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 nop /* this guy is needed for .LSTARTFDEDLSI1 below (watch for HACK) */ 21 ALIGN 22__kernel_sigreturn: 23.LSTART_sigreturn: 24 popl %eax /* XXX does this mean it needs unwind info? */ 25 movl $__NR_sigreturn, %eax 26 SYSCALL_ENTER_KERNEL 27.LEND_sigreturn: 28 nop 29 .size __kernel_sigreturn,.-.LSTART_sigreturn 30 31 .globl __kernel_rt_sigreturn 32 .type __kernel_rt_sigreturn,@function 33 ALIGN 34__kernel_rt_sigreturn: 35.LSTART_rt_sigreturn: 36 movl $__NR_rt_sigreturn, %eax 37 SYSCALL_ENTER_KERNEL 38.LEND_rt_sigreturn: 39 nop 40 .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn 41 .previous 42 43 .section .eh_frame,"a",@progbits 44.LSTARTFRAMEDLSI1: 45 .long .LENDCIEDLSI1-.LSTARTCIEDLSI1 46.LSTARTCIEDLSI1: 47 .long 0 /* CIE ID */ 48 .byte 1 /* Version number */ 49 .string "zRS" /* 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 0 /* DW_CFA_nop */ 56 .align 4 57.LENDCIEDLSI1: 58 .long .LENDFDEDLSI1-.LSTARTFDEDLSI1 /* Length FDE */ 59.LSTARTFDEDLSI1: 60 .long .LSTARTFDEDLSI1-.LSTARTFRAMEDLSI1 /* CIE pointer */ 61 /* HACK: The dwarf2 unwind routines will subtract 1 from the 62 return address to get an address in the middle of the 63 presumed call instruction. Since we didn't get here via 64 a call, we need to include the nop before the real start 65 to make up for it. */ 66 .long .LSTART_sigreturn-1-. /* PC-relative start address */ 67 .long .LEND_sigreturn-.LSTART_sigreturn+1 68 .uleb128 0 /* Augmentation */ 69 /* What follows are the instructions for the table generation. 70 We record the locations of each register saved. This is 71 complicated by the fact that the "CFA" is always assumed to 72 be the value of the stack pointer in the caller. This means 73 that we must define the CFA of this body of code to be the 74 saved value of the stack pointer in the sigcontext. Which 75 also means that there is no fixed relation to the other 76 saved registers, which means that we must use DW_CFA_expression 77 to compute their addresses. It also means that when we 78 adjust the stack with the popl, we have to do it all over again. */ 79 80#define do_cfa_expr(offset) \ 81 .byte 0x0f; /* DW_CFA_def_cfa_expression */ \ 82 .uleb128 1f-0f; /* length */ \ 830: .byte 0x74; /* DW_OP_breg4 */ \ 84 .sleb128 offset; /* offset */ \ 85 .byte 0x06; /* DW_OP_deref */ \ 861: 87 88#define do_expr(regno, offset) \ 89 .byte 0x10; /* DW_CFA_expression */ \ 90 .uleb128 regno; /* regno */ \ 91 .uleb128 1f-0f; /* length */ \ 920: .byte 0x74; /* DW_OP_breg4 */ \ 93 .sleb128 offset; /* offset */ \ 941: 95 96 do_cfa_expr(IA32_SIGCONTEXT_sp+4) 97 do_expr(0, IA32_SIGCONTEXT_ax+4) 98 do_expr(1, IA32_SIGCONTEXT_cx+4) 99 do_expr(2, IA32_SIGCONTEXT_dx+4) 100 do_expr(3, IA32_SIGCONTEXT_bx+4) 101 do_expr(5, IA32_SIGCONTEXT_bp+4) 102 do_expr(6, IA32_SIGCONTEXT_si+4) 103 do_expr(7, IA32_SIGCONTEXT_di+4) 104 do_expr(8, IA32_SIGCONTEXT_ip+4) 105 106 .byte 0x42 /* DW_CFA_advance_loc 2 -- nop; popl eax. */ 107 108 do_cfa_expr(IA32_SIGCONTEXT_sp) 109 do_expr(0, IA32_SIGCONTEXT_ax) 110 do_expr(1, IA32_SIGCONTEXT_cx) 111 do_expr(2, IA32_SIGCONTEXT_dx) 112 do_expr(3, IA32_SIGCONTEXT_bx) 113 do_expr(5, IA32_SIGCONTEXT_bp) 114 do_expr(6, IA32_SIGCONTEXT_si) 115 do_expr(7, IA32_SIGCONTEXT_di) 116 do_expr(8, IA32_SIGCONTEXT_ip) 117 118 .align 4 119.LENDFDEDLSI1: 120 121 .long .LENDFDEDLSI2-.LSTARTFDEDLSI2 /* Length FDE */ 122.LSTARTFDEDLSI2: 123 .long .LSTARTFDEDLSI2-.LSTARTFRAMEDLSI1 /* CIE pointer */ 124 /* HACK: See above wrt unwind library assumptions. */ 125 .long .LSTART_rt_sigreturn-1-. /* PC-relative start address */ 126 .long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1 127 .uleb128 0 /* Augmentation */ 128 /* What follows are the instructions for the table generation. 129 We record the locations of each register saved. This is 130 slightly less complicated than the above, since we don't 131 modify the stack pointer in the process. */ 132 133 do_cfa_expr(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_sp) 134 do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ax) 135 do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_cx) 136 do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_dx) 137 do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bx) 138 do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_bp) 139 do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_si) 140 do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_di) 141 do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ip) 142 143 .align 4 144.LENDFDEDLSI2: 145 .previous 146