1/* 2 * Common code for the sigreturn entry points in vDSO images. 3 * So far this code is the same for both int80 and sysenter versions. 4 * This file is #include'd by int80.S et al to define them first thing. 5 * The kernel assumes that the addresses of these routines are constant 6 * for all vDSO implementations. 7 */ 8 9#include <linux/linkage.h> 10#include <asm/unistd_32.h> 11#include <asm/asm-offsets.h> 12 13#ifndef SYSCALL_ENTER_KERNEL 14#define SYSCALL_ENTER_KERNEL int $0x80 15#endif 16 17 .text 18 .globl __kernel_sigreturn 19 .type __kernel_sigreturn,@function 20 ALIGN 21__kernel_sigreturn: 22.LSTART_sigreturn: 23 popl %eax 24 movl $__NR_sigreturn, %eax 25 SYSCALL_ENTER_KERNEL 26.LEND_sigreturn: 27 nop 28 .size __kernel_sigreturn,.-.LSTART_sigreturn 29 30 .globl __kernel_rt_sigreturn 31 .type __kernel_rt_sigreturn,@function 32 ALIGN 33__kernel_rt_sigreturn: 34.LSTART_rt_sigreturn: 35 movl $__NR_rt_sigreturn, %eax 36 SYSCALL_ENTER_KERNEL 37.LEND_rt_sigreturn: 38 nop 39 .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn 40 .previous 41 42 .section .eh_frame,"a",@progbits 43.LSTARTFRAMEDLSI1: 44 .long .LENDCIEDLSI1-.LSTARTCIEDLSI1 45.LSTARTCIEDLSI1: 46 .long 0 /* CIE ID */ 47 .byte 1 /* Version number */ 48 .string "zRS" /* NUL-terminated augmentation string */ 49 .uleb128 1 /* Code alignment factor */ 50 .sleb128 -4 /* Data alignment factor */ 51 .byte 8 /* Return address register column */ 52 .uleb128 1 /* Augmentation value length */ 53 .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ 54 .byte 0 /* DW_CFA_nop */ 55 .align 4 56.LENDCIEDLSI1: 57 .long .LENDFDEDLSI1-.LSTARTFDEDLSI1 /* Length FDE */ 58.LSTARTFDEDLSI1: 59 .long .LSTARTFDEDLSI1-.LSTARTFRAMEDLSI1 /* CIE pointer */ 60 /* HACK: The dwarf2 unwind routines will subtract 1 from the 61 return address to get an address in the middle of the 62 presumed call instruction. Since we didn't get here via 63 a call, we need to include the nop before the real start 64 to make up for it. */ 65 .long .LSTART_sigreturn-1-. /* PC-relative start address */ 66 .long .LEND_sigreturn-.LSTART_sigreturn+1 67 .uleb128 0 /* Augmentation */ 68 /* What follows are the instructions for the table generation. 69 We record the locations of each register saved. This is 70 complicated by the fact that the "CFA" is always assumed to 71 be the value of the stack pointer in the caller. This means 72 that we must define the CFA of this body of code to be the 73 saved value of the stack pointer in the sigcontext. Which 74 also means that there is no fixed relation to the other 75 saved registers, which means that we must use DW_CFA_expression 76 to compute their addresses. It also means that when we 77 adjust the stack with the popl, we have to do it all over again. */ 78 79#define do_cfa_expr(offset) \ 80 .byte 0x0f; /* DW_CFA_def_cfa_expression */ \ 81 .uleb128 1f-0f; /* length */ \ 820: .byte 0x74; /* DW_OP_breg4 */ \ 83 .sleb128 offset; /* offset */ \ 84 .byte 0x06; /* DW_OP_deref */ \ 851: 86 87#define do_expr(regno, offset) \ 88 .byte 0x10; /* DW_CFA_expression */ \ 89 .uleb128 regno; /* regno */ \ 90 .uleb128 1f-0f; /* length */ \ 910: .byte 0x74; /* DW_OP_breg4 */ \ 92 .sleb128 offset; /* offset */ \ 931: 94 95 do_cfa_expr(IA32_SIGCONTEXT_sp+4) 96 do_expr(0, IA32_SIGCONTEXT_ax+4) 97 do_expr(1, IA32_SIGCONTEXT_cx+4) 98 do_expr(2, IA32_SIGCONTEXT_dx+4) 99 do_expr(3, IA32_SIGCONTEXT_bx+4) 100 do_expr(5, IA32_SIGCONTEXT_bp+4) 101 do_expr(6, IA32_SIGCONTEXT_si+4) 102 do_expr(7, IA32_SIGCONTEXT_di+4) 103 do_expr(8, IA32_SIGCONTEXT_ip+4) 104 105 .byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */ 106 107 do_cfa_expr(IA32_SIGCONTEXT_sp) 108 do_expr(0, IA32_SIGCONTEXT_ax) 109 do_expr(1, IA32_SIGCONTEXT_cx) 110 do_expr(2, IA32_SIGCONTEXT_dx) 111 do_expr(3, IA32_SIGCONTEXT_bx) 112 do_expr(5, IA32_SIGCONTEXT_bp) 113 do_expr(6, IA32_SIGCONTEXT_si) 114 do_expr(7, IA32_SIGCONTEXT_di) 115 do_expr(8, IA32_SIGCONTEXT_ip) 116 117 .align 4 118.LENDFDEDLSI1: 119 120 .long .LENDFDEDLSI2-.LSTARTFDEDLSI2 /* Length FDE */ 121.LSTARTFDEDLSI2: 122 .long .LSTARTFDEDLSI2-.LSTARTFRAMEDLSI1 /* CIE pointer */ 123 /* HACK: See above wrt unwind library assumptions. */ 124 .long .LSTART_rt_sigreturn-1-. /* PC-relative start address */ 125 .long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1 126 .uleb128 0 /* Augmentation */ 127 /* What follows are the instructions for the table generation. 128 We record the locations of each register saved. This is 129 slightly less complicated than the above, since we don't 130 modify the stack pointer in the process. */ 131 132 do_cfa_expr(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_sp) 133 do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ax) 134 do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_cx) 135 do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_dx) 136 do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bx) 137 do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bp) 138 do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_si) 139 do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_di) 140 do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ip) 141 142 .align 4 143.LENDFDEDLSI2: 144 .previous 145