diff options
Diffstat (limited to 'gdb/alphanbsd-tdep.c')
| -rw-r--r-- | gdb/alphanbsd-tdep.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/gdb/alphanbsd-tdep.c b/gdb/alphanbsd-tdep.c new file mode 100644 index 00000000000..3f3ae529e52 --- /dev/null +++ b/gdb/alphanbsd-tdep.c @@ -0,0 +1,146 @@ +/* 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); +} |