freebsd-unwind.h revision 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 (at) marino.st> 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 #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 39 static _Unwind_Reason_Code 40 x86_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 */ 121 122 static _Unwind_Reason_Code 123 x86_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
Indexes created Wed May 06 00:24:28 UTC 2026