gdb/config/pa/nm-hppab.h

   1 /* HPPA PA-RISC machine native support for BSD, for GDB.
   2    Copyright 1991, 1992 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #include "somsolib.h"
  21
  22 #define U_REGS_OFFSET 0
  23
  24 #define KERNEL_U_ADDR 0
  25
  26 /* What a coincidence! */
  27 #define REGISTER_U_ADDR(addr, blockend, regno)                          \
  28 { addr = (int)(blockend) + REGISTER_BYTE (regno);}
  29
  30 /* 3rd argument to ptrace is supposed to be a caddr_t.  */
  31
  32 #define PTRACE_ARG3_TYPE caddr_t
  33
  34 /* HPUX 8.0, in its infinite wisdom, has chosen to prototype ptrace
  35    with five arguments, so programs written for normal ptrace lose.  */
  36 #define FIVE_ARG_PTRACE
  37
  38
  39 /* This macro defines the register numbers (from REGISTER_NAMES) that
  40    are effectively unavailable to the user through ptrace().  It allows
  41    us to include the whole register set in REGISTER_NAMES (inorder to
  42    better support remote debugging).  If it is used in
  43    fetch/store_inferior_registers() gdb will not complain about I/O errors
  44    on fetching these registers.  If all registers in REGISTER_NAMES
  45    are available, then return false (0).  */
  46
  47 #define CANNOT_STORE_REGISTER(regno)            \
  48                    ((regno) == 0) ||     \
  49                    ((regno) == PCSQ_HEAD_REGNUM) || \
  50                    ((regno) >= PCSQ_TAIL_REGNUM && (regno) < IPSW_REGNUM) ||  \
  51                    ((regno) > IPSW_REGNUM && (regno) < FP4_REGNUM)
  52
  53 /* fetch_inferior_registers is in hppab-nat.c.  */
  54 #define FETCH_INFERIOR_REGISTERS
  55
  56 /* attach/detach works to some extent under BSD and HPUX.  So long
  57    as the process you're attaching to isn't blocked waiting on io,
  58    blocked waiting on a signal, or in a system call things work
  59    fine.  (The problems in those cases are related to the fact that
  60    the kernel can't provide complete register information for the
  61    target process...  Which really pisses off GDB.)  */
  62
  63 #define ATTACH_DETACH
  64
  65 /* The PA-BSD kernel has support for using the data memory break bit
  66    to implement fast watchpoints.
  67
  68    Watchpoints on the PA act much like traditional page protection
  69    schemes, but with some notable differences.
  70
  71    First, a special bit in the page table entry is used to cause
  72    a trap when a specific page is written to.  This avoids having
  73    to overload watchpoints on the page protection bits.  This makes
  74    it possible for the kernel to easily decide if a trap was caused
  75    by a watchpoint or by the user writing to protected memory and can
  76    signal the user program differently in each case.
  77
  78    Second, the PA has a bit in the processor status word which causes
  79    data memory breakpoints (aka watchpoints) to be disabled for a single
  80    instruction.  This bit can be used to avoid the overhead of unprotecting
  81    and reprotecting pages when it becomes necessary to step over a watchpoint.
  82
  83
  84    When the kernel receives a trap indicating a write to a page which
  85    is being watched, the kernel performs a couple of simple actions.  First
  86    is sets the magic "disable memory breakpoint" bit in the processor
  87    status word, it then sends a SIGTRAP to the process which caused the
  88    trap.
  89
  90    GDB will take control and catch the signal for the inferior.  GDB then
  91    examines the PSW-X bit to determine if the SIGTRAP was caused by a
  92    watchpoint firing.  If so GDB single steps the inferior over the
  93    instruction which caused the watchpoint to trigger (note because the
  94    kernel disabled the data memory break bit for one instruction no trap
  95    will be taken!).  GDB will then determines the appropriate action to
  96    take.  (this may include restarting the inferior if the watchpoint
  97    fired because of a write to an address on the same page as a watchpoint,
  98    but no write to the watched address occured).  */
  99
 100 #define TARGET_HAS_HARDWARE_WATCHPOINTS /* Enable the code in procfs.c */
 101
 102 /* The PA can watch any number of locations, there's no need for it to reject
 103    anything (generic routines already check that all intermediates are
 104    in memory).  */
 105 #define TARGET_CAN_USE_HARDWARE_WATCHPOINT(type, cnt, ot) \
 106         ((type) == bp_hardware_watchpoint)
 107
 108 /* When a hardware watchpoint fires off the PC will be left at the
 109    instruction which caused the watchpoint.  It will be necessary for
 110    GDB to step over the watchpoint.
 111
 112    On a PA running BSD, it is trivial to identify when it will be
 113    necessary to step over a hardware watchpoint as we can examine
 114    the PSW-X bit.  If the bit is on, then we trapped because of a
 115    watchpoint, else we trapped for some other reason.  */
 116 #define STOPPED_BY_WATCHPOINT(W) \
 117   ((W).kind == TARGET_WAITKIND_STOPPED \
 118    && (W).value.sig == TARGET_SIGNAL_TRAP \
 119    && ((int) read_register (IPSW_REGNUM) & 0x00100000))
 120
 121 /* The PA can single step over a watchpoint if the kernel has set the
 122    "X" bit in the processor status word (disable data memory breakpoint
 123    for one instruction).
 124
 125    The kernel will always set this bit before notifying the inferior
 126    that it hit a watchpoint.  Thus, the inferior can single step over
 127    the instruction which caused the watchpoint to fire.  This avoids
 128    the traditional need to disable the watchpoint, step the inferior,
 129    then enable the watchpoint again.  */
 130 #define HAVE_STEPPABLE_WATCHPOINT
 131
 132 /* Use these macros for watchpoint insertion/deletion.  */
 133 /* type can be 0: write watch, 1: read watch, 2: access watch (read/write) */
 134 #define target_insert_watchpoint(addr, len, type) hppa_set_watchpoint (addr, len, 1)
 135 #define target_remove_watchpoint(addr, len, type) hppa_set_watchpoint (addr, len, 0)