root/main.c

/*   */

DEFINITIONS

1. main
2. mpenter
3. mpmain
4. startothers

   1 #include "types.h"
   2 #include "defs.h"
   3 #include "param.h"
   4 #include "memlayout.h"
   5 #include "mmu.h"
   6 #include "proc.h"
   7 #include "x86.h"
   8 
   9 static void startothers(void);
  10 static void mpmain(void)  __attribute__((noreturn));
  11 extern pde_t *kpgdir;
  12 extern char end[]; // first address after kernel loaded from ELF file
  13 
  14 // Bootstrap processor starts running C code here.
  15 // Allocate a real stack and switch to it, first
  16 // doing some setup required for memory allocator to work.
  17 int
  18 main(void)
     /*   */
  19 {
  20   kinit1(end, P2V(4*1024*1024)); // phys page allocator
  21   kvmalloc();      // kernel page table
  22   mpinit();        // detect other processors
  23   lapicinit();     // interrupt controller
  24   seginit();       // segment descriptors
  25   picinit();       // disable pic
  26   ioapicinit();    // another interrupt controller
  27   consoleinit();   // console hardware
  28   uartinit();      // serial port
  29   pinit();         // process table
  30   tvinit();        // trap vectors
  31   binit();         // buffer cache
  32   fileinit();      // file table
  33   ideinit();       // disk 
  34   startothers();   // start other processors
  35   kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers()
  36   userinit();      // first user process
  37   mpmain();        // finish this processor's setup
  38 }
  39 
  40 // Other CPUs jump here from entryother.S.
  41 static void
  42 mpenter(void)
     /*   */
  43 {
  44   switchkvm();
  45   seginit();
  46   lapicinit();
  47   mpmain();
  48 }
  49 
  50 // Common CPU setup code.
  51 static void
  52 mpmain(void)
     /*   */
  53 {
  54   cprintf("cpu%d: starting %d\n", cpuid(), cpuid());
  55   idtinit();       // load idt register
  56   xchg(&(mycpu()->started), 1); // tell startothers() we're up
  57   scheduler();     // start running processes
  58 }
  59 
  60 pde_t entrypgdir[];  // For entry.S
  61 
  62 // Start the non-boot (AP) processors.
  63 static void
  64 startothers(void)
     /*   */
  65 {
  66   extern uchar _binary_entryother_start[], _binary_entryother_size[];
  67   uchar *code;
  68   struct cpu *c;
  69   char *stack;
  70 
  71   // Write entry code to unused memory at 0x7000.
  72   // The linker has placed the image of entryother.S in
  73   // _binary_entryother_start.
  74   code = P2V(0x7000);
  75   memmove(code, _binary_entryother_start, (uint)_binary_entryother_size);
  76 
  77   for(c = cpus; c < cpus+ncpu; c++){
  78     if(c == mycpu())  // We've started already.
  79       continue;
  80 
  81     // Tell entryother.S what stack to use, where to enter, and what
  82     // pgdir to use. We cannot use kpgdir yet, because the AP processor
  83     // is running in low  memory, so we use entrypgdir for the APs too.
  84     stack = kalloc();
  85     *(void**)(code-4) = stack + KSTACKSIZE;
  86     *(void(**)(void))(code-8) = mpenter;
  87     *(int**)(code-12) = (void *) V2P(entrypgdir);
  88 
  89     lapicstartap(c->apicid, V2P(code));
  90 
  91     // wait for cpu to finish mpmain()
  92     while(c->started == 0)
  93       ;
  94   }
  95 }
  96 
  97 // The boot page table used in entry.S and entryother.S.
  98 // Page directories (and page tables) must start on page boundaries,
  99 // hence the __aligned__ attribute.
 100 // PTE_PS in a page directory entry enables 4Mbyte pages.
 101 
 102 __attribute__((__aligned__(PGSIZE)))
 103 pde_t entrypgdir[NPDENTRIES] = {
 104   // Map VA's [0, 4MB) to PA's [0, 4MB)
 105   [0] = (0) | PTE_P | PTE_W | PTE_PS,
 106   // Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
 107   [KERNBASE>>PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS,
 108 };
 109 
 110 //PAGEBREAK!
 111 // Blank page.
 112 //PAGEBREAK!
 113 // Blank page.
 114 //PAGEBREAK!
 115 // Blank page.
 116 

/*   */