arch/x86_64/ia32/vsyscall-sysenter.S

   1 /*
   2  * Code for the vsyscall page.  This version uses the sysenter instruction.
   3  */
   4
   5 #include <asm/ia32_unistd.h>
   6 #include <asm/offset.h>
   7
   8         .text
   9         .section .text.vsyscall,"ax"
  10         .globl __kernel_vsyscall
  11         .type __kernel_vsyscall,@function
  12 __kernel_vsyscall:
  13 .LSTART_vsyscall:
  14         push    %ecx
  15 .Lpush_ecx:
  16         push    %edx
  17 .Lpush_edx:
  18         push    %ebp
  19 .Lenter_kernel:
  20         movl    %esp,%ebp
  21         sysenter
  22         .space 7,0x90
  23         jmp     .Lenter_kernel
  24         /* 16: System call normal return point is here! */
  25         pop     %ebp
  26 .Lpop_ebp:
  27         pop     %edx
  28 .Lpop_edx:
  29         pop     %ecx
  30 .Lpop_ecx:
  31         ret
  32 .LEND_vsyscall:
  33         .size __kernel_vsyscall,.-.LSTART_vsyscall
  34
  35         .section .eh_frame,"a",@progbits
  36 .LSTARTFRAME:
  37         .long .LENDCIE-.LSTARTCIE
  38 .LSTARTCIE:
  39         .long 0                 /* CIE ID */
  40         .byte 1                 /* Version number */
  41         .string "zR"            /* NUL-terminated augmentation string */
  42         .uleb128 1              /* Code alignment factor */
  43         .sleb128 -4             /* Data alignment factor */
  44         .byte 8                 /* Return address register column */
  45         .uleb128 1              /* Augmentation value length */
  46         .byte 0x1b              /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
  47         .byte 0x0c              /* DW_CFA_def_cfa */
  48         .uleb128 4
  49         .uleb128 4
  50         .byte 0x88              /* DW_CFA_offset, column 0x8 */
  51         .uleb128 1
  52         .align 4
  53 .LENDCIE:
  54
  55         .long .LENDFDE1-.LSTARTFDE1     /* Length FDE */
  56 .LSTARTFDE1:
  57         .long .LSTARTFDE1-.LSTARTFRAME  /* CIE pointer */
  58         .long .LSTART_vsyscall-.        /* PC-relative start address */
  59         .long .LEND_vsyscall-.LSTART_vsyscall
  60         .uleb128 0                      /* Augmentation length */
  61         /* What follows are the instructions for the table generation.
  62            We have to record all changes of the stack pointer.  */
  63         .byte 0x04              /* DW_CFA_advance_loc4 */
  64         .long .Lpush_ecx-.LSTART_vsyscall
  65         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  66         .byte 0x08              /* RA at offset 8 now */
  67         .byte 0x04              /* DW_CFA_advance_loc4 */
  68         .long .Lpush_edx-.Lpush_ecx
  69         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  70         .byte 0x0c              /* RA at offset 12 now */
  71         .byte 0x04              /* DW_CFA_advance_loc4 */
  72         .long .Lenter_kernel-.Lpush_edx
  73         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  74         .byte 0x10              /* RA at offset 16 now */
  75         .byte 0x85, 0x04        /* DW_CFA_offset %ebp -16 */
  76         /* Finally the epilogue.  */
  77         .byte 0x04              /* DW_CFA_advance_loc4 */
  78         .long .Lpop_ebp-.Lenter_kernel
  79         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  80         .byte 0x12              /* RA at offset 12 now */
  81         .byte 0xc5              /* DW_CFA_restore %ebp */
  82         .byte 0x04              /* DW_CFA_advance_loc4 */
  83         .long .Lpop_edx-.Lpop_ebp
  84         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  85         .byte 0x08              /* RA at offset 8 now */
  86         .byte 0x04              /* DW_CFA_advance_loc4 */
  87         .long .Lpop_ecx-.Lpop_edx
  88         .byte 0x0e              /* DW_CFA_def_cfa_offset */
  89         .byte 0x04              /* RA at offset 4 now */
  90         .align 4
  91 .LENDFDE1:
  92
  93 #define SYSCALL_ENTER_KERNEL    int $0x80
  94 #include "vsyscall-sigreturn.S"