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#include "nbsd-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 46static const int sparc32obsd_page_size = 4096; 47 48static int 49sparc32obsd_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 70static struct sparc_frame_cache * 71sparc32obsd_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 101static void 102sparc32obsd_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 111static void 112sparc32obsd_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_prev_register (next_frame, cache->saved_regs, regnum, 122 optimizedp, lvalp, addrp, realnump, valuep); 123} 124 125static const struct frame_unwind sparc32obsd_frame_unwind = 126{ 127 SIGTRAMP_FRAME, 128 sparc32obsd_frame_this_id, 129 sparc32obsd_frame_prev_register 130}; 131 132static const struct frame_unwind * 133sparc32obsd_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 146static void 147sparc32obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 148{ 149 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 150 151 /* OpenBSD doesn't support the 128-bit `long double' from the psABI. */ 152 set_gdbarch_long_double_bit (gdbarch, 64); 153 set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big); 154 155 set_gdbarch_pc_in_sigtramp (gdbarch, sparc32obsd_pc_in_sigtramp); 156 frame_unwind_append_sniffer (gdbarch, sparc32obsd_sigtramp_frame_sniffer); 157 158 set_solib_svr4_fetch_link_map_offsets 159 (gdbarch, nbsd_ilp32_solib_svr4_fetch_link_map_offsets); 160} 161 162 163/* Provide a prototype to silence -Wmissing-prototypes. */ 164void _initialize_sparc32obsd_tdep (void); 165 166void 167_initialize_sparc32obsd_tdep (void) 168{ 169 gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF, 170 sparc32obsd_init_abi); 171} 172