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8a112c90 MK |
1 | /* Target-dependent code for OpenBSD/alpha. |
2 | ||
3 | Copyright (C) 2006 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
20 | Boston, MA 02110-1301, USA. */ | |
21 | ||
22 | #include "defs.h" | |
23 | #include "frame.h" | |
24 | #include "gdbcore.h" | |
25 | #include "osabi.h" | |
26 | ||
27 | #include "alpha-tdep.h" | |
28 | #include "alphabsd-tdep.h" | |
29 | #include "solib-svr4.h" | |
30 | ||
31 | /* Signal trampolines. */ | |
32 | ||
33 | /* The OpenBSD kernel maps the signal trampoline at some random | |
34 | location in user space, which means that the traditional BSD way of | |
35 | detecting it won't work. | |
36 | ||
37 | The signal trampoline will be mapped at an address that is page | |
38 | aligned. We recognize the signal trampoline by looking for the | |
39 | sigreturn system call. */ | |
40 | ||
41 | static const int alphaobsd_page_size = 8192; | |
42 | ||
43 | static LONGEST | |
44 | alphaobsd_sigtramp_offset (CORE_ADDR pc) | |
45 | { | |
46 | return (pc & (alphaobsd_page_size - 1)); | |
47 | } | |
48 | ||
49 | static int | |
50 | alphaobsd_pc_in_sigtramp (CORE_ADDR pc, char *name) | |
51 | { | |
52 | CORE_ADDR start_pc = (pc & ~(alphaobsd_page_size - 1)); | |
53 | unsigned insn; | |
54 | ||
55 | if (name) | |
56 | return 0; | |
57 | ||
58 | /* Check for "". */ | |
59 | insn = alpha_read_insn (start_pc + 5 * ALPHA_INSN_SIZE); | |
60 | if (insn != 0x201f0067) | |
61 | return 0; | |
62 | ||
63 | /* Check for "". */ | |
64 | insn = alpha_read_insn (start_pc + 6 * ALPHA_INSN_SIZE); | |
65 | if (insn != 0x00000083) | |
66 | return 0; | |
67 | ||
68 | return 1; | |
69 | } | |
70 | ||
71 | static CORE_ADDR | |
72 | alphaobsd_sigcontext_addr (struct frame_info *next_frame) | |
73 | { | |
74 | CORE_ADDR pc = frame_pc_unwind (next_frame); | |
75 | ||
76 | if (alphaobsd_sigtramp_offset (pc) < 3 * ALPHA_INSN_SIZE) | |
77 | { | |
78 | /* On entry, a pointer the `struct sigcontext' is passed in %a2. */ | |
79 | return frame_unwind_register_unsigned (next_frame, ALPHA_A0_REGNUM + 2); | |
80 | } | |
81 | else if (alphaobsd_sigtramp_offset (pc) < 4 * ALPHA_INSN_SIZE) | |
82 | { | |
83 | /* It is stored on the stack Before calling the signal handler. */ | |
84 | CORE_ADDR sp; | |
85 | sp = frame_unwind_register_unsigned (next_frame, ALPHA_SP_REGNUM); | |
86 | return get_frame_memory_unsigned (next_frame, sp, 8); | |
87 | } | |
88 | else | |
89 | { | |
90 | /* It is reloaded into %a0 for the sigreturn(2) call. */ | |
91 | return frame_unwind_register_unsigned (next_frame, ALPHA_A0_REGNUM); | |
92 | } | |
93 | } | |
94 | \f | |
95 | ||
96 | static void | |
97 | alphaobsd_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch) | |
98 | { | |
99 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
100 | ||
101 | /* Hook into the DWARF CFI frame unwinder. */ | |
102 | alpha_dwarf2_init_abi (info, gdbarch); | |
103 | ||
104 | /* Hook into the MDEBUG frame unwinder. */ | |
105 | alpha_mdebug_init_abi (info, gdbarch); | |
106 | ||
107 | /* OpenBSD/alpha 3.0 and earlier does not provide single step | |
108 | support via ptrace(2); use software single-stepping for now. */ | |
109 | set_gdbarch_software_single_step (gdbarch, alpha_software_single_step); | |
110 | ||
111 | /* OpenBSD/alpha has SVR4-style shared libraries. */ | |
112 | set_solib_svr4_fetch_link_map_offsets | |
113 | (gdbarch, svr4_lp64_fetch_link_map_offsets); | |
114 | ||
115 | tdep->dynamic_sigtramp_offset = alphaobsd_sigtramp_offset; | |
116 | tdep->pc_in_sigtramp = alphaobsd_pc_in_sigtramp; | |
117 | tdep->sigcontext_addr = alphaobsd_sigcontext_addr; | |
118 | ||
119 | tdep->jb_pc = 2; | |
120 | tdep->jb_elt_size = 8; | |
121 | ||
122 | set_gdbarch_regset_from_core_section | |
123 | (gdbarch, alphanbsd_regset_from_core_section); | |
124 | } | |
125 | \f | |
126 | ||
127 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
128 | void _initialize_alphaobsd_tdep (void); | |
129 | ||
130 | void | |
131 | _initialize_alphaobsd_tdep (void) | |
132 | { | |
133 | gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_OPENBSD_ELF, | |
134 | alphaobsd_init_abi); | |
135 | } |