gdb/amd64obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/amd64.
   2
   3    Copyright 2003, 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 "frame.h"
  24 #include "gdbcore.h"
  25 #include "symtab.h"
  26 #include "objfiles.h"
  27 #include "osabi.h"
  28 #include "regset.h"
  29 #include "target.h"
  30
  31 #include "gdb_assert.h"
  32 #include "gdb_string.h"
  33
  34 #include "amd64-tdep.h"
  35 #include "i387-tdep.h"
  36 #include "solib-svr4.h"
  37
  38 /* Support for core dumps.  */
  39
  40 static void
  41 amd64obsd_supply_regset (const struct regset *regset,
  42                          struct regcache *regcache, int regnum,
  43                          const void *regs, size_t len)
  44 {
  45   const struct gdbarch_tdep *tdep = regset->descr;
  46
  47   gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE);
  48
  49   i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
  50   amd64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset);
  51 }
  52
  53 static const struct regset *
  54 amd64obsd_regset_from_core_section (struct gdbarch *gdbarch,
  55                                     const char *sect_name, size_t sect_size)
  56 {
  57   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  58
  59   /* OpenBSD core dumps don't use seperate register sets for the
  60      general-purpose and floating-point registers.  */
  61
  62   if (strcmp (sect_name, ".reg") == 0
  63       && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE)
  64     {
  65       if (tdep->gregset == NULL)
  66         {
  67           tdep->gregset = XMALLOC (struct regset);
  68           tdep->gregset->descr = tdep;
  69           tdep->gregset->supply_regset = amd64obsd_supply_regset;
  70         }
  71       return tdep->gregset;
  72     }
  73
  74   return NULL;
  75 }
  76 \f
  77
  78 /* Support for signal handlers.  */
  79
  80 /* Default page size.  */
  81 static const int amd64obsd_page_size = 4096;
  82
  83 /* Return whether the frame preceding NEXT_FRAME corresponds to an
  84    OpenBSD sigtramp routine.  */
  85
  86 static int
  87 amd64obsd_sigtramp_p (struct frame_info *next_frame)
  88 {
  89   CORE_ADDR pc = frame_pc_unwind (next_frame);
  90   CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
  91   const char sigreturn[] =
  92   {
  93     0x48, 0xc7, 0xc0,
  94     0x67, 0x00, 0x00, 0x00,     /* movq $SYS_sigreturn, %rax */
  95     0xcd, 0x80                  /* int $0x80 */
  96   };
  97   char *name, *buf;
  98
  99   /* If the function has a valid symbol name, it isn't a
 100      trampoline.  */
 101   find_pc_partial_function (pc, &name, NULL, NULL);
 102   if (name != NULL)
 103     return 0;
 104
 105   /* If the function lives in a valid section (even without a starting
 106      point) it isn't a trampoline.  */
 107   if (find_pc_section (pc) != NULL)
 108     return 0;
 109
 110   /* If we can't read the instructions at START_PC, return zero.  */
 111   buf = alloca (sizeof sigreturn);
 112   if (target_read_memory (start_pc + 0x7, buf, sizeof sigreturn))
 113     return 0;
 114
 115   /* Check for sigreturn(2).  */
 116   if (memcmp (buf, sigreturn, sizeof sigreturn))
 117     return 0;
 118
 119   return 1;
 120 }
 121
 122 /* Assuming NEXT_FRAME is for a frame following a BSD sigtramp
 123    routine, return the address of the associated sigcontext structure.  */
 124
 125 static CORE_ADDR
 126 amd64obsd_sigcontext_addr (struct frame_info *next_frame)
 127 {
 128   /* The %rsp register points at `struct sigcontext' upon entry of a
 129      signal trampoline.  */
 130   return frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM);
 131 }
 132 \f
 133 /* OpenBSD 3.5 or later.  */
 134
 135 /* Mapping between the general-purpose registers in `struct reg'
 136    format and GDB's register cache layout.  */
 137
 138 /* From <machine/reg.h>.  */
 139 int amd64obsd_r_reg_offset[] =
 140 {
 141   14 * 8,                       /* %rax */
 142   13 * 8,                       /* %rbx */
 143   3 * 8,                        /* %rcx */
 144   2 * 8,                        /* %rdx */
 145   1 * 8,                        /* %rsi */
 146   0 * 8,                        /* %rdi */
 147   12 * 8,                       /* %rbp */
 148   15 * 8,                       /* %rsp */
 149   4 * 8,                        /* %r8 .. */
 150   5 * 8,
 151   6 * 8,
 152   7 * 8,
 153   8 * 8,
 154   9 * 8,
 155   10 * 8,
 156   11 * 8,                       /* ... %r15 */
 157   16 * 8,                       /* %rip */
 158   17 * 8,                       /* %eflags */
 159   18 * 8,                       /* %cs */
 160   19 * 8,                       /* %ss */
 161   20 * 8,                       /* %ds */
 162   21 * 8,                       /* %es */
 163   22 * 8,                       /* %fs */
 164   23 * 8                        /* %gs */
 165 };
 166
 167 /* From <machine/signal.h>.  */
 168 static int amd64obsd_sc_reg_offset[] =
 169 {
 170   14 * 8,                       /* %rax */
 171   13 * 8,                       /* %rbx */
 172   3 * 8,                        /* %rcx */
 173   2 * 8,                        /* %rdx */
 174   1 * 8,                        /* %rsi */
 175   0 * 8,                        /* %rdi */
 176   12 * 8,                       /* %rbp */
 177   24 * 8,                       /* %rsp */
 178   4 * 8,                        /* %r8 ... */
 179   5 * 8,
 180   6 * 8,
 181   7 * 8,
 182   8 * 8,
 183   9 * 8,
 184   10 * 8,
 185   11 * 8,                       /* ... %r15 */
 186   21 * 8,                       /* %rip */
 187   23 * 8,                       /* %eflags */
 188   22 * 8,                       /* %cs */
 189   25 * 8,                       /* %ss */
 190   18 * 8,                       /* %ds */
 191   17 * 8,                       /* %es */
 192   16 * 8,                       /* %fs */
 193   15 * 8                        /* %gs */
 194 };
 195
 196 static void
 197 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 198 {
 199   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 200
 201   amd64_init_abi (info, gdbarch);
 202
 203   /* Initialize general-purpose register set details.  */
 204   tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
 205   tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
 206   tdep->sizeof_gregset = 24 * 8;
 207
 208   set_gdbarch_regset_from_core_section (gdbarch,
 209                                         amd64obsd_regset_from_core_section);
 210
 211   tdep->jb_pc_offset = 7 * 8;
 212
 213   tdep->sigtramp_p = amd64obsd_sigtramp_p;
 214   tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
 215   tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
 216   tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
 217
 218   /* OpenBSD uses SVR4-style shared libraries.  */
 219   set_solib_svr4_fetch_link_map_offsets
 220     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 221 }
 222 \f
 223
 224 /* Provide a prototype to silence -Wmissing-prototypes.  */
 225 void _initialize_amd64obsd_tdep (void);
 226
 227 void
 228 _initialize_amd64obsd_tdep (void)
 229 {
 230   /* The OpenBSD/amd64 native dependent code makes this assumption.  */
 231   gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS);
 232
 233   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 234                           GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);
 235
 236   /* OpenBSD uses traditional (a.out) NetBSD-style core dumps.  */
 237   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 238                           GDB_OSABI_NETBSD_AOUT, amd64obsd_init_abi);
 239 }