gdb/i386-netbsd-nat.c

   1 /* Native-dependent code for NetBSD/i386.
   2
   3    Copyright (C) 2004-2021 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 3 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, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdbcore.h"
  22 #include "regcache.h"
  23 #include "target.h"
  24
  25 #include "i386-tdep.h"
  26 #include "i386-bsd-nat.h"
  27
  28 /* Support for debugging kernel virtual memory images.  */
  29
  30 #include <sys/types.h>
  31 #include <machine/frame.h>
  32 #include <machine/pcb.h>
  33
  34 #include "netbsd-nat.h"
  35 #include "bsd-kvm.h"
  36
  37 static int
  38 i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
  39 {
  40   struct switchframe sf;
  41
  42   /* The following is true for NetBSD 1.6.2:
  43
  44      The pcb contains %esp and %ebp at the point of the context switch
  45      in cpu_switch().  At that point we have a stack frame as
  46      described by `struct switchframe', which for NetBSD 1.6.2 has the
  47      following layout:
  48
  49      interrupt level
  50      %edi
  51      %esi
  52      %ebx
  53      %eip
  54
  55      we reconstruct the register state as it would look when we just
  56      returned from cpu_switch().  */
  57
  58   /* The stack pointer shouldn't be zero.  */
  59   if (pcb->pcb_esp == 0)
  60     return 0;
  61
  62   read_memory (pcb->pcb_esp, (gdb_byte *)&sf, sizeof sf);
  63   pcb->pcb_esp += sizeof (struct switchframe);
  64   regcache->raw_supply (I386_EDI_REGNUM, &sf.sf_edi);
  65   regcache->raw_supply (I386_ESI_REGNUM, &sf.sf_esi);
  66   regcache->raw_supply (I386_EBP_REGNUM, &pcb->pcb_ebp);
  67   regcache->raw_supply (I386_ESP_REGNUM, &pcb->pcb_esp);
  68   regcache->raw_supply (I386_EBX_REGNUM, &sf.sf_ebx);
  69   regcache->raw_supply (I386_EIP_REGNUM, &sf.sf_eip);
  70
  71   return 1;
  72 }
  73
  74 static i386_bsd_nat_target<nbsd_nat_target> the_i386_nbsd_nat_target;
  75
  76 void _initialize_i386nbsd_nat ();
  77 void
  78 _initialize_i386nbsd_nat ()
  79 {
  80   add_inf_child_target (&the_i386_nbsd_nat_target);
  81
  82   /* Support debugging kernel virtual memory images.  */
  83   bsd_kvm_add_target (i386nbsd_supply_pcb);
  84 }