xv6-cs450/main.c
Robert Morris 1afc9d3fca add some comments
find out the hard way why user and kernel must have separate segment descriptors
2010-08-05 21:16:55 -04:00

105 lines
2.6 KiB
C

#include "types.h"
#include "defs.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
static void bootothers(void);
static void mpmain(void);
void jkstack(void) __attribute__((noreturn));
void mainc(void);
// Bootstrap processor starts running C code here.
int
main(void)
{
mpinit(); // collect info about this machine
lapicinit(mpbcpu());
ksegment(); // set up segments
picinit(); // interrupt controller
ioapicinit(); // another interrupt controller
consoleinit(); // I/O devices & their interrupts
uartinit(); // serial port
pminit(); // discover how much memory there is
jkstack(); // call mainc() on a properly-allocated stack
}
void
jkstack(void)
{
char *kstack = kalloc(PGSIZE);
if (!kstack)
panic("jkstack\n");
char *top = kstack + PGSIZE;
asm volatile("movl %0,%%esp" : : "r" (top));
asm volatile("call mainc");
panic("jkstack");
}
void
mainc(void)
{
cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
kvmalloc(); // initialze the kernel page table
pinit(); // process table
tvinit(); // trap vectors
binit(); // buffer cache
fileinit(); // file table
iinit(); // inode cache
ideinit(); // disk
if(!ismp)
timerinit(); // uniprocessor timer
userinit(); // first user process
bootothers(); // start other processors
// Finish setting up this processor in mpmain.
mpmain();
}
// Common CPU setup code.
// Bootstrap CPU comes here from mainc().
// Other CPUs jump here from bootother.S.
static void
mpmain(void)
{
if(cpunum() != mpbcpu()) {
ksegment();
lapicinit(cpunum());
}
vminit(); // turn on paging
cprintf("cpu%d: starting\n", cpu->id);
idtinit(); // load idt register
xchg(&cpu->booted, 1);
scheduler(); // start running processes
}
static void
bootothers(void)
{
extern uchar _binary_bootother_start[], _binary_bootother_size[];
uchar *code;
struct cpu *c;
char *stack;
// Write bootstrap code to unused memory at 0x7000. The linker has
// placed the start of bootother.S there.
code = (uchar *) 0x7000;
memmove(code, _binary_bootother_start, (uint)_binary_bootother_size);
for(c = cpus; c < cpus+ncpu; c++){
if(c == cpus+cpunum()) // We've started already.
continue;
// Fill in %esp, %eip and start code on cpu.
stack = kalloc(KSTACKSIZE);
*(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpmain;
lapicstartap(c->id, (uint)code);
// Wait for cpu to finish mpmain()
while(c->booted == 0)
;
}
}