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-rw-r--r--gdb/alphanbsd-tdep.c146
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diff --git a/gdb/alphanbsd-tdep.c b/gdb/alphanbsd-tdep.c
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+/* Target-dependent code for NetBSD/Alpha.
+ Copyright 2002 Free Software Foundation, Inc.
+ Contributed by Wasabi Systems, 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 2 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include "defs.h"
+#include "gdbcore.h"
+#include "value.h"
+#include "solib-svr4.h"
+
+#include "alpha-tdep.h"
+
+/* Fetch (and possibly build) an appropriate link_map_offsets
+ structure for NetBSD/alpha targets using the struct offsets
+ defined in <link.h> (but without actual reference to that file).
+
+ This makes it possible to access NetBSD/alpha shared libraries
+ from a GDB that was not built on a NetBSD/alpha host (for cross
+ debugging). */
+
+static struct link_map_offsets *
+alphanbsd_solib_svr4_fetch_link_map_offsets (void)
+{
+ static struct link_map_offsets lmo;
+ static struct link_map_offsets *lmp = NULL;
+
+ if (lmp == NULL)
+ {
+ lmp = &lmo;
+
+ lmo.r_debug_size = 32;
+
+ lmo.r_map_offset = 8;
+ lmo.r_map_size = 8;
+
+ lmo.link_map_size = 40;
+
+ lmo.l_addr_offset = 0;
+ lmo.l_addr_size = 8;
+
+ lmo.l_name_offset = 8;
+ lmo.l_name_size = 8;
+
+ lmo.l_next_offset = 24;
+ lmo.l_next_size = 8;
+
+ lmo.l_prev_offset = 32;
+ lmo.l_prev_size = 8;
+ }
+
+ return lmp;
+}
+
+/* Under NetBSD/alpha, signal handler invocations can be identified by the
+ designated code sequence that is used to return from a signal handler.
+ In particular, the return address of a signal handler points to the
+ following code sequence:
+
+ ldq a0, 0(sp)
+ lda sp, 16(sp)
+ lda v0, 295(zero) # __sigreturn14
+ call_pal callsys
+
+ Each instruction has a unique encoding, so we simply attempt to match
+ the instruction the PC is pointing to with any of the above instructions.
+ If there is a hit, we know the offset to the start of the designated
+ sequence and can then check whether we really are executing in the
+ signal trampoline. If not, -1 is returned, otherwise the offset from the
+ start of the return sequence is returned. */
+static const unsigned int sigtramp_retcode[] =
+{
+ 0xa61e0000, /* ldq a0, 0(sp) */
+ 0x23de0010, /* lda sp, 16(sp) */
+ 0x201f0127, /* lda v0, 295(zero) */
+ 0x00000083, /* call_pal callsys */
+};
+#define RETCODE_NWORDS \
+ (sizeof (sigtramp_retcode) / sizeof (sigtramp_retcode[0]))
+
+LONGEST
+alphanbsd_sigtramp_offset (CORE_ADDR pc)
+{
+ unsigned int ret[4], w;
+ LONGEST off;
+ int i;
+
+ if (read_memory_nobpt (pc, (char *) &w, 4) != 0)
+ return -1;
+
+ for (i = 0; i < RETCODE_NWORDS; i++)
+ {
+ if (w == sigtramp_retcode[i])
+ break;
+ }
+ if (i == RETCODE_NWORDS)
+ return (-1);
+
+ off = i * 4;
+ pc -= off;
+
+ if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)
+ return -1;
+
+ if (memcmp (ret, sigtramp_retcode, sizeof (sigtramp_retcode)) == 0)
+ return off;
+
+ return -1;
+}
+
+static void
+alphanbsd_init_abi (struct gdbarch_info info,
+ struct gdbarch *gdbarch)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ /* NetBSD/alpha does not provide single step support via ptrace(2); we
+ must use software single-stepping. */
+ set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
+
+ set_solib_svr4_fetch_link_map_offsets (gdbarch,
+ alphanbsd_solib_svr4_fetch_link_map_offsets);
+
+ tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
+}
+
+void
+_initialize_alphanbsd_tdep (void)
+{
+ alpha_gdbarch_register_os_abi (ALPHA_ABI_NETBSD, alphanbsd_init_abi);
+}