gdb/gdbserver/linux-mips-low.c

   1 /* GNU/Linux/MIPS specific low level interface, for the remote server for GDB.
   2    Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2005
   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., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "server.h"
  23 #include "linux-low.h"
  24
  25 #ifdef HAVE_SYS_REG_H
  26 #include <sys/reg.h>
  27 #endif
  28
  29 #define mips_num_regs 90
  30
  31 #include <asm/ptrace.h>
  32
  33 /* Return the ptrace ``address'' of register REGNO. */
  34
  35 /* Matches mips_generic32_regs */
  36 static int mips_regmap[] = {
  37   0,  1,  2,  3,  4,  5,  6,  7,
  38   8,  9,  10, 11, 12, 13, 14, 15,
  39   16, 17, 18, 19, 20, 21, 22, 23,
  40   24, 25, 26, 27, 28, 29, 30, 31,
  41
  42   -1, MMLO, MMHI, BADVADDR, CAUSE, PC,
  43
  44   FPR_BASE,      FPR_BASE + 1,  FPR_BASE + 2,  FPR_BASE + 3,
  45   FPR_BASE + 4,  FPR_BASE + 5,  FPR_BASE + 6,  FPR_BASE + 7,
  46   FPR_BASE + 8,  FPR_BASE + 8,  FPR_BASE + 10, FPR_BASE + 11,
  47   FPR_BASE + 12, FPR_BASE + 13, FPR_BASE + 14, FPR_BASE + 15,
  48   FPR_BASE + 16, FPR_BASE + 17, FPR_BASE + 18, FPR_BASE + 19,
  49   FPR_BASE + 20, FPR_BASE + 21, FPR_BASE + 22, FPR_BASE + 23,
  50   FPR_BASE + 24, FPR_BASE + 25, FPR_BASE + 26, FPR_BASE + 27,
  51   FPR_BASE + 28, FPR_BASE + 29, FPR_BASE + 30, FPR_BASE + 31,
  52   FPC_CSR, FPC_EIR,
  53
  54   -1, -1,
  55   -1, -1, -1, -1, -1, -1, -1, -1,
  56   -1, -1, -1, -1, -1, -1, -1, -1,
  57 };
  58
  59 /* From mips-linux-nat.c.  */
  60
  61 /* Pseudo registers can not be read.  ptrace does not provide a way to
  62    read (or set) PS_REGNUM, and there's no point in reading or setting
  63    ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or FCRIR via
  64    ptrace().  */
  65
  66 static int
  67 mips_cannot_fetch_register (int regno)
  68 {
  69   if (mips_regmap[regno] == -1)
  70     return 1;
  71
  72   if (find_regno ("zero") == regno)
  73     return 1;
  74
  75   return 0;
  76 }
  77
  78 static int
  79 mips_cannot_store_register (int regno)
  80 {
  81   if (mips_regmap[regno] == -1)
  82     return 1;
  83
  84   if (find_regno ("zero") == regno)
  85     return 1;
  86
  87   if (find_regno ("cause") == regno)
  88     return 1;
  89
  90   if (find_regno ("bad") == regno)
  91     return 1;
  92
  93   if (find_regno ("fir") == regno)
  94     return 1;
  95
  96   return 0;
  97 }
  98
  99 static CORE_ADDR
 100 mips_get_pc ()
 101 {
 102   unsigned long pc;
 103   collect_register_by_name ("pc", &pc);
 104   return pc;
 105 }
 106
 107 static void
 108 mips_set_pc (CORE_ADDR pc)
 109 {
 110   unsigned long newpc = pc;
 111   supply_register_by_name ("pc", &newpc);
 112 }
 113
 114 /* Correct in either endianness.  */
 115 static const unsigned long mips_breakpoint = 0x0005000d;
 116 #define mips_breakpoint_len 4
 117
 118 /* We only place breakpoints in empty marker functions, and thread locking
 119    is outside of the function.  So rather than importing software single-step,
 120    we can just run until exit.  */
 121 static CORE_ADDR
 122 mips_reinsert_addr ()
 123 {
 124   unsigned long pc;
 125   collect_register_by_name ("ra", &pc);
 126   return pc;
 127 }
 128
 129 static int
 130 mips_breakpoint_at (CORE_ADDR where)
 131 {
 132   unsigned long insn;
 133
 134   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 135   if (insn == mips_breakpoint)
 136     return 1;
 137
 138   /* If necessary, recognize more trap instructions here.  GDB only uses the
 139      one.  */
 140   return 0;
 141 }
 142
 143 struct linux_target_ops the_low_target = {
 144   mips_num_regs,
 145   mips_regmap,
 146   mips_cannot_fetch_register,
 147   mips_cannot_store_register,
 148   mips_get_pc,
 149   mips_set_pc,
 150   (const unsigned char *) &mips_breakpoint,
 151   mips_breakpoint_len,
 152   mips_reinsert_addr,
 153   0,
 154   mips_breakpoint_at,
 155 };