1 /* GNU/Linux/Nios II specific low level interface, for the remote server for
3 Copyright (C) 2008-2015 Free Software Foundation, Inc.
5 Contributed by Mentor Graphics, Inc.
7 This file is part of GDB.
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.
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.
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/>. */
23 #include "linux-low.h"
24 #include "elf/common.h"
25 #include "nat/gdb_ptrace.h"
27 #include "gdb_proc_service.h"
28 #include <asm/ptrace.h>
30 #ifndef PTRACE_GET_THREAD_AREA
31 #define PTRACE_GET_THREAD_AREA 25
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. */
39 #define nios2_num_regs 49
41 /* Defined in auto-generated file nios2-linux.c. */
43 void init_registers_nios2_linux (void);
44 extern const struct target_desc *tdesc_nios2_linux;
46 /* This union is used to convert between int and byte buffer
47 representations of register contents. */
55 /* Return the ptrace ``address'' of register REGNO. */
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,
68 /* Implement the arch_setup linux_target_ops method. */
71 nios2_arch_setup (void)
73 current_process ()->tdesc = tdesc_nios2_linux;
76 /* Implement the cannot_fetch_register linux_target_ops method. */
79 nios2_cannot_fetch_register (int regno)
81 if (nios2_regmap[regno] == -1)
87 /* Implement the cannot_store_register linux_target_ops method. */
90 nios2_cannot_store_register (int regno)
92 if (nios2_regmap[regno] == -1)
98 /* Implement the get_pc linux_target_ops method. */
101 nios2_get_pc (struct regcache *regcache)
103 union nios2_register pc;
105 collect_register_by_name (regcache, "pc", pc.buf);
109 /* Implement the set_pc linux_target_ops method. */
112 nios2_set_pc (struct regcache *regcache, CORE_ADDR pc)
114 union nios2_register newpc;
117 supply_register_by_name (regcache, "pc", newpc.buf);
120 /* Breakpoint support. Also see comments on nios2_breakpoint_from_pc
123 #if defined(__nios2_arch__) && __nios2_arch__ == 2
124 #define NIOS2_BREAKPOINT 0xb7fd0020
125 #define CDX_BREAKPOINT 0xd7c9
127 #define NIOS2_BREAKPOINT 0x003b6ffa
130 static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT;
131 #define nios2_breakpoint_len 4
133 /* Implement the breakpoint_reinsert_addr linux_target_ops method. */
136 nios2_reinsert_addr (void)
138 union nios2_register ra;
139 struct regcache *regcache = get_thread_regcache (current_thread, 1);
141 collect_register_by_name (regcache, "ra", ra.buf);
145 /* Implement the breakpoint_at linux_target_ops method. */
148 nios2_breakpoint_at (CORE_ADDR where)
152 /* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */
153 #if defined(__nios2_arch__) && __nios2_arch__ == 2
154 (*the_target->read_memory) (where, (unsigned char *) &insn, 2);
155 if (insn == CDX_BREAKPOINT)
159 (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
160 if (insn == nios2_breakpoint)
165 /* Fetch the thread-local storage pointer for libthread_db. */
168 ps_get_thread_area (const struct ps_prochandle *ph,
169 lwpid_t lwpid, int idx, void **base)
171 if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
174 /* IDX is the bias from the thread pointer to the beginning of the
175 thread descriptor. It has to be subtracted due to implementation
176 quirks in libthread_db. */
177 *base = (void *) ((char *) *base - idx);
182 /* Helper functions to collect/supply a single register REGNO. */
185 nios2_collect_register (struct regcache *regcache, int regno,
186 union nios2_register *reg)
188 union nios2_register tmp_reg;
190 collect_register (regcache, regno, &tmp_reg.reg32);
191 reg->reg32 = tmp_reg.reg32;
195 nios2_supply_register (struct regcache *regcache, int regno,
196 const union nios2_register *reg)
198 supply_register (regcache, regno, reg->buf);
201 /* We have only a single register set on Nios II. */
204 nios2_fill_gregset (struct regcache *regcache, void *buf)
206 union nios2_register *regset = buf;
209 for (i = 1; i < nios2_num_regs; i++)
210 nios2_collect_register (regcache, i, regset + i);
214 nios2_store_gregset (struct regcache *regcache, const void *buf)
216 const union nios2_register *regset = buf;
219 for (i = 0; i < nios2_num_regs; i++)
220 nios2_supply_register (regcache, i, regset + i);
223 static struct regset_info nios2_regsets[] =
225 { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
226 nios2_num_regs * 4, GENERAL_REGS,
227 nios2_fill_gregset, nios2_store_gregset },
228 { 0, 0, 0, -1, -1, NULL, NULL }
231 static struct regsets_info nios2_regsets_info =
233 nios2_regsets, /* regsets */
235 NULL, /* disabled_regsets */
238 static struct usrregs_info nios2_usrregs_info =
244 static struct regs_info regs_info =
246 NULL, /* regset_bitmap */
251 static const struct regs_info *
252 nios2_regs_info (void)
257 struct linux_target_ops the_low_target =
261 nios2_cannot_fetch_register,
262 nios2_cannot_store_register,
267 /* We only register the 4-byte breakpoint, even on R2 targets which also
268 support 2-byte breakpoints. Since there is no supports_z_point_type
269 function provided, gdbserver never inserts software breakpoints itself
270 and instead relies on GDB to insert the breakpoint of the correct length
271 via a memory write. */
272 (const unsigned char *) &nios2_breakpoint,
273 nios2_breakpoint_len,
280 initialize_low_arch (void)
282 init_registers_nios2_linux ();
284 initialize_regsets_info (&nios2_regsets_info);