gdb/amd64-nat.c

   1 /* Native-dependent code for AMD64.
   2
   3    Copyright (C) 2003-2021 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 "gdbarch.h"
  22 #include "regcache.h"
  23
  24 #include "i386-tdep.h"
  25 #include "amd64-tdep.h"
  26 #include "amd64-nat.h"
  27
  28 /* The following bits of code help with implementing debugging 32-bit
  29    code natively on AMD64.  The idea is to define two mappings between
  30    the register number as used by GDB and the register set used by the
  31    host to represent the general-purpose registers; one for 32-bit
  32    code and one for 64-bit code.  The mappings are specified by the
  33    following variables and consist of an array of offsets within the
  34    register set indexed by register number, and the number of
  35    registers supported by the mapping.  We don't need mappings for the
  36    floating-point and SSE registers, since the difference between
  37    64-bit and 32-bit variants are negligible.  The difference in the
  38    number of SSE registers is already handled by the target code.  */
  39
  40 /* General-purpose register mapping for native 32-bit code.  */
  41 int *amd64_native_gregset32_reg_offset;
  42 int amd64_native_gregset32_num_regs = I386_NUM_GREGS;
  43
  44 /* General-purpose register mapping for native 64-bit code.  */
  45 int *amd64_native_gregset64_reg_offset;
  46 int amd64_native_gregset64_num_regs = AMD64_NUM_GREGS;
  47
  48 /* Return the offset of REGNUM within the appropriate native
  49    general-purpose register set.  */
  50
  51 static int
  52 amd64_native_gregset_reg_offset (struct gdbarch *gdbarch, int regnum)
  53 {
  54   int *reg_offset = amd64_native_gregset64_reg_offset;
  55   int num_regs = amd64_native_gregset64_num_regs;
  56
  57   gdb_assert (regnum >= 0);
  58
  59   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
  60     {
  61       reg_offset = amd64_native_gregset32_reg_offset;
  62       num_regs = amd64_native_gregset32_num_regs;
  63     }
  64
  65   if (num_regs > gdbarch_num_regs (gdbarch))
  66     num_regs = gdbarch_num_regs (gdbarch);
  67
  68   if (regnum >= num_regs)
  69     return -1;
  70
  71   return reg_offset[regnum];
  72 }
  73
  74 /* Return whether the native general-purpose register set supplies
  75    register REGNUM.  */
  76
  77 int
  78 amd64_native_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
  79 {
  80   return (amd64_native_gregset_reg_offset (gdbarch, regnum) != -1);
  81 }
  82
  83
  84 /* Supply register REGNUM, whose contents are stored in GREGS, to
  85    REGCACHE.  If REGNUM is -1, supply all appropriate registers.  */
  86
  87 void
  88 amd64_supply_native_gregset (struct regcache *regcache,
  89                              const void *gregs, int regnum)
  90 {
  91   const char *regs = (const char *) gregs;
  92   struct gdbarch *gdbarch = regcache->arch ();
  93   int num_regs = amd64_native_gregset64_num_regs;
  94   int i;
  95
  96   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
  97     num_regs = amd64_native_gregset32_num_regs;
  98
  99   if (num_regs > gdbarch_num_regs (gdbarch))
 100     num_regs = gdbarch_num_regs (gdbarch);
 101
 102   for (i = 0; i < num_regs; i++)
 103     {
 104       if (regnum == -1 || regnum == i)
 105         {
 106           int offset = amd64_native_gregset_reg_offset (gdbarch, i);
 107
 108           if (offset != -1)
 109             regcache->raw_supply (i, regs + offset);
 110         }
 111     }
 112 }
 113
 114 /* Collect register REGNUM from REGCACHE and store its contents in
 115    GREGS.  If REGNUM is -1, collect and store all appropriate
 116    registers.  */
 117
 118 void
 119 amd64_collect_native_gregset (const struct regcache *regcache,
 120                               void *gregs, int regnum)
 121 {
 122   char *regs = (char *) gregs;
 123   struct gdbarch *gdbarch = regcache->arch ();
 124   int num_regs = amd64_native_gregset64_num_regs;
 125   int i;
 126
 127   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 128     {
 129       num_regs = amd64_native_gregset32_num_regs;
 130
 131       /* Make sure %eax, %ebx, %ecx, %edx, %esi, %edi, %ebp, %esp and
 132          %eip get zero-extended to 64 bits.  */
 133       for (i = 0; i <= I386_EIP_REGNUM; i++)
 134         {
 135           if (regnum == -1 || regnum == i)
 136             memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
 137         }
 138       /* Ditto for %cs, %ss, %ds, %es, %fs, and %gs.  */
 139       for (i = I386_CS_REGNUM; i <= I386_GS_REGNUM; i++)
 140         {
 141           if (regnum == -1 || regnum == i)
 142             memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
 143         }
 144     }
 145
 146   if (num_regs > gdbarch_num_regs (gdbarch))
 147     num_regs = gdbarch_num_regs (gdbarch);
 148
 149   for (i = 0; i < num_regs; i++)
 150     {
 151       if (regnum == -1 || regnum == i)
 152         {
 153           int offset = amd64_native_gregset_reg_offset (gdbarch, i);
 154
 155           if (offset != -1)
 156             regcache->raw_collect (i, regs + offset);
 157         }
 158     }
 159 }