1/* 2 * Common code for the sigreturn entry points on the vsyscall page. 3 * This code uses SYSCALL_ENTER_KERNEL (either syscall or int $0x80) 4 * to enter the kernel. 5 * This file is #include'd by vsyscall-*.S to define them after the 6 * vsyscall entry point. The addresses we get for these entry points 7 * by doing ".balign 32" must match in both versions of the page. 8 */ 9 10 .code32 11 .section .text.sigreturn,"ax" 12 .balign 32 13 .globl __kernel_sigreturn 14 .type __kernel_sigreturn,@function 15__kernel_sigreturn: 16.LSTART_sigreturn: 17 popl %eax 18 movl $__NR_ia32_sigreturn, %eax 19 SYSCALL_ENTER_KERNEL 20.LEND_sigreturn: 21 .size __kernel_sigreturn,.-.LSTART_sigreturn 22 23 .section .text.rtsigreturn,"ax" 24 .balign 32 25 .globl __kernel_rt_sigreturn 26 .type __kernel_rt_sigreturn,@function 27__kernel_rt_sigreturn: 28.LSTART_rt_sigreturn: 29 movl $__NR_ia32_rt_sigreturn, %eax 30 SYSCALL_ENTER_KERNEL 31.LEND_rt_sigreturn: 32 .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn 33 34 .section .eh_frame,"a",@progbits 35.LSTARTFRAMES: 36 .long .LENDCIES-.LSTARTCIES 37.LSTARTCIES: 38 .long 0 /* CIE ID */ 39 .byte 1 /* Version number */ 40 .string "zRS" /* NUL-terminated augmentation string */ 41 .uleb128 1 /* Code alignment factor */ 42 .sleb128 -4 /* Data alignment factor */ 43 .byte 8 /* Return address register column */ 44 .uleb128 1 /* Augmentation value length */ 45 .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ 46 .byte 0x0c /* DW_CFA_def_cfa */ 47 .uleb128 4 48 .uleb128 4 49 .byte 0x88 /* DW_CFA_offset, column 0x8 */ 50 .uleb128 1 51 .align 4 52.LENDCIES: 53 54 .long .LENDFDE2-.LSTARTFDE2 /* Length FDE */ 55.LSTARTFDE2: 56 .long .LSTARTFDE2-.LSTARTFRAMES /* CIE pointer */ 57 /* HACK: The dwarf2 unwind routines will subtract 1 from the 58 return address to get an address in the middle of the 59 presumed call instruction. Since we didn't get here via 60 a call, we need to include the nop before the real start 61 to make up for it. */ 62 .long .LSTART_sigreturn-1-. /* PC-relative start address */ 63 .long .LEND_sigreturn-.LSTART_sigreturn+1 64 .uleb128 0 /* Augmentation length */ 65 /* What follows are the instructions for the table generation. 66 We record the locations of each register saved. This is 67 complicated by the fact that the "CFA" is always assumed to 68 be the value of the stack pointer in the caller. This means 69 that we must define the CFA of this body of code to be the 70 saved value of the stack pointer in the sigcontext. Which 71 also means that there is no fixed relation to the other 72 saved registers, which means that we must use DW_CFA_expression 73 to compute their addresses. It also means that when we 74 adjust the stack with the popl, we have to do it all over again. */ 75 76#define do_cfa_expr(offset) \ 77 .byte 0x0f; /* DW_CFA_def_cfa_expression */ \ 78 .uleb128 1f-0f; /* length */ \ 790: .byte 0x74; /* DW_OP_breg4 */ \ 80 .sleb128 offset; /* offset */ \ 81 .byte 0x06; /* DW_OP_deref */ \ 821: 83 84#define do_expr(regno, offset) \ 85 .byte 0x10; /* DW_CFA_expression */ \ 86 .uleb128 regno; /* regno */ \ 87 .uleb128 1f-0f; /* length */ \ 880: .byte 0x74; /* DW_OP_breg4 */ \ 89 .sleb128 offset; /* offset */ \ 901: 91 92 do_cfa_expr(IA32_SIGCONTEXT_esp+4) 93 do_expr(0, IA32_SIGCONTEXT_eax+4) 94 do_expr(1, IA32_SIGCONTEXT_ecx+4) 95 do_expr(2, IA32_SIGCONTEXT_edx+4) 96 do_expr(3, IA32_SIGCONTEXT_ebx+4) 97 do_expr(5, IA32_SIGCONTEXT_ebp+4) 98 do_expr(6, IA32_SIGCONTEXT_esi+4) 99 do_expr(7, IA32_SIGCONTEXT_edi+4) 100 do_expr(8, IA32_SIGCONTEXT_eip+4) 101 102 .byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */ 103 104 do_cfa_expr(IA32_SIGCONTEXT_esp) 105 do_expr(0, IA32_SIGCONTEXT_eax) 106 do_expr(1, IA32_SIGCONTEXT_ecx) 107 do_expr(2, IA32_SIGCONTEXT_edx) 108 do_expr(3, IA32_SIGCONTEXT_ebx) 109 do_expr(5, IA32_SIGCONTEXT_ebp) 110 do_expr(6, IA32_SIGCONTEXT_esi) 111 do_expr(7, IA32_SIGCONTEXT_edi) 112 do_expr(8, IA32_SIGCONTEXT_eip) 113 114 .align 4 115.LENDFDE2: 116 117 .long .LENDFDE3-.LSTARTFDE3 /* Length FDE */ 118.LSTARTFDE3: 119 .long .LSTARTFDE3-.LSTARTFRAMES /* CIE pointer */ 120 /* HACK: See above wrt unwind library assumptions. */ 121 .long .LSTART_rt_sigreturn-1-. /* PC-relative start address */ 122 .long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1 123 .uleb128 0 /* Augmentation */ 124 /* What follows are the instructions for the table generation. 125 We record the locations of each register saved. This is 126 slightly less complicated than the above, since we don't 127 modify the stack pointer in the process. */ 128 129 do_cfa_expr(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esp) 130 do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eax) 131 do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ecx) 132 do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edx) 133 do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebx) 134 do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebp) 135 do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esi) 136 do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edi) 137 do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eip) 138 139 .align 4 140.LENDFDE3: 141 142#include "../../i386/kernel/vsyscall-note.S" 143