diff options
Diffstat (limited to 'libgcc/config/i386/freebsd-unwind.h')
| -rw-r--r-- | libgcc/config/i386/freebsd-unwind.h | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/libgcc/config/i386/freebsd-unwind.h b/libgcc/config/i386/freebsd-unwind.h new file mode 100644 index 0000000000..a8e8edb993 --- /dev/null +++ b/libgcc/config/i386/freebsd-unwind.h @@ -0,0 +1,212 @@ +/* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86. + Copyright (C) 2015-2017 Free Software Foundation, Inc. + Contributed by John Marino <gnugcc@marino.st> + +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 +<http://www.gnu.org/licenses/>. */ + +/* Do code reading to identify a signal frame, and set the frame + state data appropriately. See unwind-dw2.c for the structs. */ + +#include <sys/types.h> +#include <signal.h> +#include <unistd.h> +#include <sys/sysctl.h> +#include <sys/ucontext.h> +#include <sys/user.h> +#include <machine/sigframe.h> + +#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.<pid> 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. + + <pc + 00>: lea 0x10(%rsp),%rdi + <pc + 05>: pushq $0x0 + <pc + 17>: mov $0x1a1,%rax + <pc + 14>: 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 + * <sigcode>: + * 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 <sigcode+0x15> + * 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__ */ |