1 /* Target-dependent code for OpenBSD/sparc.
2
3 Copyright 2004, 2005 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., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 #include "defs.h"
23 #include "floatformat.h"
24 #include "frame.h"
25 #include "frame-unwind.h"
26 #include "osabi.h"
27 #include "solib-svr4.h"
28 #include "symtab.h"
29 #include "trad-frame.h"
30
31 #include "gdb_assert.h"
32
33 #include "obsd-tdep.h"
34 #include "sparc-tdep.h"
35
36 /* Signal trampolines. */
37
38 /* The OpenBSD kernel maps the signal trampoline at some random
39 location in user space, which means that the traditional BSD way of
40 detecting it won't work.
41
42 The signal trampoline will be mapped at an address that is page
43 aligned. We recognize the signal trampoline by the looking for the
44 sigreturn system call. */
45
46 static const int sparc32obsd_page_size = 4096;
47
48 static int
sparc32obsd_pc_in_sigtramp(CORE_ADDR pc,char * name)49 sparc32obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
50 {
51 CORE_ADDR start_pc = (pc & ~(sparc32obsd_page_size - 1));
52 unsigned long insn;
53
54 if (name)
55 return 0;
56
57 /* Check for "restore %g0, SYS_sigreturn, %g1". */
58 insn = sparc_fetch_instruction (start_pc + 0xec);
59 if (insn != 0x83e82067)
60 return 0;
61
62 /* Check for "t ST_SYSCALL". */
63 insn = sparc_fetch_instruction (start_pc + 0xf4);
64 if (insn != 0x91d02000)
65 return 0;
66
67 return 1;
68 }
69
70 static struct sparc_frame_cache *
sparc32obsd_frame_cache(struct frame_info * next_frame,void ** this_cache)71 sparc32obsd_frame_cache (struct frame_info *next_frame, void **this_cache)
72 {
73 struct sparc_frame_cache *cache;
74 CORE_ADDR addr;
75
76 if (*this_cache)
77 return *this_cache;
78
79 cache = sparc_frame_cache (next_frame, this_cache);
80 gdb_assert (cache == *this_cache);
81
82 /* If we couldn't find the frame's function, we're probably dealing
83 with an on-stack signal trampoline. */
84 if (cache->pc == 0)
85 {
86 cache->pc = frame_pc_unwind (next_frame);
87 cache->pc &= ~(sparc32obsd_page_size - 1);
88
89 /* Since we couldn't find the frame's function, the cache was
90 initialized under the assumption that we're frameless. */
91 cache->frameless_p = 0;
92 addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
93 cache->base = addr;
94 }
95
96 cache->saved_regs = sparc32nbsd_sigcontext_saved_regs (next_frame);
97
98 return cache;
99 }
100
101 static void
sparc32obsd_frame_this_id(struct frame_info * next_frame,void ** this_cache,struct frame_id * this_id)102 sparc32obsd_frame_this_id (struct frame_info *next_frame, void **this_cache,
103 struct frame_id *this_id)
104 {
105 struct sparc_frame_cache *cache =
106 sparc32obsd_frame_cache (next_frame, this_cache);
107
108 (*this_id) = frame_id_build (cache->base, cache->pc);
109 }
110
111 static void
sparc32obsd_frame_prev_register(struct frame_info * next_frame,void ** this_cache,int regnum,int * optimizedp,enum lval_type * lvalp,CORE_ADDR * addrp,int * realnump,void * valuep)112 sparc32obsd_frame_prev_register (struct frame_info *next_frame,
113 void **this_cache,
114 int regnum, int *optimizedp,
115 enum lval_type *lvalp, CORE_ADDR *addrp,
116 int *realnump, void *valuep)
117 {
118 struct sparc_frame_cache *cache =
119 sparc32obsd_frame_cache (next_frame, this_cache);
120
121 trad_frame_get_prev_register (next_frame, cache->saved_regs, regnum,
122 optimizedp, lvalp, addrp, realnump, valuep);
123 }
124
125 static const struct frame_unwind sparc32obsd_frame_unwind =
126 {
127 SIGTRAMP_FRAME,
128 sparc32obsd_frame_this_id,
129 sparc32obsd_frame_prev_register
130 };
131
132 static const struct frame_unwind *
sparc32obsd_sigtramp_frame_sniffer(struct frame_info * next_frame)133 sparc32obsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
134 {
135 CORE_ADDR pc = frame_pc_unwind (next_frame);
136 char *name;
137
138 find_pc_partial_function (pc, &name, NULL, NULL);
139 if (sparc32obsd_pc_in_sigtramp (pc, name))
140 return &sparc32obsd_frame_unwind;
141
142 return NULL;
143 }
144
145
146 static void
sparc32obsd_init_abi(struct gdbarch_info info,struct gdbarch * gdbarch)147 sparc32obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
148 {
149 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
150
151 /* OpenBSD/sparc is very similar to NetBSD/sparc ELF. */
152 sparc32nbsd_elf_init_abi (info, gdbarch);
153
154 set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
155
156 frame_unwind_append_sniffer (gdbarch, sparc32obsd_sigtramp_frame_sniffer);
157 }
158
159
160 /* Provide a prototype to silence -Wmissing-prototypes. */
161 void _initialize_sparc32obsd_tdep (void);
162
163 void
_initialize_sparc32obsd_tdep(void)164 _initialize_sparc32obsd_tdep (void)
165 {
166 gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF,
167 sparc32obsd_init_abi);
168 }
169