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 45static const int sparc32obsd_page_size = 4096; 46 47static int 48sparc32obsd_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 69static struct sparc_frame_cache * 70sparc32obsd_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 100static void 101sparc32obsd_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 110static void 111sparc32obsd_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, void *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 124static const struct frame_unwind sparc32obsd_frame_unwind = 125{ 126 SIGTRAMP_FRAME, 127 sparc32obsd_frame_this_id, 128 sparc32obsd_frame_prev_register 129}; 130 131static const struct frame_unwind * 132sparc32obsd_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} 143 144 145static void 146sparc32obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 147{ 148 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 149 150 /* OpenBSD doesn't support the 128-bit `long double' from the psABI. */ 151 set_gdbarch_long_double_bit (gdbarch, 64); 152 set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big); 153 154 frame_unwind_append_sniffer (gdbarch, sparc32obsd_sigtramp_frame_sniffer); 155 156 set_solib_svr4_fetch_link_map_offsets 157 (gdbarch, svr4_ilp32_fetch_link_map_offsets); 158} 159 160 161/* Provide a prototype to silence -Wmissing-prototypes. */ 162void _initialize_sparc32obsd_tdep (void); 163 164void 165_initialize_sparc32obsd_tdep (void) 166{ 167 gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_OPENBSD_ELF, 168 sparc32obsd_init_abi); 169} 170