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., 59 Temple Place - Suite 330,
  24    Boston, MA 02111-1307, USA.  */
  25
  26 #include "defs.h"
  27 #include "inferior.h"
  28 #include "target.h"
  29 #include <sys/ptrace.h>
  30
  31 /* Use an extra level of indirection for ptrace calls.
  32    This lets us breakpoint usefully on call_ptrace.   It also
  33    allows us to pass an extra argument to ptrace without
  34    using an ANSI-C specific macro.  */
  35
  36 #define ptrace call_ptrace
  37
  38 #if !defined (offsetof)
  39 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
  40 #endif
  41
  42 /* U_REGS_OFFSET is the offset of the registers within the u area.  */
  43 #if !defined (U_REGS_OFFSET)
  44 #define U_REGS_OFFSET \
  45   ptrace (PT_READ_U, inferior_pid, \
  46           (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
  47     - KERNEL_U_ADDR
  48 #endif
  49
  50 /* Fetch one register.  */
  51
  52 static void
  53 fetch_register (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", REGISTER_NAME (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 (int regno)
  90 {
  91   if (regno == -1)
  92     for (regno = 0; regno < NUM_REGS; regno++)
  93       fetch_register (regno);
  94   else
  95     fetch_register (regno);
  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   register int i;
 108   unsigned int offset = U_REGS_OFFSET;
 109   int scratch;
 110
 111   if (regno >= 0)
 112     {
 113       if (CANNOT_STORE_REGISTER (regno))
 114         return;
 115       regaddr = register_addr (regno, offset);
 116       errno = 0;
 117       if (regno == PCOQ_HEAD_REGNUM || regno == PCOQ_TAIL_REGNUM)
 118         {
 119           scratch = *(int *) &registers[REGISTER_BYTE (regno)] | 0x3;
 120           ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 121                   scratch);
 122           if (errno != 0)
 123             {
 124               /* Error, even if attached.  Failing to write these two
 125                  registers is pretty serious.  */
 126               sprintf (buf, "writing register number %d", regno);
 127               perror_with_name (buf);
 128             }
 129         }
 130       else
 131         for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
 132           {
 133             errno = 0;
 134             ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 135                     *(int *) &registers[REGISTER_BYTE (regno) + i]);
 136             if (errno != 0)
 137               {
 138                 /* Warning, not error, in case we are attached; sometimes the
 139                    kernel doesn't let us at the registers.  */
 140                 char *err = safe_strerror (errno);
 141                 char *msg = alloca (strlen (err) + 128);
 142                 sprintf (msg, "writing register %s: %s",
 143                          REGISTER_NAME (regno), err);
 144                 warning (msg);
 145                 return;
 146               }
 147             regaddr += sizeof (int);
 148           }
 149     }
 150   else
 151     for (regno = 0; regno < NUM_REGS; regno++)
 152       store_inferior_registers (regno);
 153 }
 154
 155 /* PT_PROT is specific to the PA BSD kernel and isn't documented
 156    anywhere (except here).
 157
 158    PT_PROT allows one to enable/disable the data memory break bit
 159    for pages of memory in an inferior process.  This bit is used
 160    to cause "Data memory break traps" to occur when the appropriate
 161    page is written to.
 162
 163    The arguments are as follows:
 164
 165    PT_PROT -- The ptrace action to perform.
 166
 167    INFERIOR_PID -- The pid of the process who's page table entries
 168    will be modified.
 169
 170    PT_ARGS -- The *address* of a 3 word block of memory which has
 171    additional information:
 172
 173    word 0 -- The start address to watch.  This should be a page-aligned
 174    address.
 175
 176    word 1 -- The ending address to watch.  Again, this should be a
 177    page aligned address.
 178
 179    word 2 -- Nonzero to enable the data memory break bit on the
 180    given address range or zero to disable the data memory break
 181    bit on the given address range.
 182
 183    This call may fail if the given addresses are not valid in the inferior
 184    process.  This most often happens when restarting a program which
 185    has watchpoints inserted on heap or stack memory.  */
 186
 187 #define PT_PROT 21
 188
 189 int
 190 hppa_set_watchpoint (int addr, int len, int flag)
 191 {
 192   int pt_args[3];
 193   pt_args[0] = addr;
 194   pt_args[1] = addr + len;
 195   pt_args[2] = flag;
 196
 197   /* Mask off the lower 12 bits since we want to work on a page basis.  */
 198   pt_args[0] >>= 12;
 199   pt_args[1] >>= 12;
 200
 201   /* Rounding adjustments.  */
 202   pt_args[1] -= pt_args[0];
 203   pt_args[1]++;
 204
 205   /* Put the lower 12 bits back as zero.  */
 206   pt_args[0] <<= 12;
 207   pt_args[1] <<= 12;
 208
 209   /* Do it.  */
 210   return ptrace (PT_PROT, inferior_pid, (PTRACE_ARG3_TYPE) pt_args, 0);
 211 }