gdb/gdbserver/linux-mips-low.c

   1 /* GNU/Linux/MIPS specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2005, 2006
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "server.h"
  23 #include "linux-low.h"
  24
  25 #include <sys/ptrace.h>
  26
  27 #include "gdb_proc_service.h"
  28
  29 #ifndef PTRACE_GET_THREAD_AREA
  30 #define PTRACE_GET_THREAD_AREA 25
  31 #endif
  32
  33 #ifdef HAVE_SYS_REG_H
  34 #include <sys/reg.h>
  35 #endif
  36
  37 #define mips_num_regs 90
  38
  39 #include <asm/ptrace.h>
  40
  41 /* Return the ptrace ``address'' of register REGNO. */
  42
  43 /* Matches mips_generic32_regs */
  44 static int mips_regmap[] = {
  45   0,  1,  2,  3,  4,  5,  6,  7,
  46   8,  9,  10, 11, 12, 13, 14, 15,
  47   16, 17, 18, 19, 20, 21, 22, 23,
  48   24, 25, 26, 27, 28, 29, 30, 31,
  49
  50   -1, MMLO, MMHI, BADVADDR, CAUSE, PC,
  51
  52   FPR_BASE,      FPR_BASE + 1,  FPR_BASE + 2,  FPR_BASE + 3,
  53   FPR_BASE + 4,  FPR_BASE + 5,  FPR_BASE + 6,  FPR_BASE + 7,
  54   FPR_BASE + 8,  FPR_BASE + 8,  FPR_BASE + 10, FPR_BASE + 11,
  55   FPR_BASE + 12, FPR_BASE + 13, FPR_BASE + 14, FPR_BASE + 15,
  56   FPR_BASE + 16, FPR_BASE + 17, FPR_BASE + 18, FPR_BASE + 19,
  57   FPR_BASE + 20, FPR_BASE + 21, FPR_BASE + 22, FPR_BASE + 23,
  58   FPR_BASE + 24, FPR_BASE + 25, FPR_BASE + 26, FPR_BASE + 27,
  59   FPR_BASE + 28, FPR_BASE + 29, FPR_BASE + 30, FPR_BASE + 31,
  60   FPC_CSR, FPC_EIR,
  61
  62   -1, -1,
  63   -1, -1, -1, -1, -1, -1, -1, -1,
  64   -1, -1, -1, -1, -1, -1, -1, -1,
  65 };
  66
  67 /* From mips-linux-nat.c.  */
  68
  69 /* Pseudo registers can not be read.  ptrace does not provide a way to
  70    read (or set) PS_REGNUM, and there's no point in reading or setting
  71    ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or FCRIR via
  72    ptrace().  */
  73
  74 static int
  75 mips_cannot_fetch_register (int regno)
  76 {
  77   if (mips_regmap[regno] == -1)
  78     return 1;
  79
  80   if (find_regno ("zero") == regno)
  81     return 1;
  82
  83   return 0;
  84 }
  85
  86 static int
  87 mips_cannot_store_register (int regno)
  88 {
  89   if (mips_regmap[regno] == -1)
  90     return 1;
  91
  92   if (find_regno ("zero") == regno)
  93     return 1;
  94
  95   if (find_regno ("cause") == regno)
  96     return 1;
  97
  98   if (find_regno ("bad") == regno)
  99     return 1;
 100
 101   if (find_regno ("fir") == regno)
 102     return 1;
 103
 104   return 0;
 105 }
 106
 107 static CORE_ADDR
 108 mips_get_pc ()
 109 {
 110   unsigned long pc;
 111   collect_register_by_name ("pc", &pc);
 112   return pc;
 113 }
 114
 115 static void
 116 mips_set_pc (CORE_ADDR pc)
 117 {
 118   unsigned long newpc = pc;
 119   supply_register_by_name ("pc", &newpc);
 120 }
 121
 122 /* Correct in either endianness.  */
 123 static const unsigned long mips_breakpoint = 0x0005000d;
 124 #define mips_breakpoint_len 4
 125
 126 /* We only place breakpoints in empty marker functions, and thread locking
 127    is outside of the function.  So rather than importing software single-step,
 128    we can just run until exit.  */
 129 static CORE_ADDR
 130 mips_reinsert_addr ()
 131 {
 132   unsigned long pc;
 133   collect_register_by_name ("ra", &pc);
 134   return pc;
 135 }
 136
 137 static int
 138 mips_breakpoint_at (CORE_ADDR where)
 139 {
 140   unsigned long insn;
 141
 142   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 143   if (insn == mips_breakpoint)
 144     return 1;
 145
 146   /* If necessary, recognize more trap instructions here.  GDB only uses the
 147      one.  */
 148   return 0;
 149 }
 150
 151 /* Fetch the thread-local storage pointer for libthread_db.  */
 152
 153 ps_err_e
 154 ps_get_thread_area (const struct ps_prochandle *ph,
 155                     lwpid_t lwpid, int idx, void **base)
 156 {
 157   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 158     return PS_ERR;
 159
 160   /* IDX is the bias from the thread pointer to the beginning of the
 161      thread descriptor.  It has to be subtracted due to implementation
 162      quirks in libthread_db.  */
 163   *base = (void *) ((char *)*base - idx);
 164
 165   return PS_OK;
 166 }
 167
 168 struct linux_target_ops the_low_target = {
 169   mips_num_regs,
 170   mips_regmap,
 171   mips_cannot_fetch_register,
 172   mips_cannot_store_register,
 173   mips_get_pc,
 174   mips_set_pc,
 175   (const unsigned char *) &mips_breakpoint,
 176   mips_breakpoint_len,
 177   mips_reinsert_addr,
 178   0,
 179   mips_breakpoint_at,
 180 };