/* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86. Copyright (C) 2015-2017 Free Software Foundation, Inc. Contributed by John Marino This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see . */ /* Do code reading to identify a signal frame, and set the frame state data appropriately. See unwind-dw2.c for the structs. */ #include #include #include #include #include #include #include #define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg #ifdef __x86_64__ #define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state #ifdef KERN_PROC_SIGTRAMP /* FreeBSD past 9.3 provides a kern.proc.sigtramp. sysctl that returns the location of the signal trampoline. Use this to find out whether we're in a trampoline. */ static int x86_64_outside_sigtramp_range (unsigned char *pc) { static int sigtramp_range_determined = 0; static unsigned char *sigtramp_start, *sigtramp_end; if (sigtramp_range_determined == 0) { struct kinfo_sigtramp kst = {0}; size_t len = sizeof (kst); int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid() }; sigtramp_range_determined = 1; if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0) { sigtramp_range_determined = 2; sigtramp_start = kst.ksigtramp_start; sigtramp_end = kst.ksigtramp_end; } } if (sigtramp_range_determined < 2) /* sysctl failed if < 2 */ return 1; return (pc < sigtramp_start || pc >= sigtramp_end); } #endif static _Unwind_Reason_Code x86_64_freebsd_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState *fs) { struct sigframe *sf; long new_cfa; #ifndef KERN_PROC_SIGTRAMP /* Prior to FreeBSD 9, the signal trampoline was located immediately before the ps_strings. To support non-executable stacks on AMD64, the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately this means looking frame patterns again (sys/amd64/amd64/sigtramp.S) rather than using the robust and convenient KERN_PS_STRINGS trick. : lea 0x10(%rsp),%rdi : pushq $0x0 : mov $0x1a1,%rax : syscall If we can't find this pattern, we're at the end of the stack. */ if (!( *(unsigned int *)(context->ra) == 0x247c8d48 && *(unsigned int *)(context->ra + 4) == 0x48006a10 && *(unsigned int *)(context->ra + 8) == 0x01a1c0c7 && *(unsigned int *)(context->ra + 12) == 0x050f0000 )) return _URC_END_OF_STACK; #else if (x86_64_outside_sigtramp_range(context->ra)) return _URC_END_OF_STACK; #endif sf = (struct sigframe *) context->cfa; new_cfa = sf->REG_NAME(rsp); fs->regs.cfa_how = CFA_REG_OFFSET; fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__; fs->regs.cfa_offset = new_cfa - (long) context->cfa; /* The SVR4 register numbering macros aren't usable in libgcc. */ fs->regs.reg[0].how = REG_SAVED_OFFSET; fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa; fs->regs.reg[1].how = REG_SAVED_OFFSET; fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa; fs->regs.reg[2].how = REG_SAVED_OFFSET; fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa; fs->regs.reg[3].how = REG_SAVED_OFFSET; fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa; fs->regs.reg[4].how = REG_SAVED_OFFSET; fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa; fs->regs.reg[5].how = REG_SAVED_OFFSET; fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa; fs->regs.reg[6].how = REG_SAVED_OFFSET; fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa; fs->regs.reg[8].how = REG_SAVED_OFFSET; fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa; fs->regs.reg[9].how = REG_SAVED_OFFSET; fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa; fs->regs.reg[10].how = REG_SAVED_OFFSET; fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa; fs->regs.reg[11].how = REG_SAVED_OFFSET; fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa; fs->regs.reg[12].how = REG_SAVED_OFFSET; fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa; fs->regs.reg[13].how = REG_SAVED_OFFSET; fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa; fs->regs.reg[14].how = REG_SAVED_OFFSET; fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa; fs->regs.reg[15].how = REG_SAVED_OFFSET; fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa; fs->regs.reg[16].how = REG_SAVED_OFFSET; fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa; fs->retaddr_column = 16; fs->signal_frame = 1; return _URC_NO_REASON; } #else /* Next section is for i386 */ #define MD_FALLBACK_FRAME_STATE_FOR x86_freebsd_fallback_frame_state /* * We can't use KERN_PS_STRINGS anymore if we want to support FreeBSD32 * compat on AMD64. The sigtramp is in a shared page in that case so the * x86_sigtramp_range only works on a true i386 system. We have to * search for the sigtramp frame if we want it working everywhere. */ static _Unwind_Reason_Code x86_freebsd_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState *fs) { struct sigframe *sf; long new_cfa; /* * i386 sigtramp frame we are looking for follows. * Apparently PSL_VM is variable, so we can't look past context->ra + 4 * : * 0: ff 54 24 10 call *0x10(%esp) *SIGF_HANDLER * 4: 8d 44 24 20 lea 0x20(%esp),%eax SIGF_UC * 8: 50 push %eax * 9: f7 40 54 00 00 02 00 testl $0x20000,0x54(%eax) $PSL_VM * 10: 75 03 jne 15 * 12: 8e 68 14 mov 0x14(%eax),%gs UC_GS * 15: b8 a1 01 00 00 mov 0x1a1,%eax $SYS_sigreturn */ if (!( *(unsigned int *)(context->ra - 4) == 0x102454ff && *(unsigned int *)(context->ra) == 0x2024448d )) return _URC_END_OF_STACK; sf = (struct sigframe *) context->cfa; new_cfa = sf->REG_NAME(esp); fs->regs.cfa_how = CFA_REG_OFFSET; fs->regs.cfa_reg = 4; fs->regs.cfa_offset = new_cfa - (long) context->cfa; /* The SVR4 register numbering macros aren't usable in libgcc. */ fs->regs.reg[0].how = REG_SAVED_OFFSET; fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa; fs->regs.reg[3].how = REG_SAVED_OFFSET; fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa; fs->regs.reg[1].how = REG_SAVED_OFFSET; fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa; fs->regs.reg[2].how = REG_SAVED_OFFSET; fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa; fs->regs.reg[6].how = REG_SAVED_OFFSET; fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa; fs->regs.reg[7].how = REG_SAVED_OFFSET; fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa; fs->regs.reg[5].how = REG_SAVED_OFFSET; fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa; fs->regs.reg[8].how = REG_SAVED_OFFSET; fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa; fs->retaddr_column = 8; fs->signal_frame = 1; return _URC_NO_REASON; } #endif /* ifdef __x86_64__ */