gdb/gdbserver/linux-xtensa-low.c

   1 /* GNU/Linux/Xtensa specific low level interface, for the remote server for GDB.
   2    Copyright (C) 2007-2016 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19
  20 #include "server.h"
  21 #include "linux-low.h"
  22
  23 /* Defined in auto-generated file reg-xtensa.c.  */
  24 void init_registers_xtensa (void);
  25 extern const struct target_desc *tdesc_xtensa;
  26
  27 #include <asm/ptrace.h>
  28 #include <xtensa-config.h>
  29 #include "arch/xtensa.h"
  30 #include "gdb_proc_service.h"
  31
  32 #include "xtensa-xtregs.c"
  33
  34 enum regnum {
  35         R_PC=0, R_PS,
  36         R_LBEG, R_LEND, R_LCOUNT,
  37         R_SAR,
  38         R_WS, R_WB,
  39         R_A0 = 64
  40 };
  41
  42 static void
  43 xtensa_fill_gregset (struct regcache *regcache, void *buf)
  44 {
  45   elf_greg_t* rset = (elf_greg_t*)buf;
  46   const struct target_desc *tdesc = regcache->tdesc;
  47   int ar0_regnum;
  48   char *ptr;
  49   int i;
  50
  51   /* Take care of AR registers.  */
  52
  53   ar0_regnum = find_regno (tdesc, "ar0");
  54   ptr = (char*)&rset[R_A0];
  55
  56   for (i = ar0_regnum; i < ar0_regnum + XCHAL_NUM_AREGS; i++)
  57     {
  58       collect_register (regcache, i, ptr);
  59       ptr += register_size (tdesc, i);
  60     }
  61
  62   /* Loop registers, if hardware has it.  */
  63
  64 #if XCHAL_HAVE_LOOPS
  65   collect_register_by_name (regcache, "lbeg", (char*)&rset[R_LBEG]);
  66   collect_register_by_name (regcache, "lend", (char*)&rset[R_LEND]);
  67   collect_register_by_name (regcache, "lcount", (char*)&rset[R_LCOUNT]);
  68 #endif
  69
  70   collect_register_by_name (regcache, "sar", (char*)&rset[R_SAR]);
  71   collect_register_by_name (regcache, "pc", (char*)&rset[R_PC]);
  72   collect_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
  73   collect_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
  74   collect_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
  75 }
  76
  77 static void
  78 xtensa_store_gregset (struct regcache *regcache, const void *buf)
  79 {
  80   const elf_greg_t* rset = (const elf_greg_t*)buf;
  81   const struct target_desc *tdesc = regcache->tdesc;
  82   int ar0_regnum;
  83   char *ptr;
  84   int i;
  85
  86   /* Take care of AR registers.  */
  87
  88   ar0_regnum = find_regno (tdesc, "ar0");
  89   ptr = (char *)&rset[R_A0];
  90
  91   for (i = ar0_regnum; i < ar0_regnum + XCHAL_NUM_AREGS; i++)
  92     {
  93       supply_register (regcache, i, ptr);
  94       ptr += register_size (tdesc, i);
  95     }
  96
  97   /* Loop registers, if hardware has it.  */
  98
  99 #if XCHAL_HAVE_LOOPS
 100   supply_register_by_name (regcache, "lbeg", (char*)&rset[R_LBEG]);
 101   supply_register_by_name (regcache, "lend", (char*)&rset[R_LEND]);
 102   supply_register_by_name (regcache, "lcount", (char*)&rset[R_LCOUNT]);
 103 #endif
 104
 105   supply_register_by_name (regcache, "sar", (char*)&rset[R_SAR]);
 106   supply_register_by_name (regcache, "pc", (char*)&rset[R_PC]);
 107   supply_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
 108   supply_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
 109   supply_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
 110 }
 111
 112 /* Xtensa GNU/Linux PTRACE interface includes extended register set.  */
 113
 114 static void
 115 xtensa_fill_xtregset (struct regcache *regcache, void *buf)
 116 {
 117   const xtensa_regtable_t *ptr;
 118
 119   for (ptr = xtensa_regmap_table; ptr->name; ptr++)
 120     {
 121       collect_register_by_name (regcache, ptr->name,
 122                                 (char*)buf + ptr->ptrace_offset);
 123     }
 124 }
 125
 126 static void
 127 xtensa_store_xtregset (struct regcache *regcache, const void *buf)
 128 {
 129   const xtensa_regtable_t *ptr;
 130
 131   for (ptr = xtensa_regmap_table; ptr->name; ptr++)
 132     {
 133       supply_register_by_name (regcache, ptr->name,
 134                                 (char*)buf + ptr->ptrace_offset);
 135     }
 136 }
 137
 138 static struct regset_info xtensa_regsets[] = {
 139   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 140     GENERAL_REGS,
 141     xtensa_fill_gregset, xtensa_store_gregset },
 142   { PTRACE_GETXTREGS, PTRACE_SETXTREGS, 0, XTENSA_ELF_XTREG_SIZE,
 143     EXTENDED_REGS,
 144     xtensa_fill_xtregset, xtensa_store_xtregset },
 145   NULL_REGSET
 146 };
 147
 148 #if XCHAL_HAVE_BE
 149 #define XTENSA_BREAKPOINT {0xd2,0x0f}
 150 #else
 151 #define XTENSA_BREAKPOINT {0x2d,0xf0}
 152 #endif
 153
 154 static const gdb_byte xtensa_breakpoint[] = XTENSA_BREAKPOINT;
 155 #define xtensa_breakpoint_len 2
 156
 157 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 158
 159 static const gdb_byte *
 160 xtensa_sw_breakpoint_from_kind (int kind, int *size)
 161 {
 162   *size = xtensa_breakpoint_len;
 163   return xtensa_breakpoint;
 164 }
 165
 166 static int
 167 xtensa_breakpoint_at (CORE_ADDR where)
 168 {
 169     unsigned long insn;
 170
 171     (*the_target->read_memory) (where, (unsigned char *) &insn,
 172                                 xtensa_breakpoint_len);
 173     return memcmp((char *) &insn,
 174                   xtensa_breakpoint, xtensa_breakpoint_len) == 0;
 175 }
 176
 177 /* Called by libthread_db.  */
 178
 179 ps_err_e
 180 ps_get_thread_area (struct ps_prochandle *ph,
 181                     lwpid_t lwpid, int idx, void **base)
 182 {
 183   xtensa_elf_gregset_t regs;
 184
 185   if (ptrace (PTRACE_GETREGS, lwpid, NULL, &regs) != 0)
 186     return PS_ERR;
 187
 188   /* IDX is the bias from the thread pointer to the beginning of the
 189      thread descriptor.  It has to be subtracted due to implementation
 190      quirks in libthread_db.  */
 191   *base = (void *) ((char *) regs.threadptr - idx);
 192
 193   return PS_OK;
 194 }
 195
 196 static struct regsets_info xtensa_regsets_info =
 197   {
 198     xtensa_regsets, /* regsets */
 199     0, /* num_regsets */
 200     NULL, /* disabled_regsets */
 201   };
 202
 203 static struct regs_info regs_info =
 204   {
 205     NULL, /* regset_bitmap */
 206     NULL, /* usrregs */
 207     &xtensa_regsets_info
 208   };
 209
 210 static void
 211 xtensa_arch_setup (void)
 212 {
 213   current_process ()->tdesc = tdesc_xtensa;
 214 }
 215
 216 /* Support for hardware single step.  */
 217
 218 static int
 219 xtensa_supports_hardware_single_step (void)
 220 {
 221   return 1;
 222 }
 223
 224 static const struct regs_info *
 225 xtensa_regs_info (void)
 226 {
 227   return &regs_info;
 228 }
 229
 230 struct linux_target_ops the_low_target = {
 231   xtensa_arch_setup,
 232   xtensa_regs_info,
 233   0,
 234   0,
 235   NULL, /* fetch_register */
 236   linux_get_pc_32bit,
 237   linux_set_pc_32bit,
 238   NULL, /* breakpoint_kind_from_pc */
 239   xtensa_sw_breakpoint_from_kind,
 240   NULL,
 241   0,
 242   xtensa_breakpoint_at,
 243   NULL, /* supports_z_point_type */
 244   NULL, /* insert_point */
 245   NULL, /* remove_point */
 246   NULL, /* stopped_by_watchpoint */
 247   NULL, /* stopped_data_address */
 248   NULL, /* collect_ptrace_register */
 249   NULL, /* supply_ptrace_register */
 250   NULL, /* siginfo_fixup */
 251   NULL, /* new_process */
 252   NULL, /* new_thread */
 253   NULL, /* new_fork */
 254   NULL, /* prepare_to_resume */
 255   NULL, /* process_qsupported */
 256   NULL, /* supports_tracepoints */
 257   NULL, /* get_thread_area */
 258   NULL, /* install_fast_tracepoint_jump_pad */
 259   NULL, /* emit_ops */
 260   NULL, /* get_min_fast_tracepoint_insn_len */
 261   NULL, /* supports_range_stepping */
 262   NULL, /* breakpoint_kind_from_current_state */
 263   xtensa_supports_hardware_single_step,
 264 };
 265
 266
 267 void
 268 initialize_low_arch (void)
 269 {
 270   /* Initialize the Linux target descriptions.  */
 271   init_registers_xtensa ();
 272
 273   initialize_regsets_info (&xtensa_regsets_info);
 274 }