1 files changed, 178 insertions, 0 deletions
diff --git a/gdb/vax-obsd-tdep.c b/gdb/vax-obsd-tdep.c
new file mode 100644
index 0000000..ee48ac6
--- /dev/null
+++ b/gdb/vax-obsd-tdep.c
@@ -0,0 +1,178 @@
+/* Target-dependent code for OpenBSD/vax.
+
+   Copyright (C) 2005-2016 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 "arch-utils.h"
+#include "frame.h"
+#include "frame-unwind.h"
+#include "osabi.h"
+#include "symtab.h"
+#include "trad-frame.h"
+
+#include "vax-tdep.h"
+
+/* Signal trampolines.  */
+
+/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
+   in virtual memory.  The randomness makes it somewhat tricky to
+   detect it, but fortunately we can rely on the fact that the start
+   of the sigtramp routine is page-aligned.  We recognize the
+   trampoline by looking for the code that invokes the sigreturn
+   system call.  The offset where we can find that code varies from
+   release to release.
+
+   By the way, the mapping mentioned above is read-only, so you cannot
+   place a breakpoint in the signal trampoline.  */
+
+/* Default page size.  */
+static const int vaxobsd_page_size = 4096;
+
+/* Offset for sigreturn(2).  */
+static const int vaxobsd_sigreturn_offset = 0x11;
+
+/* Instruction sequence for sigreturn(2).  VAX doesn't have
+   fixed-length instructions so we include the ensuing exit(2) to
+   reduce the chance of spurious matches.  */
+static const gdb_byte vaxobsd_sigreturn[] = {
+  0xbc, 0x8f, 0x67, 0x00,	/* chmk $SYS_sigreturn */
+  0xbc, 0x01			/* chmk $SYS_exit */
+};
+
+static int
+vaxobsd_sigtramp_sniffer (const struct frame_unwind *self,
+			  struct frame_info *this_frame,
+			  void **this_cache)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  CORE_ADDR start_pc = (pc & ~(vaxobsd_page_size - 1));
+  CORE_ADDR sigreturn_addr = start_pc + vaxobsd_sigreturn_offset;
+  gdb_byte *buf;
+  const char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  if (name)
+    return 0;
+
+  buf = (gdb_byte *) alloca (sizeof vaxobsd_sigreturn);
+  if (!safe_frame_unwind_memory (this_frame, sigreturn_addr,
+				 buf, sizeof vaxobsd_sigreturn))
+    return 0;
+
+  if (memcmp(buf, vaxobsd_sigreturn, sizeof vaxobsd_sigreturn) == 0)
+    return 1;
+
+  return 0;
+}
+
+static struct trad_frame_cache *
+vaxobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
+{
+  struct trad_frame_cache *cache;
+  CORE_ADDR addr, base, func;
+
+  if (*this_cache)
+    return (struct trad_frame_cache *) *this_cache;
+
+  cache = trad_frame_cache_zalloc (this_frame);
+  *this_cache = cache;
+
+  func = get_frame_pc (this_frame);
+  func &= ~(vaxobsd_page_size - 1);
+
+  base = get_frame_register_unsigned (this_frame, VAX_SP_REGNUM);
+  addr = get_frame_memory_unsigned (this_frame, base - 4, 4);
+
+  trad_frame_set_reg_addr (cache, VAX_SP_REGNUM, addr + 8);
+  trad_frame_set_reg_addr (cache, VAX_FP_REGNUM, addr + 12);
+  trad_frame_set_reg_addr (cache, VAX_AP_REGNUM, addr + 16);
+  trad_frame_set_reg_addr (cache, VAX_PC_REGNUM, addr + 20);
+  trad_frame_set_reg_addr (cache, VAX_PS_REGNUM, addr + 24);
+
+  /* Construct the frame ID using the function start.  */
+  trad_frame_set_id (cache, frame_id_build (base, func));
+
+  return cache;
+}
+
+static void
+vaxobsd_sigtramp_frame_this_id (struct frame_info *this_frame,
+				void **this_cache, struct frame_id *this_id)
+{
+  struct trad_frame_cache *cache =
+    vaxobsd_sigtramp_frame_cache (this_frame, this_cache);
+
+  trad_frame_get_id (cache, this_id);
+}
+
+static struct value *
+vaxobsd_sigtramp_frame_prev_register (struct frame_info *this_frame,
+				      void **this_cache, int regnum)
+{
+  struct trad_frame_cache *cache =
+    vaxobsd_sigtramp_frame_cache (this_frame, this_cache);
+
+  return trad_frame_get_register (cache, this_frame, regnum);
+}
+
+static const struct frame_unwind vaxobsd_sigtramp_frame_unwind = {
+  SIGTRAMP_FRAME,
+  default_frame_unwind_stop_reason,
+  vaxobsd_sigtramp_frame_this_id,
+  vaxobsd_sigtramp_frame_prev_register,
+  NULL,
+  vaxobsd_sigtramp_sniffer
+};
+
+
+/* OpenBSD a.out.  */
+
+static void
+vaxobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  frame_unwind_append_unwinder (gdbarch, &vaxobsd_sigtramp_frame_unwind);
+}
+
+/* FIXME: kettenis/20050821: Since OpenBSD/vax binaries are
+   indistingushable from NetBSD/vax a.out binaries, building a GDB
+   that should support both these targets will probably not work as
+   expected.  */
+#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT
+
+static enum gdb_osabi
+vaxobsd_aout_osabi_sniffer (bfd *abfd)
+{
+  if (strcmp (bfd_get_target (abfd), "a.out-vax-netbsd") == 0)
+    return GDB_OSABI_OPENBSD_AOUT;
+
+  return GDB_OSABI_UNKNOWN;
+}
+
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+void _initialize_vaxobsd_tdep (void);
+
+void
+_initialize_vaxobsd_tdep (void)
+{
+  gdbarch_register_osabi_sniffer (bfd_arch_vax, bfd_target_aout_flavour,
+				  vaxobsd_aout_osabi_sniffer);
+
+  gdbarch_register_osabi (bfd_arch_vax, 0, GDB_OSABI_OPENBSD_AOUT,
+			  vaxobsd_init_abi);
+}