gdb/gdbserver/linux-nios2-low.c

   1 /* GNU/Linux/Nios II specific low level interface, for the remote server for
   2    GDB.
   3    Copyright (C) 2008-2013 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 <sys/ptrace.h>
  25 #include <endian.h>
  26 #include "gdb_proc_service.h"
  27 #include <asm/ptrace.h>
  28
  29 #ifndef PTRACE_GET_THREAD_AREA
  30 #define PTRACE_GET_THREAD_AREA 25
  31 #endif
  32
  33 /* The following definition must agree with the number of registers
  34    defined in "struct user_regs" in GLIBC
  35    (ports/sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with
  36    NIOS2_NUM_REGS in GDB proper.  */
  37
  38 #define nios2_num_regs 49
  39
  40 /* Defined in auto-generated file nios2-linux.c.  */
  41
  42 void init_registers_nios2_linux (void);
  43
  44 /* This union is used to convert between int and byte buffer
  45    representations of register contents.  */
  46
  47 union nios2_register
  48 {
  49   unsigned char buf[4];
  50   int reg32;
  51 };
  52
  53 /* Return the ptrace ``address'' of register REGNO. */
  54
  55 static int nios2_regmap[] = {
  56   -1,  1,  2,  3,  4,  5,  6,  7,
  57   8,  9,  10, 11, 12, 13, 14, 15,
  58   16, 17, 18, 19, 20, 21, 22, 23,
  59   24, 25, 26, 27, 28, 29, 30, 31,
  60   32, 33, 34, 35, 36, 37, 38, 39,
  61   40, 41, 42, 43, 44, 45, 46, 47,
  62   48,
  63   0
  64 };
  65
  66 /* Implement the arch_setup linux_target_ops method.  */
  67
  68 static void
  69 nios2_arch_setup (void)
  70 {
  71   init_registers_nios2_linux ();
  72 }
  73
  74 /* Implement the cannot_fetch_register linux_target_ops method.  */
  75
  76 static int
  77 nios2_cannot_fetch_register (int regno)
  78 {
  79   if (nios2_regmap[regno] == -1)
  80     return 1;
  81
  82   return 0;
  83 }
  84
  85 /* Implement the cannot_store_register linux_target_ops method.  */
  86
  87 static int
  88 nios2_cannot_store_register (int regno)
  89 {
  90   if (nios2_regmap[regno] == -1)
  91     return 1;
  92
  93   return 0;
  94 }
  95
  96 /* Implement the get_pc linux_target_ops method.  */
  97
  98 static CORE_ADDR
  99 nios2_get_pc (struct regcache *regcache)
 100 {
 101   union nios2_register pc;
 102
 103   collect_register_by_name (regcache, "pc", pc.buf);
 104   return pc.reg32;
 105 }
 106
 107 /* Implement the set_pc linux_target_ops method.  */
 108
 109 static void
 110 nios2_set_pc (struct regcache *regcache, CORE_ADDR pc)
 111 {
 112   union nios2_register newpc;
 113
 114   newpc.reg32 = pc;
 115   supply_register_by_name (regcache, "pc", newpc.buf);
 116 }
 117
 118 /* Breakpoint support.  */
 119
 120 static const unsigned int nios2_breakpoint = 0x003b6ffa;
 121 #define nios2_breakpoint_len 4
 122
 123 /* Implement the breakpoint_reinsert_addr linux_target_ops method.  */
 124
 125 static CORE_ADDR
 126 nios2_reinsert_addr (void)
 127 {
 128   union nios2_register ra;
 129   struct regcache *regcache = get_thread_regcache (current_inferior, 1);
 130
 131   collect_register_by_name (regcache, "ra", ra.buf);
 132   return ra.reg32;
 133 }
 134
 135 /* Implement the breakpoint_at linux_target_ops method.  */
 136
 137 static int
 138 nios2_breakpoint_at (CORE_ADDR where)
 139 {
 140   unsigned int insn;
 141
 142   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 143   if (insn == nios2_breakpoint)
 144     return 1;
 145   return 0;
 146 }
 147
 148 /* Fetch the thread-local storage pointer for libthread_db.  */
 149
 150 ps_err_e
 151 ps_get_thread_area (const struct ps_prochandle *ph,
 152                     lwpid_t lwpid, int idx, void **base)
 153 {
 154   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 155     return PS_ERR;
 156
 157   /* IDX is the bias from the thread pointer to the beginning of the
 158      thread descriptor.  It has to be subtracted due to implementation
 159      quirks in libthread_db.  */
 160   *base = (void *) ((char *) *base - idx);
 161
 162   return PS_OK;
 163 }
 164
 165 #ifdef HAVE_PTRACE_GETREGS
 166
 167 /* Helper functions to collect/supply a single register REGNO.  */
 168
 169 static void
 170 nios2_collect_register (struct regcache *regcache, int regno,
 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
 180 nios2_supply_register (struct regcache *regcache, int regno,
 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
 189 nios2_fill_gregset (struct regcache *regcache, void *buf)
 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 #endif /* HAVE_PTRACE_GETREGS */
 208
 209 struct regset_info target_regsets[] =
 210 {
 211 #ifdef HAVE_PTRACE_GETREGS
 212   { PTRACE_GETREGS, PTRACE_SETREGS, 0, nios2_num_regs * 4, GENERAL_REGS,
 213     nios2_fill_gregset, nios2_store_gregset },
 214 #endif /* HAVE_PTRACE_GETREGS */
 215   { 0, 0, 0, -1, -1, NULL, NULL }
 216 };
 217
 218 struct linux_target_ops the_low_target =
 219 {
 220   nios2_arch_setup,
 221   nios2_num_regs,
 222   nios2_regmap,
 223   NULL,
 224   nios2_cannot_fetch_register,
 225   nios2_cannot_store_register,
 226   NULL,
 227   nios2_get_pc,
 228   nios2_set_pc,
 229   (const unsigned char *) &nios2_breakpoint,
 230   nios2_breakpoint_len,
 231   nios2_reinsert_addr,
 232   0,
 233   nios2_breakpoint_at,
 234 };