gnu-unwind.h revision 1.1.1.2
1 /* DWARF2 EH unwinding support for GNU Hurd: x86. 2 Copyright (C) 2020-2022 Free Software Foundation, Inc. 3 Contributed by Samuel Thibault <samuel.thibault (at) gnu.org> 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 GCC is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 Under Section 7 of GPL version 3, you are granted additional 18 permissions described in the GCC Runtime Library Exception, version 19 3.1, as published by the Free Software Foundation. 20 21 You should have received a copy of the GNU General Public License and 22 a copy of the GCC Runtime Library Exception along with this program; 23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 <http://www.gnu.org/licenses/>. */ 25 26 /* Do code reading to identify a signal frame, and set the frame 27 state data appropriately. See unwind-dw2.c for the structs. */ 28 29 #ifndef inhibit_libc 30 31 #include <signal.h> 32 33 #define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state 34 35 static _Unwind_Reason_Code 36 x86_gnu_fallback_frame_state 37 (struct _Unwind_Context *context, _Unwind_FrameState *fs) 38 { 39 struct handler_args { 40 int signo; 41 union 42 { 43 struct 44 { 45 long int sigcode; 46 struct sigcontext *scp; 47 } legacy; 48 struct 49 { 50 siginfo_t *siginfop; 51 ucontext_t *uctxp; 52 } posix; 53 }; 54 } *handler_args; 55 long int sigcode; 56 unsigned long usp; 57 58 /* 59 * i386 sigtramp frame we are looking for follows. 60 * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly) 61 * 62 * rpc_wait_trampoline: 63 * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap 64 * 5: 9a 00 00 00 00 07 00 lcall $7,$0 65 * 12: 89 01 movl %eax, (%ecx) 66 * 14: 89 dc movl %ebx, %esp switch to signal stack 67 * 68 * trampoline: 69 * 16: ff d2 call *%edx call the handler function 70 * RA HERE 71 * 18: 83 c4 0c addl $12, %esp pop its args 72 * 21: c3 ret return to sigreturn 73 * 74 * firewall: 75 * 22: f4 hlt 76 */ 77 78 if (!( *(unsigned int *)(context->ra ) == 0xc30cc483 79 && *(unsigned char *)(context->ra + 4) == 0xf4 80 81 && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89 82 && *(unsigned int *)(context->ra - 8) == 0x01890007 83 && *(unsigned int *)(context->ra - 12) == 0x00000000 84 && *(unsigned int *)(context->ra - 16) == 0x9affffff 85 && *(unsigned short *)(context->ra - 18) == 0xe7b8)) 86 return _URC_END_OF_STACK; 87 88 handler_args = context->cfa; 89 sigcode = handler_args->legacy.sigcode; 90 if (sigcode >= -16 && sigcode < 4096) 91 { 92 /* This cannot be a SIGINFO pointer, assume legacy. */ 93 struct sigcontext *scp = handler_args->legacy.scp; 94 usp = scp->sc_uesp; 95 96 fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp; 97 fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp; 98 fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp; 99 fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp; 100 fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp; 101 fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp; 102 fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp; 103 fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp; 104 } 105 else 106 { 107 /* This is not a valid sigcode, assume SIGINFO. */ 108 ucontext_t *uctxp = handler_args->posix.uctxp; 109 gregset_t *gregset = &uctxp->uc_mcontext.gregs; 110 usp = (*gregset)[REG_UESP]; 111 112 fs->regs.reg[0].loc.offset = (unsigned long)&(*gregset)[REG_EAX] - usp; 113 fs->regs.reg[1].loc.offset = (unsigned long)&(*gregset)[REG_ECX] - usp; 114 fs->regs.reg[2].loc.offset = (unsigned long)&(*gregset)[REG_EDX] - usp; 115 fs->regs.reg[3].loc.offset = (unsigned long)&(*gregset)[REG_EBX] - usp; 116 fs->regs.reg[5].loc.offset = (unsigned long)&(*gregset)[REG_EBP] - usp; 117 fs->regs.reg[6].loc.offset = (unsigned long)&(*gregset)[REG_ESI] - usp; 118 fs->regs.reg[7].loc.offset = (unsigned long)&(*gregset)[REG_EDI] - usp; 119 fs->regs.reg[8].loc.offset = (unsigned long)&(*gregset)[REG_EIP] - usp; 120 } 121 122 fs->regs.cfa_how = CFA_REG_OFFSET; 123 fs->regs.cfa_reg = 4; 124 fs->regs.cfa_offset = usp - (unsigned long) context->cfa; 125 126 fs->regs.reg[0].how = REG_SAVED_OFFSET; 127 fs->regs.reg[1].how = REG_SAVED_OFFSET; 128 fs->regs.reg[2].how = REG_SAVED_OFFSET; 129 fs->regs.reg[3].how = REG_SAVED_OFFSET; 130 fs->regs.reg[5].how = REG_SAVED_OFFSET; 131 fs->regs.reg[6].how = REG_SAVED_OFFSET; 132 fs->regs.reg[7].how = REG_SAVED_OFFSET; 133 fs->regs.reg[8].how = REG_SAVED_OFFSET; 134 135 fs->retaddr_column = 8; 136 fs->signal_frame = 1; 137 138 return _URC_NO_REASON; 139 } 140 141 #endif /* ifndef inhibit_libc */ 142
Indexes created Sun Mar 01 05:31:48 UTC 2026