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
amd64_native_gregset_reg_offset(struct gdbarch * gdbarch,int regnum)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
amd64_native_gregset_supplies_p(struct gdbarch * gdbarch,int regnum)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
amd64_supply_native_gregset(struct regcache * regcache,const void * gregs,int regnum)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
amd64_collect_native_gregset(const struct regcache * regcache,void * gregs,int regnum)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 }
160