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) 2008-2015 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 <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 extern const struct target_desc *tdesc_nios2_linux;
  44
  45 /* This union is used to convert between int and byte buffer
  46    representations of register contents.  */
  47
  48 union nios2_register
  49 {
  50   unsigned char buf[4];
  51   int reg32;
  52 };
  53
  54 /* Return the ptrace ``address'' of register REGNO. */
  55
  56 static int nios2_regmap[] = {
  57   -1,  1,  2,  3,  4,  5,  6,  7,
  58   8,  9,  10, 11, 12, 13, 14, 15,
  59   16, 17, 18, 19, 20, 21, 22, 23,
  60   24, 25, 26, 27, 28, 29, 30, 31,
  61   32, 33, 34, 35, 36, 37, 38, 39,
  62   40, 41, 42, 43, 44, 45, 46, 47,
  63   48,
  64   0
  65 };
  66
  67 /* Implement the arch_setup linux_target_ops method.  */
  68
  69 static void
  70 nios2_arch_setup (void)
  71 {
  72   current_process ()->tdesc = tdesc_nios2_linux;
  73 }
  74
  75 /* Implement the cannot_fetch_register linux_target_ops method.  */
  76
  77 static int
  78 nios2_cannot_fetch_register (int regno)
  79 {
  80   if (nios2_regmap[regno] == -1)
  81     return 1;
  82
  83   return 0;
  84 }
  85
  86 /* Implement the cannot_store_register linux_target_ops method.  */
  87
  88 static int
  89 nios2_cannot_store_register (int regno)
  90 {
  91   if (nios2_regmap[regno] == -1)
  92     return 1;
  93
  94   return 0;
  95 }
  96
  97 /* Implement the get_pc linux_target_ops method.  */
  98
  99 static CORE_ADDR
 100 nios2_get_pc (struct regcache *regcache)
 101 {
 102   union nios2_register pc;
 103
 104   collect_register_by_name (regcache, "pc", pc.buf);
 105   return pc.reg32;
 106 }
 107
 108 /* Implement the set_pc linux_target_ops method.  */
 109
 110 static void
 111 nios2_set_pc (struct regcache *regcache, CORE_ADDR pc)
 112 {
 113   union nios2_register newpc;
 114
 115   newpc.reg32 = pc;
 116   supply_register_by_name (regcache, "pc", newpc.buf);
 117 }
 118
 119 /* Breakpoint support.  */
 120
 121 static const unsigned int nios2_breakpoint = 0x003b6ffa;
 122 #define nios2_breakpoint_len 4
 123
 124 /* Implement the breakpoint_reinsert_addr linux_target_ops method.  */
 125
 126 static CORE_ADDR
 127 nios2_reinsert_addr (void)
 128 {
 129   union nios2_register ra;
 130   struct regcache *regcache = get_thread_regcache (current_thread, 1);
 131
 132   collect_register_by_name (regcache, "ra", ra.buf);
 133   return ra.reg32;
 134 }
 135
 136 /* Implement the breakpoint_at linux_target_ops method.  */
 137
 138 static int
 139 nios2_breakpoint_at (CORE_ADDR where)
 140 {
 141   unsigned int insn;
 142
 143   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 144   if (insn == nios2_breakpoint)
 145     return 1;
 146   return 0;
 147 }
 148
 149 /* Fetch the thread-local storage pointer for libthread_db.  */
 150
 151 ps_err_e
 152 ps_get_thread_area (const struct ps_prochandle *ph,
 153                     lwpid_t lwpid, int idx, void **base)
 154 {
 155   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 156     return PS_ERR;
 157
 158   /* IDX is the bias from the thread pointer to the beginning of the
 159      thread descriptor.  It has to be subtracted due to implementation
 160      quirks in libthread_db.  */
 161   *base = (void *) ((char *) *base - idx);
 162
 163   return PS_OK;
 164 }
 165
 166 #ifdef HAVE_PTRACE_GETREGS
 167
 168 /* Helper functions to collect/supply a single register REGNO.  */
 169
 170 static void
 171 nios2_collect_register (struct regcache *regcache, int regno,
 172                         union nios2_register *reg)
 173 {
 174   union nios2_register tmp_reg;
 175
 176   collect_register (regcache, regno, &tmp_reg.reg32);
 177   reg->reg32 = tmp_reg.reg32;
 178 }
 179
 180 static void
 181 nios2_supply_register (struct regcache *regcache, int regno,
 182                        const union nios2_register *reg)
 183 {
 184   supply_register (regcache, regno, reg->buf);
 185 }
 186
 187 /* We have only a single register set on Nios II.  */
 188
 189 static void
 190 nios2_fill_gregset (struct regcache *regcache, void *buf)
 191 {
 192   union nios2_register *regset = buf;
 193   int i;
 194
 195   for (i = 1; i < nios2_num_regs; i++)
 196     nios2_collect_register (regcache, i, regset + i);
 197 }
 198
 199 static void
 200 nios2_store_gregset (struct regcache *regcache, const void *buf)
 201 {
 202   const union nios2_register *regset = buf;
 203   int i;
 204
 205   for (i = 0; i < nios2_num_regs; i++)
 206     nios2_supply_register (regcache, i, regset + i);
 207 }
 208 #endif /* HAVE_PTRACE_GETREGS */
 209
 210 static struct regset_info nios2_regsets[] =
 211 {
 212 #ifdef HAVE_PTRACE_GETREGS
 213   { PTRACE_GETREGS, PTRACE_SETREGS, 0, nios2_num_regs * 4, GENERAL_REGS,
 214     nios2_fill_gregset, nios2_store_gregset },
 215 #endif /* HAVE_PTRACE_GETREGS */
 216   { 0, 0, 0, -1, -1, NULL, NULL }
 217 };
 218
 219 static struct regsets_info nios2_regsets_info =
 220   {
 221     nios2_regsets, /* regsets */
 222     0, /* num_regsets */
 223     NULL, /* disabled_regsets */
 224   };
 225
 226 static struct usrregs_info nios2_usrregs_info =
 227   {
 228     nios2_num_regs,
 229     nios2_regmap,
 230   };
 231
 232 static struct regs_info regs_info =
 233   {
 234     NULL, /* regset_bitmap */
 235     &nios2_usrregs_info,
 236     &nios2_regsets_info
 237   };
 238
 239 static const struct regs_info *
 240 nios2_regs_info (void)
 241 {
 242   return &regs_info;
 243 }
 244
 245 struct linux_target_ops the_low_target =
 246 {
 247   nios2_arch_setup,
 248   nios2_regs_info,
 249   nios2_cannot_fetch_register,
 250   nios2_cannot_store_register,
 251   NULL,
 252   nios2_get_pc,
 253   nios2_set_pc,
 254   (const unsigned char *) &nios2_breakpoint,
 255   nios2_breakpoint_len,
 256   nios2_reinsert_addr,
 257   0,
 258   nios2_breakpoint_at,
 259 };
 260
 261 void
 262 initialize_low_arch (void)
 263 {
 264   init_registers_nios2_linux ();
 265
 266   initialize_regsets_info (&nios2_regsets_info);
 267 }