1/* DWARF2 EH unwinding support for Alpha Linux.
2   Copyright (C) 2004, 2005, 2009 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 3, or (at your option)
9any later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.
15
16Under Section 7 of GPL version 3, you are granted additional
17permissions described in the GCC Runtime Library Exception, version
183.1, as published by the Free Software Foundation.
19
20You should have received a copy of the GNU General Public License and
21a copy of the GCC Runtime Library Exception along with this program;
22see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23<http://www.gnu.org/licenses/>.  */
24
25/* Do code reading to identify a signal frame, and set the frame
26   state data appropriately.  See unwind-dw2.c for the structs.  */
27
28#include <signal.h>
29#include <sys/ucontext.h>
30
31#define MD_FALLBACK_FRAME_STATE_FOR alpha_fallback_frame_state
32
33static _Unwind_Reason_Code
34alpha_fallback_frame_state (struct _Unwind_Context *context,
35			    _Unwind_FrameState *fs)
36{
37  unsigned int *pc = context->ra;
38  struct sigcontext *sc;
39  long new_cfa, i;
40
41  if (pc[0] != 0x47fe0410		/* mov $30,$16 */
42      || pc[2] != 0x00000083		/* callsys */)
43    return _URC_END_OF_STACK;
44  if (context->cfa == 0)
45    return _URC_END_OF_STACK;
46  if (pc[1] == 0x201f0067)		/* lda $0,NR_sigreturn */
47    sc = context->cfa;
48  else if (pc[1] == 0x201f015f)	/* lda $0,NR_rt_sigreturn */
49    {
50      struct rt_sigframe {
51	struct siginfo info;
52	struct ucontext uc;
53      } *rt_ = context->cfa;
54      sc = &rt_->uc.uc_mcontext;
55    }
56  else
57    return _URC_END_OF_STACK;
58  new_cfa = sc->sc_regs[30];
59  fs->regs.cfa_how = CFA_REG_OFFSET;
60  fs->regs.cfa_reg = 30;
61  fs->regs.cfa_offset = new_cfa - (long) context->cfa;
62  for (i = 0; i < 30; ++i)
63    {
64      fs->regs.reg[i].how = REG_SAVED_OFFSET;
65      fs->regs.reg[i].loc.offset
66	= (long)&sc->sc_regs[i] - new_cfa;
67    }
68  for (i = 0; i < 31; ++i)
69    {
70      fs->regs.reg[i+32].how = REG_SAVED_OFFSET;
71      fs->regs.reg[i+32].loc.offset
72	= (long)&sc->sc_fpregs[i] - new_cfa;
73    }
74  fs->regs.reg[64].how = REG_SAVED_OFFSET;
75  fs->regs.reg[64].loc.offset = (long)&sc->sc_pc - new_cfa;
76  fs->retaddr_column = 64;
77  return _URC_NO_REASON;
78}
79