| /* 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 int |
| alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name) |
| { |
| return (alphanbsd_sigtramp_offset (pc) >= 0); |
| } |
| |
| static void |
| alphanbsd_init_abi (struct gdbarch_info info, |
| struct gdbarch *gdbarch) |
| { |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| |
| set_gdbarch_pc_in_sigtramp (gdbarch, alphanbsd_pc_in_sigtramp); |
| |
| /* 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; |
| |
| tdep->jb_pc = 2; |
| tdep->jb_elt_size = 8; |
| } |
| |
| void |
| _initialize_alphanbsd_tdep (void) |
| { |
| alpha_gdbarch_register_os_abi (ALPHA_ABI_NETBSD, alphanbsd_init_abi); |
| } |