| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Code for the vsyscall page. This version uses the sysenter instruction. |
| 3 | * |
| 4 | * NOTE: |
| 5 | * 1) __kernel_vsyscall _must_ be first in this page. |
| 6 | * 2) there are alignment constraints on this stub, see vsyscall-sigreturn.S |
| 7 | * for details. |
| 8 | */ |
| 9 | |
| 10 | .text |
| 11 | .globl __kernel_vsyscall |
| 12 | .type __kernel_vsyscall,@function |
| 13 | __kernel_vsyscall: |
| 14 | .LSTART_vsyscall: |
| 15 | push %ecx |
| 16 | .Lpush_ecx: |
| 17 | push %edx |
| 18 | .Lpush_edx: |
| 19 | push %ebp |
| 20 | .Lenter_kernel: |
| 21 | movl %esp,%ebp |
| 22 | sysenter |
| 23 | |
| 24 | /* 7: align return point with nop's to make disassembly easier */ |
| 25 | .space 7,0x90 |
| 26 | |
| 27 | /* 14: System call restart point is here! (SYSENTER_RETURN - 2) */ |
| 28 | jmp .Lenter_kernel |
| 29 | /* 16: System call normal return point is here! */ |
| 30 | .globl SYSENTER_RETURN /* Symbol used by entry.S. */ |
| 31 | SYSENTER_RETURN: |
| 32 | pop %ebp |
| 33 | .Lpop_ebp: |
| 34 | pop %edx |
| 35 | .Lpop_edx: |
| 36 | pop %ecx |
| 37 | .Lpop_ecx: |
| 38 | ret |
| 39 | .LEND_vsyscall: |
| 40 | .size __kernel_vsyscall,.-.LSTART_vsyscall |
| 41 | .previous |
| 42 | |
| 43 | .section .eh_frame,"a",@progbits |
| 44 | .LSTARTFRAMEDLSI: |
| 45 | .long .LENDCIEDLSI-.LSTARTCIEDLSI |
| 46 | .LSTARTCIEDLSI: |
| 47 | .long 0 /* CIE ID */ |
| 48 | .byte 1 /* Version number */ |
| 49 | .string "zR" /* NUL-terminated augmentation string */ |
| 50 | .uleb128 1 /* Code alignment factor */ |
| 51 | .sleb128 -4 /* Data alignment factor */ |
| 52 | .byte 8 /* Return address register column */ |
| 53 | .uleb128 1 /* Augmentation value length */ |
| 54 | .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ |
| 55 | .byte 0x0c /* DW_CFA_def_cfa */ |
| 56 | .uleb128 4 |
| 57 | .uleb128 4 |
| 58 | .byte 0x88 /* DW_CFA_offset, column 0x8 */ |
| 59 | .uleb128 1 |
| 60 | .align 4 |
| 61 | .LENDCIEDLSI: |
| 62 | .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */ |
| 63 | .LSTARTFDEDLSI: |
| 64 | .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */ |
| 65 | .long .LSTART_vsyscall-. /* PC-relative start address */ |
| 66 | .long .LEND_vsyscall-.LSTART_vsyscall |
| 67 | .uleb128 0 |
| 68 | /* What follows are the instructions for the table generation. |
| 69 | We have to record all changes of the stack pointer. */ |
| 70 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 71 | .long .Lpush_ecx-.LSTART_vsyscall |
| 72 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 73 | .byte 0x08 /* RA at offset 8 now */ |
| 74 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 75 | .long .Lpush_edx-.Lpush_ecx |
| 76 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 77 | .byte 0x0c /* RA at offset 12 now */ |
| 78 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 79 | .long .Lenter_kernel-.Lpush_edx |
| 80 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 81 | .byte 0x10 /* RA at offset 16 now */ |
| 82 | .byte 0x85, 0x04 /* DW_CFA_offset %ebp -16 */ |
| 83 | /* Finally the epilogue. */ |
| 84 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 85 | .long .Lpop_ebp-.Lenter_kernel |
| 86 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 87 | .byte 0x0c /* RA at offset 12 now */ |
| 88 | .byte 0xc5 /* DW_CFA_restore %ebp */ |
| 89 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 90 | .long .Lpop_edx-.Lpop_ebp |
| 91 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 92 | .byte 0x08 /* RA at offset 8 now */ |
| 93 | .byte 0x04 /* DW_CFA_advance_loc4 */ |
| 94 | .long .Lpop_ecx-.Lpop_edx |
| 95 | .byte 0x0e /* DW_CFA_def_cfa_offset */ |
| 96 | .byte 0x04 /* RA at offset 4 now */ |
| 97 | .align 4 |
| 98 | .LENDFDEDLSI: |
| 99 | .previous |
| 100 | |
| 101 | /* |
| 102 | * Get the common code for the sigreturn entry points. |
| 103 | */ |
| 104 | #include "vsyscall-sigreturn.S" |