#include "types.h"

#include "defs.h"

#include "param.h"

#include "memlayout.h"

#include "mmu.h"

#include "spinlock.h"

#include "rwlock.h"

#include "proc.h"

#include "x86.h"

static void startothers(void);

static void mpmain(void) __attribute__((noreturn));

extern pde_t *kpgdir;

// Bootstrap processor starts running C code here.

// Allocate a real stack and switch to it, first

// doing some setup required for memory allocator to work.

int

main(void)

{

kvmalloc(); // kernel page table

mpinit(); // collect info about this machine

lapicinit(mpbcpu());

seginit(); // set up segments

cprintf("\ncpu%d: starting xv6\n\n", cpu->id);

picinit(); // interrupt controller

ioapicinit(); // another interrupt controller

consoleinit(); // I/O devices & their interrupts

uartinit(); // serial port

pinit(); // process table

tvinit(); // trap vectors

binit(); // buffer cache

fileinit(); // file table

iinit(); // inode cache

ideinit(); // disk

if(!ismp)

timerinit(); // uniprocessor timer

startothers(); // start other processors (must come before kinit)

kinit(); // initialize memory allocator

userinit(); // first user process (must come after kinit)

// Finish setting up this processor in mpmain.

mpmain();

}

// Other CPUs jump here from entryother.S.

static void

mpenter(void)

{

switchkvm();

seginit();

lapicinit(cpunum());

mpmain();

}

// Common CPU setup code.

static void

mpmain(void)

{

cprintf("cpu%d: starting\n", cpu->id);

idtinit(); // load idt register

xchg(&cpu->started, 1); // tell startothers() we're up

scheduler(); // start running processes

}

pde_t entrypgdir[]; // For entry.S

// Start the non-boot (AP) processors.

static void

startothers(void)

{

extern uchar _binary_entryother_start[], _binary_entryother_size[];

uchar *code;

struct cpu *c;

char *stack;

// Write entry code to unused memory at 0x7000.

// The linker has placed the image of entryother.S in

// _binary_entryother_start.

code = p2v(0x7000);

memmove(code, _binary_entryother_start, (uint)_binary_entryother_size);

for(c = cpus; c < cpus+ncpu; c++){

if(c == cpus+cpunum()) // We've started already.

continue;

// Tell entryother.S what stack to use, where to enter, and what

// pgdir to use. We cannot use kpgdir yet, because the AP processor

// is running in low memory, so we use entrypgdir for the APs too.

// kalloc can return addresses above 4Mbyte (the machine may have

// much more physical memory than 4Mbyte), which aren't mapped by

// entrypgdir, so we must allocate a stack using enter_alloc();

// this introduces the constraint that xv6 cannot use kalloc until

// after these last enter_alloc invocations.

stack = enter_alloc();

*(void**)(code-4) = stack + KSTACKSIZE;

*(void**)(code-8) = mpenter;

*(int**)(code-12) = (void *) v2p(entrypgdir);

lapicstartap(c->id, v2p(code));

// wait for cpu to finish mpmain()

while(c->started == 0)

;

}

}

// Boot page table used in entry.S and entryother.S.

// Page directories (and page tables), must start on a page boundary,

// hence the "__aligned__" attribute.

// Use PTE_PS in page directory entry to enable 4Mbyte pages.

__attribute__((__aligned__(PGSIZE)))

pde_t entrypgdir[NPDENTRIES] = {

// Map VA's [0, 4MB) to PA's [0, 4MB)

[0] = (0) + PTE_P + PTE_W + PTE_PS,

// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)

[KERNBASE>>PDXSHIFT] = (0) + PTE_P + PTE_W + PTE_PS,

};

//PAGEBREAK!

// Blank page.