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[/] [openrisc/] [trunk/] [gnu-old/] [gdb-6.8/] [gdb/] [i386obsd-nat.c] - Blame information for rev 157

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1 24 jeremybenn
/* Native-dependent code for OpenBSD/i386.
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   Copyright (C) 2002, 2003, 2004, 2006, 2007, 2008
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   Free Software Foundation, Inc.
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   This file is part of GDB.
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   This program is free software; you can redistribute it and/or modify
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   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3 of the License, or
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   (at your option) any later version.
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   This program is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
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   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
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#include "defs.h"
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#include "gdbcore.h"
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#include "regcache.h"
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#include "target.h"
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#include <machine/frame.h>
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#include <machine/pcb.h>
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#include "i386-tdep.h"
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#include "i386bsd-nat.h"
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#include "bsd-kvm.h"
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static int
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i386obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
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{
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  struct switchframe sf;
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  /* The following is true for OpenBSD 3.6:
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     The pcb contains %esp and %ebp at the point of the context switch
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     in cpu_switch().  At that point we have a stack frame as
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     described by `struct switchframe', which for OpenBSD 3.6 has the
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     following layout:
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     interrupt level
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     %edi
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     %esi
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     %ebx
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     %eip
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     we reconstruct the register state as it would look when we just
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     returned from cpu_switch().  */
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  /* The stack pointer shouldn't be zero.  */
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  if (pcb->pcb_esp == 0)
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    return 0;
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  /* Read the stack frame, and check its validity.  We do this by
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     checking if the saved interrupt priority level in the stack frame
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     looks reasonable..  */
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  read_memory (pcb->pcb_esp, (char *) &sf, sizeof sf);
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  if ((unsigned int) sf.sf_ppl < 0x100 && (sf.sf_ppl & 0xf) == 0)
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    {
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      /* Yes, we have a frame that matches cpu_switch().  */
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      pcb->pcb_esp += sizeof (struct switchframe);
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      regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
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      regcache_raw_supply (regcache, I386_ESI_REGNUM, &sf.sf_esi);
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      regcache_raw_supply (regcache, I386_EBX_REGNUM, &sf.sf_ebx);
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      regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf.sf_eip);
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    }
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  else
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    {
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      /* No, the pcb must have been last updated by savectx().  */
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      pcb->pcb_esp += 4;
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      regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf);
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    }
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  regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
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  regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
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  return 1;
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}
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/* Prevent warning from -Wmissing-prototypes.  */
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void _initialize_i386obsd_nat (void);
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void
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_initialize_i386obsd_nat (void)
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{
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  /* We've got nothing to add to the common *BSD/i386 target.  */
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  add_target (i386bsd_target ());
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  /* Support debugging kernel virtual memory images.  */
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  bsd_kvm_add_target (i386obsd_supply_pcb);
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  /* OpenBSD provides a vm.psstrings sysctl that we can use to locate
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     the sigtramp.  That way we can still recognize a sigtramp if its
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     location is changed in a new kernel.  This is especially
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     important for OpenBSD, since it uses a different memory layout
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     than NetBSD, yet we cannot distinguish between the two.
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     Of course this is still based on the assumption that the sigtramp
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     is placed directly under the location where the program arguments
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     and environment can be found.  */
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#ifdef VM_PSSTRINGS
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  {
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    struct _ps_strings _ps;
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    int mib[2];
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    size_t len;
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    mib[0] = CTL_VM;
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    mib[1] = VM_PSSTRINGS;
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    len = sizeof (_ps);
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    if (sysctl (mib, 2, &_ps, &len, NULL, 0) == 0)
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      {
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        i386obsd_sigtramp_start_addr = (u_long) _ps.val - 128;
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        i386obsd_sigtramp_end_addr = (u_long) _ps.val;
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      }
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  }
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#endif
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}

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