1/*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * William Jolitz. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#include <private/bionic_asm.h> 34 35// The internal structure of a jmp_buf is totally private. 36// Current layout (changes from release to release): 37// 38// word name description 39// 0 edx registers 40// 1 ebx 41// 2 esp 42// 3 ebp 43// 4 esi 44// 5 edi 45// 6 sigmask 64-bit signal mask (not used with _setjmp / _longjmp) 46// 7 " " 47// 8 sigflag/cookie setjmp cookie in top 31 bits, signal mask flag in low bit 48// 9 checksum checksum of the core registers, to give better error messages. 49 50#define _JB_EDX 0 51#define _JB_EBX 1 52#define _JB_ESP 2 53#define _JB_EBP 3 54#define _JB_ESI 4 55#define _JB_EDI 5 56#define _JB_SIGMASK 6 57#define _JB_SIGFLAG 8 58#define _JB_CHECKSUM 9 59 60.macro m_calculate_checksum dst, src 61 movl $0, \dst 62 .irp i,0,1,2,3,4,5 63 xorl (\i*4)(\src), \dst 64 .endr 65.endm 66 67ENTRY_WEAK_FOR_NATIVE_BRIDGE(setjmp) 68 mov $1,%eax 69 jmp .L_sigsetjmp 70END(setjmp) 71 72ENTRY_WEAK_FOR_NATIVE_BRIDGE(_setjmp) 73 movl $0,%eax 74 jmp .L_sigsetjmp 75END(_setjmp) 76 77ENTRY_WEAK_FOR_NATIVE_BRIDGE(sigsetjmp) 78 movl 8(%esp),%eax 79 80.L_sigsetjmp: 81 PIC_PROLOGUE 82 pushl %eax 83 call PIC_PLT(__bionic_setjmp_cookie_get) 84 addl $4,%esp 85 PIC_EPILOGUE 86 87 // Record the setjmp cookie and whether or not we're saving the signal mask. 88 movl 4(%esp),%ecx 89 movl %eax,(_JB_SIGFLAG * 4)(%ecx) 90 91 // Do we need to save the signal mask? 92 testl $1,%eax 93 jz 1f 94 95 // Save the current signal mask. 96 pushl %ecx 97 PIC_PROLOGUE 98 leal (_JB_SIGMASK * 4)(%ecx),%eax 99 pushl %eax 100 pushl $0 // NULL 101 pushl $2 // SIG_SETMASK 102 call PIC_PLT(sigprocmask64) 103 addl $12,%esp 104 PIC_EPILOGUE 105 popl %ecx 106 1071: 108 // Fetch the setjmp cookie and clear the signal flag bit. 109 movl (_JB_SIGFLAG * 4)(%ecx),%eax 110 andl $-2,%eax 111 112 // Save the callee-save registers. 113 movl 0(%esp),%edx 114 115.macro m_mangle_register reg, offset 116 movl \reg,(\offset * 4)(%ecx) 117 xorl %eax,(\offset * 4)(%ecx) 118.endm 119 m_mangle_register %edx, _JB_EDX 120 m_mangle_register %ebx, _JB_EBX 121 m_mangle_register %esp, _JB_ESP 122 m_mangle_register %ebp, _JB_EBP 123 m_mangle_register %esi, _JB_ESI 124 m_mangle_register %edi, _JB_EDI 125 126 m_calculate_checksum %eax, %ecx 127 movl %eax, (_JB_CHECKSUM * 4)(%ecx) 128 129 xorl %eax,%eax 130 ret 131END(sigsetjmp) 132 133ENTRY_WEAK_FOR_NATIVE_BRIDGE(siglongjmp) 134 movl 4(%esp),%edx 135 136 // Check the checksum before doing anything. 137 m_calculate_checksum %eax, %edx 138 xorl (_JB_CHECKSUM * 4)(%edx), %eax 139 jnz 3f 140 141 // Do we have a signal mask to restore? 142 movl (_JB_SIGFLAG * 4)(%edx), %eax 143 testl $1,%eax 144 jz 1f 145 146 // Restore the signal mask. 147 leal (_JB_SIGMASK * 4)(%edx),%eax 148 PIC_PROLOGUE 149 pushl $0 // NULL 150 pushl %eax 151 pushl $2 // SIG_SETMASK 152 call PIC_PLT(sigprocmask64) 153 addl $12,%esp 154 PIC_EPILOGUE 155 1561: 157 // Restore the callee-save registers. 158 movl 4(%esp),%edx 159 movl 8(%esp),%eax 160 161 // Fetch the setjmp cookie and clear the signal flag bit. 162 movl (_JB_SIGFLAG * 4)(%edx),%ecx 163 andl $-2,%ecx 164 165 // Carefully unmangle esp/ebp without ever having an invalid value in the 166 // register (http://b/152210274). 167 movl (_JB_ESP * 4)(%edx),%edi 168 xorl %ecx,%edi 169 movl %edi,%esp 170 movl (_JB_EBP * 4)(%edx),%edi 171 xorl %ecx,%edi 172 movl %edi,%ebp 173 174 // The others don't matter as much, but we do need to finish using the cookie 175 // from %ecx before we clobber it, so we seed each register with the cookie. 176 movl %ecx,%ebx 177 movl %ecx,%esi 178 movl %ecx,%edi 179 xorl (_JB_EDX * 4)(%edx),%ecx 180 xorl (_JB_EBX * 4)(%edx),%ebx 181 xorl (_JB_ESI * 4)(%edx),%esi 182 xorl (_JB_EDI * 4)(%edx),%edi 183 184 PIC_PROLOGUE 185 pushl %eax 186 pushl %ecx 187 pushl (_JB_SIGFLAG * 4)(%edx) 188 call PIC_PLT(__bionic_setjmp_cookie_check) 189 addl $4,%esp 190 popl %ecx 191 popl %eax 192 PIC_EPILOGUE 193 194 testl %eax,%eax 195 jnz 2f 196 incl %eax 1972: 198 movl %ecx,0(%esp) 199 ret 200 2013: 202 PIC_PROLOGUE 203 pushl (_JB_SIGMASK * 4)(%edx) 204 call PIC_PLT(__bionic_setjmp_checksum_mismatch) 205END(siglongjmp) 206 207ALIAS_SYMBOL_WEAK_FOR_NATIVE_BRIDGE(longjmp, siglongjmp) 208ALIAS_SYMBOL_WEAK_FOR_NATIVE_BRIDGE(_longjmp, siglongjmp) 209