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/tmp/gdb-8.1/gdb/amd64-obsd-nat.c
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1 /* Native-dependent code for OpenBSD/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 "gdbcore.h"
22 #include "regcache.h"
23 #include "target.h"
24
25 #include "amd64-tdep.h"
26 #include "amd64-nat.h"
27 #include "obsd-nat.h"
28
29 /* Mapping between the general-purpose registers in OpenBSD/amd64
30 `struct reg' format and GDB's register cache layout for
31 OpenBSD/i386.
32
33 Note that most (if not all) OpenBSD/amd64 registers are 64-bit,
34 while the OpenBSD/i386 registers are all 32-bit, but since we're
35 little-endian we get away with that. */
36
37 /* From <machine/reg.h>. */
38 static int amd64obsd32_r_reg_offset[] =
39 {
40 14 * 8, /* %eax */
41 3 * 8, /* %ecx */
42 2 * 8, /* %edx */
43 13 * 8, /* %ebx */
44 15 * 8, /* %esp */
45 12 * 8, /* %ebp */
46 1 * 8, /* %esi */
47 0 * 8, /* %edi */
48 16 * 8, /* %eip */
49 17 * 8, /* %eflags */
50 18 * 8, /* %cs */
51 19 * 8, /* %ss */
52 20 * 8, /* %ds */
53 21 * 8, /* %es */
54 22 * 8, /* %fs */
55 23 * 8 /* %gs */
56 };
57
58
59 /* Support for debugging kernel virtual memory images. */
60
61 #include <sys/types.h>
62 #include <machine/frame.h>
63 #include <machine/pcb.h>
64
65 #include "bsd-kvm.h"
66
67 static int
68 amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
69 {
70 struct switchframe sf;
71 int regnum;
72
73 /* The following is true for OpenBSD 3.5:
74
75 The pcb contains the stack pointer at the point of the context
76 switch in cpu_switch(). At that point we have a stack frame as
77 described by `struct switchframe', which for OpenBSD 3.5 has the
78 following layout:
79
80 interrupt level
81 %r15
82 %r14
83 %r13
84 %r12
85 %rbp
86 %rbx
87 return address
88
89 Together with %rsp in the pcb, this accounts for all callee-saved
90 registers specified by the psABI. From this information we
91 reconstruct the register state as it would look when we just
92 returned from cpu_switch().
93
94 For core dumps the pcb is saved by savectx(). In that case the
95 stack frame only contains the return address, and there is no way
96 to recover the other registers. */
97
98 /* The stack pointer shouldn't be zero. */
99 if (pcb->pcb_rsp == 0)
100 return 0;
101
102 /* Read the stack frame, and check its validity. */
103 read_memory (pcb->pcb_rsp, (gdb_byte *) &sf, sizeof sf);
104 if (sf.sf_rbp == pcb->pcb_rbp)
105 {
106 /* Yes, we have a frame that matches cpu_switch(). */
107 pcb->pcb_rsp += sizeof (struct switchframe);
108 regcache_raw_supply (regcache, 12, &sf.sf_r12);
109 regcache_raw_supply (regcache, 13, &sf.sf_r13);
110 regcache_raw_supply (regcache, 14, &sf.sf_r14);
111 regcache_raw_supply (regcache, 15, &sf.sf_r15);
112 regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &sf.sf_rbx);
113 regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf.sf_rip);
114 }
115 else
116 {
117 /* No, the pcb must have been last updated by savectx(). */
118 pcb->pcb_rsp += 8;
119 regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf);
120 }
121
122 regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
123 regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
124
125 return 1;
126 }
127
128 void
129 _initialize_amd64obsd_nat (void)
130 {
131 amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset;
132 amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset);
133 amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset;
134
135 /* Add some extra features to the common *BSD/amd64 target. */
136 obsd_add_target (amd64bsd_target ());
137
138 /* Support debugging kernel virtual memory images. */
139 bsd_kvm_add_target (amd64obsd_supply_pcb);
140 }
amd64-nat.h
obsd_add_target
void obsd_add_target(struct target_ops *t)
Definition: obsd-nat.c:181
AMD64_RBX_REGNUM
Definition: amd64-tdep.h:35
AMD64_RIP_REGNUM
Definition: amd64-tdep.h:50
amd64obsd32_r_reg_offset
static int amd64obsd32_r_reg_offset[]
Definition: amd64-obsd-nat.c:38
amd64_native_gregset32_num_regs
int amd64_native_gregset32_num_regs
Definition: amd64-nat.c:42
obsd-nat.h
amd64obsd_supply_pcb
static int amd64obsd_supply_pcb(struct regcache *regcache, struct pcb *pcb)
Definition: amd64-obsd-nat.c:68
defs.h
amd64_native_gregset32_reg_offset
int * amd64_native_gregset32_reg_offset
Definition: amd64-nat.c:41
amd64_native_gregset64_reg_offset
int * amd64_native_gregset64_reg_offset
Definition: amd64-nat.c:45
regcache.h
bsd-kvm.h
AMD64_RSP_REGNUM
Definition: amd64-tdep.h:41
amd64obsd_r_reg_offset
int amd64obsd_r_reg_offset[]
Definition: amd64-obsd-tdep.c:130
amd64-tdep.h
regnum
int regnum
Definition: aarch64-tdep.c:77
read_memory
void read_memory(CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
Definition: corefile.c:258
AMD64_RBP_REGNUM
Definition: amd64-tdep.h:40
gdb_byte
bfd_byte gdb_byte
Definition: common-types.h:38
gdbcore.h
amd64bsd_target
struct target_ops * amd64bsd_target(void)
Definition: amd64-bsd-nat.c:201
target.h
regcache_raw_supply
void regcache_raw_supply(struct regcache *regcache, int regnum, const void *buf)
Definition: regcache.c:1004
regcache
Definition: regcache.h:232
bsd_kvm_add_target
void bsd_kvm_add_target(int(*supply_pcb)(struct regcache *, struct pcb *))
Definition: bsd-kvm.c:354
_initialize_amd64obsd_nat
void _initialize_amd64obsd_nat(void)
Definition: amd64-obsd-nat.c:129