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/* DWARF2 EH unwinding support for ARC Linux.
Copyright (C) 2017-2022 Free Software Foundation, Inc.
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/>. */
/* This order is defined by a structure in the kernel, in file
arch/arc/kernel/signal.c. */
#define REGISTER_IN_STACK(REG_NAME, ID) \
REG_NAME,
enum registers_stack_order {
REGISTER_STACK_ORDER_START = -1,
#include "config/arc/linux-unwind-reg.def"
REGISTER_STACK_ORDER_SIZE,
};
struct register_position {
int reg_id;
int offset_in_stack;
};
#undef REGISTER_IN_STACK
#define REGISTER_SIZE_IN_WORDS 4
#define REGISTER_IN_STACK(REG_NAME, ID) (int) ID,
int
register_id_for_index[REGISTER_STACK_ORDER_SIZE] = {
#include "config/arc/linux-unwind-reg.def"
};
#undef REGISTER_IN_STACK
#ifndef inhibit_libc
/* Do code reading to identify a signal frame, and set the frame
state data appropriately. See unwind-dw2.c for the structs. */
#include <signal.h>
#include <asm/unistd.h>
/*
00010edc <__default_rt_sa_restorer>:
10edc: 208a 12c2 mov r8,139
10ee0: 781e trap_s 0
10ee2: 7ee0 j_s [blink]
*/
#if __BIG_ENDIAN__
#define MOV_R8_139 0x8a20c212
#define TRAP_S_J_S_BLINK 0x1e78e07e
#define SWI 0x6f223f00
#elif __LITTLE_ENDIAN__
#define MOV_R8_139 0x12c2208a
#define TRAP_S_J_S_BLINK 0x7ee0781e
#define SWI 0x003f226f
#endif
#define MD_FALLBACK_FRAME_STATE_FOR arc_fallback_frame_state
static __attribute__((noinline)) _Unwind_Reason_Code
arc_fallback_frame_state (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
struct rt_sigframe {
siginfo_t info;
ucontext_t uc;
unsigned int sigret_magic;
};
struct rt_sigframe *rt_;
u_int32_t *pc = (u_int32_t *) context->ra;
struct sigcontext *sc;
_Unwind_Ptr new_cfa;
int i;
#ifdef __ARC700__
if (pc[1] != SWI)
return _URC_END_OF_STACK;
#else
if (pc[1] != TRAP_S_J_S_BLINK)
return _URC_END_OF_STACK;
#endif
if (pc[0] == MOV_R8_139)
{
rt_ = context->cfa;
sc = &rt_->uc.uc_mcontext;
}
else
return _URC_END_OF_STACK;
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;
unsigned long *regs = &sc->regs.scratch.bta;
for (i = 0; i < REGISTER_STACK_ORDER_SIZE; i++)
{
if (register_id_for_index[i] == -1)
continue;
fs->regs.reg[register_id_for_index[i]].how = REG_SAVED_OFFSET;
fs->regs.reg[register_id_for_index[i]].loc.offset
= ((_Unwind_Ptr) &(regs[i])) - new_cfa;
}
fs->signal_frame = 1;
fs->retaddr_column = __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__;
fs->regs.reg[fs->retaddr_column].how = REG_SAVED_VAL_OFFSET;
fs->regs.reg[fs->retaddr_column].loc.offset =
((_Unwind_Ptr) (regs[ret])) - new_cfa;
return _URC_NO_REASON;
}
#endif
#define MD_FROB_UPDATE_CONTEXT arc_frob_update_context
/* Save fp register for unwinding to work. */
static void
arc_frob_update_context (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
_Unwind_Word fp_val;
asm ("mov %0,fp" : "=r" (fp_val));
switch (fs->regs.reg[27].how)
{
case REG_UNSAVED:
case REG_UNDEFINED:
if (context->reg[27] == NULL)
_Unwind_SetGRValue (context, 27, fp_val);
break;
default:
break;
}
}