1/* $OpenBSD: _setjmp.S,v 1.9 2020/12/13 21:21:32 bluhm Exp $ */ 2/*- 3 * Copyright (c) 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <machine/asm.h> 35#include <machine/setjmp.h> 36 37 .global __jmpxor 38 39/* 40 * C library -- _setjmp, _longjmp 41 * 42 * _longjmp(a,v) 43 * will generate a "return(v)" from the last call to 44 * _setjmp(a) 45 * by restoring registers from the stack. 46 * The previous signal state is NOT restored. 47 */ 48 49ENTRY(_setjmp) 50 call 1f 511: popl %ecx 52 addl $__jmpxor-1b,%ecx # load cookie address 53 movl 4(%esp),%eax # parameter, pointer to env 54 movl 0(%esp),%edx # caller address 55 xorl 0(%ecx),%edx # use eip cookie 56 movl %edx,(_JB_EIP * 4)(%eax) 57 movl %ebx,(_JB_EBX * 4)(%eax) 58 movl %esp,%edx 59 xorl 4(%ecx),%edx # use esp cookie 60 movl %edx,(_JB_ESP * 4)(%eax) 61 movl 8(%ecx),%ecx # load ebp cookie over cookie address 62 xorl %ebp,%ecx 63 movl %ecx,(_JB_EBP * 4)(%eax) 64 movl %esi,(_JB_ESI * 4)(%eax) 65 movl %edi,(_JB_EDI * 4)(%eax) 66 fnstcw (_JB_FCW * 4)(%eax) 67 xorl %eax,%eax 68 ret 69END(_setjmp) 70 71ENTRY(_longjmp) 72 call 1f 731: popl %ecx 74 addl $__jmpxor-1b,%ecx # load cookie address 75 movl 4(%esp),%edx # parameter, pointer to env 76 movl 8(%esp),%eax # parameter, val 77 fldcw (_JB_FCW * 4)(%edx) 78 movl (_JB_EBX * 4)(%edx),%ebx 79 movl (_JB_ESP * 4)(%edx),%esi 80 xorl 4(%ecx),%esi # use esp cookie 81 movl %esi,%esp # un-xor'ed esp is safe to use 82 movl (_JB_EBP * 4)(%edx),%ebp 83 xorl 8(%ecx),%ebp # use ebp cookie 84 movl (_JB_ESI * 4)(%edx),%esi 85 movl (_JB_EDI * 4)(%edx),%edi 86 movl 0(%ecx),%ecx # load eip cookie over cookie address 87 xorl (_JB_EIP * 4)(%edx),%ecx 88 testl %eax,%eax 89 jnz 1f 90 incl %eax 911: movl %ecx,0(%esp) 92 ret 93END(_longjmp) 94