1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/* Target-dependent code for GNU/Linux on Alpha.
Copyright 2002 Free Software Foundation, Inc.
This file is part of GDB.
This program 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 2 of the License, or
(at your option) any later version.
This program 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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "frame.h"
#include "gdbcore.h"
#include "value.h"
#include "alpha-tdep.h"
/* Under GNU/Linux, signal handler invocations can be identified by the
designated code sequence that is used to return from a signal
handler. In particular, the return address of a signal handler
points to the following sequence (the first instruction is quadword
aligned):
bis $30,$30,$16
addq $31,0x67,$0
call_pal callsys
Each instruction has a unique encoding, so we simply attempt to
match the instruction the pc is pointing to with any of the above
instructions. If there is a hit, we know the offset to the start
of the designated sequence and can then check whether we really are
executing in a designated sequence. If not, -1 is returned,
otherwise the offset from the start of the desingated sequence is
returned.
There is a slight chance of false hits: code could jump into the
middle of the designated sequence, in which case there is no
guarantee that we are in the middle of a sigreturn syscall. Don't
think this will be a problem in praxis, though. */
LONGEST
alpha_linux_sigtramp_offset (CORE_ADDR pc)
{
unsigned int i[3], w;
long off;
if (read_memory_nobpt (pc, (char *) &w, 4) != 0)
return -1;
off = -1;
switch (w)
{
case 0x47de0410:
off = 0;
break; /* bis $30,$30,$16 */
case 0x43ecf400:
off = 4;
break; /* addq $31,0x67,$0 */
case 0x00000083:
off = 8;
break; /* call_pal callsys */
default:
return -1;
}
pc -= off;
if (pc & 0x7)
{
/* designated sequence is not quadword aligned */
return -1;
}
if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0)
return -1;
if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083)
return off;
return -1;
}
static int
alpha_linux_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
{
return (alpha_linux_sigtramp_offset (pc) >= 0);
}
static CORE_ADDR
alpha_linux_sigcontext_addr (struct frame_info *frame)
{
return (frame->frame - 0x298); /* sizeof(struct sigcontext) */
}
static void
alpha_linux_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
set_gdbarch_pc_in_sigtramp (gdbarch, alpha_linux_pc_in_sigtramp);
tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
tdep->jb_pc = 2;
tdep->jb_elt_size = 8;
}
void
_initialize_alpha_linux_tdep (void)
{
alpha_gdbarch_register_os_abi (ALPHA_ABI_LINUX, alpha_linux_init_abi);
}
|
