| 1 | /* Target-dependent code for SDE on MIPS processors. |
| 2 | |
| 3 | Copyright (C) 2014-2020 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 (struct frame_info *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 (struct frame_info *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 (struct frame_info *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 | struct frame_info *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 | SIGTRAMP_FRAME, |
| 168 | default_frame_unwind_stop_reason, |
| 169 | mips_sde_frame_this_id, |
| 170 | mips_sde_frame_prev_register, |
| 171 | NULL, |
| 172 | mips_sde_frame_sniffer |
| 173 | }; |
| 174 | |
| 175 | /* Implement the this_base, this_locals, and this_args hooks |
| 176 | for the normal unwinder. */ |
| 177 | |
| 178 | static CORE_ADDR |
| 179 | mips_sde_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 180 | { |
| 181 | struct trad_frame_cache *this_trad_cache |
| 182 | = mips_sde_frame_cache (this_frame, this_cache); |
| 183 | |
| 184 | return trad_frame_get_this_base (this_trad_cache); |
| 185 | } |
| 186 | |
| 187 | static const struct frame_base mips_sde_frame_base = |
| 188 | { |
| 189 | &mips_sde_frame_unwind, |
| 190 | mips_sde_frame_base_address, |
| 191 | mips_sde_frame_base_address, |
| 192 | mips_sde_frame_base_address |
| 193 | }; |
| 194 | |
| 195 | static const struct frame_base * |
| 196 | mips_sde_frame_base_sniffer (struct frame_info *this_frame) |
| 197 | { |
| 198 | if (mips_sde_frame_sniffer (&mips_sde_frame_unwind, this_frame, NULL)) |
| 199 | return &mips_sde_frame_base; |
| 200 | else |
| 201 | return NULL; |
| 202 | } |
| 203 | |
| 204 | static void |
| 205 | mips_sde_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, |
| 206 | void *obj) |
| 207 | { |
| 208 | enum gdb_osabi *os_ident_ptr = (enum gdb_osabi *) obj; |
| 209 | const char *name; |
| 210 | |
| 211 | name = bfd_section_name (sect); |
| 212 | |
| 213 | /* The presence of a section with a ".sde" prefix is indicative |
| 214 | of an SDE binary. */ |
| 215 | if (startswith (name, ".sde")) |
| 216 | *os_ident_ptr = GDB_OSABI_SDE; |
| 217 | } |
| 218 | |
| 219 | /* OSABI sniffer for MIPS SDE. */ |
| 220 | |
| 221 | static enum gdb_osabi |
| 222 | mips_sde_elf_osabi_sniffer (bfd *abfd) |
| 223 | { |
| 224 | enum gdb_osabi osabi = GDB_OSABI_UNKNOWN; |
| 225 | unsigned int elfosabi; |
| 226 | |
| 227 | /* If the generic sniffer gets a hit, return and let other sniffers |
| 228 | get a crack at it. */ |
| 229 | for (asection *sect : gdb_bfd_sections (abfd)) |
| 230 | generic_elf_osabi_sniff_abi_tag_sections (abfd, sect, &osabi); |
| 231 | if (osabi != GDB_OSABI_UNKNOWN) |
| 232 | return GDB_OSABI_UNKNOWN; |
| 233 | |
| 234 | elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI]; |
| 235 | |
| 236 | if (elfosabi == ELFOSABI_NONE) |
| 237 | { |
| 238 | /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the |
| 239 | file are conforming to the base specification for that machine |
| 240 | (there are no OS-specific extensions). In order to determine the |
| 241 | real OS in use we must look for OS notes that have been added. |
| 242 | |
| 243 | For SDE, we simply look for sections named with .sde as prefixes. */ |
| 244 | bfd_map_over_sections (abfd, |
| 245 | mips_sde_elf_osabi_sniff_abi_tag_sections, |
| 246 | &osabi); |
| 247 | } |
| 248 | return osabi; |
| 249 | } |
| 250 | |
| 251 | static void |
| 252 | mips_sde_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 253 | { |
| 254 | frame_unwind_append_unwinder (gdbarch, &mips_sde_frame_unwind); |
| 255 | frame_base_append_sniffer (gdbarch, mips_sde_frame_base_sniffer); |
| 256 | } |
| 257 | |
| 258 | void _initialize_mips_sde_tdep (); |
| 259 | void |
| 260 | _initialize_mips_sde_tdep () |
| 261 | { |
| 262 | gdbarch_register_osabi_sniffer (bfd_arch_mips, |
| 263 | bfd_target_elf_flavour, |
| 264 | mips_sde_elf_osabi_sniffer); |
| 265 | |
| 266 | gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_SDE, mips_sde_init_abi); |
| 267 | } |