arch/i386-pc/kernel/smpbootstrap.s

   1 # smpbootstrap.c
   2 #
   3 #  Created on: Nov 19, 2009
   4 #      Author: misc
   5
   6         .code16
   7         cli
   8         jmp     boot16
   9
  10         .align  4                       # The config variables are passed here...
  11 arg1:   .long   0
  12 arg2:   .long   0
  13 arg3:   .long   0
  14 sp:     .long   0
  15 ip:     .long   0
  16 gdt:    .short  0
  17         .short  0
  18         .short  0
  19         .short  0
  20         .short  0x1000                  # 0x08: small CS selector
  21         .short  0x0000
  22         .short  0x9a00
  23         .short  0x0040
  24         .short  0x1000                  # 0x10: small DS selector
  25         .short  0x0000
  26         .short  0x9200
  27         .short  0x0040
  28         .short  0xffff                  # 0x18: 4GB CS selector
  29         .short  0x0000
  30         .short  0x9a00
  31         .short  0x00cf
  32         .short  0xffff                  # 0x20: 4GB DS selector
  33         .short  0x0000
  34         .short  0x9200
  35         .short  0x00cf
  36 gdtr:   .short  39
  37         .long   0
  38 target: .long   0
  39         .short  0x18
  40
  41 boot16: mov     $0, %eax
  42         mov     %cs, %ax                # Find out where the code resides
  43         mov     %ax, %ds
  44         shl     $4, %eax
  45         leal    gdt(%eax), %ebx         # Load physical address of 32-bit gdt
  46         movl    %ebx, gdtr+2            # Set up 32-bit gdt address
  47         leal    kick(%eax), %ebx        # Load physical address of flat-mode code
  48         movl    %ebx, target            # Set up entry address
  49         movw    %ax, gdt+10             # Set base address of 32-bit code segment (bits 0:15)
  50         movw    %ax, gdt+18             # Set base address of 32-bit data segment (bits 0:15)
  51         shr     $16, %eax
  52         movb    %al, gdt+12             # Set base address of 32-bit code segment (bits 16:23)
  53         movb    %al, gdt+20             # Set base address of 32-bit data segment (bits 16:23)
  54         ADDR32 DATA32 lgdt gdtr         # Load gdt
  55         movl    %cr0, %eax              # Enter protected mode
  56         orb     $1, %al
  57         movl    %eax, %cr0
  58         ljmp    $0x8, $boot32           # Please note that the %cs segment selector has to have it's base address properly adjusted
  59
  60         .code32
  61 boot32: movw    $0x10, %ax              # Setup the temporary 32-bit data selector
  62         movw    %ax, %ds
  63         movw    $0x20, %ax              # Set stack to large 32-bit data segment
  64         movw    %ax, %ss
  65         movl    sp, %esp                # Load stack pointer
  66         movl    arg3, %ebx              # Prepare arguments for the C entry point
  67         pushl   %ebx
  68         movl    arg2, %ebx
  69         pushl   %ebx
  70         movl    arg1, %ebx
  71         pushl   %ebx
  72         movl    ip, %ebx                # Prepare entry address
  73         ljmp    *target
  74
  75 kick:   mov     %ax, %ds                # Switch to large data segments
  76         mov     %ax, %es
  77         movl    $0, %ebp
  78         call    *%ebx                   # Jump to the C entry point