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/* Copyright (C) 2009-2021 Free Software Foundation, Inc.
Contributed by ARM Ltd.
This file 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.
This file is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
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
<>. */
/* Always include AArch64 unwinder header file. */
#include "config/aarch64/aarch64-unwind.h"
#ifndef inhibit_libc
#include <signal.h>
#include <sys/ucontext.h>
/* Since insns are always stored LE, on a BE system the opcodes will
be loaded byte-reversed. Therefore, define two sets of opcodes,
one for LE and one for BE. */
#if __AARCH64EB__
#define MOVZ_X8_8B 0x681180d2
#define SVC_0 0x010000d4
#define MOVZ_X8_8B 0xd2801168
#define SVC_0 0xd4000001
#define MD_FALLBACK_FRAME_STATE_FOR aarch64_fallback_frame_state
static _Unwind_Reason_Code
aarch64_fallback_frame_state (struct _Unwind_Context *context,
_Unwind_FrameState * fs)
/* The kernel creates an rt_sigframe on the stack immediately prior
to delivering a signal.
This structure must have the same shape as the linux kernel
equivalent. */
struct rt_sigframe
siginfo_t info;
ucontext_t uc;
struct rt_sigframe *rt_;
_Unwind_Ptr new_cfa;
unsigned *pc = context->ra;
struct sigcontext *sc;
struct _aarch64_ctx *extension_marker;
int i;
/* A signal frame will have a return address pointing to
__default_sa_restorer. This code is hardwired as:
0xd2801168 movz x8, #0x8b
0xd4000001 svc 0x0
if (pc[0] != MOVZ_X8_8B || pc[1] != SVC_0)
rt_ = context->cfa;
sc = &rt_->uc.uc_mcontext;
/* This define duplicates the definition in */
#define SP_REGNUM 31
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 (i = 0; i < AARCH64_DWARF_NUMBER_R; i++)
fs->regs.reg[AARCH64_DWARF_R0 + i].how = REG_SAVED_OFFSET;
fs->regs.reg[AARCH64_DWARF_R0 + i].loc.offset =
(_Unwind_Ptr) & (sc->regs[i]) - new_cfa;
/* The core context may be extended with an arbitrary set of
additional contexts appended sequentially. Each additional
context contains a magic identifier and size in bytes. The size
field can be used to skip over unrecognized context extensions.
The end of the context sequence is marked by a context with magic
0 or size 0. */
for (extension_marker = (struct _aarch64_ctx *) &sc->__reserved;
extension_marker = (struct _aarch64_ctx *)
((unsigned char *) extension_marker + extension_marker->size))
if (extension_marker->magic == FPSIMD_MAGIC)
struct fpsimd_context *ctx =
(struct fpsimd_context *) extension_marker;
int i;
for (i = 0; i < AARCH64_DWARF_NUMBER_V; i++)
_Unwind_Sword offset;
fs->regs.reg[AARCH64_DWARF_V0 + i].how = REG_SAVED_OFFSET;
/* sigcontext contains 32 128bit registers for V0 to
V31. The kernel will have saved the contents of the
V registers. We want to unwind the callee save D
registers. Each D register comprises the least
significant half of the corresponding V register. We
need to offset into the saved V register dependent on
our endianness to find the saved D register. */
offset = (_Unwind_Ptr) & (ctx->vregs[i]) - new_cfa;
/* The endianness adjustment code below expects that a
saved V register is 16 bytes. */
gcc_assert (sizeof (ctx->vregs[0]) == 16);
#if defined (__AARCH64EB__)
offset = offset + 8;
fs->regs.reg[AARCH64_DWARF_V0 + i].loc.offset = offset;
/* There is context provided that we do not recognize! */
fs->regs.reg[31].how = REG_SAVED_OFFSET;
fs->regs.reg[31].loc.offset = (_Unwind_Ptr) & (sc->sp) - new_cfa;
fs->signal_frame = 1;
fs->regs.reg[__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__].loc.offset =
(_Unwind_Ptr) (sc->pc) - new_cfa;
fs->retaddr_column = __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__;
return _URC_NO_REASON;