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/* Native-dependent code for OpenBSD/amd64.

   Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "gdbcore.h"

#include "regcache.h"

#include "target.h"

#include "gdb_assert.h"

#include "amd64-tdep.h"

#include "amd64-nat.h"

/* Mapping between the general-purpose registers in OpenBSD/amd64

   `struct reg' format and GDB's register cache layout for

   OpenBSD/i386.

   Note that most (if not all) OpenBSD/amd64 registers are 64-bit,

   while the OpenBSD/i386 registers are all 32-bit, but since we're

   little-endian we get away with that.  */

/* From <machine/reg.h>.  */

static int amd64obsd32_r_reg_offset[] =

{

  14 * 8,                       /* %eax */

  3 * 8,                        /* %ecx */

  2 * 8,                        /* %edx */

  13 * 8,                       /* %ebx */

  15 * 8,                       /* %esp */

  12 * 8,                       /* %ebp */

  1 * 8,                        /* %esi */

  16 * 8,                       /* %eip */

  17 * 8,                       /* %eflags */

  18 * 8,                       /* %cs */

  19 * 8,                       /* %ss */

  20 * 8,                       /* %ds */

  21 * 8,                       /* %es */

  22 * 8,                       /* %fs */

  23 * 8                        /* %gs */

};

/* Support for debugging kernel virtual memory images.  */

#include <sys/types.h>

#include <machine/frame.h>

#include <machine/pcb.h>

#include "bsd-kvm.h"

static int

amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)

{

  struct switchframe sf;

  int regnum;

  /* The following is true for OpenBSD 3.5:

     The pcb contains the stack pointer at the point of the context

     switch in cpu_switch().  At that point we have a stack frame as

     described by `struct switchframe', which for OpenBSD 3.5 has the

     following layout:

     interrupt level

     %r15

     %r14

     %r13

     %r12

     %rbp

     %rbx

     return address

     Together with %rsp in the pcb, this accounts for all callee-saved

     registers specified by the psABI.  From this information we

     reconstruct the register state as it would look when we just

     returned from cpu_switch().

     For core dumps the pcb is saved by savectx().  In that case the

     stack frame only contains the return address, and there is no way

     to recover the other registers.  */

  /* The stack pointer shouldn't be zero.  */

  if (pcb->pcb_rsp == 0)

    return 0;

  /* Read the stack frame, and check its validity.  */

  read_memory (pcb->pcb_rsp, (gdb_byte *) &sf, sizeof sf);

  if (sf.sf_rbp == pcb->pcb_rbp)

    {

      /* Yes, we have a frame that matches cpu_switch().  */

      pcb->pcb_rsp += sizeof (struct switchframe);

      regcache_raw_supply (regcache, 12, &sf.sf_r12);

      regcache_raw_supply (regcache, 13, &sf.sf_r13);

      regcache_raw_supply (regcache, 14, &sf.sf_r14);

      regcache_raw_supply (regcache, 15, &sf.sf_r15);

      regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &sf.sf_rbx);

      regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf.sf_rip);

    }

  else

    {

      /* No, the pcb must have been last updated by savectx().  */

      pcb->pcb_rsp += 8;

      regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf);

    }

  regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);

  regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);

  return 1;

}

/* Provide a prototype to silence -Wmissing-prototypes.  */

void _initialize_amd64obsd_nat (void);

void

_initialize_amd64obsd_nat (void)

{

  amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset;

  amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset);

  amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset;

  /* We've got nothing to add to the common *BSD/amd64 target.  */

  add_target (amd64bsd_target ());

  /* Support debugging kernel virtual memory images.  */

  bsd_kvm_add_target (amd64obsd_supply_pcb);

}