gdb/mips-nat.c

   1 /* Low level DECstation interface to ptrace, for GDB when running native.
   2    Copyright 1988, 1989, 1991, 1992, 1995 Free Software Foundation, Inc.
   3    Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
   4    and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "inferior.h"
  25 #include "gdbcore.h"
  26 #include <sys/ptrace.h>
  27 #include <sys/types.h>
  28 #include <sys/param.h>
  29 #include <sys/user.h>
  30 #undef JB_S0
  31 #undef JB_S1
  32 #undef JB_S2
  33 #undef JB_S3
  34 #undef JB_S4
  35 #undef JB_S5
  36 #undef JB_S6
  37 #undef JB_S7
  38 #undef JB_SP
  39 #undef JB_S8
  40 #undef JB_PC
  41 #undef JB_SR
  42 #undef NJBREGS
  43 #include <setjmp.h>             /* For JB_XXX.  */
  44
  45 /* Size of elements in jmpbuf */
  46
  47 #define JB_ELEMENT_SIZE 4
  48
  49 /* Map gdb internal register number to ptrace ``address''.
  50    These ``addresses'' are defined in DECstation <sys/ptrace.h> */
  51
  52 #define REGISTER_PTRACE_ADDR(regno) \
  53    (regno < 32 ?                GPR_BASE + regno \
  54   : regno == PC_REGNUM ?        PC      \
  55   : regno == CAUSE_REGNUM ?     CAUSE   \
  56   : regno == HI_REGNUM ?        MMHI    \
  57   : regno == LO_REGNUM ?        MMLO    \
  58   : regno == FCRCS_REGNUM ?     FPC_CSR \
  59   : regno == FCRIR_REGNUM ?     FPC_EIR \
  60   : regno >= FP0_REGNUM ?       FPR_BASE + (regno - FP0_REGNUM) \
  61   : 0)
  62
  63 static char zerobuf[MAX_REGISTER_RAW_SIZE] =
  64 {0};
  65
  66 static void fetch_core_registers (char *, unsigned, int, CORE_ADDR);
  67
  68 /* Get all registers from the inferior */
  69
  70 void
  71 fetch_inferior_registers (int regno)
  72 {
  73   register unsigned int regaddr;
  74   char buf[MAX_REGISTER_RAW_SIZE];
  75   register int i;
  76
  77   registers_fetched ();
  78
  79   for (regno = 1; regno < NUM_REGS; regno++)
  80     {
  81       regaddr = REGISTER_PTRACE_ADDR (regno);
  82       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  83         {
  84           *(int *) &buf[i] = ptrace (PT_READ_U, inferior_pid,
  85                                      (PTRACE_ARG3_TYPE) regaddr, 0);
  86           regaddr += sizeof (int);
  87         }
  88       supply_register (regno, buf);
  89     }
  90
  91   supply_register (ZERO_REGNUM, zerobuf);
  92   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
  93   supply_register (FP_REGNUM, zerobuf);
  94 }
  95
  96 /* Store our register values back into the inferior.
  97    If REGNO is -1, do this for all registers.
  98    Otherwise, REGNO specifies which register (so we can save time).  */
  99
 100 void
 101 store_inferior_registers (int regno)
 102 {
 103   register unsigned int regaddr;
 104   char buf[80];
 105
 106   if (regno > 0)
 107     {
 108       if (regno == ZERO_REGNUM || regno == PS_REGNUM
 109           || regno == BADVADDR_REGNUM || regno == CAUSE_REGNUM
 110           || regno == FCRIR_REGNUM || regno == FP_REGNUM
 111           || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
 112         return;
 113       regaddr = REGISTER_PTRACE_ADDR (regno);
 114       errno = 0;
 115       ptrace (PT_WRITE_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 116               read_register (regno));
 117       if (errno != 0)
 118         {
 119           sprintf (buf, "writing register number %d", regno);
 120           perror_with_name (buf);
 121         }
 122     }
 123   else
 124     {
 125       for (regno = 0; regno < NUM_REGS; regno++)
 126         store_inferior_registers (regno);
 127     }
 128 }
 129
 130
 131 /* Figure out where the longjmp will land.
 132    We expect the first arg to be a pointer to the jmp_buf structure from which
 133    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
 134    This routine returns true on success. */
 135
 136 int
 137 get_longjmp_target (CORE_ADDR *pc)
 138 {
 139   CORE_ADDR jb_addr;
 140   char *buf;
 141
 142   buf = alloca (TARGET_PTR_BIT / TARGET_CHAR_BIT);
 143   jb_addr = read_register (A0_REGNUM);
 144
 145   if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
 146                           TARGET_PTR_BIT / TARGET_CHAR_BIT))
 147     return 0;
 148
 149   *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
 150
 151   return 1;
 152 }
 153
 154 /* Extract the register values out of the core file and store
 155    them where `read_register' will find them.
 156
 157    CORE_REG_SECT points to the register values themselves, read into memory.
 158    CORE_REG_SIZE is the size of that area.
 159    WHICH says which set of registers we are handling (0 = int, 2 = float
 160    on machines where they are discontiguous).
 161    REG_ADDR is the offset from u.u_ar0 to the register values relative to
 162    core_reg_sect.  This is used with old-fashioned core files to
 163    locate the registers in a large upage-plus-stack ".reg" section.
 164    Original upage address X is at location core_reg_sect+x+reg_addr.
 165  */
 166
 167 static void
 168 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
 169                       CORE_ADDR reg_addr)
 170 {
 171   register int regno;
 172   register unsigned int addr;
 173   int bad_reg = -1;
 174   register reg_ptr = -reg_addr; /* Original u.u_ar0 is -reg_addr. */
 175
 176   /* If u.u_ar0 was an absolute address in the core file, relativize it now,
 177      so we can use it as an offset into core_reg_sect.  When we're done,
 178      "register 0" will be at core_reg_sect+reg_ptr, and we can use
 179      register_addr to offset to the other registers.  If this is a modern
 180      core file without a upage, reg_ptr will be zero and this is all a big
 181      NOP.  */
 182   if (reg_ptr > core_reg_size)
 183 #ifdef KERNEL_U_ADDR
 184     reg_ptr -= KERNEL_U_ADDR;
 185 #else
 186     error ("Old mips core file can't be processed on this machine.");
 187 #endif
 188
 189   for (regno = 0; regno < NUM_REGS; regno++)
 190     {
 191       addr = register_addr (regno, reg_ptr);
 192       if (addr >= core_reg_size)
 193         {
 194           if (bad_reg < 0)
 195             bad_reg = regno;
 196         }
 197       else
 198         {
 199           supply_register (regno, core_reg_sect + addr);
 200         }
 201     }
 202   if (bad_reg >= 0)
 203     {
 204       error ("Register %s not found in core file.", REGISTER_NAME (bad_reg));
 205     }
 206   supply_register (ZERO_REGNUM, zerobuf);
 207   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
 208   supply_register (FP_REGNUM, zerobuf);
 209 }
 210
 211 /* Return the address in the core dump or inferior of register REGNO.
 212    BLOCKEND is the address of the end of the user structure.  */
 213
 214 CORE_ADDR
 215 register_addr (int regno, CORE_ADDR blockend)
 216 {
 217   CORE_ADDR addr;
 218
 219   if (regno < 0 || regno >= NUM_REGS)
 220     error ("Invalid register number %d.", regno);
 221
 222   REGISTER_U_ADDR (addr, blockend, regno);
 223
 224   return addr;
 225 }
 226 \f
 227
 228 /* Register that we are able to handle mips core file formats.
 229    FIXME: is this really bfd_target_unknown_flavour? */
 230
 231 static struct core_fns mips_core_fns =
 232 {
 233   bfd_target_unknown_flavour,           /* core_flavour */
 234   default_check_format,                 /* check_format */
 235   default_core_sniffer,                 /* core_sniffer */
 236   fetch_core_registers,                 /* core_read_registers */
 237   NULL                                  /* next */
 238 };
 239
 240 void
 241 _initialize_core_mips (void)
 242 {
 243   add_core_fns (&mips_core_fns);
 244 }