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