1 /* Target-dependent code for SDE on MIPS processors. 2 3 Copyright (C) 2014-2023 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 3 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, see <http://www.gnu.org/licenses/>. */ 19 20 #include "defs.h" 21 #include "osabi.h" 22 #include "elf-bfd.h" 23 #include "block.h" 24 #include "symtab.h" 25 26 #include "frame.h" 27 #include "frame-unwind.h" 28 #include "frame-base.h" 29 #include "trad-frame.h" 30 31 #include "mips-tdep.h" 32 33 /* Fill in the register cache *THIS_CACHE for THIS_FRAME for use 34 in the SDE frame unwinder. */ 35 36 static struct trad_frame_cache * 37 mips_sde_frame_cache (frame_info_ptr this_frame, void **this_cache) 38 { 39 struct gdbarch *gdbarch = get_frame_arch (this_frame); 40 const struct mips_regnum *regs = mips_regnum (gdbarch); 41 const int sizeof_reg_t = mips_abi_regsize (gdbarch); 42 enum mips_abi abi = mips_abi (gdbarch); 43 struct trad_frame_cache *cache; 44 CORE_ADDR xcpt_frame; 45 CORE_ADDR start_addr; 46 CORE_ADDR stack_addr; 47 CORE_ADDR pc; 48 int i; 49 50 if (*this_cache != NULL) 51 return (struct trad_frame_cache *) *this_cache; 52 cache = trad_frame_cache_zalloc (this_frame); 53 *this_cache = cache; 54 55 /* The previous registers are held in struct xcptcontext 56 which is at $sp+offs 57 58 struct xcptcontext { 59 reg_t sr; CP0 Status 60 reg_t cr; CP0 Cause 61 reg_t epc; CP0 EPC 62 reg_t vaddr; CP0 BadVAddr 63 reg_t regs[32]; General registers 64 reg_t mdlo; LO 65 reg_t mdhi; HI 66 reg_t mdex; ACX 67 ... 68 }; 69 */ 70 71 stack_addr = get_frame_register_signed (this_frame, 72 gdbarch_sp_regnum (gdbarch)); 73 switch (abi) 74 { 75 case MIPS_ABI_O32: 76 /* 40: XCPTCONTEXT 77 24: xcpt_gen() argspace (16 bytes) 78 16: _xcptcall() saved ra, rounded up ( 8 bytes) 79 00: _xcptcall() argspace (16 bytes) */ 80 xcpt_frame = stack_addr + 40; 81 break; 82 case MIPS_ABI_N32: 83 case MIPS_ABI_N64: 84 default: /* Wild guess. */ 85 /* 16: XCPTCONTEXT 86 16: xcpt_gen() argspace ( 0 bytes) 87 00: _xcptcall() saved ra, rounded up (16 bytes) */ 88 xcpt_frame = stack_addr + 16; 89 break; 90 } 91 92 trad_frame_set_reg_addr (cache, 93 MIPS_PS_REGNUM + gdbarch_num_regs (gdbarch), 94 xcpt_frame + 0 * sizeof_reg_t); 95 trad_frame_set_reg_addr (cache, 96 regs->cause + gdbarch_num_regs (gdbarch), 97 xcpt_frame + 1 * sizeof_reg_t); 98 trad_frame_set_reg_addr (cache, 99 regs->pc + gdbarch_num_regs (gdbarch), 100 xcpt_frame + 2 * sizeof_reg_t); 101 trad_frame_set_reg_addr (cache, 102 regs->badvaddr + gdbarch_num_regs (gdbarch), 103 xcpt_frame + 3 * sizeof_reg_t); 104 for (i = 0; i < MIPS_NUMREGS; i++) 105 trad_frame_set_reg_addr (cache, 106 i + MIPS_ZERO_REGNUM + gdbarch_num_regs (gdbarch), 107 xcpt_frame + (4 + i) * sizeof_reg_t); 108 trad_frame_set_reg_addr (cache, 109 regs->lo + gdbarch_num_regs (gdbarch), 110 xcpt_frame + 36 * sizeof_reg_t); 111 trad_frame_set_reg_addr (cache, 112 regs->hi + gdbarch_num_regs (gdbarch), 113 xcpt_frame + 37 * sizeof_reg_t); 114 115 pc = get_frame_pc (this_frame); 116 find_pc_partial_function (pc, NULL, &start_addr, NULL); 117 trad_frame_set_id (cache, frame_id_build (start_addr, stack_addr)); 118 119 return cache; 120 } 121 122 /* Implement the this_id function for the SDE frame unwinder. */ 123 124 static void 125 mips_sde_frame_this_id (frame_info_ptr this_frame, void **this_cache, 126 struct frame_id *this_id) 127 { 128 struct trad_frame_cache *this_trad_cache 129 = mips_sde_frame_cache (this_frame, this_cache); 130 131 trad_frame_get_id (this_trad_cache, this_id); 132 } 133 134 /* Implement the prev_register function for the SDE frame unwinder. */ 135 136 static struct value * 137 mips_sde_frame_prev_register (frame_info_ptr this_frame, 138 void **this_cache, 139 int prev_regnum) 140 { 141 struct trad_frame_cache *trad_cache 142 = mips_sde_frame_cache (this_frame, this_cache); 143 144 return trad_frame_get_register (trad_cache, this_frame, prev_regnum); 145 } 146 147 /* Implement the sniffer function for the SDE frame unwinder. */ 148 149 static int 150 mips_sde_frame_sniffer (const struct frame_unwind *self, 151 frame_info_ptr this_frame, 152 void **this_cache) 153 { 154 CORE_ADDR pc = get_frame_pc (this_frame); 155 const char *name; 156 157 find_pc_partial_function (pc, &name, NULL, NULL); 158 return (name 159 && (strcmp (name, "_xcptcall") == 0 160 || strcmp (name, "_sigtramp") == 0)); 161 } 162 163 /* Data structure for the SDE frame unwinder. */ 164 165 static const struct frame_unwind mips_sde_frame_unwind = 166 { 167 "mips sde sigtramp", 168 SIGTRAMP_FRAME, 169 default_frame_unwind_stop_reason, 170 mips_sde_frame_this_id, 171 mips_sde_frame_prev_register, 172 NULL, 173 mips_sde_frame_sniffer 174 }; 175 176 /* Implement the this_base, this_locals, and this_args hooks 177 for the normal unwinder. */ 178 179 static CORE_ADDR 180 mips_sde_frame_base_address (frame_info_ptr this_frame, void **this_cache) 181 { 182 struct trad_frame_cache *this_trad_cache 183 = mips_sde_frame_cache (this_frame, this_cache); 184 185 return trad_frame_get_this_base (this_trad_cache); 186 } 187 188 static const struct frame_base mips_sde_frame_base = 189 { 190 &mips_sde_frame_unwind, 191 mips_sde_frame_base_address, 192 mips_sde_frame_base_address, 193 mips_sde_frame_base_address 194 }; 195 196 static const struct frame_base * 197 mips_sde_frame_base_sniffer (frame_info_ptr this_frame) 198 { 199 if (mips_sde_frame_sniffer (&mips_sde_frame_unwind, this_frame, NULL)) 200 return &mips_sde_frame_base; 201 else 202 return NULL; 203 } 204 205 static void 206 mips_sde_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, 207 void *obj) 208 { 209 enum gdb_osabi *os_ident_ptr = (enum gdb_osabi *) obj; 210 const char *name; 211 212 name = bfd_section_name (sect); 213 214 /* The presence of a section with a ".sde" prefix is indicative 215 of an SDE binary. */ 216 if (startswith (name, ".sde")) 217 *os_ident_ptr = GDB_OSABI_SDE; 218 } 219 220 /* OSABI sniffer for MIPS SDE. */ 221 222 static enum gdb_osabi 223 mips_sde_elf_osabi_sniffer (bfd *abfd) 224 { 225 enum gdb_osabi osabi = GDB_OSABI_UNKNOWN; 226 unsigned int elfosabi; 227 228 /* If the generic sniffer gets a hit, return and let other sniffers 229 get a crack at it. */ 230 for (asection *sect : gdb_bfd_sections (abfd)) 231 generic_elf_osabi_sniff_abi_tag_sections (abfd, sect, &osabi); 232 if (osabi != GDB_OSABI_UNKNOWN) 233 return GDB_OSABI_UNKNOWN; 234 235 elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI]; 236 237 if (elfosabi == ELFOSABI_NONE) 238 { 239 /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the 240 file are conforming to the base specification for that machine 241 (there are no OS-specific extensions). In order to determine the 242 real OS in use we must look for OS notes that have been added. 243 244 For SDE, we simply look for sections named with .sde as prefixes. */ 245 bfd_map_over_sections (abfd, 246 mips_sde_elf_osabi_sniff_abi_tag_sections, 247 &osabi); 248 } 249 return osabi; 250 } 251 252 static void 253 mips_sde_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 254 { 255 frame_unwind_append_unwinder (gdbarch, &mips_sde_frame_unwind); 256 frame_base_append_sniffer (gdbarch, mips_sde_frame_base_sniffer); 257 } 258 259 void _initialize_mips_sde_tdep (); 260 void 261 _initialize_mips_sde_tdep () 262 { 263 gdbarch_register_osabi_sniffer (bfd_arch_mips, 264 bfd_target_elf_flavour, 265 mips_sde_elf_osabi_sniffer); 266 267 gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_SDE, mips_sde_init_abi); 268 } 269