16:10:52 +02:00
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panic("load_icode: overflow in proghdr");
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2006-09-06 19:27:19 +02:00
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if(ph->va + ph->memsz >= p->sz)
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2006-09-07 16:10:52 +02:00
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panic("load_icode: icode too large");
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2006-06-28 18:35:03 +02:00
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// Load/clear the segment
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2006-07-16 17:41:47 +02:00
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memmove(p->mem + ph->va, binary + ph->offset, ph->filesz);
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memset(p->mem + ph->va + ph->filesz, 0, ph->memsz - ph->filesz);
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2006-06-28 18:35:03 +02:00
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}
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2006-06-22 22:47:23 +02:00
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}
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