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/tmp/gdb-8.1/gdb/amd64-nat.c
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1 /* Native-dependent code for AMD64.
2
3 Copyright (C) 2003-2018 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 follwing 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 negligable. 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 /* Kernels that predate Linux 2.6.25 don't provide access to
72 these segment registers in user_regs_struct. */
73 #ifndef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
74 if (regnum == AMD64_FSBASE_REGNUM || regnum == AMD64_GSBASE_REGNUM)
75 return -1;
76 #endif
77
78 return reg_offset[regnum];
79 }
80
81 /* Return whether the native general-purpose register set supplies
82 register REGNUM. */
83
84 int
85 amd64_native_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
86 {
87 return (amd64_native_gregset_reg_offset (gdbarch, regnum) != -1);
88 }
89
90
91 /* Supply register REGNUM, whose contents are stored in GREGS, to
92 REGCACHE. If REGNUM is -1, supply all appropriate registers. */
93
94 void
95 amd64_supply_native_gregset (struct regcache *regcache,
96 const void *gregs, int regnum)
97 {
98 const char *regs = (const char *) gregs;
99 struct gdbarch *gdbarch = regcache->arch ();
100 int num_regs = amd64_native_gregset64_num_regs;
101 int i;
102
103 if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
104 num_regs = amd64_native_gregset32_num_regs;
105
106 if (num_regs > gdbarch_num_regs (gdbarch))
107 num_regs = gdbarch_num_regs (gdbarch);
108
109 for (i = 0; i < num_regs; i++)
110 {
111 if (regnum == -1 || regnum == i)
112 {
113 int offset = amd64_native_gregset_reg_offset (gdbarch, i);
114
115 if (offset != -1)
116 regcache_raw_supply (regcache, i, regs + offset);
117 }
118 }
119 }
120
121 /* Collect register REGNUM from REGCACHE and store its contents in
122 GREGS. If REGNUM is -1, collect and store all appropriate
123 registers. */
124
125 void
126 amd64_collect_native_gregset (const struct regcache *regcache,
127 void *gregs, int regnum)
128 {
129 char *regs = (char *) gregs;
130 struct gdbarch *gdbarch = regcache->arch ();
131 int num_regs = amd64_native_gregset64_num_regs;
132 int i;
133
134 if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
135 {
136 num_regs = amd64_native_gregset32_num_regs;
137
138 /* Make sure %eax, %ebx, %ecx, %edx, %esi, %edi, %ebp, %esp and
139 %eip get zero-extended to 64 bits. */
140 for (i = 0; i <= I386_EIP_REGNUM; i++)
141 {
142 if (regnum == -1 || regnum == i)
143 memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
144 }
145 /* Ditto for %cs, %ss, %ds, %es, %fs, and %gs. */
146 for (i = I386_CS_REGNUM; i <= I386_GS_REGNUM; i++)
147 {
148 if (regnum == -1 || regnum == i)
149 memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
150 }
151 }
152
153 if (num_regs > gdbarch_num_regs (gdbarch))
154 num_regs = gdbarch_num_regs (gdbarch);
155
156 for (i = 0; i < num_regs; i++)
157 {
158 if (regnum == -1 || regnum == i)
159 {
160 int offset = amd64_native_gregset_reg_offset (gdbarch, i);
161
162 if (offset != -1)
163 regcache_raw_collect (regcache, i, regs + offset);
164 }
165 }
166 }
gdbarch
Definition: gdbarch.c:127
I386_NUM_GREGS
#define I386_NUM_GREGS
Definition: i386-tdep.h:332
reg_offset
static int reg_offset[]
Definition: i386-gnu-nat.c:46
gdbarch::num_regs
int num_regs
Definition: gdbarch.c:200
amd64-nat.h
amd64_collect_native_gregset
void amd64_collect_native_gregset(const struct regcache *regcache, void *gregs, int regnum)
Definition: amd64-nat.c:126
amd64_native_gregset32_num_regs
int amd64_native_gregset32_num_regs
Definition: amd64-nat.c:42
memset
void * memset(T *s, int c, size_t n)=delete
gdbarch_num_regs
int gdbarch_num_regs(struct gdbarch *gdbarch)
Definition: gdbarch.c:2039
defs.h
amd64_native_gregset64_num_regs
int amd64_native_gregset64_num_regs
Definition: amd64-nat.c:46
I386_CS_REGNUM
Definition: i386-tdep.h:281
amd64_supply_native_gregset
void amd64_supply_native_gregset(struct regcache *regcache, const void *gregs, int regnum)
Definition: amd64-nat.c:95
amd64_native_gregset32_reg_offset
int * amd64_native_gregset32_reg_offset
Definition: amd64-nat.c:41
I386_GS_REGNUM
Definition: i386-tdep.h:286
I386_EIP_REGNUM
Definition: i386-tdep.h:279
amd64_native_gregset64_reg_offset
int * amd64_native_gregset64_reg_offset
Definition: amd64-nat.c:45
regcache.h
gdbarch.h
AMD64_NUM_GREGS
#define AMD64_NUM_GREGS
Definition: amd64-tdep.h:86
amd64-tdep.h
regnum
int regnum
Definition: aarch64-tdep.c:77
gdb_assert
#define gdb_assert(expr)
Definition: gdb_assert.h:32
amd64_native_gregset_reg_offset
static int amd64_native_gregset_reg_offset(struct gdbarch *gdbarch, int regnum)
Definition: amd64-nat.c:52
amd64_native_gregset_supplies_p
int amd64_native_gregset_supplies_p(struct gdbarch *gdbarch, int regnum)
Definition: amd64-nat.c:85
offset
int offset
Definition: agent.c:65
regcache::arch
gdbarch * arch() const
Definition: regcache.c:221
regcache_raw_supply
void regcache_raw_supply(struct regcache *regcache, int regnum, const void *buf)
Definition: regcache.c:1004
regcache
Definition: regcache.h:232
gdbarch_bfd_arch_info
const struct bfd_arch_info * gdbarch_bfd_arch_info(struct gdbarch *gdbarch)
Definition: gdbarch.c:1500
regcache_raw_collect
void regcache_raw_collect(const struct regcache *regcache, int regnum, void *buf)
Definition: regcache.c:1085
AMD64_FSBASE_REGNUM
Definition: amd64-tdep.h:81
i386-tdep.h
AMD64_GSBASE_REGNUM
Definition: amd64-tdep.h:82