1 /* Target-dependent code for OpenBSD/alpha.
3 Copyright (C) 2006-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "obsd-tdep.h"
26 #include "alpha-tdep.h"
27 #include "alphabsd-tdep.h"
28 #include "solib-svr4.h"
30 /* Signal trampolines. */
32 /* The OpenBSD kernel maps the signal trampoline at some random
33 location in user space, which means that the traditional BSD way of
34 detecting it won't work.
36 The signal trampoline will be mapped at an address that is page
37 aligned. We recognize the signal trampoline by looking for the
38 sigreturn system call. */
40 static const int alphaobsd_page_size = 8192;
43 alphaobsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
45 return (pc & (alphaobsd_page_size - 1));
49 alphaobsd_pc_in_sigtramp (struct gdbarch *gdbarch,
50 CORE_ADDR pc, const char *name)
52 CORE_ADDR start_pc = (pc & ~(alphaobsd_page_size - 1));
59 insn = alpha_read_insn (gdbarch, start_pc + 5 * ALPHA_INSN_SIZE);
60 if (insn != 0x201f0067)
64 insn = alpha_read_insn (gdbarch, start_pc + 6 * ALPHA_INSN_SIZE);
65 if (insn != 0x00000083)
72 alphaobsd_sigcontext_addr (struct frame_info *this_frame)
74 struct gdbarch *gdbarch = get_frame_arch (this_frame);
75 CORE_ADDR pc = get_frame_pc (this_frame);
77 if (alphaobsd_sigtramp_offset (gdbarch, pc) < 3 * ALPHA_INSN_SIZE)
79 /* On entry, a pointer the `struct sigcontext' is passed in %a2. */
80 return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM + 2);
82 else if (alphaobsd_sigtramp_offset (gdbarch, pc) < 4 * ALPHA_INSN_SIZE)
84 /* It is stored on the stack Before calling the signal handler. */
86 sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM);
87 return get_frame_memory_unsigned (this_frame, sp, 8);
91 /* It is reloaded into %a0 for the sigreturn(2) call. */
92 return get_frame_register_unsigned (this_frame, ALPHA_A0_REGNUM);
98 alphaobsd_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
100 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
102 /* Hook into the DWARF CFI frame unwinder. */
103 alpha_dwarf2_init_abi (info, gdbarch);
105 /* Hook into the MDEBUG frame unwinder. */
106 alpha_mdebug_init_abi (info, gdbarch);
108 /* OpenBSD/alpha 3.0 and earlier does not provide single step
109 support via ptrace(2); use software single-stepping for now. */
110 set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
112 /* OpenBSD/alpha has SVR4-style shared libraries. */
113 set_solib_svr4_fetch_link_map_offsets
114 (gdbarch, svr4_lp64_fetch_link_map_offsets);
115 set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
117 tdep->dynamic_sigtramp_offset = alphaobsd_sigtramp_offset;
118 tdep->pc_in_sigtramp = alphaobsd_pc_in_sigtramp;
119 tdep->sigcontext_addr = alphaobsd_sigcontext_addr;
122 tdep->jb_elt_size = 8;
124 set_gdbarch_iterate_over_regset_sections
125 (gdbarch, alphanbsd_iterate_over_regset_sections);
129 /* Provide a prototype to silence -Wmissing-prototypes. */
130 void _initialize_alphaobsd_tdep (void);
133 _initialize_alphaobsd_tdep (void)
135 gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_OPENBSD_ELF,