freebsd-unwind.h revision 1.1.1.1
1/* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86. 2 Copyright (C) 2015 Free Software Foundation, Inc. 3 Contributed by John Marino <gnugcc@marino.st> 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as published by 9the Free Software Foundation; either version 3, or (at your option) 10any later version. 11 12GCC is distributed in the hope that it will be useful, 13but WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15GNU General Public License for more details. 16 17Under Section 7 of GPL version 3, you are granted additional 18permissions described in the GCC Runtime Library Exception, version 193.1, as published by the Free Software Foundation. 20 21You should have received a copy of the GNU General Public License and 22a copy of the GCC Runtime Library Exception along with this program; 23see 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#include <sys/types.h> 30#include <signal.h> 31#include <sys/ucontext.h> 32#include <machine/sigframe.h> 33 34#define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg 35 36#ifdef __x86_64__ 37#define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state 38 39static _Unwind_Reason_Code 40x86_64_freebsd_fallback_frame_state 41(struct _Unwind_Context *context, _Unwind_FrameState *fs) 42{ 43 struct sigframe *sf; 44 long new_cfa; 45 46 /* Prior to FreeBSD 9, the signal trampoline was located immediately 47 before the ps_strings. To support non-executable stacks on AMD64, 48 the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately 49 this means looking frame patterns again (sys/amd64/amd64/sigtramp.S) 50 rather than using the robust and convenient KERN_PS_STRINGS trick. 51 52 <pc + 00>: lea 0x10(%rsp),%rdi 53 <pc + 05>: pushq $0x0 54 <pc + 17>: mov $0x1a1,%rax 55 <pc + 14>: syscall 56 57 If we can't find this pattern, we're at the end of the stack. 58 */ 59 60 if (!( *(unsigned int *)(context->ra) == 0x247c8d48 61 && *(unsigned int *)(context->ra + 4) == 0x48006a10 62 && *(unsigned int *)(context->ra + 8) == 0x01a1c0c7 63 && *(unsigned int *)(context->ra + 12) == 0x050f0000 )) 64 return _URC_END_OF_STACK; 65 66 sf = (struct sigframe *) context->cfa; 67 new_cfa = sf->REG_NAME(rsp); 68 fs->regs.cfa_how = CFA_REG_OFFSET; 69 /* Register 7 is rsp */ 70 fs->regs.cfa_reg = 7; 71 fs->regs.cfa_offset = new_cfa - (long) context->cfa; 72 73 /* The SVR4 register numbering macros aren't usable in libgcc. */ 74 fs->regs.reg[0].how = REG_SAVED_OFFSET; 75 fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa; 76 fs->regs.reg[1].how = REG_SAVED_OFFSET; 77 fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa; 78 fs->regs.reg[2].how = REG_SAVED_OFFSET; 79 fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa; 80 fs->regs.reg[3].how = REG_SAVED_OFFSET; 81 fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa; 82 fs->regs.reg[4].how = REG_SAVED_OFFSET; 83 fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa; 84 fs->regs.reg[5].how = REG_SAVED_OFFSET; 85 fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa; 86 fs->regs.reg[6].how = REG_SAVED_OFFSET; 87 fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa; 88 fs->regs.reg[8].how = REG_SAVED_OFFSET; 89 fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa; 90 fs->regs.reg[9].how = REG_SAVED_OFFSET; 91 fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa; 92 fs->regs.reg[10].how = REG_SAVED_OFFSET; 93 fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa; 94 fs->regs.reg[11].how = REG_SAVED_OFFSET; 95 fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa; 96 fs->regs.reg[12].how = REG_SAVED_OFFSET; 97 fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa; 98 fs->regs.reg[13].how = REG_SAVED_OFFSET; 99 fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa; 100 fs->regs.reg[14].how = REG_SAVED_OFFSET; 101 fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa; 102 fs->regs.reg[15].how = REG_SAVED_OFFSET; 103 fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa; 104 fs->regs.reg[16].how = REG_SAVED_OFFSET; 105 fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa; 106 fs->retaddr_column = 16; 107 fs->signal_frame = 1; 108 return _URC_NO_REASON; 109} 110 111#else /* Next section is for i386 */ 112 113#define MD_FALLBACK_FRAME_STATE_FOR x86_freebsd_fallback_frame_state 114 115/* 116 * We can't use KERN_PS_STRINGS anymore if we want to support FreeBSD32 117 * compat on AMD64. The sigtramp is in a shared page in that case so the 118 * x86_sigtramp_range only works on a true i386 system. We have to 119 * search for the sigtramp frame if we want it working everywhere. 120 */ 121 122static _Unwind_Reason_Code 123x86_freebsd_fallback_frame_state 124(struct _Unwind_Context *context, _Unwind_FrameState *fs) 125{ 126 struct sigframe *sf; 127 long new_cfa; 128 129/* 130 * i386 sigtramp frame we are looking for follows. 131 * Apparently PSL_VM is variable, so we can't look past context->ra + 4 132 * <sigcode>: 133 * 0: ff 54 24 10 call *0x10(%esp) *SIGF_HANDLER 134 * 4: 8d 44 24 20 lea 0x20(%esp),%eax SIGF_UC 135 * 8: 50 push %eax 136 * 9: f7 40 54 00 00 02 00 testl $0x20000,0x54(%eax) $PSL_VM 137 * 10: 75 03 jne 15 <sigcode+0x15> 138 * 12: 8e 68 14 mov 0x14(%eax),%gs UC_GS 139 * 15: b8 a1 01 00 00 mov 0x1a1,%eax $SYS_sigreturn 140 */ 141 142 if (!( *(unsigned int *)(context->ra - 4) == 0x102454ff 143 && *(unsigned int *)(context->ra) == 0x2024448d )) 144 return _URC_END_OF_STACK; 145 146 sf = (struct sigframe *) context->cfa; 147 new_cfa = sf->REG_NAME(esp); 148 fs->regs.cfa_how = CFA_REG_OFFSET; 149 fs->regs.cfa_reg = 4; 150 fs->regs.cfa_offset = new_cfa - (long) context->cfa; 151 152 /* The SVR4 register numbering macros aren't usable in libgcc. */ 153 fs->regs.reg[0].how = REG_SAVED_OFFSET; 154 fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa; 155 fs->regs.reg[3].how = REG_SAVED_OFFSET; 156 fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa; 157 fs->regs.reg[1].how = REG_SAVED_OFFSET; 158 fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa; 159 fs->regs.reg[2].how = REG_SAVED_OFFSET; 160 fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa; 161 fs->regs.reg[6].how = REG_SAVED_OFFSET; 162 fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa; 163 fs->regs.reg[7].how = REG_SAVED_OFFSET; 164 fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa; 165 fs->regs.reg[5].how = REG_SAVED_OFFSET; 166 fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa; 167 fs->regs.reg[8].how = REG_SAVED_OFFSET; 168 fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa; 169 fs->retaddr_column = 8; 170 fs->signal_frame = 1; 171 return _URC_NO_REASON; 172} 173#endif /* ifdef __x86_64__ */ 174