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linux-nios2-low.c
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1 /* GNU/Linux/Nios II specific low level interface, for the remote server for
2  GDB.
3  Copyright (C) 2008-2015 Free Software Foundation, Inc.
4 
5  Contributed by Mentor Graphics, Inc.
6 
7  This file is part of GDB.
8 
9  This program is free software; you can redistribute it and/or modify
10  it under the terms of the GNU General Public License as published by
11  the Free Software Foundation; either version 3 of the License, or
12  (at your option) any later version.
13 
14  This program is distributed in the hope that it will be useful,
15  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  GNU General Public License for more details.
18 
19  You should have received a copy of the GNU General Public License
20  along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 
22 #include "server.h"
23 #include "linux-low.h"
24 #include "elf/common.h"
25 #include <sys/ptrace.h>
26 #include <endian.h>
27 #include "gdb_proc_service.h"
28 #include <asm/ptrace.h>
29 
30 #ifndef PTRACE_GET_THREAD_AREA
31 #define PTRACE_GET_THREAD_AREA 25
32 #endif
33 
34 /* The following definition must agree with the number of registers
35  defined in "struct user_regs" in GLIBC
36  (sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with
37  NIOS2_NUM_REGS in GDB proper. */
38 
39 #define nios2_num_regs 49
40 
41 /* Defined in auto-generated file nios2-linux.c. */
42 
43 void init_registers_nios2_linux (void);
44 extern const struct target_desc *tdesc_nios2_linux;
45 
46 /* This union is used to convert between int and byte buffer
47  representations of register contents. */
48 
50 {
51  unsigned char buf[4];
52  int reg32;
53 };
54 
55 /* Return the ptrace ``address'' of register REGNO. */
56 
57 static int nios2_regmap[] = {
58  -1, 1, 2, 3, 4, 5, 6, 7,
59  8, 9, 10, 11, 12, 13, 14, 15,
60  16, 17, 18, 19, 20, 21, 22, 23,
61  24, 25, 26, 27, 28, 29, 30, 31,
62  32, 33, 34, 35, 36, 37, 38, 39,
63  40, 41, 42, 43, 44, 45, 46, 47,
64  48,
65  0
66 };
67 
68 /* Implement the arch_setup linux_target_ops method. */
69 
70 static void
72 {
74 }
75 
76 /* Implement the cannot_fetch_register linux_target_ops method. */
77 
78 static int
80 {
81  if (nios2_regmap[regno] == -1)
82  return 1;
83 
84  return 0;
85 }
86 
87 /* Implement the cannot_store_register linux_target_ops method. */
88 
89 static int
91 {
92  if (nios2_regmap[regno] == -1)
93  return 1;
94 
95  return 0;
96 }
97 
98 /* Implement the get_pc linux_target_ops method. */
99 
100 static CORE_ADDR
102 {
103  union nios2_register pc;
104 
105  collect_register_by_name (regcache, "pc", pc.buf);
106  return pc.reg32;
107 }
108 
109 /* Implement the set_pc linux_target_ops method. */
110 
111 static void
113 {
114  union nios2_register newpc;
115 
116  newpc.reg32 = pc;
117  supply_register_by_name (regcache, "pc", newpc.buf);
118 }
119 
120 /* Breakpoint support. */
121 
122 static const unsigned int nios2_breakpoint = 0x003b6ffa;
123 #define nios2_breakpoint_len 4
124 
125 /* Implement the breakpoint_reinsert_addr linux_target_ops method. */
126 
127 static CORE_ADDR
129 {
130  union nios2_register ra;
132 
133  collect_register_by_name (regcache, "ra", ra.buf);
134  return ra.reg32;
135 }
136 
137 /* Implement the breakpoint_at linux_target_ops method. */
138 
139 static int
141 {
142  unsigned int insn;
143 
144  (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
145  if (insn == nios2_breakpoint)
146  return 1;
147  return 0;
148 }
149 
150 /* Fetch the thread-local storage pointer for libthread_db. */
151 
152 ps_err_e
154  lwpid_t lwpid, int idx, void **base)
155 {
156  if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
157  return PS_ERR;
158 
159  /* IDX is the bias from the thread pointer to the beginning of the
160  thread descriptor. It has to be subtracted due to implementation
161  quirks in libthread_db. */
162  *base = (void *) ((char *) *base - idx);
163 
164  return PS_OK;
165 }
166 
167 /* Helper functions to collect/supply a single register REGNO. */
168 
169 static void
171  union nios2_register *reg)
172 {
173  union nios2_register tmp_reg;
174 
175  collect_register (regcache, regno, &tmp_reg.reg32);
176  reg->reg32 = tmp_reg.reg32;
177 }
178 
179 static void
181  const union nios2_register *reg)
182 {
183  supply_register (regcache, regno, reg->buf);
184 }
185 
186 /* We have only a single register set on Nios II. */
187 
188 static void
190 {
191  union nios2_register *regset = buf;
192  int i;
193 
194  for (i = 1; i < nios2_num_regs; i++)
195  nios2_collect_register (regcache, i, regset + i);
196 }
197 
198 static void
199 nios2_store_gregset (struct regcache *regcache, const void *buf)
200 {
201  const union nios2_register *regset = buf;
202  int i;
203 
204  for (i = 0; i < nios2_num_regs; i++)
205  nios2_supply_register (regcache, i, regset + i);
206 }
207 
208 static struct regset_info nios2_regsets[] =
209 {
210  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
211  nios2_num_regs * 4, GENERAL_REGS,
213  { 0, 0, 0, -1, -1, NULL, NULL }
214 };
215 
216 static struct regsets_info nios2_regsets_info =
217  {
218  nios2_regsets, /* regsets */
219  0, /* num_regsets */
220  NULL, /* disabled_regsets */
221  };
222 
223 static struct usrregs_info nios2_usrregs_info =
224  {
226  nios2_regmap,
227  };
228 
229 static struct regs_info regs_info =
230  {
231  NULL, /* regset_bitmap */
233  &nios2_regsets_info
234  };
235 
236 static const struct regs_info *
238 {
239  return &regs_info;
240 }
241 
242 struct linux_target_ops the_low_target =
243 {
248  NULL,
249  nios2_get_pc,
250  nios2_set_pc,
251  (const unsigned char *) &nios2_breakpoint,
254  0,
256 };
257 
258 void
260 {
262 
263  initialize_regsets_info (&nios2_regsets_info);
264 }
unsigned int lwpid_t
void init_registers_nios2_linux(void)
struct thread_info * current_thread
Definition: inferiors.c:28
void collect_register(struct regcache *regcache, int n, void *buf)
Definition: regcache.c:414
static struct regset_info nios2_regsets[]
#define nios2_breakpoint_len
bfd_vma CORE_ADDR
Definition: common-types.h:41
void supply_register_by_name(struct regcache *regcache, const char *name, const void *buf)
Definition: regcache.c:405
#define nios2_num_regs
static const unsigned int nios2_breakpoint
void initialize_low_arch(void)
ps_err_e
struct target_ops * the_target
Definition: target.c:24
const struct target_desc * tdesc
Definition: inferiors.h:69
static CORE_ADDR nios2_get_pc(struct regcache *regcache)
void collect_register_by_name(struct regcache *regcache, const char *name, void *buf)
Definition: regcache.c:430
static void nios2_supply_register(struct regcache *regcache, int regno, const union nios2_register *reg)
unsigned char buf[4]
static int nios2_cannot_store_register(int regno)
#define PTRACE_GET_THREAD_AREA
#define PTRACE_SETREGSET
Definition: linux-ptrace.h:51
struct process_info * current_process(void)
Definition: inferiors.c:356
#define PTRACE_GETREGSET
Definition: linux-ptrace.h:47
static void nios2_collect_register(struct regcache *regcache, int regno, union nios2_register *reg)
static int nios2_regmap[]
static void nios2_store_gregset(struct regcache *regcache, const void *buf)
static CORE_ADDR nios2_reinsert_addr(void)
int(* read_memory)(CORE_ADDR memaddr, unsigned char *myaddr, int len)
Definition: target.h:160
static int nios2_breakpoint_at(CORE_ADDR where)
struct regcache * get_thread_regcache(struct thread_info *thread, int fetch)
Definition: regcache.c:27
static struct usrregs_info nios2_usrregs_info
const struct target_desc * tdesc_nios2_linux
static int nios2_cannot_fetch_register(int regno)
static void nios2_arch_setup(void)
static struct regsets_info nios2_regsets_info
ps_err_e ps_get_thread_area(const struct ps_prochandle *ph, lwpid_t lwpid, int idx, void **base)
void supply_register(struct regcache *regcache, int n, const void *buf)
Definition: regcache.c:330
static void nios2_fill_gregset(struct regcache *regcache, void *buf)
static void nios2_set_pc(struct regcache *regcache, CORE_ADDR pc)
static struct regs_info regs_info
static const struct regs_info * nios2_regs_info(void)