| /* Target-dependent code for OpenBSD/vax. |
| |
| Copyright (C) 2005, 2007, 2008 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" |
| |
| #include "gdb_string.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_p (struct frame_info *next_frame) |
| { |
| CORE_ADDR pc = frame_pc_unwind (next_frame); |
| CORE_ADDR start_pc = (pc & ~(vaxobsd_page_size - 1)); |
| CORE_ADDR sigreturn_addr = start_pc + vaxobsd_sigreturn_offset; |
| gdb_byte *buf; |
| char *name; |
| |
| find_pc_partial_function (pc, &name, NULL, NULL); |
| if (name) |
| return 0; |
| |
| buf = alloca(sizeof vaxobsd_sigreturn); |
| if (!safe_frame_unwind_memory (next_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 *next_frame, void **this_cache) |
| { |
| struct trad_frame_cache *cache; |
| CORE_ADDR addr, base, func; |
| |
| if (*this_cache) |
| return *this_cache; |
| |
| cache = trad_frame_cache_zalloc (next_frame); |
| *this_cache = cache; |
| |
| func = frame_pc_unwind (next_frame); |
| func &= ~(vaxobsd_page_size - 1); |
| |
| base = frame_unwind_register_unsigned (next_frame, VAX_SP_REGNUM); |
| addr = get_frame_memory_unsigned (next_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 *next_frame, |
| void **this_cache, struct frame_id *this_id) |
| { |
| struct trad_frame_cache *cache = |
| vaxobsd_sigtramp_frame_cache (next_frame, this_cache); |
| |
| trad_frame_get_id (cache, this_id); |
| } |
| |
| static void |
| vaxobsd_sigtramp_frame_prev_register (struct frame_info *next_frame, |
| void **this_cache, int regnum, |
| int *optimizedp, enum lval_type *lvalp, |
| CORE_ADDR *addrp, int *realnump, |
| gdb_byte *valuep) |
| { |
| struct trad_frame_cache *cache = |
| vaxobsd_sigtramp_frame_cache (next_frame, this_cache); |
| |
| trad_frame_get_register (cache, next_frame, regnum, |
| optimizedp, lvalp, addrp, realnump, valuep); |
| } |
| |
| static const struct frame_unwind vaxobsd_sigtramp_frame_unwind = { |
| SIGTRAMP_FRAME, |
| vaxobsd_sigtramp_frame_this_id, |
| vaxobsd_sigtramp_frame_prev_register |
| }; |
| |
| static const struct frame_unwind * |
| vaxobsd_sigtramp_frame_sniffer (struct frame_info *next_frame) |
| { |
| if (vaxobsd_sigtramp_p (next_frame)) |
| return &vaxobsd_sigtramp_frame_unwind; |
| |
| return NULL; |
| } |
| |
| |
| /* OpenBSD a.out. */ |
| |
| static void |
| vaxobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| { |
| frame_unwind_append_sniffer (gdbarch, vaxobsd_sigtramp_frame_sniffer); |
| } |
| |
| /* 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); |
| } |