gdb/hppab-nat.c

   1 /* Machine-dependent hooks for the unix child process stratum.  This
   2    code is for the HP PA-RISC cpu.
   3
   4    Copyright 1986, 1987, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
   5
   6    Contributed by the Center for Software Science at the
   7    University of Utah (pa-gdb-bugs@cs.utah.edu).
   8
   9 This file is part of GDB.
  10
  11 This program is free software; you can redistribute it and/or modify
  12 it under the terms of the GNU General Public License as published by
  13 the Free Software Foundation; either version 2 of the License, or
  14 (at your option) any later version.
  15
  16 This program is distributed in the hope that it will be useful,
  17 but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 GNU General Public License for more details.
  20
  21 You should have received a copy of the GNU General Public License
  22 along with this program; if not, write to the Free Software
  23 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  24
  25 #include "defs.h"
  26 #include "inferior.h"
  27 #include "target.h"
  28 #include <sys/ptrace.h>
  29
  30 /* Use an extra level of indirection for ptrace calls.
  31    This lets us breakpoint usefully on call_ptrace.   It also
  32    allows us to pass an extra argument to ptrace without
  33    using an ANSI-C specific macro.  */
  34
  35 #define ptrace call_ptrace
  36
  37 #if !defined (offsetof)
  38 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
  39 #endif
  40
  41 /* U_REGS_OFFSET is the offset of the registers within the u area.  */
  42 #if !defined (U_REGS_OFFSET)
  43 #define U_REGS_OFFSET \
  44   ptrace (PT_READ_U, inferior_pid, \
  45           (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
  46     - KERNEL_U_ADDR
  47 #endif
  48
  49 /* Fetch one register.  */
  50
  51 static void
  52 fetch_register (regno)
  53      int regno;
  54 {
  55   register unsigned int regaddr;
  56   char buf[MAX_REGISTER_RAW_SIZE];
  57   register int i;
  58
  59   /* Offset of registers within the u area.  */
  60   unsigned int offset;
  61
  62   offset = U_REGS_OFFSET;
  63
  64   regaddr = register_addr (regno, offset);
  65   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  66     {
  67       errno = 0;
  68       *(int *) &buf[i] = ptrace (PT_RUREGS, inferior_pid,
  69                                  (PTRACE_ARG3_TYPE) regaddr, 0);
  70       regaddr += sizeof (int);
  71       if (errno != 0)
  72         {
  73           /* Warning, not error, in case we are attached; sometimes the
  74              kernel doesn't let us at the registers.  */
  75           char *err = safe_strerror (errno);
  76           char *msg = alloca (strlen (err) + 128);
  77           sprintf (msg, "reading register %s: %s", reg_names[regno], err);
  78           warning (msg);
  79           goto error_exit;
  80         }
  81     }
  82   supply_register (regno, buf);
  83  error_exit:;
  84 }
  85
  86 /* Fetch all registers, or just one, from the child process.  */
  87
  88 void
  89 fetch_inferior_registers (regno)
  90      int regno;
  91 {
  92   if (regno == -1)
  93     for (regno = 0; regno < NUM_REGS; regno++)
  94       fetch_register (regno);
  95   else
  96     fetch_register (regno);
  97 }
  98
  99 /* Store our register values back into the inferior.
 100    If REGNO is -1, do this for all registers.
 101    Otherwise, REGNO specifies which register (so we can save time).  */
 102
 103 void
 104 store_inferior_registers (regno)
 105      int regno;
 106 {
 107   register unsigned int regaddr;
 108   char buf[80];
 109   extern char registers[];
 110   register int i;
 111   unsigned int offset = U_REGS_OFFSET;
 112   int scratch;
 113
 114   if (regno >= 0)
 115     {
 116       if (CANNOT_STORE_REGISTER (regno))
 117         return;
 118       regaddr = register_addr (regno, offset);
 119       errno = 0;
 120       if (regno == PCOQ_HEAD_REGNUM || regno == PCOQ_TAIL_REGNUM)
 121         {
 122           scratch = *(int *) &registers[REGISTER_BYTE (regno)] | 0x3;
 123           ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 124                   scratch);
 125           if (errno != 0)
 126             {
 127               /* Error, even if attached.  Failing to write these two
 128                  registers is pretty serious.  */
 129               sprintf (buf, "writing register number %d", regno);
 130               perror_with_name (buf);
 131             }
 132         }
 133       else
 134         for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
 135           {
 136             errno = 0;
 137             ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 138                     *(int *) &registers[REGISTER_BYTE (regno) + i]);
 139             if (errno != 0)
 140               {
 141                 /* Warning, not error, in case we are attached; sometimes the
 142                    kernel doesn't let us at the registers.  */
 143                 char *err = safe_strerror (errno);
 144                 char *msg = alloca (strlen (err) + 128);
 145                 sprintf (msg, "writing register %s: %s",
 146                          reg_names[regno], err);
 147                 warning (msg);
 148                 return;
 149               }
 150             regaddr += sizeof(int);
 151           }
 152     }
 153   else
 154     for (regno = 0; regno < NUM_REGS; regno++)
 155       store_inferior_registers (regno);
 156 }
 157
 158 /* PT_PROT is specific to the PA BSD kernel and isn't documented
 159    anywhere (except here).
 160
 161    PT_PROT allows one to enable/disable the data memory break bit
 162    for pages of memory in an inferior process.  This bit is used
 163    to cause "Data memory break traps" to occur when the appropriate
 164    page is written to.
 165
 166    The arguments are as follows:
 167
 168       PT_PROT -- The ptrace action to perform.
 169
 170       INFERIOR_PID -- The pid of the process who's page table entries
 171       will be modified.
 172
 173       PT_ARGS -- The *address* of a 3 word block of memory which has
 174       additional information:
 175
 176         word 0 -- The start address to watch.  This should be a page-aligned
 177         address.
 178
 179         word 1 -- The ending address to watch.  Again, this should be a
 180         page aligned address.
 181
 182         word 2 -- Nonzero to enable the data memory break bit on the
 183         given address range or zero to disable the data memory break
 184         bit on the given address range.
 185
 186   This call may fail if the given addresses are not valid in the inferior
 187   process.  This most often happens when restarting a program which
 188   as watchpoints inserted on heap or stack memory.  */
 189
 190 #define PT_PROT 21
 191
 192 int
 193 hppa_set_watchpoint (addr, len, flag)
 194      int addr, len, flag;
 195 {
 196   int pt_args[3];
 197   pt_args[0] = addr;
 198   pt_args[1] = addr + len;
 199   pt_args[2] = flag;
 200
 201   /* Mask off the lower 12 bits since we want to work on a page basis.  */
 202   pt_args[0] >>= 12;
 203   pt_args[1] >>= 12;
 204
 205   /* Rounding adjustments.  */
 206   pt_args[1] -= pt_args[0];
 207   pt_args[1]++;
 208
 209   /* Put the lower 12 bits back as zero.  */
 210   pt_args[0] <<= 12;
 211   pt_args[1] <<= 12;
 212
 213   /* Do it.  */
 214   return ptrace (PT_PROT, inferior_pid, (PTRACE_ARG3_TYPE) pt_args, 0);
 215 }