/* Target-dependent code for OpenBSD/alpha. Copyright (C) 2006, 2007, 2008, 2009 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 "frame.h" #include "gdbcore.h" #include "osabi.h" #include "obsd-tdep.h" #include "alpha-tdep.h" #include "alphabsd-tdep.h" #include "solib-svr4.h" /* Signal trampolines. */ /* The OpenBSD kernel maps the signal trampoline at some random location in user space, which means that the traditional BSD way of detecting it won't work. The signal trampoline will be mapped at an address that is page aligned. We recognize the signal trampoline by looking for the sigreturn system call. */ static const int alphaobsd_page_size = 8192; static LONGEST alphaobsd_sigtramp_offset (CORE_ADDR pc) { return (pc & (alphaobsd_page_size - 1)); } static int alphaobsd_pc_in_sigtramp (CORE_ADDR pc, char *name) { CORE_ADDR start_pc = (pc & ~(alphaobsd_page_size - 1)); unsigned insn; if (name) return 0; /* Check for "". */ insn = alpha_read_insn (start_pc + 5 * ALPHA_INSN_SIZE); if (insn != 0x201f0067) return 0; /* Check for "". */ insn = alpha_read_insn (start_pc + 6 * ALPHA_INSN_SIZE); if (insn != 0x00000083) return 0; return 1; } static CORE_ADDR alphaobsd_sigcontext_addr (struct frame_info *this_frame) { CORE_ADDR pc = get_frame_pc (this_frame); if (alphaobsd_sigtramp_offset (pc) < 3 * ALPHA_INSN_SIZE) { /* On entry, a pointer the `struct sigcontext' is passed in %a2. */ return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM + 2); } else if (alphaobsd_sigtramp_offset (pc) < 4 * ALPHA_INSN_SIZE) { /* It is stored on the stack Before calling the signal handler. */ CORE_ADDR sp; sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM); return get_frame_memory_unsigned (this_frame, sp, 8); } else { /* It is reloaded into %a0 for the sigreturn(2) call. */ return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM); } } static void alphaobsd_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch) { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); /* Hook into the DWARF CFI frame unwinder. */ alpha_dwarf2_init_abi (info, gdbarch); /* Hook into the MDEBUG frame unwinder. */ alpha_mdebug_init_abi (info, gdbarch); /* OpenBSD/alpha 3.0 and earlier does not provide single step support via ptrace(2); use software single-stepping for now. */ set_gdbarch_software_single_step (gdbarch, alpha_software_single_step); /* OpenBSD/alpha has SVR4-style shared libraries. */ set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_lp64_fetch_link_map_offsets); set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver); tdep->dynamic_sigtramp_offset = alphaobsd_sigtramp_offset; tdep->pc_in_sigtramp = alphaobsd_pc_in_sigtramp; tdep->sigcontext_addr = alphaobsd_sigcontext_addr; tdep->jb_pc = 2; tdep->jb_elt_size = 8; set_gdbarch_regset_from_core_section (gdbarch, alphanbsd_regset_from_core_section); } /* Provide a prototype to silence -Wmissing-prototypes. */ void _initialize_alphaobsd_tdep (void); void _initialize_alphaobsd_tdep (void) { gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_OPENBSD_ELF, alphaobsd_init_abi); }