main.c

   1 #include "types.h"
   2 #include "defs.h"
   3 #include "param.h"
   4 #include "mmu.h"
   5 #include "proc.h"
   6 #include "x86.h"
   7
   8 static void bootothers(void);
   9 static void mpmain(void);
  10 void jmpkstack(void)  __attribute__((noreturn));
  11 void mainc(void);
  12
  13 // Bootstrap processor starts running C code here.
  14 // Allocate a real stack and switch to it, first
  15 // doing some setup required for memory allocator to work.
  16 int
  17 main(void)
  18 {
  19   mpinit();        // collect info about this machine
  20   lapicinit(mpbcpu());
  21   seginit();       // set up segments
  22   kinit();         // initialize memory allocator
  23   jmpkstack();       // call mainc() on a properly-allocated stack
  24 }
  25
  26 void
  27 jmpkstack(void)
  28 {
  29   char *kstack, *top;
  30
  31   kstack = kalloc();
  32   if(kstack == 0)
  33     panic("jmpkstack kalloc");
  34   top = kstack + PGSIZE;
  35   asm volatile("movl %0,%%esp; call mainc" : : "r" (top));
  36   panic("jmpkstack");
  37 }
  38
  39 // Set up hardware and software.
  40 // Runs only on the boostrap processor.
  41 void
  42 mainc(void)
  43 {
  44   cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
  45   picinit();       // interrupt controller
  46   ioapicinit();    // another interrupt controller
  47   consoleinit();   // I/O devices & their interrupts
  48   uartinit();      // serial port
  49   kvmalloc();      // initialize the kernel page table
  50   pinit();         // process table
  51   tvinit();        // trap vectors
  52   binit();         // buffer cache
  53   fileinit();      // file table
  54   iinit();         // inode cache
  55   ideinit();       // disk
  56   if(!ismp)
  57     timerinit();   // uniprocessor timer
  58   userinit();      // first user process
  59   bootothers();    // start other processors
  60
  61   // Finish setting up this processor in mpmain.
  62   mpmain();
  63 }
  64
  65 // Common CPU setup code.
  66 // Bootstrap CPU comes here from mainc().
  67 // Other CPUs jump here from bootother.S.
  68 static void
  69 mpmain(void)
  70 {
  71   if(cpunum() != mpbcpu()){
  72     seginit();
  73     lapicinit(cpunum());
  74   }
  75   vmenable();        // turn on paging
  76   cprintf("cpu%d: starting\n", cpu->id);
  77   idtinit();       // load idt register
  78   xchg(&cpu->booted, 1); // tell bootothers() we're up
  79   scheduler();     // start running processes
  80 }
  81
  82 // Start the non-boot processors.
  83 static void
  84 bootothers(void)
  85 {
  86   extern uchar _binary_bootother_start[], _binary_bootother_size[];
  87   uchar *code;
  88   struct cpu *c;
  89   char *stack;
  90
  91   // Write bootstrap code to unused memory at 0x7000.
  92   // The linker has placed the image of bootother.S in
  93   // _binary_bootother_start.
  94   code = (uchar*)0x7000;
  95   memmove(code, _binary_bootother_start, (uint)_binary_bootother_size);
  96
  97   for(c = cpus; c < cpus+ncpu; c++){
  98     if(c == cpus+cpunum())  // We've started already.
  99       continue;
 100
 101     // Tell bootother.S what stack to use and the address of mpmain;
 102     // it expects to find these two addresses stored just before
 103     // its first instruction.
 104     stack = kalloc();
 105     *(void**)(code-4) = stack + KSTACKSIZE;
 106     *(void**)(code-8) = mpmain;
 107
 108     lapicstartap(c->id, (uint)code);
 109
 110     // Wait for cpu to finish mpmain()
 111     while(c->booted == 0)
 112       ;
 113   }
 114 }
 115
 116 // Blank page.
 117