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