Commit | Line | Data |
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3379287a | 1 | /* Target-dependent code for GNU/Linux on Alpha. |
197e01b6 | 2 | Copyright (C) 2002, 2003 Free Software Foundation, Inc. |
3379287a JT |
3 | |
4 | This file is part of GDB. | |
5 | ||
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. | |
10 | ||
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. | |
15 | ||
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 | |
197e01b6 EZ |
18 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
19 | Boston, MA 02110-1301, USA. */ | |
3379287a JT |
20 | |
21 | #include "defs.h" | |
5868c862 | 22 | #include "frame.h" |
d2427a71 | 23 | #include "gdb_assert.h" |
f1a559ae | 24 | #include "osabi.h" |
b2756930 | 25 | #include "solib-svr4.h" |
982e9687 | 26 | #include "symtab.h" |
3379287a JT |
27 | |
28 | #include "alpha-tdep.h" | |
29 | ||
d2427a71 RH |
30 | /* Under GNU/Linux, signal handler invocations can be identified by |
31 | the designated code sequence that is used to return from a signal | |
3379287a | 32 | handler. In particular, the return address of a signal handler |
d2427a71 RH |
33 | points to a sequence that copies $sp to $16, loads $0 with the |
34 | appropriate syscall number, and finally enters the kernel. | |
35 | ||
36 | This is somewhat complicated in that: | |
37 | (1) the expansion of the "mov" assembler macro has changed over | |
38 | time, from "bis src,src,dst" to "bis zero,src,dst", | |
39 | (2) the kernel has changed from using "addq" to "lda" to load the | |
40 | syscall number, | |
41 | (3) there is a "normal" sigreturn and an "rt" sigreturn which | |
42 | has a different stack layout. | |
43 | */ | |
44 | ||
45 | static long | |
46 | alpha_linux_sigtramp_offset_1 (CORE_ADDR pc) | |
3379287a | 47 | { |
d2427a71 RH |
48 | switch (alpha_read_insn (pc)) |
49 | { | |
50 | case 0x47de0410: /* bis $30,$30,$16 */ | |
51 | case 0x47fe0410: /* bis $31,$30,$16 */ | |
52 | return 0; | |
3379287a | 53 | |
d2427a71 RH |
54 | case 0x43ecf400: /* addq $31,103,$0 */ |
55 | case 0x201f0067: /* lda $0,103($31) */ | |
56 | case 0x201f015f: /* lda $0,351($31) */ | |
57 | return 4; | |
58 | ||
59 | case 0x00000083: /* call_pal callsys */ | |
60 | return 8; | |
3379287a | 61 | |
3379287a JT |
62 | default: |
63 | return -1; | |
64 | } | |
d2427a71 RH |
65 | } |
66 | ||
67 | static LONGEST | |
68 | alpha_linux_sigtramp_offset (CORE_ADDR pc) | |
69 | { | |
70 | long i, off; | |
71 | ||
72 | if (pc & 3) | |
73 | return -1; | |
74 | ||
75 | /* Guess where we might be in the sequence. */ | |
76 | off = alpha_linux_sigtramp_offset_1 (pc); | |
77 | if (off < 0) | |
78 | return -1; | |
79 | ||
80 | /* Verify that the other two insns of the sequence are as we expect. */ | |
3379287a | 81 | pc -= off; |
d2427a71 | 82 | for (i = 0; i < 12; i += 4) |
3379287a | 83 | { |
d2427a71 RH |
84 | if (i == off) |
85 | continue; | |
86 | if (alpha_linux_sigtramp_offset_1 (pc + i) != i) | |
87 | return -1; | |
3379287a | 88 | } |
3379287a | 89 | |
d2427a71 | 90 | return off; |
3379287a JT |
91 | } |
92 | ||
6c72f9f9 JT |
93 | static int |
94 | alpha_linux_pc_in_sigtramp (CORE_ADDR pc, char *func_name) | |
95 | { | |
d2427a71 | 96 | return alpha_linux_sigtramp_offset (pc) >= 0; |
6c72f9f9 JT |
97 | } |
98 | ||
5868c862 | 99 | static CORE_ADDR |
d2427a71 | 100 | alpha_linux_sigcontext_addr (struct frame_info *next_frame) |
5868c862 | 101 | { |
d2427a71 RH |
102 | CORE_ADDR pc; |
103 | ULONGEST sp; | |
104 | long off; | |
105 | ||
106 | pc = frame_pc_unwind (next_frame); | |
107 | frame_unwind_unsigned_register (next_frame, ALPHA_SP_REGNUM, &sp); | |
108 | ||
109 | off = alpha_linux_sigtramp_offset (pc); | |
110 | gdb_assert (off >= 0); | |
111 | ||
112 | /* __NR_rt_sigreturn has a couple of structures on the stack. This is: | |
113 | ||
114 | struct rt_sigframe { | |
115 | struct siginfo info; | |
116 | struct ucontext uc; | |
117 | }; | |
118 | ||
119 | offsetof (struct rt_sigframe, uc.uc_mcontext); | |
120 | */ | |
121 | if (alpha_read_insn (pc - off + 4) == 0x201f015f) | |
122 | return sp + 176; | |
123 | ||
124 | /* __NR_sigreturn has the sigcontext structure at the top of the stack. */ | |
125 | return sp; | |
5868c862 JT |
126 | } |
127 | ||
3379287a | 128 | static void |
baa490c4 | 129 | alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
3379287a | 130 | { |
d2427a71 RH |
131 | struct gdbarch_tdep *tdep; |
132 | ||
f1a559ae | 133 | /* Hook into the DWARF CFI frame unwinder. */ |
baa490c4 | 134 | alpha_dwarf2_init_abi (info, gdbarch); |
f1a559ae RH |
135 | |
136 | /* Hook into the MDEBUG frame unwinder. */ | |
d2427a71 | 137 | alpha_mdebug_init_abi (info, gdbarch); |
36a6271d | 138 | |
d2427a71 | 139 | tdep = gdbarch_tdep (gdbarch); |
36a6271d | 140 | tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset; |
5868c862 | 141 | tdep->sigcontext_addr = alpha_linux_sigcontext_addr; |
f2524b93 | 142 | tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp; |
accc6d1f JT |
143 | tdep->jb_pc = 2; |
144 | tdep->jb_elt_size = 8; | |
b2756930 | 145 | |
982e9687 UW |
146 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
147 | ||
b2756930 KB |
148 | /* Enable TLS support. */ |
149 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
150 | svr4_fetch_objfile_link_map); | |
3379287a JT |
151 | } |
152 | ||
153 | void | |
154 | _initialize_alpha_linux_tdep (void) | |
155 | { | |
05816f70 | 156 | gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX, |
70f80edf | 157 | alpha_linux_init_abi); |
3379287a | 158 | } |