unwind-arm-vxworks.c revision 1.1.1.3 
1/* Support for ARM EABI unwinding on VxWorks Downloadable Kernel Modules.
2   Copyright (C) 2017-2020 Free Software Foundation, Inc.
3
4   This file is free software; you can redistribute it and/or modify it
5   under the terms of the GNU General Public License as published by the
6   Free Software Foundation; either version 3, or (at your option) any
7   later version.
8
9   This file is distributed in the hope that it will be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   General Public License for more details.
13
14   Under Section 7 of GPL version 3, you are granted additional
15   permissions described in the GCC Runtime Library Exception, version
16   3.1, as published by the Free Software Foundation.
17
18   You should have received a copy of the GNU General Public License and
19   a copy of the GCC Runtime Library Exception along with this program;
20   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
21   <http://www.gnu.org/licenses/>.  */
22
23/* The common unwinding code refers to __gnu_Unwind_Find_exidx and
24   __cxa_type_match symbols, which are not in VxWorks kernels on ARM,
25   now llvm based.
26
27   While the common code works just fine for RTPs thanks to weak references
28   and proper positioning of __exidx_start/end from linker scripts, we need
29   symbol definitions for kernel modules.  */
30
31#ifndef __RTP__
32
33#include <private/moduleLibP.h>
34
35/* __gnu_Unwind_Find_exidx.  See if we can use _func_moduleExidxGet to
36   refine whatever we have in __exidx_start and __exidx_end.  */
37
38typedef struct
39{
40  UINT32 fnoffset;
41  UINT32 content;
42} __EIT_entry;
43
44extern __EIT_entry __exidx_start;
45extern __EIT_entry __exidx_end;
46
47__EIT_entry *
48__gnu_Unwind_Find_exidx (void *pc, int *nrec)
49{
50  __EIT_entry *pstart = 0;
51  __EIT_entry *pend = 0;
52
53  if (_func_moduleExidxGet != NULL)
54    _func_moduleExidxGet (pc,
55			  (void *) &__exidx_start, (void *) &__exidx_end,
56			  (void **) &pstart, (void **) &pend);
57
58  if (!pstart)
59    {
60      pstart = &__exidx_start;
61      pend = &__exidx_end;
62    }
63
64  *nrec = pend - pstart;
65
66  return pstart;
67}
68
69/* __cxa_type_match.  A dummy version to be overridden by the libstdc++ one
70 when we link with it.  */
71
72void * __attribute__((weak))
73__cxa_type_match ()
74{
75  return (void *) 0;
76}
77
78#endif
79