gdb/mips-nat.c

   1 /* Low level DECstation interface to ptrace, for GDB when running native.
   2    Copyright 1988, 1989, 1991, 1992, 1993, 1995, 1996, 1999, 2000, 2001
   3    Free Software Foundation, Inc.
   4    Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
   5    and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
   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 2 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, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, USA.  */
  23
  24 #include "defs.h"
  25 #include "inferior.h"
  26 #include "gdbcore.h"
  27 #include "regcache.h"
  28 #include <sys/ptrace.h>
  29 #include <sys/types.h>
  30 #include <sys/param.h>
  31 #include <sys/user.h>
  32 #undef JB_S0
  33 #undef JB_S1
  34 #undef JB_S2
  35 #undef JB_S3
  36 #undef JB_S4
  37 #undef JB_S5
  38 #undef JB_S6
  39 #undef JB_S7
  40 #undef JB_SP
  41 #undef JB_S8
  42 #undef JB_PC
  43 #undef JB_SR
  44 #undef NJBREGS
  45 #include <setjmp.h>             /* For JB_XXX.  */
  46
  47 /* Size of elements in jmpbuf */
  48
  49 #define JB_ELEMENT_SIZE 4
  50
  51 /* Map gdb internal register number to ptrace ``address''.
  52    These ``addresses'' are defined in DECstation <sys/ptrace.h> */
  53
  54 static int
  55 register_ptrace_addr (int regno)
  56 {
  57   return (regno < 32 ? GPR_BASE + regno
  58           : regno == PC_REGNUM ? PC
  59           : regno == CAUSE_REGNUM ? CAUSE
  60           : regno == HI_REGNUM ? MMHI
  61           : regno == LO_REGNUM ? MMLO
  62           : regno == FCRCS_REGNUM ? FPC_CSR
  63           : regno == FCRIR_REGNUM ? FPC_EIR
  64           : regno >= FP0_REGNUM ? FPR_BASE + (regno - FP0_REGNUM)
  65           : 0);
  66 }
  67
  68 static void fetch_core_registers (char *, unsigned, int, CORE_ADDR);
  69
  70 /* Get all registers from the inferior */
  71
  72 void
  73 fetch_inferior_registers (int regno)
  74 {
  75   unsigned int regaddr;
  76   char buf[MAX_REGISTER_SIZE];
  77   int i;
  78   char zerobuf[MAX_REGISTER_SIZE];
  79   memset (zerobuf, 0, MAX_REGISTER_SIZE);
  80
  81   deprecated_registers_fetched ();
  82
  83   for (regno = 1; regno < NUM_REGS; regno++)
  84     {
  85       regaddr = register_ptrace_addr (regno);
  86       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  87         {
  88           *(int *) &buf[i] = ptrace (PT_READ_U, PIDGET (inferior_ptid),
  89                                      (PTRACE_ARG3_TYPE) regaddr, 0);
  90           regaddr += sizeof (int);
  91         }
  92       supply_register (regno, buf);
  93     }
  94
  95   supply_register (ZERO_REGNUM, zerobuf);
  96   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
  97   supply_register (DEPRECATED_FP_REGNUM, zerobuf);
  98 }
  99
 100 /* Store our register values back into the inferior.
 101    If REGNO is -1, do this for all registers.
 102    Otherwise, REGNO specifies which register (so we can save time).  */
 103
 104 void
 105 store_inferior_registers (int regno)
 106 {
 107   unsigned int regaddr;
 108   char buf[80];
 109
 110   if (regno > 0)
 111     {
 112       if (regno == ZERO_REGNUM || regno == PS_REGNUM
 113           || regno == BADVADDR_REGNUM || regno == CAUSE_REGNUM
 114           || regno == FCRIR_REGNUM || regno == DEPRECATED_FP_REGNUM
 115           || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
 116         return;
 117       regaddr = register_ptrace_addr (regno);
 118       errno = 0;
 119       ptrace (PT_WRITE_U, PIDGET (inferior_ptid), (PTRACE_ARG3_TYPE) regaddr,
 120               read_register (regno));
 121       if (errno != 0)
 122         {
 123           sprintf (buf, "writing register number %d", regno);
 124           perror_with_name (buf);
 125         }
 126     }
 127   else
 128     {
 129       for (regno = 0; regno < NUM_REGS; regno++)
 130         store_inferior_registers (regno);
 131     }
 132 }
 133
 134
 135 /* Figure out where the longjmp will land.
 136    We expect the first arg to be a pointer to the jmp_buf structure from which
 137    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
 138    This routine returns true on success. */
 139
 140 int
 141 get_longjmp_target (CORE_ADDR *pc)
 142 {
 143   CORE_ADDR jb_addr;
 144   char *buf;
 145
 146   buf = alloca (TARGET_PTR_BIT / TARGET_CHAR_BIT);
 147   jb_addr = read_register (A0_REGNUM);
 148
 149   if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
 150                           TARGET_PTR_BIT / TARGET_CHAR_BIT))
 151     return 0;
 152
 153   *pc = extract_unsigned_integer (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
 154
 155   return 1;
 156 }
 157
 158 /* Extract the register values out of the core file and store
 159    them where `read_register' will find them.
 160
 161    CORE_REG_SECT points to the register values themselves, read into memory.
 162    CORE_REG_SIZE is the size of that area.
 163    WHICH says which set of registers we are handling (0 = int, 2 = float
 164    on machines where they are discontiguous).
 165    REG_ADDR is the offset from u.u_ar0 to the register values relative to
 166    core_reg_sect.  This is used with old-fashioned core files to
 167    locate the registers in a large upage-plus-stack ".reg" section.
 168    Original upage address X is at location core_reg_sect+x+reg_addr.
 169  */
 170
 171 static void
 172 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
 173                       CORE_ADDR reg_addr)
 174 {
 175   int regno;
 176   unsigned int addr;
 177   int bad_reg = -1;
 178   reg_ptr = -reg_addr;  /* Original u.u_ar0 is -reg_addr. */
 179
 180   char zerobuf[MAX_REGISTER_SIZE];
 181   memset (zerobuf, 0, MAX_REGISTER_SIZE);
 182
 183
 184   /* If u.u_ar0 was an absolute address in the core file, relativize it now,
 185      so we can use it as an offset into core_reg_sect.  When we're done,
 186      "register 0" will be at core_reg_sect+reg_ptr, and we can use
 187      register_addr to offset to the other registers.  If this is a modern
 188      core file without a upage, reg_ptr will be zero and this is all a big
 189      NOP.  */
 190   if (reg_ptr > core_reg_size)
 191 #ifdef KERNEL_U_ADDR
 192     reg_ptr -= KERNEL_U_ADDR;
 193 #else
 194     error ("Old mips core file can't be processed on this machine.");
 195 #endif
 196
 197   for (regno = 0; regno < NUM_REGS; regno++)
 198     {
 199       addr = register_addr (regno, reg_ptr);
 200       if (addr >= core_reg_size)
 201         {
 202           if (bad_reg < 0)
 203             bad_reg = regno;
 204         }
 205       else
 206         {
 207           supply_register (regno, core_reg_sect + addr);
 208         }
 209     }
 210   if (bad_reg >= 0)
 211     {
 212       error ("Register %s not found in core file.", REGISTER_NAME (bad_reg));
 213     }
 214   supply_register (ZERO_REGNUM, zerobuf);
 215   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
 216   supply_register (DEPRECATED_FP_REGNUM, zerobuf);
 217 }
 218
 219 /* Return the address in the core dump or inferior of register REGNO.
 220    BLOCKEND is the address of the end of the user structure.  */
 221
 222 CORE_ADDR
 223 register_addr (int regno, CORE_ADDR blockend)
 224 {
 225   CORE_ADDR addr;
 226
 227   if (regno < 0 || regno >= NUM_REGS)
 228     error ("Invalid register number %d.", regno);
 229
 230   REGISTER_U_ADDR (addr, blockend, regno);
 231
 232   return addr;
 233 }
 234 \f
 235
 236 /* Register that we are able to handle mips core file formats.
 237    FIXME: is this really bfd_target_unknown_flavour? */
 238
 239 static struct core_fns mips_core_fns =
 240 {
 241   bfd_target_unknown_flavour,           /* core_flavour */
 242   default_check_format,                 /* check_format */
 243   default_core_sniffer,                 /* core_sniffer */
 244   fetch_core_registers,                 /* core_read_registers */
 245   NULL                                  /* next */
 246 };
 247
 248 void
 249 _initialize_core_mips (void)
 250 {
 251   add_core_fns (&mips_core_fns);
 252 }