gdb/i386nbsd-nat.c

   1 /* Native-dependent code for NetBSD/i386.
   2
   3    Copyright 2004 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "gdbcore.h"
  24 #include "regcache.h"
  25 #include "target.h"
  26
  27 #include "i386-tdep.h"
  28 #include "i386bsd-nat.h"
  29
  30 /* Support for debugging kernel virtual memory images.  */
  31
  32 #include <sys/types.h>
  33 #include <machine/frame.h>
  34 #include <machine/pcb.h>
  35
  36 #include "bsd-kvm.h"
  37
  38 static int
  39 i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
  40 {
  41   struct switchframe sf;
  42
  43   /* The following is true for NetBSD 1.6.2:
  44
  45      The pcb contains %esp and %ebp at the point of the context switch
  46      in cpu_switch().  At that point we have a stack frame as
  47      described by `struct switchframe', which for NetBSD 1.6.2 has the
  48      following layout:
  49
  50      interrupt level
  51      %edi
  52      %esi
  53      %ebx
  54      %eip
  55
  56      we reconstruct the register state as it would look when we just
  57      returned from cpu_switch().  */
  58
  59   /* The stack pointer shouldn't be zero.  */
  60   if (pcb->pcb_esp == 0)
  61     return 0;
  62
  63   read_memory (pcb->pcb_esp, (char *) &sf, sizeof sf);
  64   pcb->pcb_esp += sizeof (struct switchframe);
  65   regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
  66   regcache_raw_supply (regcache, I386_ESI_REGNUM, &sf.sf_esi);
  67   regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
  68   regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
  69   regcache_raw_supply (regcache, I386_EBX_REGNUM, &sf.sf_ebx);
  70   regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf.sf_eip);
  71
  72   return 1;
  73 }
  74 \f
  75
  76 /* Provide a prototype to silence -Wmissing-prototypes.  */
  77 void _initialize_i386nbsd_nat (void);
  78
  79 void
  80 _initialize_i386nbsd_nat (void)
  81 {
  82   /* We've got nothing to add to the common *BSD/i386 target.  */
  83   add_target (i386bsd_target ());
  84
  85   /* Support debugging kernel virtual memory images.  */
  86   bsd_kvm_add_target (i386nbsd_supply_pcb);
  87 }