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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-7.1/] [gdb/] [vaxobsd-tdep.c] - Blame information for rev 227

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1 227 jeremybenn
/* Target-dependent code for OpenBSD/vax.
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   Copyright (C) 2005, 2007, 2008, 2009, 2010 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 "arch-utils.h"
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#include "frame.h"
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#include "frame-unwind.h"
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#include "osabi.h"
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#include "symtab.h"
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#include "trad-frame.h"
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#include "vax-tdep.h"
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#include "gdb_string.h"
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/* Signal trampolines.  */
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/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
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   in virtual memory.  The randomness makes it somewhat tricky to
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   detect it, but fortunately we can rely on the fact that the start
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   of the sigtramp routine is page-aligned.  We recognize the
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   trampoline by looking for the code that invokes the sigreturn
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   system call.  The offset where we can find that code varies from
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   release to release.
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   By the way, the mapping mentioned above is read-only, so you cannot
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   place a breakpoint in the signal trampoline.  */
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/* Default page size.  */
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static const int vaxobsd_page_size = 4096;
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/* Offset for sigreturn(2).  */
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static const int vaxobsd_sigreturn_offset = 0x11;
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/* Instruction sequence for sigreturn(2).  VAX doesn't have
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   fixed-length instructions so we include the ensuing exit(2) to
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   reduce the chance of spurious matches.  */
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static const gdb_byte vaxobsd_sigreturn[] = {
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  0xbc, 0x8f, 0x67, 0x00,       /* chmk $SYS_sigreturn */
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  0xbc, 0x01                    /* chmk $SYS_exit */
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};
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static int
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vaxobsd_sigtramp_sniffer (const struct frame_unwind *self,
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                          struct frame_info *this_frame,
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                          void **this_cache)
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{
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  CORE_ADDR pc = get_frame_pc (this_frame);
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  CORE_ADDR start_pc = (pc & ~(vaxobsd_page_size - 1));
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  CORE_ADDR sigreturn_addr = start_pc + vaxobsd_sigreturn_offset;
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  gdb_byte *buf;
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  char *name;
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  find_pc_partial_function (pc, &name, NULL, NULL);
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  if (name)
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    return 0;
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  buf = alloca(sizeof vaxobsd_sigreturn);
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  if (!safe_frame_unwind_memory (this_frame, sigreturn_addr,
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                                 buf, sizeof vaxobsd_sigreturn))
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    return 0;
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  if (memcmp(buf, vaxobsd_sigreturn, sizeof vaxobsd_sigreturn) == 0)
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    return 1;
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  return 0;
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}
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static struct trad_frame_cache *
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vaxobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
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{
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  struct trad_frame_cache *cache;
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  CORE_ADDR addr, base, func;
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  if (*this_cache)
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    return *this_cache;
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  cache = trad_frame_cache_zalloc (this_frame);
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  *this_cache = cache;
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  func = get_frame_pc (this_frame);
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  func &= ~(vaxobsd_page_size - 1);
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  base = get_frame_register_unsigned (this_frame, VAX_SP_REGNUM);
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  addr = get_frame_memory_unsigned (this_frame, base - 4, 4);
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  trad_frame_set_reg_addr (cache, VAX_SP_REGNUM, addr + 8);
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  trad_frame_set_reg_addr (cache, VAX_FP_REGNUM, addr + 12);
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  trad_frame_set_reg_addr (cache, VAX_AP_REGNUM, addr + 16);
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  trad_frame_set_reg_addr (cache, VAX_PC_REGNUM, addr + 20);
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  trad_frame_set_reg_addr (cache, VAX_PS_REGNUM, addr + 24);
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  /* Construct the frame ID using the function start.  */
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  trad_frame_set_id (cache, frame_id_build (base, func));
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  return cache;
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}
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static void
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vaxobsd_sigtramp_frame_this_id (struct frame_info *this_frame,
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                                void **this_cache, struct frame_id *this_id)
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{
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  struct trad_frame_cache *cache =
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    vaxobsd_sigtramp_frame_cache (this_frame, this_cache);
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  trad_frame_get_id (cache, this_id);
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}
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static struct value *
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vaxobsd_sigtramp_frame_prev_register (struct frame_info *this_frame,
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                                      void **this_cache, int regnum)
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{
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  struct trad_frame_cache *cache =
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    vaxobsd_sigtramp_frame_cache (this_frame, this_cache);
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  return trad_frame_get_register (cache, this_frame, regnum);
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}
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static const struct frame_unwind vaxobsd_sigtramp_frame_unwind = {
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  SIGTRAMP_FRAME,
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  vaxobsd_sigtramp_frame_this_id,
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  vaxobsd_sigtramp_frame_prev_register,
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  NULL,
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  vaxobsd_sigtramp_sniffer
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};
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/* OpenBSD a.out.  */
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static void
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vaxobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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  frame_unwind_append_unwinder (gdbarch, &vaxobsd_sigtramp_frame_unwind);
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}
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/* FIXME: kettenis/20050821: Since OpenBSD/vax binaries are
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   indistingushable from NetBSD/vax a.out binaries, building a GDB
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   that should support both these targets will probably not work as
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   expected.  */
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#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT
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static enum gdb_osabi
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vaxobsd_aout_osabi_sniffer (bfd *abfd)
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{
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  if (strcmp (bfd_get_target (abfd), "a.out-vax-netbsd") == 0)
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    return GDB_OSABI_OPENBSD_AOUT;
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  return GDB_OSABI_UNKNOWN;
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}
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/* Provide a prototype to silence -Wmissing-prototypes.  */
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void _initialize_vaxobsd_tdep (void);
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void
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_initialize_vaxobsd_tdep (void)
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{
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  gdbarch_register_osabi_sniffer (bfd_arch_vax, bfd_target_aout_flavour,
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                                  vaxobsd_aout_osabi_sniffer);
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  gdbarch_register_osabi (bfd_arch_vax, 0, GDB_OSABI_OPENBSD_AOUT,
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                          vaxobsd_init_abi);
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}

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