gdb/mips-nat.c

   1 /* Low level DECstation interface to ptrace, for GDB when running native.
   2    Copyright 1988, 1989, 1991, 1992 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include <sys/ptrace.h>
  26 #include <setjmp.h>             /* For JB_XXX.  */
  27
  28 #include <sys/types.h>
  29 #include <sys/param.h>
  30 #include "gdbcore.h"
  31
  32 /* These are needed on various systems to expand REGISTER_U_ADDR.  */
  33 #include <sys/dir.h>
  34 #include <sys/file.h>
  35 #include <sys/stat.h>
  36 #include <sys/user.h>
  37 #include <sys/ptrace.h>
  38
  39 /* Size of elements in jmpbuf */
  40
  41 #define JB_ELEMENT_SIZE 4
  42
  43 /* Map gdb internal register number to ptrace ``address''.
  44    These ``addresses'' are defined in DECstation <sys/ptrace.h> */
  45
  46 #define REGISTER_PTRACE_ADDR(regno) \
  47    (regno < 32 ?                GPR_BASE + regno \
  48   : regno == PC_REGNUM ?        PC      \
  49   : regno == CAUSE_REGNUM ?     CAUSE   \
  50   : regno == HI_REGNUM ?        MMHI    \
  51   : regno == LO_REGNUM ?        MMLO    \
  52   : regno == FCRCS_REGNUM ?     FPC_CSR \
  53   : regno == FCRIR_REGNUM ?     FPC_EIR \
  54   : regno >= FP0_REGNUM ?       FPR_BASE + (regno - FP0_REGNUM) \
  55   : 0)
  56
  57 static const char zerobuf[MAX_REGISTER_RAW_SIZE];
  58
  59 /* Get all registers from the inferior */
  60
  61 void
  62 fetch_inferior_registers (regno)
  63      int regno;
  64 {
  65   register unsigned int regaddr;
  66   char buf[MAX_REGISTER_RAW_SIZE];
  67   register int i;
  68
  69   registers_fetched ();
  70
  71   for (regno = 1; regno < NUM_REGS; regno++)
  72     {
  73       regaddr = REGISTER_PTRACE_ADDR (regno);
  74       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  75         {
  76           *(int *) &buf[i] = ptrace (PT_READ_U, inferior_pid,
  77                                      (PTRACE_ARG3_TYPE) regaddr, 0);
  78           regaddr += sizeof (int);
  79         }
  80       supply_register (regno, buf);
  81     }
  82
  83   supply_register (ZERO_REGNUM, zerobuf);
  84   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
  85   supply_register (FP_REGNUM, zerobuf);
  86 }
  87
  88 /* Store our register values back into the inferior.
  89    If REGNO is -1, do this for all registers.
  90    Otherwise, REGNO specifies which register (so we can save time).  */
  91
  92 void
  93 store_inferior_registers (regno)
  94      int regno;
  95 {
  96   register unsigned int regaddr;
  97   char buf[80];
  98
  99   if (regno == 0)
 100     return;
 101
 102   if (regno > 0)
 103     {
 104       regaddr = REGISTER_PTRACE_ADDR (regno);
 105       errno = 0;
 106       ptrace (PT_WRITE_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 107               read_register (regno));
 108       if (errno != 0)
 109         {
 110           sprintf (buf, "writing register number %d", regno);
 111           perror_with_name (buf);
 112         }
 113     }
 114   else
 115     {
 116       for (regno = 0; regno < NUM_REGS; regno++)
 117         {
 118           if (regno == ZERO_REGNUM || regno == PS_REGNUM
 119               || regno == BADVADDR_REGNUM || regno == CAUSE_REGNUM
 120               || regno == FCRIR_REGNUM || regno == FP_REGNUM
 121               || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
 122             continue;
 123           regaddr = register_addr (regno, 1);
 124           errno = 0;
 125           ptrace (6, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 126                   read_register (regno));
 127           if (errno != 0)
 128             {
 129               sprintf (buf, "writing all regs, number %d", regno);
 130               perror_with_name (buf);
 131             }
 132         }
 133     }
 134 }
 135
 136
 137 /* Figure out where the longjmp will land.
 138    We expect the first arg to be a pointer to the jmp_buf structure from which
 139    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
 140    This routine returns true on success. */
 141
 142 int
 143 get_longjmp_target(pc)
 144      CORE_ADDR *pc;
 145 {
 146   CORE_ADDR jb_addr;
 147
 148   jb_addr = read_register(A0_REGNUM);
 149
 150   if (target_read_memory(jb_addr + JB_PC * JB_ELEMENT_SIZE, pc,
 151                          sizeof(CORE_ADDR)))
 152     return 0;
 153
 154   SWAP_TARGET_AND_HOST(pc, sizeof(CORE_ADDR));
 155
 156   return 1;
 157 }
 158
 159 /* Extract the register values out of the core file and store
 160    them where `read_register' will find them.
 161
 162    CORE_REG_SECT points to the register values themselves, read into memory.
 163    CORE_REG_SIZE is the size of that area.
 164    WHICH says which set of registers we are handling (0 = int, 2 = float
 165          on machines where they are discontiguous).
 166    REG_ADDR is the offset from u.u_ar0 to the register values relative to
 167             core_reg_sect.  This is used with old-fashioned core files to
 168             locate the registers in a large upage-plus-stack ".reg" section.
 169             Original upage address X is at location core_reg_sect+x+reg_addr.
 170  */
 171
 172 void
 173 fetch_core_registers (core_reg_sect, core_reg_size, which, reg_addr)
 174      char *core_reg_sect;
 175      unsigned core_reg_size;
 176      int which;
 177      unsigned reg_addr;
 178 {
 179   register int regno;
 180   register unsigned int addr;
 181   int bad_reg = -1;
 182   register reg_ptr = -reg_addr;         /* Original u.u_ar0 is -reg_addr. */
 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     reg_ptr -= KERNEL_U_ADDR;
 192
 193   for (regno = 0; regno < NUM_REGS; regno++)
 194     {
 195       addr = register_addr (regno, reg_ptr);
 196       if (addr >= core_reg_size) {
 197         if (bad_reg < 0)
 198           bad_reg = regno;
 199       } else {
 200         supply_register (regno, core_reg_sect + addr);
 201       }
 202     }
 203   if (bad_reg >= 0)
 204     {
 205       error ("Register %s not found in core file.", reg_names[bad_reg]);
 206     }
 207   supply_register (ZERO_REGNUM, zerobuf);
 208   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
 209   supply_register (FP_REGNUM, zerobuf);
 210 }
 211
 212 /* Return the address in the core dump or inferior of register REGNO.
 213    BLOCKEND is the address of the end of the user structure.  */
 214
 215 unsigned int
 216 register_addr (regno, blockend)
 217      int regno;
 218      int blockend;
 219 {
 220   int addr;
 221
 222   if (regno < 0 || regno >= NUM_REGS)
 223     error ("Invalid register number %d.", regno);
 224
 225   REGISTER_U_ADDR (addr, blockend, regno);
 226
 227   return addr;
 228 }