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/* DWARF2 EH unwinding support for FreeBSD/ARM64 (aarch64).
Copyright (C) 2017-2021 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
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
<>. */
/* Identify a signal frame, and set the frame state data appropriately.
See unwind-dw2.c for the structs. */
/* Always include AArch64 unwinder header file. */
#include "config/aarch64/aarch64-unwind.h"
#include <sys/types.h>
#include <signal.h>
#include <unistd.h>
#include <sys/ucontext.h>
#include <machine/frame.h>
#include <sys/user.h>
#include <sys/sysctl.h>
#define REG_NAME(reg) mc_gpregs.gp_## reg
#define XREG(num) mc_gpregs.gp_x[num]
#define MD_FALLBACK_FRAME_STATE_FOR aarch64_freebsd_fallback_frame_state
static int
aarch64_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);
static _Unwind_Reason_Code
(struct _Unwind_Context *context, _Unwind_FrameState *fs)
int n;
struct sigframe *sf;
mcontext_t *sc;
_Unwind_Ptr new_cfa;
if (aarch64_outside_sigtramp_range(context->ra))
sf = (struct sigframe *) context->cfa;
sc = &sf->sf_uc.uc_mcontext;
new_cfa = (_Unwind_Ptr) sc;
fs->regs.cfa_how = CFA_REG_OFFSET;
fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
for (n = 0; n < 32; n++)
fs->regs.reg[n].how = REG_SAVED_OFFSET;
for (n = 0; n < 30; n++)
fs->regs.reg[n].loc.offset = (_Unwind_Ptr) &(sc->XREG(n)) - new_cfa;
fs->regs.reg[30].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(lr)) - new_cfa;
fs->regs.reg[31].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(sp)) - new_cfa;
fs->regs.reg[DARC].how = REG_SAVED_OFFSET;
fs->regs.reg[DARC].loc.offset = (_Unwind_Ptr) &(sc->REG_NAME(elr)) - new_cfa;
fs->retaddr_column = DARC;
fs->signal_frame = 1;
return _URC_NO_REASON;