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cfaf379b3a
* config/vax/obsd.mt (TDEPFILES): Add vaxobsd-tdep.o. * Makefile.in (vaxobsd-tdep.o): New dependency.
191 lines
5.5 KiB
C
191 lines
5.5 KiB
C
/* Target-dependent code for OpenBSD/vax.
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Copyright 2005 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 2 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, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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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_p (struct frame_info *next_frame)
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{
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CORE_ADDR pc = frame_pc_unwind (next_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 (next_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 *next_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 (next_frame);
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*this_cache = cache;
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func = frame_pc_unwind (next_frame);
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func &= ~(vaxobsd_page_size - 1);
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base = frame_unwind_register_unsigned (next_frame, VAX_SP_REGNUM);
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addr = get_frame_memory_unsigned (next_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 *next_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 (next_frame, this_cache);
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trad_frame_get_id (cache, this_id);
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}
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static void
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vaxobsd_sigtramp_frame_prev_register (struct frame_info *next_frame,
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void **this_cache, int regnum,
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int *optimizedp, enum lval_type *lvalp,
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CORE_ADDR *addrp, int *realnump,
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gdb_byte *valuep)
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{
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struct trad_frame_cache *cache =
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vaxobsd_sigtramp_frame_cache (next_frame, this_cache);
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trad_frame_get_register (cache, next_frame, regnum,
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optimizedp, lvalp, addrp, realnump, valuep);
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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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};
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static const struct frame_unwind *
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vaxobsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
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{
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if (vaxobsd_sigtramp_p (next_frame))
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return &vaxobsd_sigtramp_frame_unwind;
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return NULL;
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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_sniffer (gdbarch, vaxobsd_sigtramp_frame_sniffer);
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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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