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 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 * 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 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 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 * 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 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 164 _initialize_sparc32obsd_tdep (void) 165 { 166 gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF, 167 sparc32obsd_init_abi); 168 } 169