/* * Code for the vsyscall page. This version uses the sysenter instruction. * * NOTE: * 1) __kernel_vsyscall _must_ be first in this page. * 2) there are alignment constraints on this stub, see vsyscall-sigreturn.S * for details. */ .text .globl __kernel_vsyscall .type __kernel_vsyscall,@function __kernel_vsyscall: .LSTART_vsyscall: push %ecx .Lpush_ecx: push %edx .Lpush_edx: push %ebp .Lenter_kernel: movl %esp,%ebp sysenter /* 7: align return point with nop's to make disassembly easier */ .space 7,0x90 /* 14: System call restart point is here! (SYSENTER_RETURN - 2) */ jmp .Lenter_kernel /* 16: System call normal return point is here! */ .globl SYSENTER_RETURN /* Symbol used by entry.S. */ SYSENTER_RETURN: pop %ebp .Lpop_ebp: pop %edx .Lpop_edx: pop %ecx .Lpop_ecx: ret .LEND_vsyscall: .size __kernel_vsyscall,.-.LSTART_vsyscall .previous .section .eh_frame,"a",@progbits .LSTARTFRAMEDLSI: .long .LENDCIEDLSI-.LSTARTCIEDLSI .LSTARTCIEDLSI: .long 0 /* CIE ID */ .byte 1 /* Version number */ .string "zR" /* NUL-terminated augmentation string */ .uleb128 1 /* Code alignment factor */ .sleb128 -4 /* Data alignment factor */ .byte 8 /* Return address register column */ .uleb128 1 /* Augmentation value length */ .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ .byte 0x0c /* DW_CFA_def_cfa */ .uleb128 4 .uleb128 4 .byte 0x88 /* DW_CFA_offset, column 0x8 */ .uleb128 1 .align 4 .LENDCIEDLSI: .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */ .LSTARTFDEDLSI: .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */ .long .LSTART_vsyscall-. /* PC-relative start address */ .long .LEND_vsyscall-.LSTART_vsyscall .uleb128 0 /* What follows are the instructions for the table generation. We have to record all changes of the stack pointer. */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lpush_ecx-.LSTART_vsyscall .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x08 /* RA at offset 8 now */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lpush_edx-.Lpush_ecx .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x0c /* RA at offset 12 now */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lenter_kernel-.Lpush_edx .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x10 /* RA at offset 16 now */ .byte 0x85, 0x04 /* DW_CFA_offset %ebp -16 */ /* Finally the epilogue. */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lpop_ebp-.Lenter_kernel .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x0c /* RA at offset 12 now */ .byte 0xc5 /* DW_CFA_restore %ebp */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lpop_edx-.Lpop_ebp .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x08 /* RA at offset 8 now */ .byte 0x04 /* DW_CFA_advance_loc4 */ .long .Lpop_ecx-.Lpop_edx .byte 0x0e /* DW_CFA_def_cfa_offset */ .byte 0x04 /* RA at offset 4 now */ .align 4 .LENDFDEDLSI: .previous /* * Get the common code for the sigreturn entry points. */ #include "vsyscall-sigreturn.S"