gdb/amd64fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2015 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 "arch-utils.h"
  22 #include "frame.h"
  23 #include "gdbcore.h"
  24 #include "regcache.h"
  25 #include "osabi.h"
  26
  27 #include "amd64-tdep.h"
  28 #include "bsd-uthread.h"
  29 #include "fbsd-tdep.h"
  30 #include "solib-svr4.h"
  31
  32 /* Support for signal handlers.  */
  33
  34 /* Return whether THIS_FRAME corresponds to a FreeBSD sigtramp
  35    routine.  */
  36
  37 static const gdb_byte amd64fbsd_sigtramp_code[] =
  38 {
  39   0x48, 0x8d, 0x7c, 0x24, 0x10, /* lea     SIGF_UC(%rsp),%rdi */
  40   0x6a, 0x00,                   /* pushq   $0 */
  41   0x48, 0xc7, 0xc0, 0xa1, 0x01, 0x00, 0x00,
  42                                 /* movq    $SYS_sigreturn,%rax */
  43   0x0f, 0x05                    /* syscall */
  44 };
  45
  46 static int
  47 amd64fbsd_sigtramp_p (struct frame_info *this_frame)
  48 {
  49   CORE_ADDR pc = get_frame_pc (this_frame);
  50   gdb_byte buf[sizeof amd64fbsd_sigtramp_code];
  51
  52   if (!safe_frame_unwind_memory (this_frame, pc, buf, sizeof buf))
  53     return 0;
  54   if (memcmp (buf, amd64fbsd_sigtramp_code, sizeof amd64fbsd_sigtramp_code)
  55       != 0)
  56     return 0;
  57
  58   return 1;
  59 }
  60
  61 /* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
  62    address of the associated sigcontext structure.  */
  63
  64 static CORE_ADDR
  65 amd64fbsd_sigcontext_addr (struct frame_info *this_frame)
  66 {
  67   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  68   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  69   CORE_ADDR sp;
  70   gdb_byte buf[8];
  71
  72   /* The `struct sigcontext' (which really is an `ucontext_t' on
  73      FreeBSD/amd64) lives at a fixed offset in the signal frame.  See
  74      <machine/sigframe.h>.  */
  75   get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
  76   sp = extract_unsigned_integer (buf, 8, byte_order);
  77   return sp + 16;
  78 }
  79 \f
  80 /* FreeBSD 5.1-RELEASE or later.  */
  81
  82 /* Mapping between the general-purpose registers in `struct reg'
  83    format and GDB's register cache layout.
  84
  85    Note that some registers are 32-bit, but since we're little-endian
  86    we get away with that.  */
  87
  88 /* From <machine/reg.h>.  */
  89 static int amd64fbsd_r_reg_offset[] =
  90 {
  91   14 * 8,                       /* %rax */
  92   11 * 8,                       /* %rbx */
  93   13 * 8,                       /* %rcx */
  94   12 * 8,                       /* %rdx */
  95   9 * 8,                        /* %rsi */
  96   8 * 8,                        /* %rdi */
  97   10 * 8,                       /* %rbp */
  98   20 * 8,                       /* %rsp */
  99   7 * 8,                        /* %r8 ...  */
 100   6 * 8,
 101   5 * 8,
 102   4 * 8,
 103   3 * 8,
 104   2 * 8,
 105   1 * 8,
 106   0 * 8,                        /* ... %r15 */
 107   17 * 8,                       /* %rip */
 108   19 * 8,                       /* %eflags */
 109   18 * 8,                       /* %cs */
 110   21 * 8,                       /* %ss */
 111   -1,                           /* %ds */
 112   -1,                           /* %es */
 113   -1,                           /* %fs */
 114   -1                            /* %gs */
 115 };
 116
 117 /* Location of the signal trampoline.  */
 118 CORE_ADDR amd64fbsd_sigtramp_start_addr;
 119 CORE_ADDR amd64fbsd_sigtramp_end_addr;
 120
 121 /* From <machine/signal.h>.  */
 122 int amd64fbsd_sc_reg_offset[] =
 123 {
 124   24 + 6 * 8,                   /* %rax */
 125   24 + 7 * 8,                   /* %rbx */
 126   24 + 3 * 8,                   /* %rcx */
 127   24 + 2 * 8,                   /* %rdx */
 128   24 + 1 * 8,                   /* %rsi */
 129   24 + 0 * 8,                   /* %rdi */
 130   24 + 8 * 8,                   /* %rbp */
 131   24 + 22 * 8,                  /* %rsp */
 132   24 + 4 * 8,                   /* %r8 ...  */
 133   24 + 5 * 8,
 134   24 + 9 * 8,
 135   24 + 10 * 8,
 136   24 + 11 * 8,
 137   24 + 12 * 8,
 138   24 + 13 * 8,
 139   24 + 14 * 8,                  /* ... %r15 */
 140   24 + 19 * 8,                  /* %rip */
 141   24 + 21 * 8,                  /* %eflags */
 142   24 + 20 * 8,                  /* %cs */
 143   24 + 23 * 8,                  /* %ss */
 144   -1,                           /* %ds */
 145   -1,                           /* %es */
 146   -1,                           /* %fs */
 147   -1                            /* %gs */
 148 };
 149
 150 /* From /usr/src/lib/libc/amd64/gen/_setjmp.S.  */
 151 static int amd64fbsd_jmp_buf_reg_offset[] =
 152 {
 153   -1,                           /* %rax */
 154   1 * 8,                        /* %rbx */
 155   -1,                           /* %rcx */
 156   -1,                           /* %rdx */
 157   -1,                           /* %rsi */
 158   -1,                           /* %rdi */
 159   3 * 8,                        /* %rbp */
 160   2 * 8,                        /* %rsp */
 161   -1,                           /* %r8 ...  */
 162   -1,
 163   -1,
 164   -1,                           /* ... %r11 */
 165   4 * 8,                        /* %r12 ...  */
 166   5 * 8,
 167   6 * 8,
 168   7 * 8,                        /* ... %r15 */
 169   0 * 8                         /* %rip */
 170 };
 171
 172 static void
 173 amd64fbsd_supply_uthread (struct regcache *regcache,
 174                           int regnum, CORE_ADDR addr)
 175 {
 176   gdb_byte buf[8];
 177   int i;
 178
 179   gdb_assert (regnum >= -1);
 180
 181   for (i = 0; i < ARRAY_SIZE (amd64fbsd_jmp_buf_reg_offset); i++)
 182     {
 183       if (amd64fbsd_jmp_buf_reg_offset[i] != -1
 184           && (regnum == -1 || regnum == i))
 185         {
 186           read_memory (addr + amd64fbsd_jmp_buf_reg_offset[i], buf, 8);
 187           regcache_raw_supply (regcache, i, buf);
 188         }
 189     }
 190 }
 191
 192 static void
 193 amd64fbsd_collect_uthread (const struct regcache *regcache,
 194                            int regnum, CORE_ADDR addr)
 195 {
 196   gdb_byte buf[8];
 197   int i;
 198
 199   gdb_assert (regnum >= -1);
 200
 201   for (i = 0; i < ARRAY_SIZE (amd64fbsd_jmp_buf_reg_offset); i++)
 202     {
 203       if (amd64fbsd_jmp_buf_reg_offset[i] != -1
 204           && (regnum == -1 || regnum == i))
 205         {
 206           regcache_raw_collect (regcache, i, buf);
 207           write_memory (addr + amd64fbsd_jmp_buf_reg_offset[i], buf, 8);
 208         }
 209     }
 210 }
 211
 212 static void
 213 amd64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 214 {
 215   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 216
 217   /* Generic FreeBSD support. */
 218   fbsd_init_abi (info, gdbarch);
 219
 220   /* Obviously FreeBSD is BSD-based.  */
 221   i386bsd_init_abi (info, gdbarch);
 222
 223   tdep->gregset_reg_offset = amd64fbsd_r_reg_offset;
 224   tdep->gregset_num_regs = ARRAY_SIZE (amd64fbsd_r_reg_offset);
 225   tdep->sizeof_gregset = 22 * 8;
 226
 227   amd64_init_abi (info, gdbarch);
 228
 229   tdep->sigtramp_p = amd64fbsd_sigtramp_p;
 230   tdep->sigtramp_start = amd64fbsd_sigtramp_start_addr;
 231   tdep->sigtramp_end = amd64fbsd_sigtramp_end_addr;
 232   tdep->sigcontext_addr = amd64fbsd_sigcontext_addr;
 233   tdep->sc_reg_offset = amd64fbsd_sc_reg_offset;
 234   tdep->sc_num_regs = ARRAY_SIZE (amd64fbsd_sc_reg_offset);
 235
 236   /* FreeBSD provides a user-level threads implementation.  */
 237   bsd_uthread_set_supply_uthread (gdbarch, amd64fbsd_supply_uthread);
 238   bsd_uthread_set_collect_uthread (gdbarch, amd64fbsd_collect_uthread);
 239
 240   /* FreeBSD uses SVR4-style shared libraries.  */
 241   set_solib_svr4_fetch_link_map_offsets
 242     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 243 }
 244 \f
 245
 246 /* Provide a prototype to silence -Wmissing-prototypes.  */
 247 void _initialize_amd64fbsd_tdep (void);
 248
 249 void
 250 _initialize_amd64fbsd_tdep (void)
 251 {
 252   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 253                           GDB_OSABI_FREEBSD_ELF, amd64fbsd_init_abi);
 254 }