1 /* Native-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 "gdbcore.h"
24 #include "regcache.h"
25 #include "target.h"
26
27 #include "gdb_assert.h"
28
29 #include "obsd-nat.h"
30 #include "amd64-tdep.h"
31 #include "amd64-nat.h"
32
33 /* Mapping between the general-purpose registers in OpenBSD/amd64
34 `struct reg' format and GDB's register cache layout for
35 OpenBSD/i386.
36
37 Note that most (if not all) OpenBSD/amd64 registers are 64-bit,
38 while the OpenBSD/i386 registers are all 32-bit, but since we're
39 little-endian we get away with that. */
40
41 /* From <machine/reg.h>. */
42 static int amd64obsd32_r_reg_offset[] =
43 {
44 14 * 8, /* %eax */
45 3 * 8, /* %ecx */
46 2 * 8, /* %edx */
47 13 * 8, /* %ebx */
48 15 * 8, /* %esp */
49 12 * 8, /* %ebp */
50 1 * 8, /* %esi */
51 0 * 8, /* %edi */
52 16 * 8, /* %eip */
53 17 * 8, /* %eflags */
54 18 * 8, /* %cs */
55 19 * 8, /* %ss */
56 20 * 8, /* %ds */
57 21 * 8, /* %es */
58 22 * 8, /* %fs */
59 23 * 8 /* %gs */
60 };
61
62
63 /* Support for debugging kernel virtual memory images. */
64
65 #include <sys/types.h>
66 #include <machine/frame.h>
67 #include <machine/pcb.h>
68
69 #include "bsd-kvm.h"
70
71 static int
amd64obsd_supply_pcb(struct regcache * regcache,struct pcb * pcb)72 amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
73 {
74 struct switchframe sf;
75 int regnum;
76
77 /* The following is true for OpenBSD 3.5:
78
79 The pcb contains the stack pointer at the point of the context
80 switch in cpu_switch(). At that point we have a stack frame as
81 described by `struct switchframe', which for OpenBSD 3.5 has the
82 following layout:
83
84 interrupt level
85 %r15
86 %r14
87 %r13
88 %r12
89 %rbp
90 %rbx
91 return address
92
93 Together with %rsp in the pcb, this accounts for all callee-saved
94 registers specified by the psABI. From this information we
95 reconstruct the register state as it would look when we just
96 returned from cpu_switch().
97
98 For core dumps the pcb is saved by savectx(). In that case the
99 stack frame only contains the return address, and there is no way
100 to recover the other registers. */
101
102 /* The stack pointer shouldn't be zero. */
103 if (pcb->pcb_rsp == 0)
104 return 0;
105
106 /* Read the stack frame, and check its validity. */
107 read_memory (pcb->pcb_rsp, (char *) &sf, sizeof sf);
108 if (sf.sf_rbp == pcb->pcb_rbp)
109 {
110 /* Yes, we have a frame that matches cpu_switch(). */
111 pcb->pcb_rsp += sizeof (struct switchframe);
112 regcache_raw_supply (regcache, 12, &sf.sf_r12);
113 regcache_raw_supply (regcache, 13, &sf.sf_r13);
114 regcache_raw_supply (regcache, 14, &sf.sf_r14);
115 regcache_raw_supply (regcache, 15, &sf.sf_r15);
116 regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &sf.sf_rbx);
117 regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf.sf_rip);
118 }
119 else
120 {
121 /* No, the pcb must have been last updated by savectx(). */
122 pcb->pcb_rsp += 8;
123 regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf);
124 }
125
126 regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
127 regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
128
129 return 1;
130 }
131
132
133 /* Provide a prototype to silence -Wmissing-prototypes. */
134 void _initialize_amd64obsd_nat (void);
135
136 void
_initialize_amd64obsd_nat(void)137 _initialize_amd64obsd_nat (void)
138 {
139 struct target_ops *t;
140
141 amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset;
142 amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset);
143 amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset;
144
145 /* Add some extra features to the common *BSD/amd64 target. */
146 t = amd64bsd_target ();
147 t->to_pid_to_str = obsd_pid_to_str;
148 t->to_find_new_threads = obsd_find_new_threads;
149 t->to_wait = obsd_wait;
150 add_target (t);
151
152 /* Support debugging kernel virtual memory images. */
153 bsd_kvm_add_target (amd64obsd_supply_pcb);
154 }
155