1 /* DWARF2 EH unwinding support for AMD x86-64 and x86. 2 Copyright (C) 2004-2013 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25 /* Do code reading to identify a signal frame, and set the frame 26 state data appropriately. See unwind-dw2.c for the structs. 27 Don't use this at all if inhibit_libc is used. */ 28 29 #ifndef inhibit_libc 30 31 /* There's no sys/ucontext.h for glibc 2.0, so no 32 signal-turned-exceptions for them. There's also no configure-run for 33 the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H. Using the 34 target libc version macro should be enough. */ 35 #if defined __GLIBC__ && !(__GLIBC__ == 2 && __GLIBC_MINOR__ == 0) 36 37 #include <signal.h> 38 #include <sys/ucontext.h> 39 40 #ifdef __x86_64__ 41 42 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_fallback_frame_state 43 44 static _Unwind_Reason_Code 45 x86_64_fallback_frame_state (struct _Unwind_Context *context, 46 _Unwind_FrameState *fs) 47 { 48 unsigned char *pc = context->ra; 49 struct sigcontext *sc; 50 long new_cfa; 51 52 /* movq $__NR_rt_sigreturn, %rax ; syscall. */ 53 #ifdef __LP64__ 54 #define RT_SIGRETURN_SYSCALL 0x050f0000000fc0c7ULL 55 #else 56 #define RT_SIGRETURN_SYSCALL 0x050f40000201c0c7ULL 57 #endif 58 if (*(unsigned char *)(pc+0) == 0x48 59 && *(unsigned long long *)(pc+1) == RT_SIGRETURN_SYSCALL) 60 { 61 struct ucontext *uc_ = context->cfa; 62 /* The void * cast is necessary to avoid an aliasing warning. 63 The aliasing warning is correct, but should not be a problem 64 because it does not alias anything. */ 65 sc = (struct sigcontext *) (void *) &uc_->uc_mcontext; 66 } 67 else 68 return _URC_END_OF_STACK; 69 70 new_cfa = sc->rsp; 71 fs->regs.cfa_how = CFA_REG_OFFSET; 72 /* Register 7 is rsp */ 73 fs->regs.cfa_reg = 7; 74 fs->regs.cfa_offset = new_cfa - (long) context->cfa; 75 76 /* The SVR4 register numbering macros aren't usable in libgcc. */ 77 fs->regs.reg[0].how = REG_SAVED_OFFSET; 78 fs->regs.reg[0].loc.offset = (long)&sc->rax - new_cfa; 79 fs->regs.reg[1].how = REG_SAVED_OFFSET; 80 fs->regs.reg[1].loc.offset = (long)&sc->rdx - new_cfa; 81 fs->regs.reg[2].how = REG_SAVED_OFFSET; 82 fs->regs.reg[2].loc.offset = (long)&sc->rcx - new_cfa; 83 fs->regs.reg[3].how = REG_SAVED_OFFSET; 84 fs->regs.reg[3].loc.offset = (long)&sc->rbx - new_cfa; 85 fs->regs.reg[4].how = REG_SAVED_OFFSET; 86 fs->regs.reg[4].loc.offset = (long)&sc->rsi - new_cfa; 87 fs->regs.reg[5].how = REG_SAVED_OFFSET; 88 fs->regs.reg[5].loc.offset = (long)&sc->rdi - new_cfa; 89 fs->regs.reg[6].how = REG_SAVED_OFFSET; 90 fs->regs.reg[6].loc.offset = (long)&sc->rbp - new_cfa; 91 fs->regs.reg[8].how = REG_SAVED_OFFSET; 92 fs->regs.reg[8].loc.offset = (long)&sc->r8 - new_cfa; 93 fs->regs.reg[9].how = REG_SAVED_OFFSET; 94 fs->regs.reg[9].loc.offset = (long)&sc->r9 - new_cfa; 95 fs->regs.reg[10].how = REG_SAVED_OFFSET; 96 fs->regs.reg[10].loc.offset = (long)&sc->r10 - new_cfa; 97 fs->regs.reg[11].how = REG_SAVED_OFFSET; 98 fs->regs.reg[11].loc.offset = (long)&sc->r11 - new_cfa; 99 fs->regs.reg[12].how = REG_SAVED_OFFSET; 100 fs->regs.reg[12].loc.offset = (long)&sc->r12 - new_cfa; 101 fs->regs.reg[13].how = REG_SAVED_OFFSET; 102 fs->regs.reg[13].loc.offset = (long)&sc->r13 - new_cfa; 103 fs->regs.reg[14].how = REG_SAVED_OFFSET; 104 fs->regs.reg[14].loc.offset = (long)&sc->r14 - new_cfa; 105 fs->regs.reg[15].how = REG_SAVED_OFFSET; 106 fs->regs.reg[15].loc.offset = (long)&sc->r15 - new_cfa; 107 fs->regs.reg[16].how = REG_SAVED_OFFSET; 108 fs->regs.reg[16].loc.offset = (long)&sc->rip - new_cfa; 109 fs->retaddr_column = 16; 110 fs->signal_frame = 1; 111 return _URC_NO_REASON; 112 } 113 114 #else /* ifdef __x86_64__ */ 115 116 #define MD_FALLBACK_FRAME_STATE_FOR x86_fallback_frame_state 117 118 static _Unwind_Reason_Code 119 x86_fallback_frame_state (struct _Unwind_Context *context, 120 _Unwind_FrameState *fs) 121 { 122 unsigned char *pc = context->ra; 123 struct sigcontext *sc; 124 long new_cfa; 125 126 /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80 */ 127 if (*(unsigned short *)(pc+0) == 0xb858 128 && *(unsigned int *)(pc+2) == 119 129 && *(unsigned short *)(pc+6) == 0x80cd) 130 sc = context->cfa + 4; 131 /* movl $__NR_rt_sigreturn,%eax ; int $0x80 */ 132 else if (*(unsigned char *)(pc+0) == 0xb8 133 && *(unsigned int *)(pc+1) == 173 134 && *(unsigned short *)(pc+5) == 0x80cd) 135 { 136 struct rt_sigframe { 137 int sig; 138 siginfo_t *pinfo; 139 void *puc; 140 siginfo_t info; 141 struct ucontext uc; 142 } *rt_ = context->cfa; 143 /* The void * cast is necessary to avoid an aliasing warning. 144 The aliasing warning is correct, but should not be a problem 145 because it does not alias anything. */ 146 sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext; 147 } 148 else 149 return _URC_END_OF_STACK; 150 151 new_cfa = sc->esp; 152 fs->regs.cfa_how = CFA_REG_OFFSET; 153 fs->regs.cfa_reg = 4; 154 fs->regs.cfa_offset = new_cfa - (long) context->cfa; 155 156 /* The SVR4 register numbering macros aren't usable in libgcc. */ 157 fs->regs.reg[0].how = REG_SAVED_OFFSET; 158 fs->regs.reg[0].loc.offset = (long)&sc->eax - new_cfa; 159 fs->regs.reg[3].how = REG_SAVED_OFFSET; 160 fs->regs.reg[3].loc.offset = (long)&sc->ebx - new_cfa; 161 fs->regs.reg[1].how = REG_SAVED_OFFSET; 162 fs->regs.reg[1].loc.offset = (long)&sc->ecx - new_cfa; 163 fs->regs.reg[2].how = REG_SAVED_OFFSET; 164 fs->regs.reg[2].loc.offset = (long)&sc->edx - new_cfa; 165 fs->regs.reg[6].how = REG_SAVED_OFFSET; 166 fs->regs.reg[6].loc.offset = (long)&sc->esi - new_cfa; 167 fs->regs.reg[7].how = REG_SAVED_OFFSET; 168 fs->regs.reg[7].loc.offset = (long)&sc->edi - new_cfa; 169 fs->regs.reg[5].how = REG_SAVED_OFFSET; 170 fs->regs.reg[5].loc.offset = (long)&sc->ebp - new_cfa; 171 fs->regs.reg[8].how = REG_SAVED_OFFSET; 172 fs->regs.reg[8].loc.offset = (long)&sc->eip - new_cfa; 173 fs->retaddr_column = 8; 174 fs->signal_frame = 1; 175 return _URC_NO_REASON; 176 } 177 178 #define MD_FROB_UPDATE_CONTEXT x86_frob_update_context 179 180 /* Fix up for kernels that have vDSO, but don't have S flag in it. */ 181 182 static void 183 x86_frob_update_context (struct _Unwind_Context *context, 184 _Unwind_FrameState *fs ATTRIBUTE_UNUSED) 185 { 186 unsigned char *pc = context->ra; 187 188 /* movl $__NR_rt_sigreturn,%eax ; {int $0x80 | syscall} */ 189 if (*(unsigned char *)(pc+0) == 0xb8 190 && *(unsigned int *)(pc+1) == 173 191 && (*(unsigned short *)(pc+5) == 0x80cd 192 || *(unsigned short *)(pc+5) == 0x050f)) 193 _Unwind_SetSignalFrame (context, 1); 194 } 195 196 #endif /* ifdef __x86_64__ */ 197 #endif /* not glibc 2.0 */ 198 #endif /* ifdef inhibit_libc */ 199