| 1 | /* Target-dependent code for GNU/Linux x86-64. |
| 2 | |
| 3 | Copyright 2001, 2003, 2004 Free Software Foundation, Inc. |
| 4 | Contributed by Jiri Smid, SuSE Labs. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "inferior.h" |
| 25 | #include "gdbcore.h" |
| 26 | #include "regcache.h" |
| 27 | #include "osabi.h" |
| 28 | |
| 29 | #include "gdb_string.h" |
| 30 | |
| 31 | #include "amd64-tdep.h" |
| 32 | #include "amd64-linux-tdep.h" |
| 33 | |
| 34 | /* Register indexes to 'struct user' come from <sys/reg.h>. */ |
| 35 | |
| 36 | #define USER_R15 0 |
| 37 | #define USER_R14 1 |
| 38 | #define USER_R13 2 |
| 39 | #define USER_R12 3 |
| 40 | #define USER_RBP 4 |
| 41 | #define USER_RBX 5 |
| 42 | #define USER_R11 6 |
| 43 | #define USER_R10 7 |
| 44 | #define USER_R9 8 |
| 45 | #define USER_R8 9 |
| 46 | #define USER_RAX 10 |
| 47 | #define USER_RCX 11 |
| 48 | #define USER_RDX 12 |
| 49 | #define USER_RSI 13 |
| 50 | #define USER_RDI 14 |
| 51 | #define USER_RIP 16 |
| 52 | #define USER_CS 17 |
| 53 | #define USER_EFLAGS 18 |
| 54 | #define USER_RSP 19 |
| 55 | #define USER_SS 20 |
| 56 | #define USER_DS 23 |
| 57 | #define USER_ES 24 |
| 58 | #define USER_FS 25 |
| 59 | #define USER_GS 26 |
| 60 | |
| 61 | /* Mapping between the general-purpose registers in `struct user' |
| 62 | format and GDB's register array layout. */ |
| 63 | |
| 64 | static int user_to_gdb_regmap[] = |
| 65 | { |
| 66 | USER_RAX, USER_RBX, USER_RCX, USER_RDX, |
| 67 | USER_RSI, USER_RDI, USER_RBP, USER_RSP, |
| 68 | USER_R8, USER_R9, USER_R10, USER_R11, |
| 69 | USER_R12, USER_R13, USER_R14, USER_R15, |
| 70 | USER_RIP, USER_EFLAGS, |
| 71 | USER_CS, USER_SS, |
| 72 | USER_DS, USER_ES, USER_FS, USER_GS |
| 73 | }; |
| 74 | |
| 75 | /* Fill GDB's register array with the general-purpose register values |
| 76 | in *GREGSETP. */ |
| 77 | |
| 78 | void |
| 79 | amd64_linux_supply_gregset (char *regp) |
| 80 | { |
| 81 | int i; |
| 82 | |
| 83 | for (i = 0; i < AMD64_NUM_GREGS; i++) |
| 84 | supply_register (i, regp + (user_to_gdb_regmap[i] * 8)); |
| 85 | } |
| 86 | |
| 87 | /* Fill register REGNO (if it is a general-purpose register) in |
| 88 | *GREGSETPS with the value in GDB's register array. If REGNO is -1, |
| 89 | do this for all registers. */ |
| 90 | |
| 91 | void |
| 92 | amd64_linux_fill_gregset (char *regp, int regno) |
| 93 | { |
| 94 | int i; |
| 95 | |
| 96 | for (i = 0; i < AMD64_NUM_GREGS; i++) |
| 97 | if (regno == -1 || regno == i) |
| 98 | regcache_collect (i, regp + (user_to_gdb_regmap[i] * 8)); |
| 99 | } |
| 100 | |
| 101 | /* The register sets used in GNU/Linux ELF core-dumps are identical to |
| 102 | the register sets used by `ptrace'. The corresponding types are |
| 103 | `elf_gregset_t' for the general-purpose registers (with |
| 104 | `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' |
| 105 | for the floating-point registers. */ |
| 106 | |
| 107 | static void |
| 108 | fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, |
| 109 | int which, CORE_ADDR ignore) |
| 110 | { |
| 111 | switch (which) |
| 112 | { |
| 113 | case 0: /* Integer registers. */ |
| 114 | if (core_reg_size != 216) |
| 115 | warning ("Wrong size register set in core file."); |
| 116 | else |
| 117 | amd64_linux_supply_gregset (core_reg_sect); |
| 118 | break; |
| 119 | |
| 120 | case 2: /* Floating point registers. */ |
| 121 | case 3: /* "Extended" floating point registers. This is gdb-speak |
| 122 | for SSE/SSE2. */ |
| 123 | if (core_reg_size != 512) |
| 124 | warning ("Wrong size XMM register set in core file."); |
| 125 | else |
| 126 | amd64_supply_fxsave (current_regcache, -1, core_reg_sect); |
| 127 | break; |
| 128 | |
| 129 | default: |
| 130 | /* Don't know what kind of register request this is; just ignore it. */ |
| 131 | break; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | static struct core_fns amd64_core_fns = |
| 136 | { |
| 137 | bfd_target_elf_flavour, /* core_flavour */ |
| 138 | default_check_format, /* check_format */ |
| 139 | default_core_sniffer, /* core_sniffer */ |
| 140 | fetch_core_registers, /* core_read_registers */ |
| 141 | NULL /* next */ |
| 142 | }; |
| 143 | |
| 144 | #define LINUX_SIGTRAMP_INSN0 0x48 /* mov $NNNNNNNN, %rax */ |
| 145 | #define LINUX_SIGTRAMP_OFFSET0 0 |
| 146 | #define LINUX_SIGTRAMP_INSN1 0x0f /* syscall */ |
| 147 | #define LINUX_SIGTRAMP_OFFSET1 7 |
| 148 | |
| 149 | static const unsigned char linux_sigtramp_code[] = |
| 150 | { |
| 151 | /* mov $__NR_rt_sigreturn, %rax */ |
| 152 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00, |
| 153 | /* syscall */ |
| 154 | LINUX_SIGTRAMP_INSN1, 0x05 |
| 155 | }; |
| 156 | |
| 157 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) |
| 158 | |
| 159 | /* If PC is in a sigtramp routine, return the address of the start of |
| 160 | the routine. Otherwise, return 0. */ |
| 161 | |
| 162 | static CORE_ADDR |
| 163 | amd64_linux_sigtramp_start (CORE_ADDR pc) |
| 164 | { |
| 165 | unsigned char buf[LINUX_SIGTRAMP_LEN]; |
| 166 | |
| 167 | /* We only recognize a signal trampoline if PC is at the start of |
| 168 | one of the two instructions. We optimize for finding the PC at |
| 169 | the start, as will be the case when the trampoline is not the |
| 170 | first frame on the stack. We assume that in the case where the |
| 171 | PC is not at the start of the instruction sequence, there will be |
| 172 | a few trailing readable bytes on the stack. */ |
| 173 | |
| 174 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 175 | return 0; |
| 176 | |
| 177 | if (buf[0] != LINUX_SIGTRAMP_INSN0) |
| 178 | { |
| 179 | if (buf[0] != LINUX_SIGTRAMP_INSN1) |
| 180 | return 0; |
| 181 | |
| 182 | pc -= LINUX_SIGTRAMP_OFFSET1; |
| 183 | |
| 184 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 185 | return 0; |
| 186 | } |
| 187 | |
| 188 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) |
| 189 | return 0; |
| 190 | |
| 191 | return pc; |
| 192 | } |
| 193 | |
| 194 | /* Return whether PC is in a GNU/Linux sigtramp routine. */ |
| 195 | |
| 196 | static int |
| 197 | amd64_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| 198 | { |
| 199 | /* If we have NAME, we can optimize the search. The trampoline is |
| 200 | named __restore_rt. However, it isn't dynamically exported from |
| 201 | the shared C library, so the trampoline may appear to be part of |
| 202 | the preceding function. This should always be sigaction, |
| 203 | __sigaction, or __libc_sigaction (all aliases to the same |
| 204 | function). */ |
| 205 | if (name == NULL || strstr (name, "sigaction") != NULL) |
| 206 | return (amd64_linux_sigtramp_start (pc) != 0); |
| 207 | |
| 208 | return (strcmp ("__restore_rt", name) == 0); |
| 209 | } |
| 210 | |
| 211 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
| 212 | #define AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 |
| 213 | |
| 214 | /* Assuming NEXT_FRAME is a frame following a GNU/Linux sigtramp |
| 215 | routine, return the address of the associated sigcontext structure. */ |
| 216 | |
| 217 | static CORE_ADDR |
| 218 | amd64_linux_sigcontext_addr (struct frame_info *next_frame) |
| 219 | { |
| 220 | CORE_ADDR sp; |
| 221 | char buf[8]; |
| 222 | |
| 223 | frame_unwind_register (next_frame, SP_REGNUM, buf); |
| 224 | sp = extract_unsigned_integer (buf, 8); |
| 225 | |
| 226 | /* The sigcontext structure is part of the user context. A pointer |
| 227 | to the user context is passed as the third argument to the signal |
| 228 | handler, i.e. in %rdx. Unfortunately %rdx isn't preserved across |
| 229 | function calls so we can't use it. Fortunately the user context |
| 230 | is part of the signal frame and the unwound %rsp directly points |
| 231 | at it. */ |
| 232 | return sp + AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 233 | } |
| 234 | \f |
| 235 | |
| 236 | /* From <asm/sigcontext.h>. */ |
| 237 | static int amd64_linux_sc_reg_offset[] = |
| 238 | { |
| 239 | 13 * 8, /* %rax */ |
| 240 | 11 * 8, /* %rbx */ |
| 241 | 14 * 8, /* %rcx */ |
| 242 | 12 * 8, /* %rdx */ |
| 243 | 9 * 8, /* %rsi */ |
| 244 | 8 * 8, /* %rdi */ |
| 245 | 10 * 8, /* %rbp */ |
| 246 | 15 * 8, /* %rsp */ |
| 247 | 0 * 8, /* %r8 */ |
| 248 | 1 * 8, /* %r9 */ |
| 249 | 2 * 8, /* %r10 */ |
| 250 | 3 * 8, /* %r11 */ |
| 251 | 4 * 8, /* %r12 */ |
| 252 | 5 * 8, /* %r13 */ |
| 253 | 6 * 8, /* %r14 */ |
| 254 | 7 * 8, /* %r15 */ |
| 255 | 16 * 8, /* %rip */ |
| 256 | 17 * 8, /* %eflags */ |
| 257 | |
| 258 | /* FIXME: kettenis/2002030531: The registers %cs, %fs and %gs are |
| 259 | available in `struct sigcontext'. However, they only occupy two |
| 260 | bytes instead of four, which makes using them here rather |
| 261 | difficult. Leave them out for now. */ |
| 262 | -1, /* %cs */ |
| 263 | -1, /* %ss */ |
| 264 | -1, /* %ds */ |
| 265 | -1, /* %es */ |
| 266 | -1, /* %fs */ |
| 267 | -1 /* %gs */ |
| 268 | }; |
| 269 | |
| 270 | static void |
| 271 | amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 272 | { |
| 273 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 274 | amd64_init_abi (info, gdbarch); |
| 275 | |
| 276 | set_gdbarch_pc_in_sigtramp (gdbarch, amd64_linux_pc_in_sigtramp); |
| 277 | |
| 278 | tdep->sigcontext_addr = amd64_linux_sigcontext_addr; |
| 279 | tdep->sc_reg_offset = amd64_linux_sc_reg_offset; |
| 280 | tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset); |
| 281 | } |
| 282 | \f |
| 283 | |
| 284 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 285 | extern void _initialize_amd64_linux_tdep (void); |
| 286 | |
| 287 | void |
| 288 | _initialize_amd64_linux_tdep (void) |
| 289 | { |
| 290 | add_core_fns (&amd64_core_fns); |
| 291 | |
| 292 | gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, |
| 293 | GDB_OSABI_LINUX, amd64_linux_init_abi); |
| 294 | } |