| 1 | /* Target-dependent code for OpenBSD/sparc64. |
| 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 "frame.h" |
| 24 | #include "frame-unwind.h" |
| 25 | #include "osabi.h" |
| 26 | #include "regset.h" |
| 27 | #include "symtab.h" |
| 28 | #include "objfiles.h" |
| 29 | #include "solib-svr4.h" |
| 30 | #include "trad-frame.h" |
| 31 | |
| 32 | #include "gdb_assert.h" |
| 33 | |
| 34 | #include "sparc64-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>. */ |
| 44 | const 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 | |
| 57 | static void |
| 58 | sparc64obsd_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 (&sparc64obsd_core_gregset, regcache, regnum, regs); |
| 65 | sparc64_supply_fpregset (regcache, regnum, regs + 288); |
| 66 | } |
| 67 | \f |
| 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. The offset where we can find the code that |
| 78 | makes this system call varies from release to release. For OpenBSD |
| 79 | 3.6 and later releases we can find the code at offset 0xec. For |
| 80 | OpenBSD 3.5 and earlier releases, we find it at offset 0xe8. */ |
| 81 | |
| 82 | static const int sparc64obsd_page_size = 8192; |
| 83 | static const int sparc64obsd_sigreturn_offset[] = { 0xec, 0xe8, -1 }; |
| 84 | |
| 85 | static int |
| 86 | sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| 87 | { |
| 88 | CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1)); |
| 89 | unsigned long insn; |
| 90 | const int *offset; |
| 91 | |
| 92 | if (name) |
| 93 | return 0; |
| 94 | |
| 95 | for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++) |
| 96 | { |
| 97 | /* Check for "restore %g0, SYS_sigreturn, %g1". */ |
| 98 | insn = sparc_fetch_instruction (start_pc + *offset); |
| 99 | if (insn != 0x83e82067) |
| 100 | continue; |
| 101 | |
| 102 | /* Check for "t ST_SYSCALL". */ |
| 103 | insn = sparc_fetch_instruction (start_pc + *offset + 8); |
| 104 | if (insn != 0x91d02000) |
| 105 | continue; |
| 106 | |
| 107 | return 1; |
| 108 | } |
| 109 | |
| 110 | return 0; |
| 111 | } |
| 112 | |
| 113 | static struct sparc_frame_cache * |
| 114 | sparc64obsd_frame_cache (struct frame_info *next_frame, void **this_cache) |
| 115 | { |
| 116 | struct sparc_frame_cache *cache; |
| 117 | CORE_ADDR addr; |
| 118 | |
| 119 | if (*this_cache) |
| 120 | return *this_cache; |
| 121 | |
| 122 | cache = sparc_frame_cache (next_frame, this_cache); |
| 123 | gdb_assert (cache == *this_cache); |
| 124 | |
| 125 | /* If we couldn't find the frame's function, we're probably dealing |
| 126 | with an on-stack signal trampoline. */ |
| 127 | if (cache->pc == 0) |
| 128 | { |
| 129 | cache->pc = frame_pc_unwind (next_frame); |
| 130 | cache->pc &= ~(sparc64obsd_page_size - 1); |
| 131 | |
| 132 | /* Since we couldn't find the frame's function, the cache was |
| 133 | initialized under the assumption that we're frameless. */ |
| 134 | cache->frameless_p = 0; |
| 135 | addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM); |
| 136 | if (addr & 1) |
| 137 | addr += BIAS; |
| 138 | cache->base = addr; |
| 139 | } |
| 140 | |
| 141 | /* We find the appropriate instance of `struct sigcontext' at a |
| 142 | fixed offset in the signal frame. */ |
| 143 | addr = cache->base + 128 + 16; |
| 144 | cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, next_frame); |
| 145 | |
| 146 | return cache; |
| 147 | } |
| 148 | |
| 149 | static void |
| 150 | sparc64obsd_frame_this_id (struct frame_info *next_frame, void **this_cache, |
| 151 | struct frame_id *this_id) |
| 152 | { |
| 153 | struct sparc_frame_cache *cache = |
| 154 | sparc64obsd_frame_cache (next_frame, this_cache); |
| 155 | |
| 156 | (*this_id) = frame_id_build (cache->base, cache->pc); |
| 157 | } |
| 158 | |
| 159 | static void |
| 160 | sparc64obsd_frame_prev_register (struct frame_info *next_frame, |
| 161 | void **this_cache, |
| 162 | int regnum, int *optimizedp, |
| 163 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 164 | int *realnump, gdb_byte *valuep) |
| 165 | { |
| 166 | struct sparc_frame_cache *cache = |
| 167 | sparc64obsd_frame_cache (next_frame, this_cache); |
| 168 | |
| 169 | trad_frame_get_prev_register (next_frame, cache->saved_regs, regnum, |
| 170 | optimizedp, lvalp, addrp, realnump, valuep); |
| 171 | } |
| 172 | |
| 173 | static const struct frame_unwind sparc64obsd_frame_unwind = |
| 174 | { |
| 175 | SIGTRAMP_FRAME, |
| 176 | sparc64obsd_frame_this_id, |
| 177 | sparc64obsd_frame_prev_register |
| 178 | }; |
| 179 | |
| 180 | static const struct frame_unwind * |
| 181 | sparc64obsd_sigtramp_frame_sniffer (struct frame_info *next_frame) |
| 182 | { |
| 183 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 184 | char *name; |
| 185 | |
| 186 | find_pc_partial_function (pc, &name, NULL, NULL); |
| 187 | if (sparc64obsd_pc_in_sigtramp (pc, name)) |
| 188 | return &sparc64obsd_frame_unwind; |
| 189 | |
| 190 | return NULL; |
| 191 | } |
| 192 | \f |
| 193 | |
| 194 | static void |
| 195 | sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 196 | { |
| 197 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 198 | |
| 199 | tdep->gregset = regset_alloc (gdbarch, sparc64obsd_supply_gregset, NULL); |
| 200 | tdep->sizeof_gregset = 832; |
| 201 | |
| 202 | frame_unwind_append_sniffer (gdbarch, sparc64obsd_sigtramp_frame_sniffer); |
| 203 | |
| 204 | sparc64_init_abi (info, gdbarch); |
| 205 | |
| 206 | /* OpenBSD/sparc64 has SVR4-style shared libraries. */ |
| 207 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
| 208 | set_solib_svr4_fetch_link_map_offsets |
| 209 | (gdbarch, svr4_lp64_fetch_link_map_offsets); |
| 210 | } |
| 211 | \f |
| 212 | |
| 213 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 214 | void _initialize_sparc64obsd_tdep (void); |
| 215 | |
| 216 | void |
| 217 | _initialize_sparc64obsd_tdep (void) |
| 218 | { |
| 219 | gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9, |
| 220 | GDB_OSABI_OPENBSD_ELF, sparc64obsd_init_abi); |
| 221 | } |