1 /* Target-dependent code for GNU/Linux on Alpha.
2 Copyright 2002 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
26 #include "alpha-tdep.h"
28 /* Under GNU/Linux, signal handler invocations can be identified by the
29 designated code sequence that is used to return from a signal
30 handler. In particular, the return address of a signal handler
31 points to the following sequence (the first instruction is quadword
38 Each instruction has a unique encoding, so we simply attempt to
39 match the instruction the pc is pointing to with any of the above
40 instructions. If there is a hit, we know the offset to the start
41 of the designated sequence and can then check whether we really are
42 executing in a designated sequence. If not, -1 is returned,
43 otherwise the offset from the start of the desingated sequence is
46 There is a slight chance of false hits: code could jump into the
47 middle of the designated sequence, in which case there is no
48 guarantee that we are in the middle of a sigreturn syscall. Don't
49 think this will be a problem in praxis, though. */
51 alpha_linux_sigtramp_offset (CORE_ADDR pc
)
56 if (read_memory_nobpt (pc
, (char *) &w
, 4) != 0)
64 break; /* bis $30,$30,$16 */
67 break; /* addq $31,0x67,$0 */
70 break; /* call_pal callsys */
77 /* designated sequence is not quadword aligned */
80 if (read_memory_nobpt (pc
, (char *) i
, sizeof (i
)) != 0)
83 if (i
[0] == 0x47de0410 && i
[1] == 0x43ecf400 && i
[2] == 0x00000083)
90 alpha_linux_pc_in_sigtramp (CORE_ADDR pc
, char *func_name
)
92 return (alpha_linux_sigtramp_offset (pc
) >= 0);
96 alpha_linux_sigcontext_addr (struct frame_info
*frame
)
98 return (frame
->frame
- 0x298); /* sizeof(struct sigcontext) */
102 alpha_linux_init_abi (struct gdbarch_info info
,
103 struct gdbarch
*gdbarch
)
105 struct gdbarch_tdep
*tdep
= gdbarch_tdep (gdbarch
);
107 set_gdbarch_pc_in_sigtramp (gdbarch
, alpha_linux_pc_in_sigtramp
);
109 tdep
->dynamic_sigtramp_offset
= alpha_linux_sigtramp_offset
;
110 tdep
->sigcontext_addr
= alpha_linux_sigcontext_addr
;
113 tdep
->jb_elt_size
= 8;
117 _initialize_alpha_linux_tdep (void)
119 gdbarch_register_osabi (bfd_arch_alpha
, GDB_OSABI_LINUX
,
120 alpha_linux_init_abi
);