gdb/gdbserver/linux-xtensa-low.c

   1 /* GNU/Linux/Xtensa specific low level interface, for the remote server for GDB.
   2    Copyright (C) 2007-2015 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   { 0, 0, 0, -1, -1, NULL, NULL }
 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 unsigned char xtensa_breakpoint[] = XTENSA_BREAKPOINT;
 155 #define xtensa_breakpoint_len 2
 156
 157 static CORE_ADDR
 158 xtensa_get_pc (struct regcache *regcache)
 159 {
 160   unsigned long pc;
 161
 162   collect_register_by_name (regcache, "pc", &pc);
 163   return pc;
 164 }
 165
 166 static void
 167 xtensa_set_pc (struct regcache *regcache, CORE_ADDR pc)
 168 {
 169   unsigned long newpc = pc;
 170   supply_register_by_name (regcache, "pc", &newpc);
 171 }
 172
 173 static int
 174 xtensa_breakpoint_at (CORE_ADDR where)
 175 {
 176     unsigned long insn;
 177
 178     (*the_target->read_memory) (where, (unsigned char *) &insn,
 179                                 xtensa_breakpoint_len);
 180     return memcmp((char *) &insn,
 181                   xtensa_breakpoint, xtensa_breakpoint_len) == 0;
 182 }
 183
 184 /* Called by libthread_db.  */
 185
 186 ps_err_e
 187 ps_get_thread_area (const struct ps_prochandle *ph,
 188                     lwpid_t lwpid, int idx, void **base)
 189 {
 190   xtensa_elf_gregset_t regs;
 191
 192   if (ptrace (PTRACE_GETREGS, lwpid, NULL, &regs) != 0)
 193     return PS_ERR;
 194
 195   /* IDX is the bias from the thread pointer to the beginning of the
 196      thread descriptor.  It has to be subtracted due to implementation
 197      quirks in libthread_db.  */
 198   *base = (void *) ((char *) regs.threadptr - idx);
 199
 200   return PS_OK;
 201 }
 202
 203 static struct regsets_info xtensa_regsets_info =
 204   {
 205     xtensa_regsets, /* regsets */
 206     0, /* num_regsets */
 207     NULL, /* disabled_regsets */
 208   };
 209
 210 static struct regs_info regs_info =
 211   {
 212     NULL, /* regset_bitmap */
 213     NULL, /* usrregs */
 214     &xtensa_regsets_info
 215   };
 216
 217 static void
 218 xtensa_arch_setup (void)
 219 {
 220   current_process ()->tdesc = tdesc_xtensa;
 221 }
 222
 223 static const struct regs_info *
 224 xtensa_regs_info (void)
 225 {
 226   return &regs_info;
 227 }
 228
 229 struct linux_target_ops the_low_target = {
 230   xtensa_arch_setup,
 231   xtensa_regs_info,
 232   0,
 233   0,
 234   NULL, /* fetch_register */
 235   xtensa_get_pc,
 236   xtensa_set_pc,
 237   xtensa_breakpoint,
 238   xtensa_breakpoint_len,
 239   NULL,
 240   0,
 241   xtensa_breakpoint_at,
 242 };
 243
 244
 245 void
 246 initialize_low_arch (void)
 247 {
 248   /* Initialize the Linux target descriptions.  */
 249   init_registers_xtensa ();
 250
 251   initialize_regsets_info (&xtensa_regsets_info);
 252 }