Commit | Line | Data |
---|---|---|
1da177e4 LT |
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" |