1/* DWARF2 EH unwinding support for TILEPro.
2   Copyright (C) 2011-2020 Free Software Foundation, Inc.
3   Contributed by Walter Lee (walt@tilera.com)
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 3, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17Under Section 7 of GPL version 3, you are granted additional
18permissions described in the GCC Runtime Library Exception, version
193.1, as published by the Free Software Foundation.
20
21You should have received a copy of the GNU General Public License and
22a copy of the GCC Runtime Library Exception along with this program;
23see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24<http://www.gnu.org/licenses/>.  */
25
26#ifndef inhibit_libc
27
28#include <arch/abi.h>
29#include <signal.h>
30#include <sys/ucontext.h>
31#include <linux/unistd.h>
32
33/* Macro to define a copy of the kernel's __rt_sigreturn function
34   (in arch/tile/kernel/entry.S).  If that function is changed,
35   this one needs to be changed to match it.  */
36#define _sigreturn_asm(REG, NR) asm(                    \
37    ".pushsection .text.__rt_sigreturn,\"a\"\n"         \
38    ".global __rt_sigreturn\n"                          \
39    ".type __rt_sigreturn,@function\n"                  \
40    "__rt_sigreturn:\n"                                 \
41    "moveli " #REG ", " #NR "\n"                        \
42    "swint1\n"                                          \
43    ".size __rt_sigreturn, . - __rt_sigreturn\n"        \
44    ".popsection")
45#define sigreturn_asm(REG, NR) _sigreturn_asm(REG, NR)
46sigreturn_asm (TREG_SYSCALL_NR_NAME, __NR_rt_sigreturn);
47#define SIGRETURN_LEN 16
48extern char __rt_sigreturn[];
49
50#define MD_FALLBACK_FRAME_STATE_FOR tile_fallback_frame_state
51
52static _Unwind_Reason_Code
53tile_fallback_frame_state (struct _Unwind_Context *context,
54			      _Unwind_FrameState *fs)
55{
56  unsigned char *pc = context->ra;
57  struct sigcontext *sc;
58  long new_cfa;
59  int i;
60
61  struct rt_sigframe {
62    unsigned char save_area[C_ABI_SAVE_AREA_SIZE];
63    siginfo_t info;
64    ucontext_t uc;
65  } *rt_;
66
67  /* Return if this is not a signal handler.  */
68  if (memcmp (pc, __rt_sigreturn, SIGRETURN_LEN) != 0)
69    return _URC_END_OF_STACK;
70
71  /* It was a signal handler; update the reported PC to point to our
72     copy, since that will be findable with dladdr() and therefore
73     somewhat easier to help understand what actually happened. */
74  context->ra = __rt_sigreturn;
75
76  rt_ = context->cfa;
77  sc = &rt_->uc.uc_mcontext;
78
79  new_cfa = sc->sp;
80  fs->regs.cfa_how = CFA_REG_OFFSET;
81  fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
82  fs->regs.cfa_offset = new_cfa - (long) context->cfa;
83
84  for (i = 0; i < 56; ++i)
85    {
86      fs->regs.reg[i].how = REG_SAVED_OFFSET;
87      fs->regs.reg[i].loc.offset
88	= (long)&sc->gregs[i] - new_cfa;
89    }
90
91  fs->regs.reg[56].how = REG_SAVED_OFFSET;
92  fs->regs.reg[56].loc.offset = (long)&sc->pc - new_cfa;
93  fs->retaddr_column = 56;
94  fs->signal_frame = 1;
95
96  return _URC_NO_REASON;
97}
98
99#endif /* ifdef inhibit_libc  */
100