1/* 2 Copyright Oliver Kowalke 2009. 3 Distributed under the Boost Software License, Version 1.0. 4 (See accompanying file LICENSE_1_0.txt or copy at 5 http://www.boost.org/LICENSE_1_0.txt) 6*/ 7 8/**************************************************************************************** 9 * * 10 * ---------------------------------------------------------------------------------- * 11 * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | * 12 * ---------------------------------------------------------------------------------- * 13 * | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | * 14 * ---------------------------------------------------------------------------------- * 15 * | fc_mxcsr|fc_x87_cw| guard | EDI | ESI | EBX | EBP | EIP | * 16 * ---------------------------------------------------------------------------------- * 17 * ---------------------------------------------------------------------------------- * 18 * | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | * 19 * ---------------------------------------------------------------------------------- * 20 * | 0x20 | 0x24 | 0x28 | | * 21 * ---------------------------------------------------------------------------------- * 22 * | hidden | to | data | | * 23 * ---------------------------------------------------------------------------------- * 24 * * 25 ****************************************************************************************/ 26 27#ifdef __x86_64__ 28#include "make_x86_64_sysv_elf_gas.S" 29#else 30 31.file "make_i386_sysv_elf_gas.S" 32.text 33.globl make_fcontext 34.align 2 35.type make_fcontext,@function 36make_fcontext: 37 /* first arg of make_fcontext() == top of context-stack */ 38 movl 0x4(%esp), %eax 39 40 /* reserve space for first argument of context-function 41 eax might already point to a 16byte border */ 42 leal -0x8(%eax), %eax 43 44 /* shift address in EAX to lower 16 byte boundary */ 45 andl $-16, %eax 46 47 /* reserve space for context-data on context-stack, and align the stack */ 48 leal -0x34(%eax), %eax 49 50 /* third arg of make_fcontext() == address of context-function */ 51 /* stored in EBX */ 52 movl 0xc(%esp), %ecx 53 movl %ecx, 0x14(%eax) 54 55 /* save MMX control- and status-word */ 56 stmxcsr (%eax) 57 /* save x87 control-word */ 58 fnstcw 0x4(%eax) 59 60#if defined(BOOST_CONTEXT_TLS_STACK_PROTECTOR) 61 /* save stack guard */ 62 movl %gs:0x14, %ecx /* read stack guard from TLS record */ 63 movl %ecx, 0x8(%eax) /* save stack guard */ 64#endif 65 66 /* return transport_t */ 67 /* FCTX == EDI, DATA == ESI */ 68 leal 0xc(%eax), %ecx 69 movl %ecx, 0x20(%eax) 70 71 /* compute abs address of label trampoline */ 72 call 1f 73 /* address of trampoline 1 */ 741: popl %ecx 75 /* compute abs address of label trampoline */ 76 addl $trampoline-1b, %ecx 77 /* save address of trampoline as return address */ 78 /* will be entered after calling jump_fcontext() first time */ 79 movl %ecx, 0x1c(%eax) 80 81 /* compute abs address of label finish */ 82 call 2f 83 /* address of label 2 */ 842: popl %ecx 85 /* compute abs address of label finish */ 86 addl $finish-2b, %ecx 87 /* save address of finish as return-address for context-function */ 88 /* will be entered after context-function returns */ 89 movl %ecx, 0x18(%eax) 90 91 ret /* return pointer to context-data */ 92 93trampoline: 94 /* move transport_t for entering context-function */ 95 movl %edi, (%esp) 96 movl %esi, 0x4(%esp) 97 pushl %ebp 98 /* jump to context-function */ 99 jmp *%ebx 100 101finish: 102 call 3f 103 /* address of label 3 */ 1043: popl %ebx 105 /* compute address of GOT and store it in EBX */ 106 addl $_GLOBAL_OFFSET_TABLE_+[.-3b], %ebx 107 108 /* exit code is zero */ 109 xorl %eax, %eax 110 movl %eax, (%esp) 111 /* exit application */ 112 call _exit@PLT 113 hlt 114.size make_fcontext,.-make_fcontext 115 116/* Mark that we don't need executable stack. */ 117.section .note.GNU-stack,"",%progbits 118 119#endif 120
