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 #define REGISTER_PTRACE_ADDR(regno) \
  55    (regno < 32 ?                GPR_BASE + regno \
  56   : regno == PC_REGNUM ?        PC      \
  57   : regno == CAUSE_REGNUM ?     CAUSE   \
  58   : regno == HI_REGNUM ?        MMHI    \
  59   : regno == LO_REGNUM ?        MMLO    \
  60   : regno == FCRCS_REGNUM ?     FPC_CSR \
  61   : regno == FCRIR_REGNUM ?     FPC_EIR \
  62   : regno >= FP0_REGNUM ?       FPR_BASE + (regno - FP0_REGNUM) \
  63   : 0)
  64
  65 static void fetch_core_registers (char *, unsigned, int, CORE_ADDR);
  66
  67 /* Get all registers from the inferior */
  68
  69 void
  70 fetch_inferior_registers (int regno)
  71 {
  72   register unsigned int regaddr;
  73   char *buf = alloca (max_register_size (current_gdbarch));
  74   register int i;
  75   char *zerobuf = alloca (max_register_size (current_gdbarch));
  76   memset (zerobuf, 0, max_register_size (current_gdbarch));
  77
  78   deprecated_registers_fetched ();
  79
  80   for (regno = 1; regno < NUM_REGS; regno++)
  81     {
  82       regaddr = REGISTER_PTRACE_ADDR (regno);
  83       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  84         {
  85           *(int *) &buf[i] = ptrace (PT_READ_U, PIDGET (inferior_ptid),
  86                                      (PTRACE_ARG3_TYPE) regaddr, 0);
  87           regaddr += sizeof (int);
  88         }
  89       supply_register (regno, buf);
  90     }
  91
  92   supply_register (ZERO_REGNUM, zerobuf);
  93   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
  94   supply_register (FP_REGNUM, zerobuf);
  95 }
  96
  97 /* Store our register values back into the inferior.
  98    If REGNO is -1, do this for all registers.
  99    Otherwise, REGNO specifies which register (so we can save time).  */
 100
 101 void
 102 store_inferior_registers (int regno)
 103 {
 104   register unsigned int regaddr;
 105   char buf[80];
 106
 107   if (regno > 0)
 108     {
 109       if (regno == ZERO_REGNUM || regno == PS_REGNUM
 110           || regno == BADVADDR_REGNUM || regno == CAUSE_REGNUM
 111           || regno == FCRIR_REGNUM || regno == FP_REGNUM
 112           || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
 113         return;
 114       regaddr = REGISTER_PTRACE_ADDR (regno);
 115       errno = 0;
 116       ptrace (PT_WRITE_U, PIDGET (inferior_ptid), (PTRACE_ARG3_TYPE) regaddr,
 117               read_register (regno));
 118       if (errno != 0)
 119         {
 120           sprintf (buf, "writing register number %d", regno);
 121           perror_with_name (buf);
 122         }
 123     }
 124   else
 125     {
 126       for (regno = 0; regno < NUM_REGS; regno++)
 127         store_inferior_registers (regno);
 128     }
 129 }
 130
 131
 132 /* Figure out where the longjmp will land.
 133    We expect the first arg to be a pointer to the jmp_buf structure from which
 134    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
 135    This routine returns true on success. */
 136
 137 int
 138 get_longjmp_target (CORE_ADDR *pc)
 139 {
 140   CORE_ADDR jb_addr;
 141   char *buf;
 142
 143   buf = alloca (TARGET_PTR_BIT / TARGET_CHAR_BIT);
 144   jb_addr = read_register (A0_REGNUM);
 145
 146   if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
 147                           TARGET_PTR_BIT / TARGET_CHAR_BIT))
 148     return 0;
 149
 150   *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
 151
 152   return 1;
 153 }
 154
 155 /* Extract the register values out of the core file and store
 156    them where `read_register' will find them.
 157
 158    CORE_REG_SECT points to the register values themselves, read into memory.
 159    CORE_REG_SIZE is the size of that area.
 160    WHICH says which set of registers we are handling (0 = int, 2 = float
 161    on machines where they are discontiguous).
 162    REG_ADDR is the offset from u.u_ar0 to the register values relative to
 163    core_reg_sect.  This is used with old-fashioned core files to
 164    locate the registers in a large upage-plus-stack ".reg" section.
 165    Original upage address X is at location core_reg_sect+x+reg_addr.
 166  */
 167
 168 static void
 169 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
 170                       CORE_ADDR reg_addr)
 171 {
 172   register int regno;
 173   register unsigned int addr;
 174   int bad_reg = -1;
 175   register reg_ptr = -reg_addr; /* Original u.u_ar0 is -reg_addr. */
 176
 177   char *zerobuf = alloca (max_register_size (current_gdbarch));
 178   memset (zerobuf, 0, max_register_size (current_gdbarch));
 179
 180
 181   /* If u.u_ar0 was an absolute address in the core file, relativize it now,
 182      so we can use it as an offset into core_reg_sect.  When we're done,
 183      "register 0" will be at core_reg_sect+reg_ptr, and we can use
 184      register_addr to offset to the other registers.  If this is a modern
 185      core file without a upage, reg_ptr will be zero and this is all a big
 186      NOP.  */
 187   if (reg_ptr > core_reg_size)
 188 #ifdef KERNEL_U_ADDR
 189     reg_ptr -= KERNEL_U_ADDR;
 190 #else
 191     error ("Old mips core file can't be processed on this machine.");
 192 #endif
 193
 194   for (regno = 0; regno < NUM_REGS; regno++)
 195     {
 196       addr = register_addr (regno, reg_ptr);
 197       if (addr >= core_reg_size)
 198         {
 199           if (bad_reg < 0)
 200             bad_reg = regno;
 201         }
 202       else
 203         {
 204           supply_register (regno, core_reg_sect + addr);
 205         }
 206     }
 207   if (bad_reg >= 0)
 208     {
 209       error ("Register %s not found in core file.", REGISTER_NAME (bad_reg));
 210     }
 211   supply_register (ZERO_REGNUM, zerobuf);
 212   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
 213   supply_register (FP_REGNUM, zerobuf);
 214 }
 215
 216 /* Return the address in the core dump or inferior of register REGNO.
 217    BLOCKEND is the address of the end of the user structure.  */
 218
 219 CORE_ADDR
 220 register_addr (int regno, CORE_ADDR blockend)
 221 {
 222   CORE_ADDR addr;
 223
 224   if (regno < 0 || regno >= NUM_REGS)
 225     error ("Invalid register number %d.", regno);
 226
 227   REGISTER_U_ADDR (addr, blockend, regno);
 228
 229   return addr;
 230 }
 231 \f
 232
 233 /* Register that we are able to handle mips core file formats.
 234    FIXME: is this really bfd_target_unknown_flavour? */
 235
 236 static struct core_fns mips_core_fns =
 237 {
 238   bfd_target_unknown_flavour,           /* core_flavour */
 239   default_check_format,                 /* check_format */
 240   default_core_sniffer,                 /* core_sniffer */
 241   fetch_core_registers,                 /* core_read_registers */
 242   NULL                                  /* next */
 243 };
 244
 245 void
 246 _initialize_core_mips (void)
 247 {
 248   add_core_fns (&mips_core_fns);
 249 }