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#include "types.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
#include "syscall.h"
#include "elf.h"
#include "param.h"
#include "spinlock.h"
extern char edata[], end[];
extern uchar _binary__init_start[], _binary__init_size[];
void process0();
// Bootstrap processor starts running C code here.
// This is called main0 not main so that it can have
// a void return type. Gcc can't handle functions named
// main that don't return int. Really.
void
main0(void)
{
int i;
static int bcpu; // cannot be on stack
struct proc *p;
// clear BSS
memset(edata, 0, end - edata);
// Prevent release() from enabling interrupts.
for(i=0; i<NCPU; i++)
cpus[i].nlock = 1;
mp_init(); // collect info about this machine
bcpu = mp_bcpu();
// switch to bootstrap processor's stack
asm volatile("movl %0, %%esp" : : "r" (cpus[bcpu].mpstack + MPSTACK - 32));
asm volatile("movl %0, %%ebp" : : "r" (cpus[bcpu].mpstack + MPSTACK));
lapic_init(bcpu);
cprintf("\ncpu%d: starting xv6\n\n", cpu());
pinit(); // process table
binit(); // buffer cache
pic_init();
ioapic_init();
kinit(); // physical memory allocator
tvinit(); // trap vectors
idtinit(); // this CPU's interrupt descriptor table
fileinit();
iinit(); // i-node table
// initialize process 0
p = &proc[0];
p->state = RUNNABLE;
p->kstack = kalloc(KSTACKSIZE);
// cause proc[0] to start in kernel at process0
p->jmpbuf.eip = (uint) process0;
p->jmpbuf.esp = (uint) (p->kstack + KSTACKSIZE - 4);
// make sure there's a TSS
setupsegs(0);
// initialize I/O devices, let them enable interrupts
console_init();
ide_init();
// start other CPUs
mp_startthem();
// turn on timer
if(ismp)
lapic_timerinit();
else
pit8253_timerinit();
// enable interrupts on the local APIC
lapic_enableintr();
// enable interrupts on this processor.
cpus[cpu()].nlock--;
sti();
scheduler();
}
// Additional processors start here.
void
mpmain(void)
{
cprintf("cpu%d: starting\n", cpu());
idtinit(); // CPU's idt
if(cpu() == 0)
panic("mpmain on cpu 0");
lapic_init(cpu());
lapic_timerinit();
lapic_enableintr();
// make sure there's a TSS
setupsegs(0);
cpuid(0, 0, 0, 0, 0); // memory barrier
cpus[cpu()].booted = 1;
// Enable interrupts on this processor.
cpus[cpu()].nlock--;
sti();
scheduler();
}
// proc[0] starts here, called by scheduler() in the ordinary way.
void
process0(void)
{
struct proc *p0 = &proc[0];
struct proc *p1;
extern struct spinlock proc_table_lock;
struct trapframe tf;
release(&proc_table_lock);
p0->cwd = iget(rootdev, 1);
iunlock(p0->cwd);
// dummy user memory to make copyproc() happy.
// must be big enough to hold the init binary.
p0->sz = PAGE;
p0->mem = kalloc(p0->sz);
// fake a trap frame as if a user process had made a system
// call, so that copyproc will have a place for the new
// process to return to.
p0->tf = &tf;
memset(p0->tf, 0, sizeof(struct trapframe));
p0->tf->es = p0->tf->ds = p0->tf->ss = (SEG_UDATA << 3) | DPL_USER;
p0->tf->cs = (SEG_UCODE << 3) | DPL_USER;
p0->tf->eflags = FL_IF;
p0->tf->esp = p0->sz;
p1 = copyproc(p0);
load_icode(p1, _binary__init_start, (uint) _binary__init_size);
p1->state = RUNNABLE;
safestrcpy(p1->name, "init", sizeof p1->name);
proc_wait();
panic("init exited");
}
void
load_icode(struct proc *p, uchar *binary, uint size)
{
int i;
struct elfhdr *elf;
struct proghdr *ph;
elf = (struct elfhdr*) binary;
if(elf->magic != ELF_MAGIC)
panic("load_icode: not an ELF binary");
p->tf->eip = elf->entry;
// Map and load segments as directed.
ph = (struct proghdr*) (binary + elf->phoff);
for(i = 0; i < elf->phnum; i++, ph++) {
if(ph->type != ELF_PROG_LOAD)
continue;
if(ph->va + ph->memsz < ph->va)
panic("load_icode: overflow in proghdr");
if(ph->va + ph->memsz >= p->sz)
panic("load_icode: icode too large");
// Load/clear the segment
memmove(p->mem + ph->va, binary + ph->offset, ph->filesz);
memset(p->mem + ph->va + ph->filesz, 0, ph->memsz - ph->filesz);
}
}
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