1/* Target-dependent code for OpenBSD/sparc64.
2
3   Copyright 2004 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 "frame.h"
24#include "frame-unwind.h"
25#include "osabi.h"
26#include "regset.h"
27#include "symtab.h"
28#include "solib-svr4.h"
29#include "trad-frame.h"
30
31#include "gdb_assert.h"
32
33#include "sparc64-tdep.h"
34#include "nbsd-tdep.h"
35
36/* OpenBSD uses the traditional NetBSD core file format, even for
37   ports that use ELF.  The core files don't use multiple register
38   sets.  Instead, the general-purpose and floating-point registers
39   are lumped together in a single section.  Unlike on NetBSD, OpenBSD
40   uses a different layout for its general-purpose registers than the
41   layout used for ptrace(2).  */
42
43/* From <machine/reg.h>.  */
44const struct sparc_gregset sparc64obsd_core_gregset =
45{
46  0 * 8,			/* "tstate" */
47  1 * 8,			/* %pc */
48  2 * 8,			/* %npc */
49  3 * 8,			/* %y */
50  -1,				/* %fprs */
51  -1,
52  7 * 8,			/* %g1 */
53  22 * 8,			/* %l0 */
54  4				/* sizeof (%y) */
55};
56
57static void
58sparc64obsd_supply_gregset (const struct regset *regset,
59			    struct regcache *regcache,
60			    int regnum, const void *gregs, size_t len)
61{
62  const char *regs = gregs;
63
64  sparc64_supply_gregset (regset->descr, regcache, regnum, regs);
65  sparc64_supply_fpregset (regcache, regnum, regs + 288);
66}
67
68
69/* Signal trampolines.  */
70
71/* The OpenBSD kernel maps the signal trampoline at some random
72   location in user space, which means that the traditional BSD way of
73   detecting it won't work.
74
75   The signal trampoline will be mapped at an address that is page
76   aligned.  We recognize the signal trampoline by the looking for the
77   sigreturn system call.  */
78
79static const int sparc64obsd_page_size = 8192;
80
81static int
82sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
83{
84  CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
85  unsigned long insn;
86
87  if (name)
88    return 0;
89
90  /* Check for "restore %g0, SYS_sigreturn, %g1".  */
91  insn = sparc_fetch_instruction (start_pc + 0xe8);
92  if (insn != 0x83e82067)
93    return 0;
94
95  /* Check for "t ST_SYSCALL".  */
96  insn = sparc_fetch_instruction (start_pc + 0xf0);
97  if (insn != 0x91d02000)
98    return 0;
99
100  return 1;
101}
102
103static struct sparc_frame_cache *
104sparc64obsd_frame_cache (struct frame_info *next_frame, void **this_cache)
105{
106  struct sparc_frame_cache *cache;
107  CORE_ADDR addr;
108
109  if (*this_cache)
110    return *this_cache;
111
112  cache = sparc_frame_cache (next_frame, this_cache);
113  gdb_assert (cache == *this_cache);
114
115  /* If we couldn't find the frame's function, we're probably dealing
116     with an on-stack signal trampoline.  */
117  if (cache->pc == 0)
118    {
119      cache->pc = frame_pc_unwind (next_frame);
120      cache->pc &= ~(sparc64obsd_page_size - 1);
121
122      /* Since we couldn't find the frame's function, the cache was
123         initialized under the assumption that we're frameless.  */
124      cache->frameless_p = 0;
125      addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
126      cache->base = addr;
127    }
128
129  /* We find the appropriate instance of `struct sigcontext' at a
130     fixed offset in the signal frame.  */
131  addr = cache->base + BIAS + 128 + 16;
132  cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, next_frame);
133
134  return cache;
135}
136
137static void
138sparc64obsd_frame_this_id (struct frame_info *next_frame, void **this_cache,
139			   struct frame_id *this_id)
140{
141  struct sparc_frame_cache *cache =
142    sparc64obsd_frame_cache (next_frame, this_cache);
143
144  (*this_id) = frame_id_build (cache->base, cache->pc);
145}
146
147static void
148sparc64obsd_frame_prev_register (struct frame_info *next_frame,
149				 void **this_cache,
150				 int regnum, int *optimizedp,
151				 enum lval_type *lvalp, CORE_ADDR *addrp,
152				 int *realnump, void *valuep)
153{
154  struct sparc_frame_cache *cache =
155    sparc64obsd_frame_cache (next_frame, this_cache);
156
157  trad_frame_prev_register (next_frame, cache->saved_regs, regnum,
158			    optimizedp, lvalp, addrp, realnump, valuep);
159}
160
161static const struct frame_unwind sparc64obsd_frame_unwind =
162{
163  SIGTRAMP_FRAME,
164  sparc64obsd_frame_this_id,
165  sparc64obsd_frame_prev_register
166};
167
168static const struct frame_unwind *
169sparc64obsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
170{
171  CORE_ADDR pc = frame_pc_unwind (next_frame);
172  char *name;
173
174  find_pc_partial_function (pc, &name, NULL, NULL);
175  if (sparc64obsd_pc_in_sigtramp (pc, name))
176    return &sparc64obsd_frame_unwind;
177
178  return NULL;
179}
180
181
182static void
183sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
184{
185  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
186
187  tdep->gregset = XMALLOC (struct regset);
188  tdep->gregset->descr = &sparc64obsd_core_gregset;
189  tdep->gregset->supply_regset = sparc64obsd_supply_gregset;
190  tdep->sizeof_gregset = 832;
191
192  set_gdbarch_pc_in_sigtramp (gdbarch, sparc64obsd_pc_in_sigtramp);
193  frame_unwind_append_sniffer (gdbarch, sparc64obsd_sigtramp_frame_sniffer);
194
195  sparc64_init_abi (info, gdbarch);
196
197  set_solib_svr4_fetch_link_map_offsets
198    (gdbarch, nbsd_lp64_solib_svr4_fetch_link_map_offsets);
199}
200
201
202/* Provide a prototype to silence -Wmissing-prototypes.  */
203void _initialize_sparc64obsd_tdep (void);
204
205void
206_initialize_sparc64obsd_tdep (void)
207{
208  gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
209			  GDB_OSABI_OPENBSD_ELF, sparc64obsd_init_abi);
210}
211