1/* 2 * Common code for the sigreturn entry points on the vsyscall page. 3 * So far this code is the same for both int80 and sysenter versions. 4 * This file is #include'd by vsyscall-*.S to define them after the 5 * vsyscall entry point. The kernel assumes that the addresses of these 6 * routines are constant for all vsyscall implementations. 7 */ 8 9#include <asm/unistd.h> 10#include <asm/asm-offsets.h> 11 12 13/* XXX 14 Should these be named "_sigtramp" or something? 15*/ 16 17 .text 18 .org __kernel_vsyscall+32,0x90 19 .globl __kernel_sigreturn 20 .type __kernel_sigreturn,@function 21__kernel_sigreturn: 22.LSTART_sigreturn: 23 popl %eax /* XXX does this mean it needs unwind info? */ 24 movl $__NR_sigreturn, %eax 25 int $0x80 26.LEND_sigreturn: 27 .size __kernel_sigreturn,.-.LSTART_sigreturn 28 29 .balign 32 30 .globl __kernel_rt_sigreturn 31 .type __kernel_rt_sigreturn,@function 32__kernel_rt_sigreturn: 33.LSTART_rt_sigreturn: 34 movl $__NR_rt_sigreturn, %eax 35 int $0x80 36.LEND_rt_sigreturn: 37 .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn 38 .balign 32 39 .previous 40 41 .section .eh_frame,"a",@progbits 42.LSTARTFRAMEDLSI1: 43 .long .LENDCIEDLSI1-.LSTARTCIEDLSI1 44.LSTARTCIEDLSI1: 45 .long 0 /* CIE ID */ 46 .byte 1 /* Version number */ 47 .string "zRS" /* NUL-terminated augmentation string */ 48 .uleb128 1 /* Code alignment factor */ 49 .sleb128 -4 /* Data alignment factor */ 50 .byte 8 /* Return address register column */ 51 .uleb128 1 /* Augmentation value length */ 52 .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ 53 .byte 0 /* DW_CFA_nop */ 54 .align 4 55.LENDCIEDLSI1: 56 .long .LENDFDEDLSI1-.LSTARTFDEDLSI1 /* Length FDE */ 57.LSTARTFDEDLSI1: 58 .long .LSTARTFDEDLSI1-.LSTARTFRAMEDLSI1 /* CIE pointer */ 59 /* HACK: The dwarf2 unwind routines will subtract 1 from the 60 return address to get an address in the middle of the 61 presumed call instruction. Since we didn't get here via 62 a call, we need to include the nop before the real start 63 to make up for it. */ 64 .long .LSTART_sigreturn-1-. /* PC-relative start address */ 65 .long .LEND_sigreturn-.LSTART_sigreturn+1 66 .uleb128 0 /* Augmentation */ 67 /* What follows are the instructions for the table generation. 68 We record the locations of each register saved. This is 69 complicated by the fact that the "CFA" is always assumed to 70 be the value of the stack pointer in the caller. This means 71 that we must define the CFA of this body of code to be the 72 saved value of the stack pointer in the sigcontext. Which 73 also means that there is no fixed relation to the other 74 saved registers, which means that we must use DW_CFA_expression 75 to compute their addresses. It also means that when we 76 adjust the stack with the popl, we have to do it all over again. */ 77 78#define do_cfa_expr(offset) \ 79 .byte 0x0f; /* DW_CFA_def_cfa_expression */ \ 80 .uleb128 1f-0f; /* length */ \ 810: .byte 0x74; /* DW_OP_breg4 */ \ 82 .sleb128 offset; /* offset */ \ 83 .byte 0x06; /* DW_OP_deref */ \ 841: 85 86#define do_expr(regno, offset) \ 87 .byte 0x10; /* DW_CFA_expression */ \ 88 .uleb128 regno; /* regno */ \ 89 .uleb128 1f-0f; /* length */ \ 900: .byte 0x74; /* DW_OP_breg4 */ \ 91 .sleb128 offset; /* offset */ \ 921: 93 94 do_cfa_expr(SIGCONTEXT_esp+4) 95 do_expr(0, SIGCONTEXT_eax+4) 96 do_expr(1, SIGCONTEXT_ecx+4) 97 do_expr(2, SIGCONTEXT_edx+4) 98 do_expr(3, SIGCONTEXT_ebx+4) 99 do_expr(5, SIGCONTEXT_ebp+4) 100 do_expr(6, SIGCONTEXT_esi+4) 101 do_expr(7, SIGCONTEXT_edi+4) 102 do_expr(8, SIGCONTEXT_eip+4) 103 104 .byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */ 105 106 do_cfa_expr(SIGCONTEXT_esp) 107 do_expr(0, SIGCONTEXT_eax) 108 do_expr(1, SIGCONTEXT_ecx) 109 do_expr(2, SIGCONTEXT_edx) 110 do_expr(3, SIGCONTEXT_ebx) 111 do_expr(5, SIGCONTEXT_ebp) 112 do_expr(6, SIGCONTEXT_esi) 113 do_expr(7, SIGCONTEXT_edi) 114 do_expr(8, SIGCONTEXT_eip) 115 116 .align 4 117.LENDFDEDLSI1: 118 119 .long .LENDFDEDLSI2-.LSTARTFDEDLSI2 /* Length FDE */ 120.LSTARTFDEDLSI2: 121 .long .LSTARTFDEDLSI2-.LSTARTFRAMEDLSI1 /* CIE pointer */ 122 /* HACK: See above wrt unwind library assumptions. */ 123 .long .LSTART_rt_sigreturn-1-. /* PC-relative start address */ 124 .long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1 125 .uleb128 0 /* Augmentation */ 126 /* What follows are the instructions for the table generation. 127 We record the locations of each register saved. This is 128 slightly less complicated than the above, since we don't 129 modify the stack pointer in the process. */ 130 131 do_cfa_expr(RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_esp) 132 do_expr(0, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_eax) 133 do_expr(1, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ecx) 134 do_expr(2, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_edx) 135 do_expr(3, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ebx) 136 do_expr(5, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_ebp) 137 do_expr(6, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_esi) 138 do_expr(7, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_edi) 139 do_expr(8, RT_SIGFRAME_sigcontext-4 + SIGCONTEXT_eip) 140 141 .align 4 142.LENDFDEDLSI2: 143 .previous 144